View
5
Download
0
Category
Preview:
Citation preview
AECL-5109
ATOMIC ENERGY § ? S & L'ENERGIE ATOMIQUEOF CANADA LIMITED ^ f i S 9 DU CANADA LIMITEE
AN ASSESSMENT OF THE UTILIZATION OF
WASTE HEAT IN GREENHOUSES
by
STUART L. IVERSON, DANIEL R. PROWSE and JOSEPH D. CAMPBELL
Whiteshel l Nuc lear Research Establishment
Pinawa, Man i toba
January 1976
ATOMIC ENERGY OF CANADA L I M T E D
AN ASSESSMENT OF THE UTILIZATION DFWASTE MEAT IN GREENHOUSES
by
1 2S t u a r t L. I v e r s o n , D a n i e l R. P r o w s e a n d J o s e p h 0. Cam;) be
1. E n v i r o n m e n t a l R e s e a r c h B r a n c h , W!!RE
2 . C h e m i c a l Technolociy B r a n c h , W N R E
3. D e p a r t m e n t o f P l a n t S c i e n c e , U n i v e r s i t y o f M a n i t o b a ,W i n n i p e g , M a n i t o b a
W h i t e s h e l l N u c l e a r R e s e a r c h E s t a b l isiimentA t o m i c E n e r g y of C a n a d a L i m i t e d
P i n a w a , M a n i t o b a R O E 1 L 0
J a n u a r y 1 9 7 6 A H . I
Evaluation de l ' u t i l i sa t ion en serres de la chaleur perdue
par
Stuart L. Iverson, Daniel R. Prowse et Joseph D. Campbell*
*Département d'Horticulture, Université du Manitoba, Winnipeg, Manitoba
Résumé
On a f a i t une étude de fa isabi l i té économique de l'emploi de la chaleurperdue provenant du circuit du modérateur du réacteur CANDU G-2 pour chaufferles serres. Trois systèmes de récupération de la chaleur perdue ont étécompares à un système classique alimenté par gaz. Chaque système derécupération de la chaleur perdue comprend la recirculation de l'eau légèretiède provenant des échangeurs thermiques modifiés du modérateur, au moyend'un système de distribution amenant cette eau tiède à des échangeursthermiques à tubes munis d'ai lettes dans les serres. Le système de distributionétait destiné à une entreprise de culture de légumes en serres devant couvrirde 8 à 10 hectares (20-25 acres) en bordure de la zone d'exclusion du réacteurmesurant 914 m. Deux configurations de serres ont été évaluées, l'uneconsistant en serres individuelles reliées par un corridor pour former desunités9de 4047 m (1 acre) tandis que l'autre é ta i t une serre unique couvrant4047 m\
Les plus bas coûts calculés pour le chauffage et la ventilation dessystèmes de récupération de la chaleur perdue étaient de $9.55 par an parmètre carré de surface de récolte sous le climat de Winnipeg, Manitoba. Uneserre classique chauffée par du gaz naturel à raison d'environ $1.50 parmille pieds cubes donnerait l ieu aux mêmes frais annuels de chauffage.
Trois améliorations possibles du système d 'ut i l isat ion de la chaleurperdue ont été étudiées. Chaque amélioration pourrait rendre le systèmeéconomiquement compétitif aux prix courants du gaz naturel. Etant donnéque l'on s'attend à une nouvelle augmentation du coût du gaz naturel etétant donné qu ' i l existe au Canada une demande pour les légumes produitssous vi t res, le concept de l ' u t i l i sa t ion en serres de la chaleur perduemérite un développement plus poussé.
L'Energie Atomique du Canada, LimitéeEtablissement de Recherches Nucléaires de Whiteshell
Pinawa, Manitoba, ROE 1L0
Janvier 1976
AECL-5109
AN ASSESSMENT OF THE UTILIZATION OF
WASTE HEAT IN GREENHOUSES
by
S t u a r t L. I v e r s o n , D a n i e l R. P r o w s e a n d J o s e p h D. C a m p b e l l *
A B S T R A C T
T h e e c o n o m i c f e a s i b i l i t y o f u t i l i z i n n w a s t e h e a t f r o mt h e m o d e r a t o r c i r c u i t o f t h e C A N D U G -2 r e a c t o r to h e a t g r e e n h o u s e sw a s e x a m i n e d . T h r e e w a s t e h e a t r e c o v e r y s y s t e m s w e r e c o m p a r e d toa c o n v e n t i o n a l g a s - f i r e d s y s t e m . E a c h w a s t e h e a t r e c o v e r y s y s t e mi n v o l v e d t h e r e c i r c u l a t i o n o f w a r m l i g h t w a t e r f r o m m o d i f i e dm o d e r a t o r h e a t e x c h a n g e r s t h r o u g h a d i s t r i b u t i o n s y s t e m to f i n n e d -t u b e h e a t e x c h a n g e r s in t h e g r e e n h o u s e s . T h e d i s t r i b u t i o n s y s t e mw a s a s s u m e d t o s e r v i c e an 8 o r 1 0 h e c t a r e ( 2 0 - 2 5 a c r e ) g r e e n h o u s ev e g e t a b l e i n d u s t r y l o c a t e d i m m e d i a t e l y o u t s i d e t h e 9 1 4 m r e a c t o re x c l u s i o n z o n e . T w o g r e e n h o u s e c o n f i g u r a t i o n s w e r e e v a l u a t e d , o n ec o n s i s t i n g o f i n d i v i d u a l h o u s e s c o n n e c t e d b y a c o r r i d o r t o f c n r4 0 4 7 ;n^ (1 a c r e ) u n i t s w h i l e t h e o t h e r w a s a s i n g l e r o o f c o v e r i n g4 0 4 7 m 2 .
( T h e l o w e s t c a l c u l a t e d h e a t i n g a n d v e n t i l a t i o n costr, f orw a s t e h e a t s y s t e m s w e r e $ 9 . 5 5 p e r y e a r p e r s q u a r e m e t e r o f q r o w i n ns u r f a c e f o r t h e c l i m a t e o f W i n n i p e g , M a n i t o b a . A c o n v e n t i o n a lg r e e n h o u s e h e a t e d by n a t u r a l g a s at a b o u t $ 1 . 5 0 p e r 1 0 0 0 s t a n d . i n !c u b i c f e e t w o u l d e x p e r i e n c e t h e s a m e a n n u a l h e a t i n g c o s t s .
T h r e e p o t e n t i a l i m p r o v e m e n t s to t h e w a s t e h e a t u t i 1 i za t i o'is y s t e m w e r e d i s c u s s e d , e a c h o f w h i c h w o u l d m a k e t h e s y s t e me c o n o m i c a l l y c o m p e t i t i v e a t c u r r e n t n a t u r a l q a s p r i c e s . S i n c e thep r i c e o f n a t u r a l g a s ^ r. e x p e c t e d to i n c r e a s e a b o v e its c u r r e n t l e v e la n d s i n c e a n u n f i l l e d , e x p a n d i n g d e m a n d f o r g r e e n h o u s e - g r o w n p r o d u c ee x i s t s in C a n a d a , t h e c o n c e p t o f w a s t e h e a t u t i l i z a t i o n in g r e e n -h o u s e s m e r i t s f u r t h e r d e v e l o p m e n t .
* D e p a r t m e n t o f P l a n t S c i e n c e , U n i v e r s i t y o f M a n i t o b a , VJ i nn i i'°'i,M a n i t o b a
A t o m i c E n e r g y o f C a n a d a L i m i t e dW h i t e s h e l l N u c l e a r R e s e a r c h E s t a b l i s h m e n t
P i n a w a , M a n i t o b a , R O E 1 1 0
January 1976 M en
F O R E W O P D
R . T . S . P o b e r t s o n
D i r e c t o r - A d v a n c e d P r o j e c t s ,n t e s h e l l N u c l e a r R e s e a r c h E s t a b l i s h m e n t
A t o m i c E n e r g y o f C a n a d a L i m i t e dPi n a w a , M a n i t o b a
A g r o u p a t W h i t e s h e 11 N u c l e a r R e s e a r c h E s t a b l i s h m e n t( W N R E J h a s b e e n e x a m i n i n g u s e s f o r n u c l e a r r e a c t o r s o t h e r t h a nt h e g e n e r a t i o n o f e l e c t r i c i t y . O n e a s p e c t o f t h i s e x a m i n a t i o nh a s been a n i n v e s t i g a t i o n o f p o s s i b l e a p p l i c a t i o n o f t h e r e a c t o r ' sl o w - g r a d e w a s t e h e a t i n f o o d p r o d u c t i o n . T h e s o u r c e o f t h i sw a s t e h e a t i s t h e c o o l i n g w a t e r d i s c h a r g e d f r o m t h e t u r b i n ec o n d e n s e r s a n d m o d e r a t o r c i r c u i t s o f o u r C A N D U - P H W * r a a c t o r s .
T h e u s e o f l o w - g r a d e w a s t e h e a t f o r f o o d p r o d u c t i o nr e q u i r e s m o r e t h a n t h e n u c l e a r e n g i n e e r i n g a n d b i o l o g i c a lc o m p e t e n c e a v a i l a b l e w i t h i n A t o m i c E n e r g y o f C a n a d a L i m i t e d . Ita l s o r e q u i r e s e x p e r t i s e i n a g r i c u l t u r e a n d a o u a c u l t u r e . S u c he x p e r t i s e i s r e a d i l y a v a i l a b l e i n t h e P l a n t S c i e n c e D e p a r t m e n t ,U n i v e r s i t y o f M a n i t o b a a n d t h e E n v i r o n m e n t C a n a d a F r e s h w a t e rI n s t i t u t e i n W i n n i p e g ; s c i e n t i s t s i n t h e s e i n s t i t u t e s a r a k n o w nt o b e i n t e r e s t e d i n w a s t e h e a t u t i l i z a t i o n f o r f o o d p r o d u c t i o n .
A W a s t e H e a t U t i l i z a t i o n f o r k i n g P a r t y w a s f o r m e d t oi n v e s t i g a t e t h e p o s s i b i l i t y o f u s i n g n u c l e a r w a s t e h e a t f o rf o o d p r o d u c t i o n b y m e a n s o f i n t e n s i v e a g r i c u l t u r e a n d a n u a c u l I'jre,a n d t o p r e p a r e s p e c i f i c p r o p o s a l s f o r s u c h u s e s . D r . J . E . G u t h r i eE n v i r o n m e n t a l R e s e a r c h B r a n c h , W M R E , c h a i r e d t h e W o r k i n g P a r t yw h i c h c o n s i s t e d t o t w o s u b - c o m m i t t e e s : A g r i c u l t u r e a n d A a u a c u l t u rT h e m e m b e r s o f t h e s u b - c o m m i t t e e s w e r e :
A g r i c u l t u r e
D r . S . L . I v e r s o n
D r . J . D. Campbe l l
D r . D. R. Prowse
E n v i r o n m e n t a l R e s e a r c h B r a n c hWNRE - C h a i r m a n
D e p a r t m e n t o f P l a n t S c i e n c e ,U n i v e r s i t y o f M a n i t o b a
C h e m i c a l T e c h n o l o g y Bv-anch,WNRE
*Canada Deuter ium Uranium - Pressur ized Heavy Water
_ '1' l.ln"e
?r. J. E. Guthrie E n v i r o n m e n t a l Research B r a n c h ,WNRE - C h a i r m a n
Dr. D. P. S c o t t * E n v i r o n m e n t C a n a d a ,F r e s h w a t e r I n s t i t u t e
'Jr. D. R. rrowse Chemical T e c h n o l o g y B r a n c h ,WNRE
Dr. Prowse's p a r t i c u l a r c o n c e r n in both s u b - c o m m i t t e e s was theheat t r a n s f e r and e n g i n e e r i n g aspects of the i n v e s t i g a t i o n .The e x p e r i e n c e of the P l a n t S c i e n c e D e p a r t m e n t in g r e e n h o u s eh o r t i c u l t u r e was made a v a i l a b l e to the a g r i c u l t u r e s u b - c o m m i t t e ethrough Dr. C a m p b e l l . The v a r i o u s a s p e c t s of fish b i o l o g yr e p r e s e n t e d in the F r e s h w a t e r Institute w e r e provided by Dr. Scott
The basic guide lines given to the Working P a r t y w e r e :
a) the studies s h o u l d identify the m a r k e t s for a g r i c u l t u r e( g r e e n h o u s e ) and a q u a c u l t u r e p r o d u c e in C a n a d a , ande x a m i n e the e c o n o m i c s of p r o d u c i n g p r o d u c e for thesem a r k e t s using n u c l e a r waste heat
b) the source of heat should be the c o o l i n g w a t e r fromthe turbine c o n d e n s e r s , or from the m o d e r a t o r c i r c u i tof a 600 M W ( e ) C A N D U - P H W n u c l e a r p o w e r r e a c t o r
c) the r e f e r e n c e c l i m a t e should be t h a t of the p r a i r i e s
d^ the research and d e v e l o p m e n t r e q u i r e d to a s s u r e thes u c c e s s of a c o m m e r c i a l a g r i c u l t u r a l or a q u a c u l t u r a lv e n t u r e u t i l i z i n g n u c l e a r w a s t e h e a t should bei denti fi ed
e) the WR-1 r e a c t o r should be c o n s i d e r e d as the s o u r c eof heat for ( d ) .
The Waste Heat U t i l i z a t i o n W o r k i n g Party s t u d i e s aredescribed in two d o c u m e n t s :
1. An A s s e s s m e n t of the U t i l i z a t i o n of Waste H e a t inG r e e n h o u s e s by S.L. I v e r s o n , D.R. Prowse andJ.D. C a m p b e l l . A t o m i c Energy of Canada L i m i t e dr e p o r t no. A E C L - 5 1 0 9 . 1 9 7 5 .
Dr. S c o t t submitted a proposal to use the c o n d e n s e r c o o l i n gw a t e r from the Douglas P o i n t N u c l e a r G e n e r a t i n g S t a t i o n fora q u a c u l t u r e as early as 1 9 6 2 .
A n A s s e s s m e n t o f N u c l e a r P o w e r P l a n t W a s t e H e a tU t i l i z a t i o n f o r F r e s h w a t e r F i s h F a r m i n g byJ . E . G u t h r i e , D . R . P r o w s e a n d D . P . S c o t t . A t o m i cE n e r g y o f C a n a d a L i m i t e d r e p o r t n o . A E C L - 4 9 2 4 .1 9 7 5 .
T h e s e d o c u m e n t s e x a m i n e t h e s h o r t - a n d l o n g - t e r m p r o s p e c t s o fp r o d u c i n g f o o d i n g r e e n h o u s e s h e a t e d w i t h t h e w a t e r d i s c h a r g e df r o m t h e m o d e r a t o r c i r c u i t o f a C A N D U r e a c t o r , 1 by i n t e n s i v ea q u a c u l t u r e ( f i s h f a r m i n g ) u s i n g t h e r e a c t o r ' s c o n d e n s e r e f f l u e n t
PREFACE
T h i s d o c u m e n t w a s w r i t t e n f o r t w o p u r p o s e s :
1. T o a s s e s s t h e e c o n o m i c f e a s i b i l i t y o f u t i l i z i n g a s p e c i f i cs o u r c e o f w a s t e h e a t i n g r e e n h o u s e s f o r t h e p r o d u c t i o n o fv e g e t a b l e s in C a n a d a .
2 . T o e x a m i n e s o m e o f t h e e c o n o m i c , h o r t i c u l t u r a l a n de n g i n e e r i n g p r o b l e m s w h i c h w i l l g o v e r n t h e u s e o fw a s t e heat, in t h e g r e e n h o u s e i n d u s t r y .
S e c t i o n t w o d e m o n s t r a t e s t h a t t h e r e is a s i z e a b l e nwn-U't.i n C a n a d a f o r t r a d i t i o n a l g r e e n h o u s e v e g e t a b l e s . S e c t i o n fiv< j
i d e n t i f i e s s p e c i f i c h e a t s o u r c e a n d g r e e n h o u s e c o m b i n a t i o n s t tui ta r e , o r w i l l s o o n b e c o m p e t i t i v e w i t h g a s h e a t e d s y s t e m s . S u i t inns i x c o n c l u d e s b y p o i n t i n g o u t s o m e o f t h e r e s e a r c h a n d d e v e 1 onr, v n •t h a t is r e q u i r e d b e f o r e a c o m m e r c i a l l y s i z e d s y s t e m c a n b e b u i l t .T h e r e m a i n d e r o f t h e r e p o r t p r e s e n t s a n d d i s c u s s e s g e n e r a l b a c k -g r o u n d i n f o r m a t i o n a n d d e t a i l s t h a t c l a r i f y a n d s u p p o r t t h e m a j o rt h e m e .
T h r e e p o t e n t i a l i m n r o v e m e n t s t o t h e w a s t e h e a tu t i l i z a t i o n s y s t e m w e r e d i s c u s s e d , e a c h o f w h i c h w o u l d m a k e t n es y s t e m e c o n o m i c a l l y c o m p e t i t i v e a t c u r r e n t n a t u r a l g a s p r i c e s .S i n c e t h e p r i c e o f n a t u r a l g a s is e x p e c t e d t o i n c r e a s e a b o v e it.:,c u r r e n t l e v e l , a n d s i n c e a n u n f i l l e d , e x D a n d i n q d e m a n d f o rg r e e n h o u s e - g r o w n p r o d u c e e x i s t s in C a n a d a , t h e c o n c e p t o f w a s re-h e a t u t i l i z a t i o n in g r e e n h o u s e s m e r i t s f u r t h e r d e v e l o p m e n t .
.CJ)NJ.E_N_T_S_
1. INTRODUCTION 1
1.1 SCOPE OF THE kEPORT .... 2
1.2 VEGETABLES PRODUCED IN GREENHOUSES 2
1.3 THE GREENHOUSE INDUSTRY IN CANADA .1
2. THE CANADIAN MARKET 7
2.1 PROBABLE MARKET FOR TOMATOES 7
2.2 PROBABLE MARKET FOR CUCUMBERS 7
2.3 PROBABLE MARKET FOR OTHER VEGETABLES 0
2.4 FUTURE PRICES AND MARKETS 'J
3. CHARACTERISTICS OF THE HEAT SOURCES ANDTHE GREENHOUSE HEATING SYSTEM IK
3.1 WASTE HEAT SOURCES IN CANDU REACTORS 18
3.2 PRELIMINARY CONSIDERATIONS 20
3.3 GREENHOUSE STRUCTURE 21
3.4 AIR CIRCULATION 23
3.5 HEATING SYSTEM REQUIREMENTS 23
4. VEGETABLE YIELD IN GREENHOUSES 3;
4.1 COMPARISON OF GROWTH CONDITIONS IN WASTE
HEAT AND CONVENTIONAL GREENHOUSE 3'J
4.2 PRODUCTION SCHEDULING 34
4.3 EXPECTED YIELDS OF TOMATOES V)
5. DESCRIPTION OF COMMERCIAl GREENHOUSE
SYSTEMS EVALUATED 3r'
5.1 HEAT SUPPLY SYSTEMS
5.1.1 Waste Heat Systems 4 15.1.1.1 Two Reactors 4?5.1.1.2 One Reactor With Fossil-
Fired Standby 4 ;>5 . 1 . 1 . 3 One R e a c t o r With F o s s i l -
Fired P e a k i n g ^ '<
'J . 1 . ?. Gas H e a t i n q S y s t e m "•'
5.2.1 Individual Houses 46
5.2.2 Block Houses 46
6. L'CCKJOMC ANALYSIS OF THE COMMERCIAL SYSTEMS 47
6.1 COSTS OF THE HEAT RECOVERY SYSTEMS 48
6.2 COSTS OF THr GREENHOUSE HEATING SYSTEMS 48
6.3 TOTAL ANNUAL COSTS 52
6.4 AREAS OF POTENTIAL SAVING 57
7. GENERAL DISCUSSION 59
3. LITERATURE CITED 62
APPENDICES
APPENDIX A - DESCRIPTION AND COST SUMMARY OF COMMERCIALGREENHOUSE SYSTEMS 65
A.I PRELIMINARY CONSIDERATIONS 65
A.2 THE GREENHOUSE FACILITY 67
A.2.1 Introduction 67
A.2.2 Design of Individual GreenhouseOperating Unit 70
A.2.2.1 Air Circulation, Heatingand Coolinn Systems 71
A.2.3 Design o': Single Roof GreenhouseOperatin. Unit 74
A.2.3.1 Air Circulation, Heatingand Cooling System 74
A.2.4 Commercial Greenhouse Facilities 75
A.2.5 Capital Cost Estimate 75
A.3 DISTRIBUTION SYSTEM WITHIN THE GREENHOUSE
FACILITY 78
A.3.1 System Description 78
A.3.2 Capital Cost 78
A.4 MODERATOR HEAT EXCHANGE AND WARM WATER
SUPPLY SYSTEM 80
A.4.1 System Design 80
A.4.2 Capital Cost of Heat Supply Systems 87
A.5 NATURAL GAS GREENHOUSE HEATING SYSTEfi 87
A. 5.1 Description 38
A.5.2 Capital Cost 88
A.6 MAINTENANCE AND OPERATING COST SUMMARY 90
APPENDIX B - STRUCTURE OF WASTE HEAT GREENHOUSEINDUSTRY 93
APPENDIX C - HEAT EXCHANGER COSTS FOR THEMODIFIED MODERATOR CIRCUIT 98
LIST OF TABLES
TABLE 1. Production of greenhouse tomatoes andcucumbers in Canada 5
TABLE 2. Value of greenhouse vegetable productionby provinces in 1972 6
TABLE 3. Estimate of additional greenhouse areapossible for tomato production in eightCanadian provinces 8
TABLE 4. Estimate of additional greenhouse ireapossible for cucumber production ineight Canadian provinces 10
TABLE 5. Additional greenhouse area possible forCanadian production of four vegetables 11
TABLE 6. Waste heat sources from CANDU fi-2nuclear power stations 19
TABLE 7. Factors affecting the yield of a givengroup of plants 31
TABLE 8. Production characteristics of potentialgreenhouse crops 35
TABLE 9. Design parameters of the four heatingsystems 43
TABLE 10. Back-up systems of the four heatingsystems 44
TABLE 11. Design parameters and capital costcomparison of the moderator waste heatrecovery systems 49
TABLE 12. Yearly operating cost comparison:moderator waste heat delivery systems 50
TABLE 13. design parameters and capital cost ofthe cjreenliDiise heating systems 53
TABLE 14. Operating cost comparison of qreenhouseheating and ventilation systems exclusiveof the cost of delivered heat andfossil fuel 54
TABLE 15. Total annual heating and ventilation costsfor the various systems at two fuel costsbased on a yearly system heat load of94 x 10 6 kWh and a boiler efficiency of 7555 ... 55
TABLE 16. The effect of various modifications on thetotal annual cost of heating 10 ha of blockgreenhouses with warmed water from themoderator circuits of two reactors 58
TABLE A-l Design parameters and capital cost summaryof warm water greenhouse heating andventilation systems 73
TABLE A-2 Systems specifications and capital costsummary of greenhouse warm waterdistribution systems 79
TABLE A-3 Design parameters and capital costsummary of moderator heat exchange systems .... 85
TABLE A-4 Design parameters and capital cost summaryof main supply piping, pumphouse, andstandby heating systems 86
TABLE A-5 Capital cost summary of natural gas
heating and ventilation systems 89
TABLE A-6 Maintenance cost summary 91
TABLE A-7 Utility operating cost summary 92TABLE B-l Five possible organizations of an industry
utilizing waste heat for greenhousevegetable production 95
TABLE C-l Design specifications and calculated costsfor moderator heat exchanger 100
LIST OF FIGURES
FIGU?: i. Effect of retail price differential betweenimported and greenhouse tomatoes on percentconsumer selection 13
FIGURE 2. Weekly wholesale quotations for freshtomatoes in Toronto, 1967 14
FIGURE 3. Retail price index for tomatoes inCanada 1971-1974 17
FIGURE 4.
FIGURE 5.
FIGURE 6.
FIGURE 7.
FIGURE S.
FIGURE 9.
FIGURE 10.
FIGURE 11.
FIGURE 12.
FIGURE 13.
FIGURE 14.
FIGURE A-l
FIGURE k-Z
FIGURE A-3
FIGURE A-4
FIGURE A-5
FIGURE A-6
FIGURE A-7
Comparison of possible locations for thereturn air duct in a waste heat greenhouse ... 24Schematic diagram of reference sincleunit greenhouse 25Heat loss from greenhouse structures undernighttime conditions 27
Typical daily variation in heating andcooling load requirements for a double-layer plastic covered greenhouse 28
Calculated heat load curve for a double-layer plastic covered greenhouse 29
Some relationships between factors affectingyield of tomatoes 32Two indices of solar energy available forplant growth in southern Ontario andWinnipeg 36
Greenhouse production schedules currentlyin use or proposed 37Layout of greenhouse facility 40
Operating cost of moderator waste heatdelivery systems versus cost of fossilfuel 51
Comparison of total operating costs forgreenhouse heating and ventilation systemsversus cost of fossil fuel 56
Schematic diagram of an operating unitbased on individual greenhouses 68Schematic diagram of an operating unitbased on single roof greenhouse 69Layout of operating units and warm waterdistribution system, based onindividual greenhouses 76
Layout of operating units and warm waterdistribution system based on singleroof greenhouse 77
Existing moderator heat exchange systemfor G-2 CANDU reactors: design temperaturesshown "'Modified moderator heat exchanqe system andwarm water supply system for singleunit station '-?Modified moderator heat exchange and warmwater supply system for multi-unit powerstation H'i
- 1 -
1. I N T R O D U C T I O N
A t p r e s e n t , a n d in t h e f o r e s e e a b l e f u t u r e , a p p r o x i m a t e l y
2 . 4 kW o f w a s t e h e a t a r e d i s s i p a t e d to t h e e n v i r o n m e n t f o r e a c h
k i l o w a t t o f e l e c t r i c i t y g e n e r a t e d in a C A N D U * p o w e r s t a t i o n . ALio.it
9 5 p e r c e n t o f t h i s h e a t is d i s s i p a t e d t o n a t u r a l w a t e r s n e a r t h e
r e a c t o r a s a s l i g h t l y w a r m e d w a t e r s t r e a m w i t h a m a x i m u m t e m p e r a t u r e
o f 3 2 ° C .
A b o u t 5 0 0 0 M W o f was; t e h e a t a r e o r e s e n t l y b e i n n d i s ? , ' ' ^ i t n d
f r o m o p e r a t i n g n u c l e a r s t a t i o n s in C a n a d a . H o w e v e r , by t h e y e a r
2 0 0 0 ^ ' , it is e s t i m a t e d t h a t a b o u t 3 0 0 , 0 0 0 M W o f w a s t e tied*-, w i l l
h a v e t o b e d i s s i p a t e d , o r a l t e r n a t i v e l y w i l l b e p o t e n t i a l l y
a v a i l a b l e a s a h e a t s o u r c e . T h e w a s t e h e a t d i s c h a r g e d in c o o l i n n
w a t e r r e p r e s e n t s a s i g n i f i c a n t l o s s o f a v a l u a b l e r e s o u r c e - e n e r a v .
H o w e v e r , i t i s v e r y l o w - g r a d e e n e r g y a n d m u s t b e c a r e f u l l y m a t c h e d
w i t h p o t e n t i a l u s e s .
T o t a l s a l e s f r o m C a n a d i a n g r e e n h o u s e p r o d u c t i o n ', n 1 9 7 3
w a s v a l u e d a t $ 8 3 , 3 3 4 ,454.^ 2 ^ . O f t h a t a m o u n t $1 3 , 0 0 2 , 9 3 5 . w a s
f r o m p r o d u c t i o n o f v e g e t a b l e s . E v e n s o , in 1 9 7 2 , i m p o r t s a c c o M i t o d
f o r o v e r 7 5 p e r c e n t o f t h e C a n a d i a n c o n s u m p t i o n o f 6 k i n d s o f
v e g e t a b l e s t h a t c o u l d b e r a i s e d i n g r e e n h o u s e s . T h e v a l u e t f
t h e s e i m p o r t s w a s $61 , 1 4 8 , 0 0 0 ' . A p r i m a r y c o m p o n e n t , 3 0 t o
5 0 p e r c e n t , o f t h e c o s t o f v e g e t a b l e p r o d u c t i o n in C a n a d i a n
g r e e n h o u s e s i s t h e c o s t o f e n e r g y . G r e e n h o u s e a g r i c u l t u r e u s e s
e n e r g y p r i m a r i l y f o r s p a c e h e a t i n g : a f o r m o f e n e r q y u s e n o t
i n c o m p a t i b l e w i t h w a s t e h e a t u t i l i z a t i o n .
T h e p r o b l e m o f u t i l i z i n g w a s t e h e a t f r o m C A N D U r e a c t o r s
f o r p r o d u c t i o n o f g r e e n h o u s e v e g e t a b l e s is e s s e n t i a l l y o n e o f
m a t c h i n g t h e c h a r a c t e r i s t i c s o f t w o c o m p l e x a n d d e m a n d i n n s y s t e m s :
* C A N a d a D e u t e r i u m U r a n i u m
- 2 -
the e'ectrical generation system of a nuclear reactor and the plant
production system of a greenhouse. The question 1s not whether it
can be done, but whether it can be done at a cost that will allow
the greenhouse product to compete in the market, and in a manner
that will not decrease the efficiency of either generator station
or greenhouse operations. Realities dictate that if, by utiliza-
tion of waste heat, reactor operations are made more complex, unsafe
or expensive, the utility will not be interested in providing heat
to a greenhouse operation. Of equal importance, however, if green-
houses heated with waste heat do not consistently produce crops
comparable in quality and yield to those grown in conventional
systems, the grower will not be interested.
1 .1 SCOPE OF THE REPORT
This report does not review the literature of either
waste heat utilization or greenhouse vegetable production, but
does examine:
1. Potential Canadian markets for greenhouse vegetables.
2. Yields of produce to be expected from a weste heatsystem as compared to those from a conventionalsystem.
3. An economic comparison of waste heat and conventionalheating systems.
We have considered only the use of greenhouses to raise
vegetables and not the broad area of cut flowers, potted plants,
bedding plants, nursery stock or vegetables for transplanting.
However, a greenhouse capable of maintaining an optimum environ-
ment for vegetables could also be used for raising flowers or
other plants. We have also not considered soil warming with
waste heat as a means of increasing agricultural production.
Although such applications might be feasible in some locations^ '
they require a separate analysis.
- 3 -
The essence of this study is the comparison of the
heating costs and production potential of waste heat and
conventional greenhouses. It has been assumed that if produce
from the waste heat system can compete with that from the
conventional system, it will be able t? compete with imported
vegetables. However, the major economic analyses of the green-
house vegetable industry^ s ' 8 ' have been outdated by recent
economic changes and an analysis of the entire industry should
be conducted, and the economics of the industry reassessed.
Such a study would contain the data necessary to determine if
greenhouse produce could compete successfully with imported
vegetables.
The questions of possible radionuclide contamination
and public acceptance of the produce have not been examined in
detail Lut it is clear that the probability of any contamination
would be extremely low. Numerical values could be calculated
once the system was designed in detail. Public acceptance of
the produce would be partially dependent on the marketing system,
but it is not expected to be a major problem.
I.2 VEGETABLES PRODUCED IN GREENHOUSES
On a world-wide b a s i s , a large variety of vegetables
are raised in greenhouses: tomatoes, c u c u m b e r s , lettuce, gherkins,
strawberries, green peppers, c h i l i , pumpkins, eggplant, kohlrabi,
horseradish, cauliflower, green beans, squash, okra, c a b b a g e ,
Chinese c a b b a g e , melons, and green salad o n i o n s . The most
important of these are tomatoes and cucumbers but it has been
suggested that green peppers, green beans and strawberries show
promise as greenhouse vegetables and, where adequate heat is no(9)problem, eggplar J:, okra and sweet corn might have possi bi 1 i ties .
- 4 -
A study of waste neat utilization* ' projected that cucumbers
and leaf lettuce would produce maximum returns, followed by
tomatoes and radishes. Strawberries, squash, eggplant and peppers
would produce lower returns Der square meter yearv . Although
mosc vegetables can be raised in the greenhouse environment, only
a few - primarily tomatoes and cucumbers - are profitable crops
in North America.
1 .3 THE GREENHOUSE INDUSTRY IN CANADA
In 1972, 131 ha (323.7 acres) of greenhouses were used
to produce tomatoes and cucumbers valued at $13,023,765. Annual
production of tomatoes has increased at a rate of about 7 percent
per year from 1956 to 1962 and about 4.5 percent per year from
1962 to 1972 (Table 1 ) . Cucumber production was almost the same
in 1972 as in 1962, but peaked in 1967 at a much higher level,
and was at a lower level in 1970 (Table 1 ) . Lettuce is the third
most important vegetable crop but accounted for only 1 percent of
total receipts in 1966' . Other vegetables such as radishes,
parsley and Chinese greens have been raised by a few growers in
Canada*6*.
The distribution of vegetable production in Canada
(Table 2) has been determined by several factors. Fuel costs are
a major part of greenhouse operations, so production has concentra-
ted in the warmer parts of Canada (Southern Ontario, Vancouver,
Victoria, the Annapolis Valley) or where fuel is very cheap
(Medicine Hat)* '. Proximity to large markets and a concentration
of grower expertise are also factors in the location of the
industry^ '. Other factors affecting the suitability of an area
include sunlight intensity, airborne pollution, frequency of
violent weather, summer humidity and supply of water low in
chlorides^ "'.
- 5 -
TABLE 1
Production of Greenhouse Tomatoes andCucumbers in Canada^ 0' '
1956
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
Tomatoes(kg x 10 6 )
2.68
6.08
7.30
8.16
8.61
9.99
9.37
10.05
11 .08
1.2.36
12.45
13.60
Cucumbers(kg x 10 6 )
4 . 5 0
9.36
12.52
12.83
14.16
14.14
15 .10
12 .68
10.77
7.55
8 .54
9.16
- 6 -
TABLE 2
(12)Value of Greenhouse Vegetable Production by Provinces in 1972
1972 Value of % ofProduction Canadian(Dollars) Total
Newfoundland andPrince Edward Island 11,445 0.1
fiova Scotia
(primarily Annapolis Valley) 609,531
Mew Brunswick 8,450
Quebec 117,903
O n t a r i o
( p r i m a r i l y Essex County) 10 ,656 ,614
Manitoba 11,942
Saskatchewan 4 ,754
Alberta(primarily near Medicine Hat) 484,310 3.7British Columbia(primarily near Vancouverand Victoria) 1 ,113,151 8.5
TOTAL 13,023,765
4
0
0
81
0
.7
.1
.9
.8
.1
- 7 -
2. THE C A N A D I A N M A R K E T
2.1 P R O B A B L E M A R K E T FOR T O M A T O E S
The C a n a d i a n g r e e n h o u s e t o m a t o is a high quality p r o d u c t
that is a v a i l a b l e o n l y on a seasonal b a s i s . Its c h i e f c o m p e t i t i o n
is from imported t o m a t o e s of lower q u a l i t y and p r i c e , and
r e l a t i v e l y c o n s t a n t a v a i l a b i l i t y . In Ontario and Nova S c o t i a ,
a p p a r e n t c o n s u m p t i o n of g r e e n h o u s e t o m a t o e s is equal to 30 p e r c e n t
or m o r e of total annual unloads (Table 3 ) . A s s u m i n g that m a r k e t s
in o t h e r p r o v i n c e s could be i n c r e a s e d to the same l e v e l , an
a d d i t i o n a l 110 ha of g r e e n h o u s e s could be used to raise tomatoes
in C a n a d a . Most of this additional g r e e n h o u s e area would be
l o c a t e d in Quebec and the four w e s t e r n p r o v i n c e s .
2.2 P R O B A B L E M A R K E T FOR C U C U M B E R S
Two types of g r e e n h o u s e c u c u m b e r s , the w h i t e spined and
the s e e d l e s s , are r a i s e d in C a n a d a . The white spined v a r i e t i e s
h a v e b e e n the m o s t c o m m o n , p a r t i c u l a r l y in O n t a r i o . They do not
have a q u a l i t y a d v a n t a g e over i m p o r t e d field c u c u m b e r s , but are
not as p e r i s h a b l e as t o m a t o e s , can be stored l o n g e r and shipped
m o r e e a s i l y . S e e d l e s s c u c u m b e r s h a v e been raised e x t e n s i v e l y in
B r i t i s h Columbia and have been i n t r o d u c e d into O n t a r i o . They have
a m o r e d e l i c a t e f l a v o u r and should command a p r e m i u m on the m a r k e t
once they have been a c c e p t e d by the c o n s u m e r . S e e d l e s s c u c u m b e r s
are m o r e p e r i s h a b l e and do not s t o r e or ship as well as the w h i t e
s p i n e d v a r i e t i e s . S t a t i s t i c s Canada does not d i f f e r e n t i a t e b e t w e e n
the two t y p e s ; t h e r e f o r e the p r o d u c t i o n of each of the two
v a r i e t i e s r.annot be d e t e r m i n e d .
TABLE 3
Estimate of Additional Greenhouse Area Possible for Tomato Productionin Eight Canadian Provinces (data from 1972)
N o v a N e w Bi i ti shS c o t i a B r u n s w i c k Q u e b e c O n t a r i o M a n i t o b a S a s k a t c h e w a n A l b e r t a C o l u m b i a
G r e e n h o u s e p r o d u c t i o n ' '
(Tei 540.7 14.C 99.3 11,869.4 11.3 4.5 160.1 382.3
Net interprovi r.cial flowof greenhouse tomatoes*"
(Te) +0 .4 +48.1 + 3 , 1 3 0 . 1 - 4 , 0 0 3 . 0 +56.7 - +41.7 - 2 7 . 7
Apparent consumption ofCanadian greenhousetomatoes (Te) 541.1 62.6 3,529.5 7,866.3 68.9 4.5 201.8 854.6
Total tomato unloads'^'(Te) 1,603.9 956.2 39,595.7 25,580.3 6,100.0 3,615.2 9.644.4 13,528.2
Apparent consumption ofijreenhou;« tomatoes asa percent of unloads 33.7 6.5 8.9 30.8 1.1 0.1 2.1 6.3
Additional greenhousetomatoes requi-ed tofill market to 30%
(Te) - 253.4 8,354.9 - 1,762.9 1,080.9 2,690.8 3,206.0
Greenhouse arearequired (ha) at15.7 kg/m2 - 1.6 53.2 - 11.2 6.9 17.1 20.4
*Te - 1000 kilogrammes
- 9 -
The p r o j e c t e d m a r k e t for g r e e n h o u s e c u c u m b e r s is mucii
s m a l l e r than t h a t for tomatoes (Table 4 ) , p r i m a r i l y because tr.5
total m a r k e t is s m a l l e r . T a b l e 4 indicates that an a d d i t i o n a l
20 ha of c u c u m b e r s could be r a i s e d which is a p p r o x i m a t e l y 19
p e r c e n t of the p r o j e c t e d a c r e a g e of t o m a t o e s .
2 . 3 P R O B A B L E M A R K E T FOR O T H E R V E G E T A B L E S
G r e e n h o u s e v e g e t a b l e s o t h e r than c u c u m b e r s and t o m a t o e s
h a v e not been r a i s e d in large e n o u g h q u a n t i t i e s to be r e p o r t e d
s e p a r a t e l y by S t a t i s t i c s C a n a d a . Table 5 s h o w s the q u a n t i t i e s
of p e p p e r s , l e t t u c e , o n i o n s , r a d i s h e s imported in 1 9 7 2 . T h e i r
y i e l d s were d e r i v e d from r e s e a r c h conducted in g r e e n h o u s e s in
K e x i c o during the w i n t e r
for C a n a d i a n c o n d i t i o n s .
K e x i c o during the w i n t e r s e a s o n ' and would have to be v e r i f i e d
P e p p e r s have been e x a m i n e d as a p o t e n t i a l g r e e n h o u s e
c r o p in O n t a r i o but it was found that they y i e l d e d a lower r e t u r n[13]
than t o m a t o e s ^ '. Lettuce y i e l d s w e l l , but w o u l d need a SDecialm a r k e t i n g e f f o r t s i n c e the g r e e n h o u s e types are l e a f , or small
h e a d e d , v a r i e t i e s , in c o n t r a s t to the large headed imported tyDes
O n i o n s and r a d i s h e s should be e a s i l y grown and m a r k e t e d , but the
r e t u r n s are not k n o w n . S i n c e l a r g e m a r k e t s a p p e a r to exist for
t h e s e v e g e t a b l e s , they w a r r a n t f u r t h e r i n v e s t i g a t i o n .
2.4 F U T U R E P R I C E S AND M A R K E T S
In this s e c t i o n , m u c h of the general d i s c u s s i o n d r a w s
s p e c i f i c data f r o m tomato m a r k e t s but it is e x p e c t e d that
s i m i l a r f o r c e s w o u l d control the prices of o t h e r p r o d u c e . The
p r i c e of g r e e n h o u s e produce is d e t e r m i n e d by the price of
c o m p e t i n g p r o d u c e d e l i v e r e d to the m a r k e t and the Drice d i f f e r -
e n t i a l the c o n s u m e r is w i l l i n g to pay for the hiaher q u a l i t y
TABLE 4
E s t i m a t e o f A d d i t i o n a l G r e e n h o u s e A r e a P o s s i b l e f o r C u c u m b e r P r o d u c t i o nin E i g h t C a n a d i a n P r o v i n c e s ( d a t a f r o m 1 9 7 2 )
Net Interprovincialflow of(cucumbers(3)
Apparent consumptionof Canadian cucumbers
Apparent consumptionof cucumbers as apercent of unloads
Additional cucumbers
Greenhouse arearequired (ha) at22.4 kg/n,Z
Scotia
352.0
41.4
Brun!wick Quebec Ontario Manitoba Saskatchewan Alberta
13-8
".1
95.3 5,106.2
-7
3,280.3
38 6 9
^ ^ + ^ ^ ^ . 1 > 8 Z 6. 6 +513.9 *245.4
^ g ^ } g g g 3 3 > 2 7 9. 5 5 ? 4.4 248.6
834.2 318.4 ,1.195.8 8,487.3 1,756.3 968.0
25 7
142.2 H9.1
5
BritishColumbia
-HI.6
689.5
2,917.1
23.3
1-9
-84.8
877.3
3,409.3
25.7
428.8 419.4
I-9
- 11 -
TABLE 5
Additional Greenhouse Area Possible for Canadian Productionof Four Vegetables (data from 1972)
Peppers L e t t u c e ^ Onions R a d i s h e s ^ 0 '
Imported*3* (Te) 14,470 116,710 8,550 4,390
Y i e l d H )(kg.nf2/year) 8.40 42.40 29.90^ ; 29.90
Area required(ha) 172 275 32 16
(a) Converted at 0.23 kg per head.
(b) Yield unknown, assumed to be the same as radishes.
(c) Converted at 0.23 kg/bunch.
grecnho.ise p r o d u c t . S o m e g r e e n h o u s e v e g e t a b l e s , such as p e p p e r s ,
o n i o n s , r a d i s h e s and w h i t e s p i n e d c u c u m b e r s , w h e r e the q u a l i t y
d i f f e r e n c e is n e g l i g i b l e and p r o d u c t d i f f e r e n t i a t i o n d i f f i c u l t ,
are sold at or n e a r the s a m e p r i c e as c o m p e t i n g p r o d u c e . O t h e r
vt}qetables s u c h as t o m a t o e s , s e e d l e s s c u c u m b e r s and l e t t u c e c a n be
d i f f e r e n t i a t e d f r o m field g r o w n c r o p s and so c o m m a n d a p r e m i u m
p r i c e due to s u p e r i o r q u a l i t y .
C o n s u m e r s can be g r o u p e d into t h r e e t y p e s : 1 ) t h o s e
t h a t are v e r y q u a l i t y c o n s c i o u s and w i l l i n g to nay a high p r e m i u m
f o r g r e e n h o u s e p r o d u c e , 2 ) t h o s e t h a t buy t h e c h e a p e s t p r o d u c e ,
and 3 ) the g r o u p of p r i m a r y i n t e r e s t to g r e e n h o u s e v e g e t a b l e
o r o d u c e r s - t h o s e t h a t p r e f e r g r e e n h o u s e p r o d u c e but a r e a l s o p r i c e
c o n s c i o u s ( F i g . 1 ) . A g r e e n h o u s e i n d u s t r y t h a t is s m a l l , r e l a t i v e
to the total m a r k e t , can c o m m a n d a h i g h e r p r i c e d i f f e r e n t i a l t h a n
o n e t n a t is l a r g e .
In M a n i t o b a , w h i c h has a small g r e e n h o u s e i n d u s t r y , the
v e g e t a b l e m a r k e t i n q board s e t s and a t t e m p t s to m a i n t a i n a c o n s t a n t( 1 4 )
p r i c e for t o m a t o e s t h r o u g h o u t the s e a s o n ^ . H o w e v e r , in T o r o n t o
w h e r e the s u p p l y is l a r g e r e l a t i v e to the m a r k e t , the p r i c e v a r i e s
t h r o u g h o u t the s e a s o n ( F i g . 2 ) . A l a r g e i n d u s t r y in M a n i t o b a w o u l d
be s u b j e c t to a p r i c e s t r u c t u r e m o r e like t h a t of T o r o n t o w h e r e the
p r i c e of g r e e n h o u s e t o m a t c e s d e c r e a s e s w i t h i n c r e a s i n g s u p p l y in
"lay t h r o u g h J u l y . The low p r i c e in O c t o b e r is d u e p a r t i a l l y to the
low p r i c e of i m p o r t s , but a l s o to the e x t r e m e l y low p r e m i u m p a i d
f o r g r e e n h o u s e t o m a t o e s . T h e r e a s o n f o r t h e low p r e m i u m is n o t
k n o w n , b u t it do>js not a p p e a r to be d u e to l o w q u a l i t y '. In
M a n i t o b a it w o u l d a p p e a r to be p o s s i b l e to m a r k e t g r e e n h o u s e t o m a t o e
t h r o u g h o u t the f i e l d t o m a t o s e a s o n . Local f i e l d t o m a t o e s are
p r o d u c e d in q u a n t i t y only d u r i n g A u g u s t a n d S e p t e m b e r a n d a c c o u n t fc
less than n a i f of the u n l o a d s ^ ' in t h o s e m o n t h s . In T o r o n t o the
- 13 -
0.60
en
0.40
ccCD
o
5
0.20
(NO PREFERENCE)
50PERCENT. PREFERENCE
100
FIGURE 1. Effect of retail price differential !)<• tweor.and greenhouse tomatoes on pet ":en1 •-•' rt';'j" -• r
1.40 -
1.20 -
0-80 -
0.60 -
0.40 -
0.20 _
N D
FIGURE I. WctHy wholesale quotations for freToronto, 1967(7).
- 15 -
f i e l d t o m a t o s e a s o n e x t e n d s f r o m J u l y t h r o u g h O c t o b e r , and in A u g u s t
a n d S e p t e m b e r n e a r l y a l l t h e u n l o a d s a r e f i e l d g r o w n . T h e s a l e s of
C a n a d i a n f i e l d g r o w n t o m a t o e s o n t h e M o n t r e a l m a r k e t a r e s i m i l a r to
t h o s e in T o r o n t o w h i l e t h e A l b e r t a , S a s k a t c h e w a n a n d B r i t i s h C o l u m b i a
m a r k e t s are s i m i l a r t o W i n n i p e g .
T w o f u t u r e t r e n d s c o u l d a f f e c t t h e r e l a t i o n s h i p b e t w e e n
m a r k e t p e n e t r a t i o n a n d p r i c e d i f f e r e n t i a l . A c o n s u m e r e d u c a t i o n
p r o g r a m m e , a d v e r t i s i n g , d i s t i n c t i v e p a c k a g i n g , e t c . w o u l d m a k e
m o r e p e o p l e a w a r e o f t h e h i g h e r q u a l i t y of a r e e n h o u s e p r o d u c e ,
m o v i n g t h e c u r v e ( F i g . 1 ) to t h e r i g h t , and i n c r e a s i n g t h e n u m b e r o f
p e o p l e w i l l i n g to p a y a g i v e n d i f f e r e n t i a l . A c o n t i n u e d i n c r e a s e in
t h e t r u e s t a n d a r d o f l i v i n g w o u l d e n a b l e m o r e p e o p l e to p a y f o r a
q u a l i t y p r o d u c t , a n d t e n d to m o v e t h e c u r v e u p w a r d . T h e r e f o r e , if t h e
s t a n d a r d o f l i v i n g c o n t i n u e s to i n c r e a s e , a n d i f g r e e n h o u s e p r o d u c e
is m a r k e t e d a g g r e s s i v e l y , t h e m a r k e t v o l u m e at a n y g i v e n p r i c e
d i f f e r e n t i a l s h o u l d e x p a n d a t a m o r e r a p i d r a t e t h a n d o e s t h e
p o p u l a t i o n o f C a n a d a .
C o m p e t i n g f i e l d g r o w n p r o d u c e c o m e s f r o m t h r e e m a j o r
s o u r c e s : C a n a d a , t h e U . S . a n d M e x i c o . D u r i n g t h e i r f i e l d s e a s o n
( p r i m a r i l y J a n u a r y t h r o u g h M a y ) M e x i c a n v e g e t a b l e s a p p e a r to s e t
t h e m a r k e t p r i c e , w h i l e t h e U . S . g r o w n v e g e t a b l e s s e t t h e m a r k e t
p r i c e b e t w e e n t h e n a n d t h e C a n a d i a n f i e l d g r o w n s e a s o n . I n d i r e c t l y ,
a l l w i n t e r v e g e t a b l e p r i c e s a r e c o n t r o l l e d by t h e c o s t of p r o d u c t i o n
in t h e s o u t h e r n U n i t e d S t a t e s , s i n c e a l a r g e c a p a c i t y f o r p r o d u c t i o n
e x i s t s w h i c h w o u l d b e u s e d if t h e p r i c e i n c r e a s e d s u f f i c i e n t l y . It
is in t h e i n t e r e s t o f t h e M e x i c a n p r o d u c e r s to m a i n t a i n t h e i r p r i c e
j u s t b e l o w t h e l e v e l a t w h i c h a d d i t i o n a l U . S . c a p a c i t y f o r p r o d u c t i o n
w o u l d b e u t i l i z e d . B e c a u s e o f t h e s e m a r k e t f o r c e s , v e g e t a b l e p r i c e s
w i l l p r o b a b l y e s c a l a t e w i t h U . S . p r o d u c t i o n c o s t s .
- 16 -
U.S. and Mexican field crop production costs are
sensitive to increases in transportation c o s t , while greenhouse
crops are more sensitive to interest rates, oil and construction
costs. Both crops are sensitive to labour costs. Recent increases
in the cost of transportation and oil may be reflected in the higher
prices paid by consumers for tomatoes in 1974 (Fiq. 3 ) . Since the
U.S. and Canada are subject to similar economic forces, it is
probable that U.S. field production costs will escalate at
approximately the same rate as Canadian field and greenhouse produc-
tion costs. The economic situation is essentially unanalyzable ,
however, since any one of the following factors could change it
rapidly:
1. Change in the U.S.-Canadian exchange rate.
2. Different rates of inflation in the U.S. and Canada whichwould increase costs of production in one relative to theother.
3. Changes in tariffs or import regulations. Increases inCanadian tariffs, or tightening of import regulationswould obviously help the local industry, but increasesin the U.S. tariffs on Mexican produce would make Canadaa relatively better market and put more pressure on localproducers .
4. A breakthrough in field vegetable production. Since muchof the labor and cost of field vegetable production isinvolved in picking, efforts are being made to developmechanical pickers and suitable vegetable varieties.Success could decrease the costs of field producevegetables .
5. A large increase in vegetable producing acreage in Mexico.Land and water are available in M e x i c o * 6 ) for producingmore vegetables which might be marketed by decreasingtheir price relative to those produced in the U.S. andCanada.
6. The development of a large greenhouse industry in the U.S.based on waste heat. Since many of the power stations tobe built in the U.S. will require cooling towers, there isinterest in developing a greenhouse agriculture system todissipate part of the heat. Since part of the greenhousecosts could be written off against the generating station,vegetable production costs could be low.
- 17 -
TC
C•H
I/)
o
en
os
a)u
O incvi
qcvi
( O ' l = L 9 6 1 ) X 3 Q N I 3 D I b d
- 1.
Iii summary, an unfilled expanding market exists in
Canada for greenhouse produce that can be sold at' premium p r i c e ,
such as tomatoes. The size of this market is dependent on the
Dremium required to yield a reasonable return. Large markets also
exist for vegetables such as lettuce and peppers that are not sold
at a premium. The profitability of these latter vegetables should
be re-examined in the light of changing economic factors.
3. CHARACTERISTICS OF THE HEAT SOURCES AND
THE GREENHOUSE HEATING SYSTEM
The search for uses of waste heat has been generally
frustrated by the relatively low temperature of the waste heat
s o u r c e , or, when a promising high temperature source has been
available, by the low total energy available from that s o u r c e .
These characteristics are to be anticipated, both now and in the
f u t u r e , since nuclear power stations are designed and operated to
maximize electrical energy production and, t h e r e f o r e , to m i n i m i z e
loss of energy.
3 .1 WASTE HEAT SOURCES IN CANDU REACTORS
The largest source of waste heat from nuclear stations
is low-grade thermal energy from the condenser cooling circuit
(Table 6 ) , and several uses for this source are currently under
evaluation^ ' or direct experimental i n v e s t i g a t i o n ^ 8 ' 1 9 ' . Of
the heat transfer systems considered which could use this s o u r c e ,
wet contact heat exchange appeared to be the only one that was
TABLE 6
Waste Heat Sources from CANDU G-2 Nuclear Power Stations(600 MW(e))
Stati onSystem
Turbi ne
Moderator
Primary
Description ofHeat Source
Saturated steam fromlow pressure turbine
Liquid heavy waterfrom calandria
Liquid heavy waterfrom purificationsystem
Des i gnTemperature of
Heat Source
29(a)
43-71
>100
Avai1ableHeat
(MW/Reactor)
1400
118
25
Des i gnTemperature of
Heat Sink
15-32(b)
15-32^5
j2(b)
(a) Design condensation temperature during winter operation.
(b) Maximum allowable discharge temperature of cooling water.
- 20 -
economically feasible. H o w e v e r , use of this system would result
in a water-saturated e n v i r o n m e n t in the g r e e n h o u s e s . B e c a u s e of
the humidity and condensation control d i f f i c u l t i e s associated
with such a s y s t e m , but primarily because of adverse plant growth
c o n d i t i o n s v , this heating system was e l i m i n a t e d from f u r t h e r
consideration. Extensive research may p e r m i t its use in the
future. C o n s e q u e n t l y , although a large amount of energy is
available in the condenser cooling w a t e r , its temperature appears
to bo too low to permit e c o n o m i c utilization in a g r e e n h o u s e
heating system under Canadian climatic c o n d i t i o n s .
It has been assumed in this study that the i n t e r m e d i a t e -
grade waste heat sources identified in CANDU stations will be
available. The heat source investigated was the m o d e r a t o r cooling
circuit. This study evaluates the cost involved in m o d i f y i n g this
circuit to supply a water stream at 55°C.
3.2 PRELIMINARY C O N S I D E R A T I O N S
The primary c h a r a c t e r i s t i c of w a s t e heat from nuclear
reactors is its low t e m p e r a t u r e . In t h e o r y , a maximum t e m p e r a t u r e
of 70°C could be obtained from the m o d e r a t o r cooling c i r c u i t .
H o w e v e r , since it would be impractical to pump heavy w a t e r from
the calandria to a greenhouse heating s y s t e m , an i n t e r m e d i a t e
heat transfer agent (assumed to be light w a t e r ) is r e q u i r e d .
Practical considerations limit the maximum temperature of this
transfer agent to about 6 0 ° C .
Several heating systems were initially c o n s i d e r e d which
could use w a t e r in the a v a i l a b l e temperature range to s a t i s f y the
requirements of a greenhouse heating system. These w e r e :
1. Dry heat exchange e m p l o y i n g forced air c i r c u l a t i o nover a finned tube heat e x c h a n g e r .
2. Dry heat exchange employing natural convectionai r heaters .
3. Contact heat exchange between greenhouse air andwarm water in an evaporative pad with forced aircirculation system.
4. Heat pumps in conjunction with dry heat exchange.
Of these systems, contact heat exchange was the leastexpensive. However, for reasons previously discussed, thissystem was not considered ^urther. A visit to an operating
(19)systenr ' which employs direct contact exchange appeared tosupport this decision.
Systems that included heat pumps had very high capitalcosts and will not be considered further at this time.
Of the two remaining dry contact systems, the forced aircirculation system appeared to have several distinct advantagesover the natural convection system. First, a forced air systemcan be designed in which the circulation fans satisfy the heatingsystem requirements, and also the requirements of a greenhousecooling system. Such a combination of fan d u t i e s , which resultsin a reduced capital expenditure for forced air systems, was notpossible in a natural convection heating system. Second, theforced air system offers horticultural advantages such as evenheat distribution, constant air movement for CO2 dispersion,good control of humidity and freedom from pipes in the growingarea. Therefore, a forced air circulation system was chosen forfurther evaluation.
3.3 GREENHOUSE STRUCTURE
Greenhouses are designed to control light intensity,carbon dioxide levels, temperature and moisture so as to assureoptimal growth of plants. Because high levels of light are
- 22
required for photosynthesis, qreenhouses are constructed of
materials (glass, plastic) which transmit 80 to 90 percent of
incident sunlight. Traditionally, greenhouses have been
constructed of single-layer glass, fiberglass, or single- or
double-layer polyethylene supported on a suitable framework.
In this study, double-layer plastic covered areenhouses
were chosen for evaluation for the followinq reasons:
1. The capital costs of constructing double-layer housesare Itss than the costs of glass or rigid fiberglassconstruction.
2. Double-layer greenhouses require only two-thirds tofive-eights of tha heating load of a single-layergreenhouse.
3. Because double-layer greenhouses are more airtightthan glass greenhouses, growth is promoted by moreefficient and economic utilization of carbon dioxideenri chment.
Disadvantages of double-layer greenhouses include the
requirement of mor.e elaborate heating and ventilation equipment
to overcome humidity and condensation, and the necessity to
replace the plastic cover every few years because of deteriora-
tion.
Greenhouses may be constructed as separated units
joined by a central corridor, or as connected units forming a
single roof over the growing area. Although the single roof
construction has a lower heat loss per unit of growing surface,
the separated unit is preferable in terms of disease control
and crop production scheduling. Consequently, both types were
evaluated. Specifically, unit greenhouses constructed of a
double-layer polyethylene skin over a supporting erch structure
were chosen. Such greenhouses have performed successfully under
winter conditions in Manitoba.
- 23 -
3.4 AIR C I R C U L A T I O N
In c o n v e n t i o n a l , f o r c e d air c i r c u l a t i o n s y s t e m s , the
d i f f e r e n c e b e t w e e n the t e m p e r a t u r e of the g r e e n h o u s e air ( 2 1 n C )
and the air f r o m the h e a t i n g u n i t is t y p i c a l l y 30 to 4 0 ° C , To
a c h i e v e the s a m e t e m p e r a t u r e i n c r e a s e in a i r f r o m a w a r m w a t e r
s y s t e m ( 5 5 ° C ) w o u l d r e q u i r e u n e c o n o m i c a l l y l a r g e h e a t t r a n s f e r
s u r f a c e s and s p e c i a l fans to o v e r c o m e the p r e s s u r e drop a s s o c i a -
ted w i t h a i r f l o w t h r o u g h the h e a t t r a n s f e r c o i l . C o n s e q u e n t l y ,
r a t h e r than h e a t a small v o l u m e of air to h i g h t e m p e r a t u r e s and
d i s t r i b u t e t h a t a i r t h r o u g h d u c t s , it is m o r e e c o n o m i c a l to h e a t
a l a r g e v o l u m e of air o v e r a s m a l l e r t e m p e r a t u r e r a n g e (5 to 7 ° C )
p r o v i d e d t h a t t h e air c i r c u l a t i o n s y s t e m c a n d i s t r i b u t e t h a t a i r
w i t h a low p r e s s u r e d r o p . To d o t h i s , a v e r y l a r g e air r e t u r n
d u c t to the h e a t i n g coil m u s t be p r o v i d e d .
T h r e e p o s s i b l e l o c a t i o n s for s u c h a d u c t a r e : 1 ) in tne
a t t i c of the g r e e n h o u s e ^ ' ° , 2 ) in the b a s e m e n t of the g r e e n h o u s e ,
a n d 3 ) t h r o u g h t h e g r o w i n g a r e a o f an a d j a c e n t g r e e n h o u s e . T h e s e
p o s s i b i l i t i e s a r e s h o w n in F i g u r e 4 t o g e t h e r w i t h a s u m m a r y of
t h e i r a d v a n t a g e s and d i s a d v a n t a g e s . The r e f e r e n c e c o n c e p t ( F i g . 5)
u s e s the a t t i c r e t u r n s y s t e m s i n c e it is l o w e s t in c o s t and c a n
be e x t r a p o l a t e d e a s i l y to l a r g e o p e n area h o u s e s . The a i r
c i r c u l a t i o n s c h e m e (Fig. 5 ) i n c l u d e s p r o v i s i o n f o r an e v a p o r a t i v e
p a d c o o l i n g s y s t e m and u s e s t h e s a m e c i r c u l a t i o n fans f o r b o t h
h e a t i n g and c o o l i n g s y s t e m s . D e t a i l s on the c o n s t r u c t i o n of the
r e f e r e n c e g r e e n h o u s e are g i v e n in A p p e n d i x A,
3.5 H E A T I N G S Y S T E M R E Q U I R E M E N T S
H e a t l o s s from a g r e e n h o u s e d e p e n d s u D o n : 1) the
c o v e r i n g m a t e r i a l , 2) the s u r f a c e area of b o t h the g r o w i n g s u r f a c e
a n d the s t r u c t u r e , 3) the o r i e n t a t i o n and l o c a t i o n , 4 ) the
t e m p e r a t u r e d i f f e r e n t i a l b e t w e e n the i n s i d e of the h o u s e and the
ATTIC
END VIEW
R I: TURNDUCT
BASEMENT
END VIEW
•I -V 1 -'. .\ *
••.ROW: v
APIA
CONSTRUCTIONCOST LOW HIGH INTERMEDIATE
AIR CIRCULATIONCOST
INTERMEDIATE HIGH LOW
DECREASEDLIGHT IN
GROWING AREA
SOME NONE NONE
EASE OFEXTRAPOLATION
TO LARGE-SCALEGREENHOUSES
EASY EASY HARDER
FIGURE 4. Comparison of possible locations for the return airduct in a wa.ite heat greenhouse.
- 25 -
TOP VIEW
FINNEDCOILS
EVAPORA' IV[
PAD
SIDE VIEW
SUMMER
EXHAUST
FANS ATTIC
MOTORI/l [)LOUVERS
FIGURE 5. Schematic diagram of ref orervj'j u i:.r It
- 26 -
;.^b!eit e n v i r o n m e n t , and 5) t h e a v e r a g e c l o u d c o v e r . H e a t i n g
svstei'is "vjst be d e s i q n e d to a c c o m m o d a t e t h e m a x i m u m h e a t l o s s
d u r i n g n i g h t - t i m e c o n d i t i o n s . For d o u b l e - l a y e r p o l y e t h y l e n e
c o v e r e d g r e e n h o u s e s , a h e a t l o s s c o e f f i c i e n t of 3.4 to 4 . 0
W / ( m L " . ' C ) is e m p l o y e d ( F i g . 6 ) .
Tne h o u r l y h e a t l o a d r e q u i r e m e n t s of a g r e e n h o u s e v a r y
s i g n i f i c a n t l y d u r i n g the d a y , and t h r o u g h o u t the y e a r . In
W e s t e r n C a n a d a d u r i n g m i d - w i n t e r , a h e a t i n g s y s t e m o p e r a t e s
c o n t i n u o u s l y . H o w e v e r , at all o t h e r t i m e s of the y e a r , o p e r a t i o n
of bot.1 h o a t i n q and c o o l i n g s y s t e m s m a y be r e q u i r e d in a g i v e n
day (Fig. 7 ) . In s u m m e r , the c o o l i n g load r e q u i r e d to m a i n t a i n2
s a t i s f a c t o r y g r e e n h o u s e t e m p e r a t u r e s can e x c e e d 631 W / m g r o w i n g
s u r f a c e , '.e. a b o u t 2.34 x 10 W for a 1 2 . 2 by 3 0 . 5 m g r e e n h o u s e
at miri-dav. By c o m p a r i s o n , m a x i m u m h e a t i n g l o a d s d u r i n g w i n t e r
m o n t h s will r a r e l y e x c e e d 1.61 :
c o v e r e d h o u s e of the s a m e s i z e .
m o n t h s will r a r e l y e x c e e d 1.61 x 10 W f o r a d o u b l e - l a y e r p l a s t i c
G r e e n h o u s e s a r e a t t r a c t i v e to h e a t s u p p l i e r s b e c a u s e of
t n e i r high h e a t c o n s u m p t i o n p e r unit land a r e a . S u c h a h i g h
d e n s i t y s y s t e m has l o w e r d i s t r i b u t i o n c o s t s p e r MM of d e l i v e r e d heat(17 1A t y p i c a l d o m e s t i c h e a t i n g s y s t e m in an u r b a n n e i g h b o r h o o d v '
has a h e a t c o n s u m p t i o n d e n s i t y b e t w e e n 0 . 3 0 and 0 . 4 0 M W / h a . In
c o m p a r i s o n , g r e e n h o u s e f a c i l i t i e s h a v e p e a k c o n s u m p t i o n d e n s i t i e s
of a b o u t 1 . 9 0 M W / h a , a v a l u e w h i c h is a p p r o a c h e d o n l y in t h e c e n t r a l
c o r e a r e a s o f m o s t c i t i e s ' .
A p e r t i n e n t f a c t o r in the e v a l u a t i o n of a g r e e n h o u s e
H e a t i n g s y s t e m is the y e a r l y h e a t i n g l o a d f a c t o r * . L i k e o t h e r
b u i l d i n g h e a t i n g s y s t e m s in C a n a d a , g r e e n h o u s e s y s t e m s h a v e a
m a x i m u m h e a t i n g load f a c t o r of a b o u t 0 . 3 0 ( F i g . 8 ) . T h e c a l c u l a -
tion of t h i s load f a c t o r , h o w e v e r , a s s u m e s c o n t i n u o u s o p e r a t i o n
y e a r l y h e a t i n g load f a c t o r = ( a c t u a l y e a r l y h e a t 1 o a d ) / ( y e a r l yh e a t l o a d e v a l u a t e d at m a x i m u m g r e e n h o u s e d e s i g n c o n d i t i o n s )
- ? • / -
0.30 -
0.25
CVJ0.20
0.15
UJa:
0.10
0.05
-60
\
O COTTER AND WALKER ( 1 1 )
• COTTER AND WALKER ( 1 1 )
O * PROWSE
\
WIND VELOCITY = 24 km/hRADIATION LOSS AS GIVENBY KONDRATYEV (21)
•40 -20 0 20OUTSIDE AIR TEMPERATURE (°C)
40
FIGURE 6. Heat loss from greenhouse structuresconditi ons.
- 28 -
too
50
0
-50
-100
-150
-POO
l
-
-
-
i
APWI1224
\
\
\
1
RILN N I P E G.2 x 30
km/h
\
1
1 1
AREA.5 m GREENHOUSEWIND
/
/
/
/
\ /
1 |
1
-
-
1
0400 0800 1200T I M E O F D A Y ( H )
1600 2000
V. Typical dally var ia t ion in heating and cooling loadrequirement f f t r a .iouble-layer p l a s t i c covered
- 29 -
o
12.2 m x 30.5 m GREENHOUSEWINNIPEG AREA24 km/h PREVAILING WINDEXCLUDES INFILTRATION LOSS
0 i i i i I 1 1
J F M A M J J A S O N D
FIGURE 8. Calculated heat load curve for a 1plastic covered greenhouse.
- 30 -
of the g r e e n h o u s e t h r o u g h o u t the y e a r . In f a c t , b e c a u s e of
re d u c e d l i g h t i n t e n s i t y and high fuel c o s t s , some c o m m e r c i a l
g r e e n h o u s e o p e r a t o r s do n o t o p e r a t e t h e i r g r e e n h o u s e s d u r i n gloo)
December, January or February v ' which further reduces the
heating load factor to between 0.22 and 0.25.
4. VEGETABLE YIELD IN GREENHOUSES
The factors affecting yield can be divided into two
categories: 1) those that affect the yield of a given group of
plants as they complete the cycle from seed to fruit, and2
2) those that pertain m o r e to yield per m /a. Examples of the
latter a r e : when the crop should be planted to take advantage
of high light levels and high prices, when the mature plants
should be removed to allow planting of young more vigorous plants,
etc. This category is called production scheduling.
4.1 COMPARISON OF GROWTH CONDITIONS IN WASTE H E A TAND CONVENTIONAL G R E E N H O U S r
Factors in category 1 (those affecting the yield of a
given group of plants) are listed in Table 7, and some of their
relationships with yield are shown in Figure 9. The increased
air flow in the reference greenhouse, in comparison with most
conventional houses, should have a beneficial influence on plant
yield. If the design of the house is such that a m a j o r portion
of the air flow is through the plant c a n o p y , and there are no
areas of extremely low velocity, the temperature variation betwee
plants will be low and the partial pressures of C 0 2 and H 2 0 at th
leaf surfaces will be similar throughout the house. When plants
- 3 1
T A B L E 7
F a c t o r s A f f e c t i n g t h e Y i e l d o f e. G i v e n G r o u n o f P l a n t s
1 a r a m e t e rP a r a m e t e rC o n t r o l
u e n e 1 1 c p o t e n t i a lof v a r i e t y
H i s t o r y of the p l a n t
Soil e n v l r o n m e n t
Aera ti on
Nutrient levelsand balances
Root space
M o i s t u r e l e v e l s
Tempera t u r e
S o i l bo rne d i s e a s e s
A e r i a l e n v i r o n m e n t
T e m p e r a t u r e
Hutni d i t y
L i g h t
C 0 o
v a r i e t y s e l e c t i o n
h o r t i c u l t u r a l u r a c t u :
s e l e c t i o n or m o d i f i c a t i o nor r o o t i n g m e d i u m
ferti1i z a t i o n
plant S D a c i n q androot m e d i u m v o l u m e
w a t e r i n g
soil h e a t i n g
s t e r i l i z e r o o t i n a ri;edi iri s o l a t e root z o n e
heat or e v a p o r a t i v e cool
venti1 a te
b u i l d i n g d e s i g n , o r i e n t a t i o nand m a t e r i a l s , r e f l e c t i v eground c o v e r , p l a n t s p a c i n a
add by b u r n i n g h y d r o c a r b o r ' ;
; i f t',_• r i ' M i •• : • • » . . , -
|- <• 1 , r I. I (_ r
0 n v v n r i w .: - ' • •
>:. n .
r. M r -•
"line
n o n "
dec re(i s<
T h e t e m p e r a t u r e , h u m i d i t y a n d C O 2 l e v e l s o f i m p o r t a n c e are t h r i v e •< t 1l e a f s u r f a c e . T h e r e f e r e n c e s y s t e m r e q u i r e s q r e a t e r a i r f l o w s f o r '<.•t r a n s f e r a n d t h u s m a y g i v e m o r e o p t i m a l t e m p e r a t u r e s , h u m i d i t y a n d • 'l e v e l s a t t h e l e a f s u r f a c e s .
- 32 -
s \
3ONV1S
i v . ? n
- 3 3 -
are a c t i v e l y t r a n s p i r i n a , C O ; ; i s t a k e n u n a n d w a t e r i c q
C o n s e q u e n t l y t h e a i r s u r r o u n d i n g t h e l e a v e s b e c o m e s s a t u r a t e d v i t ' i
w a t e r v a p o r a n d d e p l e t e d i n C O ? . H i g h h u m i d i t y e n c o u r a q e s tlu-
d e v e l o p m e n t o f f u n g a l d i s e a s e s a n d t h e l a c k o f C D ? c a n l i m i t o r o w i ;
G o o d a i r f l o w t h r o u g h t h e c a n o p y s h o u l d i n c r e a s e g r o . v t h a n d <ir:- r /• :
p r o b l e m s w i t h f u n g a l d i s e a s e s b u t t h e e f f e c t o n y i e l d , a 1 t h o u • : < :
p r e d i c t e d t o b e p o s i t i v e , c a n n o t b e e s t i m a t e d .
T h e r e f e r e n c e g r e e n h o u s e d e s i g n i n c l u d e s a n a t t i c f. > •
c i r c u l a t i o n . T h e m a j o r d i s a d v a n t a g e o f t h i s s y s t e m i s t i v s t t » ; .
a t t i c l i m i t s t h e a m o u n t o f l i g h t a v a i l a b l e t o t h e p l a n t s . T h e < j f f '
o f t h i s d e c r e a s e o n y i e l d w i l l d e p e n d o n i t s r a i n i t u d e a n d h•.*..- i,f .
i n p r a c t i c e , l i g h t i s t h e l i m i t i n g f a c t o r f o r p l a n t n r o w t . h . 7
a t t i c f l o o r c a n b e e x p e c t e d t o a b s o r b u p t o 1 0 p e r c e n t o f t h e
i n c i d e n t l i g h t a n d w i l l a l s o c a u s e l o s s b y r e f l e c t i o n . B e c a j ^ * f
t h e c o m p l e x g e o m e t r y o f t h e r e f e r e n c e g r e e n h o u s e , r e f l e c t i o n ^ c •-?
i s d i f f i c u l t t o e s t i m a t e .
D u r i n g s o m e p a r t s o f t h e y e a r ( ' i o v e m b e r t h r o u < n J a n u a r y )
l i g h t i s p r o b a b l y t h e prjc-tiai l i m i t i n g ' ' n c l o r t o u r e e n h c u s e
p r o d u c t i o n . D u r i n g S e p t e m b e r , O c t o b e r , F e b r u a r y ? n d ' \ a r c h ,
p r o d u c t i o n i s u s u a l l y l i m i t e d b y d i s e a s e , n u t r i t i j n , f t c . b u t litjh
w o u l d s t i l l b e l i m i t i n g i f t h e o t h e r f a c t o r s w e r e r e m o v e d . P u r in':
t h e r e m a i n d e r o f t h e y e a r a m p l e l i g h t i s a v a i l a b l e a n d p r o d u c t i o n ,
i n t h e d u s e n c e o f d i s e a s e a n d p o o r n u t r i t i o n , w o u l d b e l i m i t e d L y
t h e g e n e t i c p o t e n t i a l o f t h e p l a n t . I f t h i s i s t h e c o r r e c t
i n t e r p r e t a t i o n , t h e d e c r e a s e d l i g h t i n t e n s i t y w o u l d h a v e o n l y a
m a r g i n a l e f f e c t o n y i e l d s . N e v e r t h e l e s s , a l l p r a c t i c a l s t e p s t o
m a x i m i z e l i g h t , s u c h a s m i n i m i z i n g t h e s i z e o f o v e r h e a d s t r u c t u r a l
m e m b e r s , a n d i n c r e a s i n g t h e r e f l e c t i v i t y o f t h e g r e e n h o u s e f l o o r ,
m u s t b e t a k e n . S i n c e t h e f i n a l c r i t e r i o n i s y i e l d , r e s e a r c h i n d
g r e e n h o u s e i s r e q u i r e d t o d e t e r m i n e t h e e c o n o m i c p e n a l t y a s s o c i a t e
w i t h t h e a t t i c r e t u r n s y s t e m .
- 3 4 -
4 . 2 P R O D _ U r n O _ N _ S C H E D U L I N G
P r o d u c t i o n s c h e d u l e s in t h e C a n a d i a n g r e e n h o u s e i n d u s t r y
hsve o v o l v e d in r e s p o n s e t o f o u r f a c t o r s . T h e m i d w i n t e r
o c c u r r e n c e o f m a r g i n a l l i g h t l e v e l s a n d p e a k h e a t i n g l o a d s c a u s e
t h e f a l l c r o p to be t e r m i n a t e d in e a r l y D e c e m b e r a n d t h e s p r i n g
c r o p to b e p l a n t e d o u t in m i d - J a n u a r y o r l a t e r . In J u l y a n d A u g u s t ,
h i g h t e m p e r a t u r e s m a y c a u s e f r u i t m a l f o r m a t i o n s , p o o r p o l l i n a t i o n
a n d p o o r v i g o r T h e s e f a c t o r s a n d c o m p e t i t i o n f r o m f i e l d g r o w n
t o m a t o e s e n c o u r a g e t e r m i n a t i o n o f t h e s p r i n g c r o p a n d s u b s e q u e n t
p l a n t i n g o f t h e f a l l c r o p .
In t h e r e f e r e n c e g r e e n h o u s e m u c h o f t h e c o s t o f h e a t
a p p e a r s as a f i x e d c o s t ( S e c t i o n 6 ) . T h e r e w i l l , t h e r e f o r e , b e
l i t t l e m o t i v a t i o n to c l o s e d o w n t h e g r e e n h o u s e d u r i n g m i d - w i n t e r .
In s u m m e r , t h e p r o v i s i o n o f e v a p o r a t i v e c o o l i n g w i l l b e m u c h
c h e a p e r t h a n f o r a c o n v e n t i o n a l h o u s e s i n c e t h e r e f e r e n c e d e s i g n
is e q u i p p e d w i t h f a n s , l o u v e r s , e t c . t o h a n d l e l a r g e v o l u m e s o f
a i r . T h u s p r o d u c t i o n s c h e d u l e s in w a s t e h e a t g r e e n h o u s e s w i l l b e
d e t e r m i n e d by t h e a n n u a l c y c l e in l i g h t a v a i l a b i l i t y , m a r k e t f o r c e s
a n d a d e s i r e to e v e n - o u t d e m a n d s o n l a b o r a n d c r i t i c a l f a c i l i t i e s .
T h e p r o d u c t i o n c h a r a c t e r i s t i c s o f p o t e n t i a l c r o p s a r e
s h o w n in T a b l e 8 , a n d t h e a n n u a l c y c l e o f l i g h t a v a i l a b i l i t y is
g i v e n in F i g u r e 1 0 . A v a i l a b i l i t y o f l i g h t in W i n n i p e g is s l i g h t l y
h i g h e r in N o v e m b e r a n d D e c e m b e r a n d s l i g h t l y l o w e r i n J a n u a r y a n d
F e b r u a r y t h a n in s o u t h e r n O n t a r i o . It t h e r e f o r e a p p e a r s l i k e l y
t h a t p r o d u c t i o n s c h e d u l e s s i m i l a r t o s o u t h e r n O n t a r i o ( F i g . 1 1 )
c a n b e e m p l o y e d .
It a p p e a r s t h a t g r e e n h o u s e t o m a t o e s c o u l d b e m a r k e t e d
s u c c e s s f u l l y in c o m p e t i t i o n w i t h f i e l d g r o w n c r o p s in W e s t e r n ,
b u t n o t in C e n t r a l C a n a d a ( S e c t i o n 2 ) . In W e s t e r n C a n a d a ,
t h e r e f o r e , i t a p p e a r s t h a t i f it p r o v e s t o b e p o s s i b l e t o r a i s e
TABLE 8
Production Characteristics of Potential Greenhouse Crops
CropLight
Requi rementTemperatureRequi rement
GreenhouseConfi gurati on Market
Economi cReturn
Lenqthof cropcvcl e
Cucumber
Pepper
Tomato
Lettuce
Radi sh
Oni on(salad onion'(green onion
high
high
m e d - high
1 ow
1ow - med
1 ow
high
high
med
1 ow
1 o w
prob 1ow
raised beds good
total surface good
raised beds good
total surface unknown
tota1 s urface qood
total surface good
good
lower thancucumbers& tomatoes
good
unknown
unknown
unk nown
long*
long*
long*
30-90days
about30 days
about30 days
* fiese crops will continje to produce for as much as a year
• 36 -
1 r
500
B.
os
UJzX
z01t -IamUL
O
oI
500
4 0 0
3 0 0
2 0 0
100
OL
• _ WINNIPEG
0 - - SOUTHERN ONT (GUELPH)
j i I I
• • - WINNIPEG
O - SOUTHERN ONT (HARROW)
1 L I I I I I I I I _|_F M A M J J A S O N I
MONTHS
1! ' . Two i n d i " t > o . or" s o l a r e n e r g y a v a i l a b l e r o r n l a n t p.i'owtfin s r . i t h e r n O n t a r i o a n d W i n n i p e g . I n c i d e n t r a d i i t i o nw.i;; ";OiiS\ii't"! <;n ,i h o r i z o n t a l s u r f a c e ' ' .
ONTARIOCROP SYSTEM
MANITOBASYSTEM
OHIOINTERCROPSYSTEM
ON!ARIOFULL YEARSYSTEM
PROPOSEDSYSTEM y
ALTERNATIVE1 _^^-
ALTERNATIVE y
1
Ji
F
. "" SPRING CROP /(TOMATOES OR CUCUMBERS) /
^ ^ ^ ^ U T E SPRING CROP (TOMATOES) ^ ^
^ ^ LETTUCE ^ ^ /^ ^ -^ TOMATOES /
FULL YEAR CROP (TOMATOES)
SPRING CROP (TOMATOES OR CUCUMBERS) S*y
^-^^ SPRING CROP (TOMATOLS)
C;:JG CROP (TOM'T'^S, C U' L-Mf.£ Kb , F E F ^ E R S ) / ^ /
1 1 I 1 1 1
M A M J J A
FALL CROP (TOMATOES)
/FALL CROP (TOMATOES) /
/ FALL CROP (TOMATOES)
/ /
' FALL CROP (TOMATOES)
^^--^^-^TLTT^^^^^"^ RAD I
^ F A L L C R O P S ( L E T T U C E , R A D I S H E S )
I I 1 1
S 0 N D J
uctSHES
i
MONTHS
P"
- 3 8 -
•.jjdlity g r e e n h o u s e t o m a t o e s in D e c e m b e r , a p r o d u c t i o n s c h e d u l e
s u c h .is t h e o n e s h o w n in f i g u r e 11 c a n b e u s e d . If m i d - w i n t e r
p r o d u c t i o n is n o t p o s s i b l e , a s c h e d u l e s u c h a s a l t e r n a t i v e ! c o u l d
b e c o n s i d e r e d . In C e n t r a l C a n a d a , i t a p p e a r s t h a t g r e e n h o u s e
t or.?. f o e s c a n n o t be m a r k e t e d in a n y v o l u m e i, /> . g u s t o r S e p t e m b e r
a n d a s c h e d u l e s i m i l a r t o t h e c u r r e n t O n t a r i o s c h e d u l e w o u l d b e
u s e d .
In a m a r k e t s u c h a s W i n n i p e g , w h e r e t h e r e is a n u n f i l l e d
d e m a n d f o r g r e e n h o u s e t o m a t o e s , t h e t w o t o m a t o c r o p p e r y e a r
s c h e d u l e w o u l d p r o b a b l y b e m o s t p r o f i t a b l e . As t h e m a r k e t f o r
t o m a t o e s ( a n d c u c u m b e r s ) a p p r o a c h e s s a t u r a t i o n a n d p r i c e s d e c r e a s e ,
s c n e d u l e s s u c h as a l t e r n a t i v e s 1 and 2 w o u l d b e c o m e m o r e p r o f i t a b l e .
In s u m m a r y , i t a p p e a r s t h a t i n c r e a s e d a i r f l o w a n d t h e
a v a i l a b i l i t y o f i n e x p e n s i v e h e a t in t h e m i d d l e o f t h e w i n t e r a n d
e v a p o r a t i v e c o o l i n g in t h e s u m m e r s h o u l d i n c r e a s e y i e l d s . D e c r e a s e d
l i g h t in t h e g r o w i n g a r e a , d u e t o t h e l o c a t i o n o f t h e r e t u r n a i r
d u c t , w o u l d t e n d t o d e c r e a s e y i e l d s . U n d e r W e s t e r n C a n a d i a n
c l i m a t e a n d m a r k e t c o n d i t i o n s , t h e r e f e r e n c e s y s t e m s h o u l d
s i g n i f i c a n t l y o u t - y i e l d t h e c o n v e n t i o n a l h o u s e , w h i l e u n d e r s o u t h e r n
O n t a r i o c o n d i t i o n s t h e y m a y b e a b o u t e q u a l .
4 . 3 E X P E C T E D Y I E L D S O F T O M A T O E S
A v e r a g e m a r k e t a b l e y i e l d s o b t a i n e d b y 2 3 t o m a t o p r o d u c e r s
in E s s e x C o u n t y , O n t a r i o , in 1 9 6 5 a n d 1 9 6 6 w e r e 1 2 . 8 5 k q / m i n t h e2
s p r i n g a n d 4 . 4 4 k g / m f o r t h e f a l l c r o p f o r a t o t a l o f 1 7 . 2 9
k g / m . a ^ '. S p r i n g c r o p y i e l d s o f 1 8 . 7 k g / m in T h o m p s o n a n d
1 3 . 8 k q / m in W i n n i p e g h a v e b e e n r e c o ^ d e d ^ ' i n d i c a t i n g t h a t t h e
p o t e n t i a l y i e l d in M a n i t o b a is a t l e a s t e q u a l t o t h a t o f O n t a r i o .
A n o r t h e r n a r e a w i t h h i g h y i e l d s is t h e I s l e o f G u e r n s e y , w h e r e
s o m e g r o w e r s r e g u l a r l y p r o d u c e 2 0 . 2 - 2 2 . 4 k g / m 2 in a h a r v e s t p e r i o d
t h a t e x t e n d s f r o m A p r i l t o N o v e m b e r ^ '. T h e h i g h p o t e n t i a l
- 39 -
p r o d u c t i v i t y o f t h e t o m a t o i s i l l u s t r a t e d !,v a r, ••> • e r i i v n '2
N e w J e r s e y w h i c h p r o d u c e d 2 3 . 4 5 k g / m i n a t ; r e c P i O ' U ; p i ih ,
h a r v e s t p e r i o d ^ . I n t h i s s t u d y , r i n g a n d t r o u g h c..:! t:j->j •,••:•!
u s e d t o c o n t r o l s o i l b o r n e d i s e a s e s , a n d a i r m o v e m e n t t-d
v e n t i l a t i o n c o n t r o l l e d a i r b o r n e d i s e a s e s . C o l d t r e a t r . d r i t an<'
l i g h t r e f l e c t i v e g r o u n d c o v e r w e r e a l s o u s e d b u t C 0 ? e n i H ' i ; , ^
w a s n o t u s e d . G i v e n t h e g o o d d i s e a s e c o n t r o l a c h i e v e d in t n i .
• s t u d y , p l u s C 0 9 f e r t i l i z a t i o n ^ , l i g h t m o d u l a t e d iiMnp'ird t •. r •{21 \ t ? f\ \
c o n t r o l , g a m m a r a y s t i m u l a t i o n o f s e e d s • , a ^ d t'iv t 4 " -•' 2 9 ^
p r o d u c t i o n s c h e d u l i n g a l l o w e d b y g r o w i n g r o c t e c l i n i Q i ^o
a n n u a l y i e l d s u p t o 3 4 k g / m m a y b e a c h i e v a b l e . A n i n t ^ j s t ' ' •2
a n n u a l a v e r a q e o f 1 8 k g / m w o u l d b e r e a l i s t i c a n H , k ]'<-><h
s h o u l d s u r p a s s 2 2 k g / m o n a l a r g e s c a l e . I t m u s t '- :• -c= * 1 i.- •''•
h o w e v e r , t h a t a s d i s e a s e i s c o n t r o l l e d m o r e s u c c e s s r u l ' y .;n;i
a d v a n c e d h o r t i c u l t u r a l t e c h n i q u e s a r e a p p l i e d , lifj'tt w i l l
o f t e n b e c o m e t h e l i m i t i n g f a c t o r w h i c h w i l l D r e v e n t th.-_ .j t : • (.
d e s i g n f r o m p r o d u c i n g t h e s a m e y i e l d a s a c o n v e n t i o n a l d G •: i'.; n .
5. DESCRIPTION OF COMMERCIAL G P E E N u. 0 L ' L5YSTEMS _E_VALu_ATE_D ~
T o d e t e r m i n e t h e f e a s i b i l i t y o f h e a t i n g q r e e r ^ i j s o s •-•
n u c l e a r w a s t e h e a t , f o u r d i f f e r e n t h e a t s u n p 1 y s y s t e m s J n d t w •'•
g r e e n h o u s e c o n f i g u r a t i o n s w e r e e v a l u a t e d . Ti;e s y s t e m .i s-. u\w.<*.' •
w e r e :
1 . t h a t t h e g r e e n h o u s e f a c i l i t y c o u l d b e l o c a t e d o n tr,•• •e d g e o f , b u t n o t w i t h i n , t h e 9 1 4 m e x c l u s i o n z o n e ^c
a C A N D U p o w e r s t a t i o n ( F i g . 1 2 ) . T h i s i s a c o n s e r v a -t i v e a s s u m p t i o n s i n c e i t m a y b e p o s s i b l e i n s o w "c i r c u m s t a n c e s t o l o c a t e i n s i d e t h e e x c l u s i o n z o n t j .
2 . t h a t a g r e e n h o u s e f a c i l i t y o f 8 - 1 0 h e c t a r e s o f a r o w i ns u r f a c e r e p r e s e n t s a r e a s o n a b l e c o m p r o m i s e b e t w e e n t hl o w h e a t d i s t r i b u t i o n c o s t s p o s s i b l e w i t h a v e r y 1 d r ' ? 's y s t e m , a n d t h e p r o b l e m s o f f u n d i n g a n d m a r k e t i n g th. 1
p r o d u c e f r o m s u c h a s y s t e m .
- 4 0 -
LAKE OR R I V E R
2 _J
>- z:1 OL
D_ =>C- I—
i/i a:
INUCLEARSTATION
I
I II S T A T I O N F A C I L I T I E S |
Q PUMPHOUSE 914 m E X C L U S I O N L I M I T
"ann
i ii iii
• • • •• • • •• • • •
GREENHOUSEF A C I L I T Y
100 m
FIGU'KL 12. Layout of greenhouse facility.
- 41 -
'; . M i fit. t h e ? a r e e n h o u s e f a c i l i t y w o u l d s.p <.;il n i v i d t ^ ' - to p e r a t i n g u n i t s o f 0 . 4 h a g r o w i n g s u r f a c e e a c h ' op e r m i t f a m i l y - s i z e d o p e r a t i o n s ( A p p e n d i x B ) . T h r
a l s o i s a c o n s e r v a t i v e a s s u m p t i o n s i n c e t h e - N - n d L ' M ,i n t h e i n d u s t r y i s t o w a r d l a r g e r o p e r a t i n g u n - ; - s .
T u s i m p l i f y c o m p a r i s o n s , a l l f o u r h e a t i n g s y s t e m s w e r e s i ? e ;
p r o v i d e 3 5 M W ( t h e d e s i g n h e a t l o a d ) . T h i s c a p a c i t y i s <-..,{<-,, ,. •
t o m a i n t a i n a l l g r e e n h o u s e s a t 2 1 J C w i t h a n o u t s i d e t e r r H ? r . i :•.••••
o f - 4 0 ° C a n d a w i n d s p e e d o f 2 5 k m / h . A l t h o u g h 3 b "V; c r v . l d
o > t a i n e d f r o m t h e m o d e r a t o r c i r c u i t o f a s i n g l e r e a c t o r , , .;.•
s y s t e m w o u l d o n l y h a v e a n a v a i l a b i l i t y o f a b o u t 9 5 p e r - , e n i ''
o n c u r r e n t e x p e r i e n c e . T h e r e f o r e a b a c k - u o n e a t s & ; ; r - v. i
i n c l u d e d i n a l l w a s t e h e a t s y s t e m s . T h e b a c k - u p s v b t e - w o ~ ,
t o p r o v i d e 2 6 M W ( t h e s u r v i v a l h e a t l o a d ) w h i c h w o u l d • • a : n t r - " v
g r e e n h o u s e t e m p e r a t u r e s a t 7 ° C a n d p r e v e n t d a m a o e t o t • c r , ; >
w i t h a n o u t s i d e t e m p e r a t u r e o f - 4 0 ° C a n d a w i n d s o e e u :•:"..
A t e n v i r o n m e n t a l t e m p e r a t u r e s a b o v e - 2 0 c C , t h e b a r k - ; p ;. , .-
w i l l m a i n t a i n 2 1 ° C i n t h e g r e e n h o u s e .
A l l o f t h e w a s t e h e a t s y s t e m s d e l i v e r n ^ t -;> •••.-•
g r e e n h o u s e s v i a w a r m e d l i g h t w a t e r , r e c i r c u ~>. •;. t e d i n ..c'• i ^ ; . '.',• • •..
s c h e d u l e 1 0 , c a r b o n s t e e l p i p e . F l o w i n t h e sy •• t<z i s i o i n t ^ i ' i e
b y f o u r 7 5 k W p u m p s l o c a t e d i n a p u m p h o u s e ( F i g . 1 2 ) , • <> >-. ••< i o
h o u s e s t h e f o s s i 1 - f u e l e d b o i l e r s i n t h e s y s t e m s u s i n g a c- i r, r-. i . - .
m o d i f i e d r e a c t o r . A m o r e c o m p l e t e d e s c r i p t i o n o f t h e - H i r t r i L ; • i .••;•
s y s t e m i s g i v e n i n A p p e n d i x A . 4 .
5.1 HEAT SUPPLY SYSTEMS
5.1.1 Waste Heat Systems
Details of the design of these systems -;r«
Appendix A.4.
- 42 -
;•• . i . I . 1 T w o '•>-o u : to_r_s
In t h i s s y s t e m , h e a t e x c h a n g e r s a r e a d d e d t o t h e
;;v a e-\i t o r c i r c u i t s of t w o r e a c t o r s ( F i q . A . 7 ) e a c h o f w h i c h can
s u p p l y 'idlf ( 1 7 . 5 M W ) t h e d e s i g n l o a d u n d e > n rmal o p e r a t i n q
•;ondi t i o n s . The t o t a l s u p p l y of h e a t is f r o m the r e a c t o r s , and
M e load f a c t o r is 0 . 3 0 7 ( T a b l e 9 ) . W h e n o n e of the r e a c t o r s is
>-:.it .icn.'n, f l o w to the r e m a i n i n g h e a t e x c h a n q e r is i n c r e a s e d and
r.••>£' o u t l e t t e m p e r a t u r e a l l o w e d to d e c r e a s e f r o m 54 to 3 5 ° C .
- d e c t n e s e c o n d i t i o n s , t h e r e m a i n i n g e x c h a n q e r is c a p a b l e of
" e o t ; n ; ' t-i e s u r v i v a l h e a t l o a d (26 M W ) a n d m a i n t a i n i n q t h e
•iroeniiojses it o r a b o u t 7 " C. C u r r e n t e x p e r i e n c e i n d i c a t e s t h a t
tic; g r e e n h o u s e s w i l l o p e r a t e f o r an a v e r a q e of 5 d a y s p e r w i n t e r
jt t h i s r e d u c e d t e m o e r a t u r e ( T a b l e 1 0 ) . T h e p r o b a b i l i t y of
c o i n c i d e n t r e a c t o r s h u t d o w n s ( T a b l e 1 0 ) , a l t h o u q h c u r r e n t l y n o t
n i g h , is e x p e c t e d to d e c r e a s e as n u c l e a r o p e r a t i n q e x p e r i e n c e
is qair.ed. It is e s t i m a t e d that, o n c e e v e r y 14 y e a r s h e a t to the
( i r e e n n o u s e s w i l l be l o s t a t s o m e t i m e d u r i n g t h e w i n t e r s e a s o n
( T a b l e 1 0 ) . T h e m a x i m u m p r o d u c t i o n l e s t f r o m s u c h an e v e n t w o u l d
l.e 2-3 m o n t h s h a r v e s t w h i l e t h e a v e r a g e l o s s s h o u l d b e m u c h l e s s
s i n c e t h e c r o D S are n o r m a l l y r e p l a n t e d d u r i n g t h e D e c e m b e r -
J a n u a r y p e r i o d .
5 . 1 . 1 . 2 O n e R e a c t o r W i t h F o s s i l - F i r e d S t a n d b y
In t h i s s y s t o m t h e m o d e r a t o r c i r c u i t s of a s i n g l e
r e a c t o r a r e m o d i f i e d to p r o v i d e a c a p a c i t y o f 23 KW w h i c h is
s u f f i c i e n t to m e e t 9 5 p e r c e n t o f t h e a n n u a l h e a t l o a d . T h e
r e m a i n i n g 5 p e r c e n t of t h e a n n u a l h e a t l o a d , a n d t h e s u r v i v a l
h e a t l o a d w h e n t h e r e a c t o r is s h u t d o w n , is m e t by a 2 6 MW f o s s i l
f i r e d s y s t e m . The n u c l e a r p a r t o f t h e s y s t e m o p e r a t e s w i t h a
load f a c t o r of 0 . 4 4 3 w h i l e t h e f o s s i l - f i r e d s t a n d b y h a s a lo a d
factor of 0.021 (Table 9).
C
- 43 -
re
:E
i-
o• A IS:
c
o
o
CD
O
\ z = -
O)
1—
T3
c
4 -
o*->ca>uwo
Q_
a;
—
~-
TJ
,—
CC
^-
o
ot3
U -
-o03O
_J
cV-
••L
13
<Di—
cc
o
' - • > '
\
E :
oo
l_
<ca;
1—
/ u a A O D t yJ O ; e j s p o , .
TAULi' 10
s y s t e m s of tlie ' o u r H o a t i n n Sv<: U-is
Two' 1 o d i f i e rtReactor, ,
Hci t ' ti'i Sy> ton1
One " o d i f i c d H e <> c t o r
5 1 . 1 n ij I • v
f o s s i l
back-up system
M i n i m u m t e n p e r a t u r e ( C )in greenhouse under designconditions on Lack-upsys tern
Days per v/inter' a' onback-up system
Most probable cause oftemperatures below C C l t ) )
Probability per winter(i4ov . - Kar . )
Other . tor
Coi nci dentReactor Shutdown;
0.07 (a)
l f i r-fd B m
Loss of11ectric itv
"i 1 ! • r e d i!oi '< e r
Loss ofElectricity
ione
L o s s o f G a 1 .o r E l e c t r i c i t y
( a ) B a s e d o n 2 4 w i n t e r r e a c t o r m o n t h s o p e r a t i o n o f P i c k e r i n q U n i t s 1 - 4 .
(t>) D e f i n e d a s f a i l u r e o f h e a t i n g s y s t e m f o r l o n n e r t h a n 3 0 m i n u t e . .
- 4 5 -
5 . 1 . 1 . - 5 O n e k e a c t o r W i t h F o s s i'i-Ki r e d P e a k i n_o
E x c e p t f o r t n e l o w e r d e s i g n e d c a p a c i t y o f tn<> •'•ni-
h e a t e x c h a n g e r s , t h i s s y s t e m i s th<? s a m e a s t h e o n e descr-i:,-
a b o v e . T h e m o d e r a t o r c i r c u i t s o f a s i n g l e r e a c t o r ,>re ' ^ l i
t o p r o v i d e a c a p a c i t y o f 1 7 . 2 M W w h i c h is s u f f i c i e n t t o ';v:'
8 5 p e r c e n t o f t h e a n n u a l h e a t l o a d . Thr- r e m a i n i n n 1 b :;er (.<.*;
t h e a n n u a l h e a t l o a d a n d t h e s u r v i v a l h e a t lo.'d w h e n *•;!<• •<"•
i s s h u t d o w n i s m e t t;v a 2 6 f /W f o s s i l - f i r e d s y s t o m . T .••,<
m o d i f i c a t i o n s i n c r e a s e t h e l o a d f a c t o r o f t h e n u c l e a r : •-> i •. •
s y s t e m t o 0 . 5 3 2 a n d t h e f o s s i l p a r t t o 0 . G 6 2 ( 7 a ' H e
5 . 1 . 2 G a s H e a t i n g S y s t e m
A s a n e x a m p l e o f c u r r e n t n r e e n h o i . s e p r a c t i c e , •>
a i r n a t u r a l g a s s y s t e m w a s a l s o e v a l u a t e d . T h i s s v s t e > r '
t o m e e t t h e s a m e t o t a l h e a t l o a d a s t h e wft>r.K: b o a t .v ';;
b a s e d o n g a s - f i r e d f u r n a c e s l o c a t e d i n e a c h h o u s e . - ;-u ^
f u r n a c e u n i t s a r e s m a l l , t h e f a i l u r e o f i n d i v i d u a l u; t
t o l e r a t e d a n d b a c k - u p c a p a b i l i t y h a s n o t b e e n p r o v i d e d .
d e s c r i p t i o n o f t h i s s y s t e m i s g i v e n i n A p p e n d i x A . 5 .
5 . 2 G R E E N H O U S E S
D e t a i l e d d e s c r i p t i o n s o f f a c i l i t i e s b a s e d o n t w o --<.
h o u s e d e s i q n s , i n d i v i d u a l h o u s e s a n d b l o c k h o u s e s , d r e .•liven
A p p e n d i x A . 2 . B o t h d e s i q n s u t i l i z e d o u b l e p l j i t i t . c u v - t , t c
m i n i m i z e h e a t l o s s . F o r c e d a i r r e c i r c u 1 a ti o n , w i t h o n ,\ 11- i c
r e t u r n s y s t e m a n d f i n n e d - t u b e h e a t e x c h a n q e r s , i s c o ^ n u . n t n t > o 1.
d e s i g n s . T o f a c i l i t a t e c o m p a r i s o n a m o n g h e a t i n n s y s t e m : . , th>-
g r e e n h o u s e f a c i l i t y b a s e d o n e a c h d e s i g n w a s s i z e d t o ; t i l w <
i
- 46
^ ' ^ v t h e i n d i v i d u a l L o u s e s n a v e h i g h e r m a t l o o s e s ':e»-
s u r f a c e j r o a , t n e f a c i l i t y h a s e d o n t h i s , 1 o s i n n h a s H 15
i'-1 M i r f a c e c o m p a r e d t o 1 0 h a f o r t h e b l o c k h o u s e d e s i q n
co
In t h i s d e s i n n , 11 . i r e e n h o u s e s e a c h 1 2 . 2 m b y 3 0 . 5 m ,
o n n e c t e d b y a c o r r i d o r t o f o r m a 0 . 4 0 h a (1 a c r e ) o p e r a t i n g
n ' t . ' h e f a c i l i t y is c o m p o s e d o f 2 0 s u c h o p e r a t i n q u n i t s w i t h a
:. t a " o r o w i n q ire.i o f R h a . T h e l a y o u t o f t h e h c a t i n q a n d a i r
. i re 11 a t i or. s y s t e m in a n i n d i v i d u a l h o u s e i s s h o w n i n F i q u r e 0 .
T n e a d v a n t a g e s o f t i n s d e s i g n a r e t n a t p r o d u c t i o n s c h e d u l i n gf ; o x i :>-; 1 1 t y i s m a x i m i z e d a n d p o s s i b i l i t i e s f o r d i s e a s e t r a n s m i s -
•5 i •• >. a r e ' n i r s i r r i z e d .
-' • •'- • ? '-' 1 c f. H 0 u s e s
In t h i s d e s i q n , e a c h o p e r a t i n q u n i t is c o m p o s e d o f 6
o u s t s 6-5.5 m i o n g c o n n e c t e d by g u t t e r s t o f o r n a c o n t i n u o u s r o o f
V' r the 0.4 ha c r o w i n g a r e a . T h i s d e s i q n h a s a l o w e r heat, l o s s
use ^iaare m e t e r of grov/ing a r e a and p r o v i d e s m o r e g r o w i n g a r e a
per a c r e of la.'... u c c u p i e d , t h e r e b y m i n i m i z i n g w a r m w a t e r d i s t r i b u -
t i o n c o s t s . T h e f a c i l i t y is c o m p o s e d o f 2 5 o p e r a t i n q u n i t s w i t h
•:• total g r o w i n g a r e a of 10 h a .
4 7 -
AL S
A d e t a i l e d b r e a k d o w n o f i n d i v i d u a l s y s t e m coirwi'ip
c o s t s is p r e s e n t e d in A p p e n d i x A . T h e m a j o r 3 S s . i T i ' . i n r r <•.:'
a r r i v i n g a t t h e c o s t s w e r e :
1. t h a t a u t i l i t y w o u l d c o n s t r u c t , m a i n t a i n anr) : • • r •t h e m o d e r a t o r h e a t e x c h a n g e s y s t e m a n d t h e nr i;•'o >• /w a r m w a t e r d i s t r i b u t i o n n e t w o r l ' t o , a n d •.•; i t ' " . .ic o n u a e r c i a l g r e e r . h o u s e f a c i l i t y ( A p n t ' ; d i ; •:] ,
? . t h a t t h e u t i l i t y w o u l d r e c o v e r i t s cotr> tf'itt ' -ri .m a i n t e n a n c e a n d o p e r a t i n g c o s t s t h r o j c h : r1-,:- : > f.t h e q r e e r i h o u s e o p e r a t o r s b u t viould n o t ;r-•'• > :a d d i t i o n a l c h » r a e f o r t h e h e a t , a n d
3. t h a t t h e c o s t e s t i m a t e s f o r c o n s t r u c t i o n o f J '! 4'.:o p e r a t i n g u n i t c a n b e l i n e a r l y e x t r a n o 1 > t ao ' '.•:.•c o s t o f c o n s t r u c t e d 2 0 - 2 5 s u c h u n i t s .
T o s i m p l i f y c o m p a r i s o n s , a l l f o s s i l f u p ] -trices ':-.
b e e n c a l c u l a t e d in m $ / k W h a l t h o u g h in s o m e c a s e c t h e n ; n v a
o r i c e f o r n a t u r a l g a s in $ / h s c f f\d^ b e e n o i v e n f c i i 1 u s i•-,•
p u r p o s e s .
In g e n e r a l , t h e g r e e n h o u s e i n d u s t r y r M > :Si. : ••''..:<<
q o s o r f u e l o i l d e p e n d i n g o n a v a i l a b i l i t y a n d p r i c e . ',<.'••:
o c a k i n g s y s t e m s , s u c h a s h y p o t h e s i s e d h e r e , m a y b e rcj-;.,i rvrj
u s e f u e l o i l f o r r e a s o n s o f a v a i l a b i l i t y ever- t h o u g h
c u r r e n t l y m o r e e x p e n s i v e o n a h e a t e q u i v a l e n t , b a s i s .
T o f u r t h e r s i m p l i f y c o m p a r i s o n s , a l l c o s t s w ? r e
c a l c u l a t e d in 1 9 7 4 d o l l a r s a n d n o a l l o w a n c e f o r e s c a 1 A t * >••') h<
b e e n m a d e .
1
- 43 -
6.1 COSTS OF THE HtAT RECOVERY SYSTEMS
The capital costs of the three waste heat recovery
systems are shown in Table 11. These include the cost of the
punphouse and main supply system piping U D to the boundary between
the nuclear station exclusion area and the greenhouse complex.
The two-unit station has the highest capital cost while the sinqle-
•.in it station with fossil-fired peak hoating has the lowest.
To calculate annual operating costs for the three
systems, two prices for fossil fuel were used. The lower price,
4.44 m$/kwh ($1.30 M s c f ) , represents approximately what the
growers in Essex County were paying for natural gas in March
1 9 ? 5 ( 3 ° ) . Tne higher price, 6.83 m$/kWh ($2.00 M s c f ) , may be
e x p e c U ' before 1980^ 3 1 ^ .
Delivered heat costs (Table 1 2 ) , based on an annual
heat load of 94 x 1 0 6 kWh, ranged from 3.0 to 4.1 m$/kWh. The
two-unit station had the lowest delivered heat cost followed by
tne one-unit station with standby. The one-unit station with
peaking was the most expensive. This relationship is true at
ill fossil fuel prices above about 2.0 m$/kWh (Fig. 1 3 ) .
6.2 COSTS OF THE GREENHOUSE HEATING SYSTEMS
The capital costs of the two types of greenhouses
heater* by warm water, including the cost of the distribution
system within the greenhouse complex are shown in Table 13. The
capital cost of the block house heated by natural gas is also
shown, but the cost of Individual houses heated by natural gas
was not calculated. It would be higher than costs for the block
house since the higher heat loss would require more heatino
equipment. On a square nieter basis, the capital outlay for
TABLE
Design Parameters and C a p i t a l C j s t Comparison or" theModera to r Waste Heat Recovery Systems
MODERATOR WASTE HEAT DELIVERY SYSTEMS
Design Specifications
rioderator Heat Recovery (t'W)
Standby Heating System (?'W)
O n e - U n i t S t a t i o n
Standby Heating Peakinq Heating
23
26
17.2
26
T v o i'ni t S t a t ion
35
CaDital Cost (i)
In-Reactor fioderator HeatExcnanger System
Main Supply System Pipirwiand Pumphouse
Cil M > e d Standby HeatintjSystern
f, 10,000
'.'. 4 0.000
TO'-H
4
i -
1 . E
75,
00 ,
30 ,
<•*( -
<• -' .
.100
00 0
} ,200,100
1 , 7 3 0 ,
TABLE 12
Y e a r l y O p e r a t i n g C o s t C o m p a r i s o n : M o d e r a t o r W a s t e H e a t D e l i v e r y S y s t e m s
Cap i ta l Charge Recovery
(30 year Cap i ta l Recoveryat 10" I n t e r e s t )
Heat De l i ve ry System
Maintenance
U t i l i t y Costs
E l e c t r i c i t y (15 m$/kWh)
Heavy Water Pumping*a '
L i g h t Water Pumping
Foss i l Fuels (75% B o i l e r E f f i c i e n c y )
(a) 4.44 m$/kWh
(b) 6.83 n$/kWh
Total Operating Cost ($/a)
Delivered Heat Cost(b' (m$/kWh)
One-Unit Stati_on
Standby Heati ng Pea kj_n_g_ Jl&a.t_i.f'3
Two Unit Stati or
181,000
60,300
20,000
20,250
159,000
54,550
20,000
20,250
27,840 83,470
42,820
309,390 337,270
324,370
3.29 3.59
3.45
128,400
382,200
4.06
188,500
54,400
20,000
20,250
283.150
3.01
(a) Based on incomplete data
(b> Based on yearly system heat load of 94 x 10 kWh
- 51 -
00oo
•a
500-
-50
400-
-4.0
300-
200-
100-
E
• 3 0
-2.0
-10
ASSUMPTIONS
75% BOILER EFFICIENCY
94 x 10b kW-h YEARLY HEAT LOAD
IO0 200h
1.0 2.0 30 4.0 5 0 6 0 7.0
COST OF FOSSIL FUEL
SINGLE UNITSTATION
TWO-UNITSTATION
($ /10 6 BTU)
(m$/kW-h)
FIGURE 13. Operating cost of moderator w-ir;t'systems versus cost of los.Al '.<:•
- 52 -
t!e noatirui and v e n t i l a t i o n system in the qas heated block house
is a p p r o x i m a t e l y naif that required for the warm w a t e r heated
•jluck h o u s e . Individual houses heated by warm w a t e r are tiie most
costly o p t i o n . A s i m i l a r r e l a t i o n s h i p is seen in o p e r a t i n g c o s t s ,
excluding the cost of heat (Table 1 4 ) , with the natural pas
systen costing a p p r o x i m a t e l y half as m u c h as the c o m p a r a b l e warm
water s y s t e m .
6•3 TOTAL ANNUAL C O S T S
Total annuc,1 costs for the c o m b i n a t i o n s of systems are
shown in Table 15 for two fuel c o s t s , and as a f u n c t i o n of fossil
fue 1 costs in Figure 1 4 . In the s y s t e m s involvinq o n e modified
r e a c t o r , the f o s s i 1 - f u e l e d standby s y s t e m is less e x p e n s i v e than
tne peakinci system at all fossil fuel costs above a p p r o x i m a t e l y
2 m $ / k W h . Since prices below this level are not e x p e c t e d in the
f u t u r e , and since the p e a k i n g system o f f e r s no a d v a n t a g e in terms
of r e l i a b i l i t y , it will not be c o n s i d e r e d f u r t h e r . G i v e n the
choice between the t w o - u n i t station and the single u n i t with
f o s s i l - f i r e d s t a n d b y , it is apparent that the t w o - u n i t station
is less e x p e n s i v e at all probable fossil fuel c o s t s . The
d i f f e r e n c e is only 3-5 p e r c e n t , h o w e v e r , so if only a single
nuclear unit is a v a i l a b l e , the s t a n d b y system is not ruled o u t ,
p a r t i c u l a r l y if greater reliability of such a system is
cons i dered .
The warm w a t e r system with two m o d i f i e d r e a c t o r s is not
c o m p e t i t i v e with a natural gas system at a fuel p r i c e of 4.4 m $ / k W h
($1.30 M s c f ) . It breaks even at a b o u t 4.58 m$/kWh and is
a p p r o x i m a t e l y 20 p e r c e n t less e x p e n s i v e at a fuel p r i c e of6.83 m $ / k W h ( $ 2 . 0 0 ) .
- 53 -
T A B L E 13
D e s i g n P a r a m e t e r s and Captial Cost ofthe G r e e n h o u s e H e a t i n g S y s t e m s
Warm Water System
Individual BlockHouse House
'.i6 t<i ft!
Bloc*.
?JL^ ]JLn_ . l y f i cati ons
Growing Surface
Hectares
Acres
Design Heat Load (!
8
20
35
10
25
35 31;
Capital Cost ($)
Distribution System 923,COO 820,000
Heating and VentilationSystem 2,060,000 2,500,000
TOTAL S 2,983,000
?5.0')0-
| , - , b ; > . ;•;•;
(1) See Reference 22
- 54 -
TABLE 14
Ope r a t i n g Cost C o m p a r i s o n of G r e e n h o u s e Heating and V e n t i l a t i o nS y s t e m s E x c l u s i v e of the Cost of D e l i v e r e d Heat and Fossil Fuel
i ! , ji'OW wlrj Si r f ;1C e
Warm Water System
I n d i v i d u a lHouse
BlockHouse
10
Natura l GasH £_at i ng Sys tern
BlockHouse
10
A t i Mj^ - O 1 ! t : S : 'J| )
C i f - i t j i ; . h a r q e R e c o v e r y
,'M <; t r i t .i t i in Sy1^ ten'30 yertrs at 10 interest rate)
Heating and Ve n t i l a t i o n System( 1 0 y e a r s a t 1 0 i n t e r e s t r a t e )
";i i o tend m e
• lCi tricjl Pumpinq Costs
Elei. trici ty (15 m$/kWh )
Vent i1 a t i o n
98
337
96
,000
,000
,560
88
406
HO
,000
,000
,500
4
249
77
,000
,000
.000
43
15
590
7
,500
,000
,000
.38
49
18
671
6
,i?0U
.150
,850
.72
24,600
18,150
372,750
3.73
1 J y t? a r p e r i o d
TABLE 15
Total Annual Heating and Ventilation Costs for the Various Systems at Two Fuel CostsBased on a Yearly System Heat Load of 94 x 10^ kWh and a Boiler Efficiency of 75,'
Fossil Fuei at 4.44
TwoModif iedReactors
! One Modified Reactor
|Fossil Fueled I Fossil Fueledj Standby
Two
1ndi vidua I ;House
8 ha
Operating $
Heat $
TotalAnnual S
S/m2
nct House!
1 C >•• a
O p e r a t i n g S
Heat 5Tc td 1."• r n „ a I S
590 ,060
283 ,150(; 873 ,210
I
i 10.91 I' i
H J_l 6 / : , R 5 0 !
j 2 8 3 , 1 5 0 •
• ? t 5 , 0 J 0 ;
' 9 . bb
1 Reactors
590,060
309,390
899,450
11 .24
6 7 1 , 8 5 0
3 0 9 , 3 9 0
981 , 2 4 0
9 . 8 1
F o s s i l Fuel a t 6 .83 nS/kWh
One Modified Reactor
M o d i f i e d I F o s s i l F j e l e d j F o s s i ' • Fue led
1
Standby
1 1 . 5 9
i, 7 I , 8 5 .1
3 3 7 . ^ 7 0
1.009,12
10.09
590,060
283,150
873,210
10.91
372.750 ! 671.R501 I
' 5 5 6 , 4 6 5 | 2 8 3 . 1 5 0
2 9 , 2 1 5
9 . 29
9 5 5 . 0 0 0 j
9.5 5
590,060
324,370
914,430
11 .43
671 ,850
3 2 4 , 3 7 0
9 9 6 , 2 2 3
? . 96
PeaHnq
590,060
382.200
972,260
12.15
671 ,850
3E2.200
1 ,054,050
10.54
Natur.i lGas
372,7501
855,799 |
1,228,599
12.2ft
- 56 -
inoo
2LUQuO
UJt—CO
to
120
100
8.0
6.0
4.0
2.0
0
<••
- >
V
/
-
10 2.0 30. i l l
^ / 2 i H 2 S 2 - ^ J J [ O B v SINGLE-UNIT
— • y TWO-UN I T
/ TWO-UNIT STATION
WITH POTENTIAL IMPROVEMENTS
ASSUMPTIONS
10 HA OF GREENHOUSE AREA75* FURNACE EFFICIENCY94 x 106 kW-h YEARLY HEAT LOAD
4 . 0 5 0 6.0 7 0 (m$/kW-h)
1.00
COST OF FOSSIL FUEL
2.00 ($/106 BTU)
1GUKL l.U. C . mparison of total operating costs for greenhouseheating and ventilation systems versus cost otfossil fuel.
57 -
6 .4 A R E A S O f P O T E N T I A L S A V I N G
S e v e r a l a r e a s o f p o t e n t i a l s a v i n g s in t h - v,an: w a t . •s y s t e m c a n b e i d e n t i f i e d :
1 . P l a t e - t y p e h e a t e x c h a n g e r s f o r u s e in n u c l e a r oyster•••are b e i n g i n v e s t i g a t e d b y A E C L a n d h a v e t h e p o t e n t i a lf o r r e d u c i n g t h e c o s t o f t h e i n - r e a c t o r m o d e r a t o r I;.:e x c h a n g e r s y s t e m ( T a b l e i l ) by 7 5 p e r c e n t ( k . H . Re t ^ i .p e r s o n a l c o m m u n i c a t i o n ) . T h i s r e d u c t i o n w n j d d t c r e at o t a l a n n u a l c o s t s b y a p p r o x i m a t e l y 1 3 n e r c c n t ( T j b u -
c . It may a l s o be p o s s i b l e to locate the qreenm.ujxe u ; '.<•<•e x c l u s i o n a r e a . T h e e f f e c t o n t o t a l c o s t <,i.,--f;ri v-ym o v i n g t h e g r e e n h o u s e c o m p l e x t o w i t h i n ',61; r of t-n<"-r e a c t o r s i s s h o w n in T a b l e 1 6 .
3 . It h a s b e e n e s t i m a t e d t h a t c o s t s o f t h e varn; w a t e rd i s t r i b u t i o n s y s t e m w i t h i n t h e g r e e n h o u s e c o m p l e xc o u l d b e d e c r e a s e d b y o n e - t h i r d if p l a s c i c r a t h e r t-idfs t e e l p i p e were u s e d . T h e e f f e c t o f s u c h a c o s t r p d u i :••••:-is s h o w n i n T a b l e 1 6 .
T h r e e p o i n t s s h o u l d b e n o t e d r e g a r d i n g t h e r e s u l t s
t a b u l a t e d in T a b l e 1 6 .
1 . A n y o n e o f t h e s u g g e s t e d c h a n g e s w o u l d ivjlc '.!:•:. t w o -r e a c t o r w a r m w a t e r s y s t e m c o m p e t i t i v e i n p r i o . w i t ht h e g a s h e a t e d g r e e n h o u s e s a t t o d a y ' s f u e l c u 3 i > .
2 . If a l l t h r e e o f t h e c o s t s a v i n g s c o u l d b e i m p l e m e n t e d ,t h e h e a t i n g a n d v e n t i l a t i o n c o s t s w o u l d b e 16 p e r c e n tb e l o w c u r r e n t c o s t s f o r g a s h e a t e d s y s t e m s .
3 . A s n o t e d i n T a b l e s 1 5 a n d 1 6 , a p p r o x i m a t e l y t w o - t h i r do f t h e t o t a l a n n u a l o p e r a t i n g c o s t s a r e w i t h i n t h eg r e e n h o u s e c o m p l e x . If p l a t e - t y p e h e a t e x c h a n q c r s c a n .b e u s e d , t h e i n - r e a c t o r m o d i f i c a t i o n s " a n d m a i nd i s t r i b u t i o n s y s t e m m a k e u p o n l y 24 p e r c e n t o f t h ea n n u a l c o s t s , w h i c h i n d i c a t e s t h a t t h e l a r g e s t n o t e n t i a lf o r s a v i n g s is in t h e g r e e n h o u s e c o m p l e x .
It s h o u l d b e n o t e d t h a t a d e t a i l e d e c o n o m i c o p t i m i z a t i o n
o f t h e p r o p o s e d s y s t e m t o o b t a i n m a x i m u m d e l i v e r e d e n e r g y c o s t s
h a s n o t bec*n m a d e . S u c h a n o p t i m i z a t i o n is p o s s i b l e a n d s h o u l d b e
d o n e s i n c e t h e v a r i a t i o n in s y s t e m p a r a m e t e r s c a n b e d e f i n e d w i t h
s u f f i c i e n t c o n f i d e n c e t o a l l o w s u c h a s t u d y . H o w e v e r , it s h o u l d
TABLE 16
The Effect of Various M o d i f i c a t i o n s on the Total Annual Cost of Hea t i n g 10 ha of BlockG r e e n h o u s e s with Warmed W a t e r from the M o d e r a t o r C i r c u i t ? of Two Rea c t o r s
Block House
10 ha
Operating $
Heat 3
Total
$/m2
AsDescri bed
671 ,850
283,150
955,000
9.55
Plate TypeHeat
Exchanges
671 ,850
160,930
832,780
8.33
LocateInside
Exd us i onArea
671 ,850
253,090
924,940
9.25
Bo
471,
130,
802,
9.
th
850
690
540
03
PlasticPi pe In
GreenhouseArea
642,759
283,150
925,908
9.26
Al 1
642,758
130,690
773.448
7.73
t
enCO
- 59 -
not be expected that such a study would result in a draiatir
r e d u c t i o n in d e l i v e r e d energy c o s t . P r e l i m i n a r y studies on tne
e f f e c t of p a r a m e t e r v a r i a t i o n s on system cost indicate t h a t ,
a l t h o u g h the a s s u m e d system m a y not be o p t i m a l , it appears to
be a close a p p r o x i m a t i o n to such a system.
7. G E N E R A L D I S C U S S I O N
Given our a s s u m p t i o n s , this study indicators t h i t , a
a natural gas p r i c e of about 4.6 m $ / k W h ($1.35 fiscf), m o d e r a t o r
h e a t will be c o m p e t i t i v e for g r e e n h o u s e h e a t i n g . Since n-is
p r i c e s above that level are f o r e c a s t for the n e a r f u t u r e , it
a p p e a r s that this problem w a r r a n t s further c o n s i d e r a t i o n , since
a large m a r k e t e x i s t s in Canada for g r e e n h o u s e p r o d u c e . Howeve- ,
an i n c r e a s e in the cost of fossil f u e l s , or use of waste h e a t ,
m u s t r e s u l t in an increase in r e t u r n s for p r o d u c e if the n r e e n -
h o u s e industry is to be p r o f i t a b l e . At a h e a t i n g and v e n t i l a t i o n2
c o s t of >9.55/m .a and the 1973 a v e r a g e p r o d u c t i o n cost in Fssex
C o u n t y ^ 3 2 ' ( e x c l u s i v e of heat and v e n t i l a t i o n ) of $10.92 m ^ . a ,2
and a s s u m i n g an a v e r a g e yield of 18 kg/m . a , the cost of
p r o d u c t i o n would be $ 1 . 1 4 / k g . A l l o w i n g the g r e e n h o u s e o p e r a t o r
a r e t u r n of 15 p e r c e n t on his i n v e s t m e n t would bring the price to
$ 1 . 2 4 / k g compared to the c u r r e n t W i n n i p e g price of $1.10/kg. If2
the heating costs could be d e c r e a s e d to $7.7 3/rn .a as was d i s c u s s e din S e c t i o n 6, the cost of p r o d u c t i o n would be $1.04/kq and the
p r i c e required to y i e l d a 15 p e r c e n t return w o u l d be $ 1 . 1 5 / k g .
S i n c e the size of the m a r k e t is highly d e p e n d e n t uDon p r i c e ,
e f f o r t s must be m a d e to d e c r e a s e heating cost or increase
p r o d u c t i o n per m .
- 60 -
The area, of t h e study w h e r e t h e least c o n c r e t e2
c a l c u l a t i o n s can be m a d e is y i e l d s / m . a . The p r o d u c t i o n p r a c t i c e s
that m a x i m i z e e c o n o m i c r e t u r n in f o s s i l - f u e l h e a t e d g r e e n h o u s e s
have b e e n o p t i m i z e d by a c o m b i n a t i o n of r e s e a r c h a n d e x p e r i e n c e .
G r e e n h o u s e s h e a t e d by w a s t e heat w i l l r e q u i r e n e w p r a c t i c e s , w h i c h
will a l m o s t c e r t a i n l y i n c r e a s e y i e l d s b e c a u s e they w i l l i n v o l v e
v e a r - r o u n d p r o d u c t i o n , but there a r e no d a t a to e s t i m a t e w h a t2
tr.ese y i e l d s m i o h t b e . If t o m a t o y i e l d s of 22 k g / m .a can be
r o u t i n e l y a c h i e v e d , as t h e y are in G u e r n s e y , e v e n h e a t i n g c o s t s
of 5 9 . 5 5 / m .a w o u l d a l l o w a r e t u r n of 15 p e r c e n t to the o p e r a t o r
at c u r r e n t W i n n i p e g p r i c e s for g r e e n h o u s e t o m a t o e s . S i n c e the
G u e r n s e y c r o p s e a s o n is c o n s i d e r a b l y l e s s than a y e a r , it m a y be
p o s s i b l e to equal or s u r p a s s t h e i r y i e l d s . A p r o g r a m m e of
p r o d u c t i o n r e s e e r c h o r i e n t e d t o w a r d g r e e n h o u s e s h e a t e d w i t h w a s t e
heat is r e q u i r e d to p r o v i d e data w i t h w h i c h to a s s e s s t h e
p r o f i t a b i l i t y of the i n d u s t r y at a n y g i v e n h e a t i n g c o s t .
In a d d i t i o n to a p r o g r a m m e of p r o d u c t i o n r e s e a r c h and
the o p t i m i z a t i o n s t u d y s u g g e s t e d e a r l i e r , v a r i o u s o t h e r d e v e l o p -
m e n t s t e p s s h o u l d be t a k e n . A E C L is i n t e r e s t e d in p l a t e - t y p e
heat e x c h a n g e r s as a m e a n s of d e c r e a s i n g p o w e r s t a t i o n c o s t s
( A p p e n d i x C ) and so t h e i r p o t e n t i a l w i l l br i n " ? s t i g a t e d r e g a r d -
less of the w a s t e heat i m p l i c a t i o n s . T h e t ^ e s t i o n of w h e t h e r the
g r e e n h o u s e f a c i l i t y s h o u l d be l o c a t e d w i t h i n the e x c l u s i o n a r e a ,
as a m e a n s of d e c r e a s i n g c o s t s , is d e p e n d e n t u p o n t h e s p a c e
a v a i l a b l e , as well as m a n y o t h e r c o n s i d e r a t i o n s . T h i s can best
be d e t e r m i n e d at a t i m e w h e n a c o m m e r c i a l o p e r a t i o n is being
c o n s i d e r e d for a p a r t i c u l a r s i t e . G r e e n h o u s e d e s i g n , h e a t i n g and
d i s t r i b u t i o n s y s t e m c o s t s can be i n v e s t i g a t e d o n l y by c o n s t r u c t i n g
and o p e r a t i n g a test g r e e n h o u s e . S u c h a g r e e n h o u s e s h o u l d a l s o
be o p e r a t e d to p r o v i d e p r o d u c t i o n d a t a .
- 6 1 -
T h e c o s t c a l c u l a t e d f o r u t i l i z a t i o n o f gorier,) t o r -i • •> ' •
t h i s s t u d y is m u c h h i g h e r t h a n t h o s e f o u n d in a r e c e n t s t u d y ,11.
t h e U n i v e r s i t y o f G u e l p h ^ '. M u c h o f t h e d i f f e r e n c e a r i s e "
b e c a u s e t h e G u e l p h s t u d y d i d n o t i n c l u d e t h e c o s t s o f m o d i f i e d 1
to t h e m o d e r a t o r c i r c u i t .
A l t h o u g h s o m e o f t h e q u e s t i o n s r a i s e d b y t h i s s t u d y c m
b e a n s w e r e d b y f u r t h e r a n a l y s i s , t h e c o n c e p t s a n d e s t i m a t e s • ; •
b e t e s t e d in t h e f i e l d . C o n s i d e r i n g t h a t t h e u n o p t i m i z e d L I T .
h e a t i n g s y s t e m f o r q r e e n h o u s e s i s c o m p e t i t i v e w i t h t h e est.ib ',•:,.<
t e c h n o l o g y o f t h e f o s s i l - f u e l h e a t i n g s y s t e m , it w o u l d a p p e a r *- ••• ."
w h i l e t o d o s o .
T h e u t i l i z a t i o n o f w a s t e h e a t f o r g r e e n h o u s e a q r i C J 1 *•;
d o e s n o t h o l d o u t t h e p r o m i s e o f " f r e e " h e a t . H o w e v e r , it d o t s
a p p e a r to b e a p r e m i s i n g c o n c e p t in t i m e s o f r i s i n g c o s t s for n
a n d e n e r g y .
8. LITERATURE CITED
1. Mooradian, A.J. and O.J.C. Runnalls. 1974. CANDU-EconomicAlternative to the Fast Breeders. Atomic Energy ofCanada Limited report AECL-4916.
Statistics Canada. 1975. Greenhouse Industry 1972-T973.Catalogue 22-202 Annual.
"?. Department of Agriculture. 1973. Annual Unload Report,Fresh Fruits and Vegetables on 12 Canadian Markets,1972. Information Canada, Ottawa Cat. No. A71-7/1972.
4. Statistics Canada. 1973. Imports, merchandise trade1970-1972. Catalogue 65-203 Annual.
5. Gill ham, R.W. 1974. The Feasibility of Using Waste Heatin the Ontario Agricultural Industry: Technical andEconomic Considerations, University of Guelph.
6. Tariff Board. 1969. Greenhouse vegetables. ReferenceMo. 14G, The Queen's Printer, Ottawa.
7. Blum, H. 1969. Marketing of Ontario's Greenhouse Productsin Competition with Imports from Mexico. FarmEconomics, Co-operatives and Statistics Branch, OntarioDepartment of Ajriculture and Food. Toronto, Ontario.
8. Fisher, G.A. and P. Hedlin. 1971. Greenhouse VegetableProduction in rssex County. Farm Economics,Co-operatives and Statistics Branch, Ontario Departmentof Agriculture and Food, Toronto, Ontario.
9. Dal ryir.ple, D.G. 1973. Controlled Environment Agriculture;a Global Review of Greenhouse Food Production. U.S.Department of Agriculture Report No. 89.
10. Yee, W.C. 1972. Agricultural and Aquacultural Uses ofWaste Heat. Oak Ridge National Laboratories reportO R I N L - 4 7 9 7 .
11. Wittwer, S.H. and S. Honma. 1969. Greenhouse Tomatoes.Guidelines for Successful Production. Michigan StateUniversity P r e s s , East Lansing.
I?. Statistic-, Canada. 1974. Greenhouse Industry 1971-1972.Catalogue 22-202 Annual.
13. Personal communication from Dr. Gordon Ward, AgricultureCanada, Experiment Station, Harrow, Ontario.
- 63 -
1 4 . P e r s o nal c o m m u n i c a t i o n f r o m J. P i a n t j e , M a n i t o b a Veqeta' !P r o d u c e r s M a r k e t i n g B o a r d , W i n n i p e g , M a n i t o b a .
1 5 . L a r z e l e r e , H . E . and R.R. D e d o l p h . 1 9 6 2 . C o n s u m e r sA c c e p t a n c e of G r e e n h o u s e Crown and S o u t h e r n F i e l d - G r o w nT o m a t o e s . M i c h . A g r . E x p . S t a . Q u a r t e r l y B u l l e t i n4 4 : 5 5 4 - 5 5 8 .
1 6 . S t a t i s t i c s C a n a d a . 1 9 7 4 . P r i c e s and P r i c e I n d e x e s .C a t a l o g u e 6 2 - 0 0 2 M o n t h l y .
17. G u t h r i e , J . E . D.R. P r o w s e and D.P. S c o t t . 1 9 7 6 . AnA s s e s s m e n t of N u c l e a r P o w e r Plant. W a s t e HeatU t i l i z a t i o n for F r e s h w a t e r Fish F a r m i n g . Atomic.E n e r g y of Canada L i m i t e d report A E C L - 4 9 2 4 .
1 8 . F u r l o n q , W . K . , L.V. W i l s o n , M . I . Lundin and i^.M. Yr-ro-^.1 9 7 3 . U s es of W a s t e Heat C o v e r i n g O R N L " c 11 v i r. i e sT h r o u g h D e c e m b e r 3 1 , 1 9 7 2 . :«.- the J o i n t A EC (GkNL ; -TVA P r o g r a m ; A c t i v i t i e s R e p o r t , O R N L - T M - 4 1 9r., J ^ n e .
1 9 . T r i m m e r , R.M. 1 9 7 4 . Lake W a b a m u n Thermal W a t e r Proj<3 •" t .Resume" and P r o g r e s s R e p o r t , Plant I n d u s t r y Divisio'i,A l b e r t a D e p a r t m e n t of A g r i c u l t u r e , S e p t e m b e r 9.
2 0 . L y o n , R . B . and R.O. S o c h a s k i . 1 9 7 5 . N u c l e a r Power forD i s t r i c t H e a t i n g . A t o m i c Energy of C a n a d a Liinitocr e p o r t A E C L - 5 1 1 7 .
2 1 . K o n d r a t y e v , K . Y a . 1 9 6 9 . R a d i a t i o n i n t h e 'U•<•.:••,,',,>;;>•,•'.>.A c a d e m i c P r e s s , New Y o r k .
2 2 . B e a t o n , N . J . , J.D. C a m p b e l l and J.S. T o w n s e n d . \'in.E c o n o m i c and T e c h n i c a l A s p e c t s of G r e e n h o u s e Tom,-**:P r o d u c t i o n in M a n i t o b a . D e p a r t m e n t of Plant Scienc;.-.A g r i c u l t u r a l E c o n o m i c s and A g r i c u l t u r a l trig i neer i m i ,U n i v e r s i t y of M a n i t o b a .
2 3 . E n v i r o n m e n t C a n a d a . 1 9 7 4 . M o n t h l y R e c o r d , Meteorol oq i C-J <O b s e r v a t i o n s in C a n a d a .
2 4 . C a m p b e l l , J . D . 1 9 7 4 . G r e e n h o u s e P r o d u c t i o n of Tomato'•-and C u c u m b e r s . T w e n t i e t h Annual P r o g r e s s R e p o r t ,A g r i c u l t u r a l R e s e a r c h E x p e r i m e n t a t i o n , and F> terr, ;-.•!•work c o n d u c t e d by the F a c u l t y of A g r i c u l t u r e ,U n i v e r s i t y of M a n i t o b a , p p . 1 0 9 - 1 1 0 .
2 5 . W i t t w e r , S.H. 1 9 6 0 . O b s e r v a t i o n s of the M o d e r n f<iro;.>•.»<.G r e e n h o u s e V e g e t a b l e I n d u s t r y . Annual report of '. LnV e g e t a b l e G r o w e r s A s s o c i a t i o n of A m e r i c a , IT>- ()-<:>-
2 6 . J e n s e n , M . H . 1 9 6 8 . I n c r e a s e d Y i e l d s T h r o u g h the 1:se ofP l a s t i c s for G r e e n h o u s e T o m a t o P r o d u c t i o n Pro f "t-t i' :of the E i g h t h N a t i o n a l A g r i c u l t u r a l P l a s t i c C o n f e r s -•p p . 5 1 - 5 8 .
- 64 -
iijnd, J.W. and R.W. Soffe. 1971. Light-ModulatedTemperature Control and the Response of GreenhouseTomatoes to Different CO2 Regimes. J. Hort. Sci.46:381-396.
Berezina, N.M. 1964. Presowing Irradiation of Seeds ofAgricultural Plants. Atomizdat, Moscow. Translatedby M.W. Gerrard and P.S. Baker, ORNL. Contract No.W-7405-eng-26.
:i\- M e c t r i c i t y C o u n c i l . 1 9 7 2 . G r o w i n g R o o m s , A G u i d e tot h e P r a c t i c a l D e s i g n o f I n s t a l l a t i o n s . G r o w e l e c t r i cH a n d b o o k N o . 1 , 3 0 Mi 11 b a n k , L o n d o n .
!'"v'-,nnal c o m m u n i c a t i o n f r o m R . P . S t o n e , O n t a r i o M i n i s t r ynf Agriculture and Food, Essex County.
i'-i•"."••<il communication from V.R. Puttagunti. , WhiteshellNuclear Research Establishment, Pinawa, Manitoba.
is'if, u."\. 1973. Greenhouse Vegetable Production Costsand Returns "in Ontario, 1973. Economics Branch,Ontario Ministry of Agriculture and Food, Chatham,'.) n t a r i 0 .
- 65
APPENDIX A
DESCRIPTION AND COST SUMMARY OF COMMERCIAL GRL!
T h e c o m m e r c i a l o r e e n h o u s e s y s t e m jv.ui'iod, i •. ..:
o f tiiree i n t e r c o n n e c t e d s y s t e m s : 1) t h r> i n - r e a i : t n r :<•
h e a t e x c h a n g e a n d w a r m w a t e r s u p p l y s y s t e m f o r t.i' ' ; I T I " / H
f a c i l i t y , 2 ) t h e w a r m w a t e r d i s t r i b u t i o n s y s t e m w i t h i •
q r e e n h o u s e f a c i l i t y , and 3 ) t h e n r e e n h o u s e a i r di ,t.ri: . :
h e a t i n g a n d c o o l i n q s y s t e m s . E a c h of t h e d e s i g n v i r i •.: . •',
t h e s e t h r e e s y s t e m s , t o g e t h e r w i t h a c a p i t a l , o p e r a t i . ' : ••
m a i n t e n a n c e c o s t s u m m a r y , w i l l b e d e s c r i b e d in V v folio,-
s u b s e c t i o n s . A s w e l l , a c a p i t a l c o s t e s t i m a t e of a ridtu
h e a t e d g r e e n h o u s e f a c i l i t y h a s b e e n p r e p a r e d . B e f o r e tkv;<
t h e s e s y s t e m s , s o m e of t h e p r e l i m i n a r y c o n s i d e r a t i o n s uiii'
r e s u l t e d in t h e f i n a l d e s i g n o f e a c h s y s t e m w i l l t;e nr-.jMM
A•] P R E L I M I N A R Y C O N S I D E R A T I O N S
T h e e s s e n t i a l s y s t e m a n d e c o n o m i c a s s u m p t i o n ' . w;,
d e t e r m i n e d t h e l a y o u t of t h e c o m m e r c i a l sv«;ten w o r ' 1 : •-1':<'
p r e v i o u s l y ( S e c t i o n 5 ) . G i v e n t h e s e a s s u m p t i o n s , s'.v •> i :
p a r a m e t e r s c o m m o n to all s y s t e m s r e m a i n e d to ho tix(;<':
1. T h e d e s i g n of t h e g r e e n h o u s e a i r circul.it.iM',h e a t i n g a n d c o o l i n o s y s t e m .
2 . T h e d e s i g n h e a t i n g l o a d f o r the qrcenhnu'.'•s t r u c t u r e .
3. T h e w a r m w a t e r s u p p l y a n d r e t u r n t e m p e r a
4 . T h t m a x i m u m d e s i o n p r e s s u r e and prev..; r*.1
in t h e w a t e r d i s t r i b u t i o n and r e t u r n '. y•>*'.• r.
- 66 -
T h e r e a s o n s f o r s e l e c t i n g a d r y c o n t a c t h e a t e x c h a n g e
s y s t e m a n d an a t t i c r e t u r n d u c t f o r r e - c i r c u l a t i n q a i r w e r e
d i s c u s s e d p r e v i o u s l y ( S e c t i o n s 3 . 2 a n d 3 . 3 ) . T h e e v a l u a t i o n o f
e a c h q r e e n h o u s e s t r u c t u r e , t h e p l a c e m e n t o f t h e f i n n e d c o i l ,
m o t o r i z e d l o u v e r s , e v a p o r a t i v e p a d a n d f a n s w e r e d i c t a t e d
p r i p . i r i l y b y the n e c e s s i t y to u s e c i r c u l a t i o n f a n s f o r b o t h
' l a t i n o a n d c o o l i n q . C o n s e q u e n t l y , r e - c i r c u l a t i o n f a n s w e r e
l o c a t e d a t t h e o p p o s i t e e n d o f t h e q r e e n h o u s e f r o m w h i c h o u t s i d e
a i r b o w l d b e d r a w n . T h e f i n a l a r r a n g e m e n t o f h e a t i n q c o i l ,
e v i p o r a c i v e c o o l i n g p a d a n d r e c i r c u l a t i o n f a n s is c o m p a r a b l e
to do e x p e r i m e n t a l d e s i g n b e i n g e v a l u a t e d at O a k R i d g e N u c l e a r( 1 8 )
L a - o r a t o r y
T h e d e s i g n h e a t i n q l o a d f o r e a c h q r e e n h o u s e s t r u c * re
w a s b a s e d o n an e x t r e m e e n v i r o n m e n t a l c o n d i t i o n o f - 4 0 ° C e x t e r i o r
a i r t e m p e r a t u r e a t n i g h t w i t h a p r e v a i l i n g w i n d s n e e d o f 2 4 k m / h .
Y e a r l y h e a t l o a d c a l c u l a t i o n s w e r e b a s e d o n m o n t h l y a v e r a g e a i r
t e m p e r a t u r e s a n d r a d i a n t h e a t f l u x e s a t W i n n i p e g , M a n i t o b a , a n d
i n c l u d e d a n a d d i t i o n a l 2 0 p e r c e n t h e a t l o a d t o p r o v i d e f o r a i r
i n f i l t r a t i o n , c o r r i d o r h e a t i n q a n d d i s t r i b u t i o n s y s t e m h e a t l o s s e s .
T w o d i f f e r e n t q r e e n h o u s e s t r u c t u r e s a n d g r e e n h o u s e
l a y o u t s w e r e c o n s i d e r e d . H o w e v e r , i r r e s p e c t i v e o f e i t h e r s t r u c t u r e
of l a y o u t , t h e d e s i g n h e a t l o a d s o f t h e r e s u l t i n g f a c i l i t y m a y b e
summarized as:
1. Maximum heat load of 35 MW du r i n g extreme w e a t h e rconditions to m a i n t a i n g r e e n h o u s e t e m p e r a t u r e s at2I"C.
2 . S u r v i v a l h e a t l o a d o f 26 MW d u r i n g e x t r e m e w e a t h e rc o n d i t i o n s t o m a i n t a i n q r e e n n o u s e t e m p e r a t u r e s a t7 ° C .
3 . Norma l n e a t l o a d o f 23 MW d u r i n g t h e c o l d e s t m o n t h o ft h e y e a r ( J a n u a r y ) t o m a i n t a i n g r e e n h o u s e t e m p e r a t u r e sa t 2 T C
The c a l c u l a t e d y e a r l y h e a t l o a d o f t h e g r e e n h o u s e
f a c i l i t y was 04 x 10 kW h / a .
- 6 7 -
Tiie m a x i m u m d e s i g n p r e s s u r e o f t h e h e a t i n w •„,,(•.
i m p o r t a n t d e s i q n p a r a m e t e r b e c a u s e o f m a t e r i a l a n d c o m n o n e t t
a s s o c i a t e d w i t h h i q h p r e s s u r e d e l i v e r y s y s t e m s . T o m i n i n« i :•>
c o s t s , a m a x i m u m s y s t e m p r e s s u r e o f 6 2 0 k P a ( 7 5 p s i q ) w.-i s
s p e c i f i e d . W h e n c o m b i n e d w i t h l o w w a t e r t e m p e r a t u r e s (-6!'"'< )
l o w p r e s s u r e s y s t e m p r e s e n t s t h e p o s s i b i l i t y o f u:;inu L ! K - a •.-••••
p i p i n g m a t e r i a l s , s u c h a s p l a s t i c o r a s b e s t o s c e m e n t . M o w , ' .
t h i s p o s s i b i l i t y w a s n o t e x p l o i t e d i n t h e f i n a l s y s t e m d e s i <••
w h i c h e m p l o y s c o n v e n t i o n a l s t e e l p i p e s y s t e m s .
T h e m o s t i m p o r t a n t d e s i g n p a r a m e t e r s t o b e s n - c i r
i n t h i s s t u d y w e r e t h e w a r m w a t e r s u p p l y t e m p e r a t u r e t o , <;r.-!
r e t u r n t e m p e r a t u r e f r o m , t h e g r e e n h o u s e f a c i l i t y . O n c e t.i;-.-
w e r e f i x e d , a l l i n d i v i d u a l s y s t e m s i n t h e c o m m e r c i a l f d i i ' i * ,
c o u l d b e d e s i g n e d . S e v e r a l c o m b i n a t i o n s o f s u p p l y a r m n > •
t e m p e r a t u r e s w e r e a s s e s s e d i n a p r e l i m i n a r y s c r e e n i n g . <;« >•
t h e c o m b i n a t i o n o f 5 4 ° C s u p p l y a n d 3 7 ° C r e t u r n t e m p e r s t;r<-
a p p e a r e d t o b e t h e m o s t s u i t a b l e c o m p r o m i s e b e t w e e n r.tic- >c><.:>td e m a n d s o f t h e g r e e n h o u s e h e a t i n g s y s t e m , trie i n - r c i c t o r '<•• •'
e x c h a n g e s y s t e m , a n d t h e w a r m w a t e r d i s t r i b u t i o n - / - i . • .
A . 2 T H E G R E E N H O U S E F A C I L I T Y
A . 2 . 1 I n t r o d u c t i o n
T w o d i f f e r e n t m e t h o d s o f g r e e n h o u s e c o n ' ; t n n . t i o n
l a y o u t w e r e a s s e s s e d i n t h i s s t u d y . In t h e f i r s t , i n d i v i d •. •
g r e e n h o u s e s w e r e s e p a r a t e l y c o n s t r u c t e d a n d t h e n j o i n e d *'.-•
b y a c o m m o n c o r r i d o r ( F i g . A - l ) . I n a l l , e l e v e n s r n o r .i t e I
i n t e r c o n n e c t e d g r e e n h o u s e s w e r e r e q u i r e d t o p r o v i d e (in i ' '
u n i t o f 0 . 4 h a . I n t h e s e c o n d l a y o u t , t h e a r e e n h n • > >. .tt .•
w a s m o d i f i e d t o e n c l o s e t h e o p e r a t i n g u n i t u n d e r a •>; n " i e r
T o f a c i l i t a t e a n a l y s i s , t h e r e s u l t i n g s t r u c t u r e c o n ' , i .'• i •
e n d g r e e n h o u s e s a n d 8 c e n t r a l g r e e n h o u s e s ( F i n . " ' )
- 68 -
TOP VIEW
SERVICEAREA
CENTRAL ACCESS CORRIDOR
SIDE VIEW
TO m
; K i' .ic diagram of an operating unit based oniual greenhouses.
- 69 -
TOP VIEW
1
1
1
1111
11
111
11111
11
11111
J. _
111
11t11
11
11111
_ l _
11
11111
t1
11111
._ X
1
11
11111
CORRIDOR
SIDE VIEW
10 in
FIGURE A-2. Schematic <iiagram o:single; roof
a n
- 70 -
E a c h l a y o u t has its s p e c i f i c a d v a n t a g e s . F o r the
i n d i v i d u a l n r o e n h o u s e l a y o u t , p l a n t d i s e a s e , t e m p e r a t u r e c o n t r o l
and p r o d u c t i o n s c h e d u l i n g Arc f a c i l i t a t e d . H o w e v e r , t h e s i n g l e
roof l a y o u t r e q u i r e s l e s s land and has a l o w e r h e a t l o s s per u n i t
of g r o w i n g s u r f a c e . For e x a m p l e , 10 ha of g r o w i n g s u r f a c e m a y
Le h e a t e d in the s i n g l e r o o f l a y o u t u s i n g the s a m e h e a d load as
is r e q u i r e d by 8 ha of g r o w i n g s u r f a c e o f the i n d i v i d u a l g r e e n -
house l a y o u t . F u r t h e r , s i n c e the s i n g l e r o o f l a y o u t is m o r e
c o m p a c t , the w a r m w a t e r d i stri b>i ti on s y s t e m b e t w e e n o p e r a t i n g
u n i t s is s h o r t e r than f o r the i n d i v i d u a l g r e e n h o u s e l a y o u t .
A. 2.2 D e s i g n of I n d i v i d u a l G r e e n h o u s e O p e r a t i n g U n i t
I n d i v i d u a l g r e e n h o u s e s ( F i g . 5 ) in t h i s o p e r a t i n g u n i t
are c o m p a r a b l e to a g r e e n h o u s e p r e s e n t l y o p e r a t i n g a t t h e
u n i v e r s i t y of M a n i t o b a . E a c h g r e e n h o u s e c o n s i s t s of a d o u b l e -
p l a s t i c l a y e r s u p p o r t e d on a s e r i e s (0.91 m s p a c i n g ) of 2.5 cm
g a l v a n i z e d p i p e a r c h e s . F o r s t r u c t u r a l r i g i d i t y , the a r c h e s a r e
j o i n e d by 2 x 4 r a f t e r s a n d f a s t e n e d to e n d p l a t e s on a iight
r e i n f o r c e d c o n c r e t e f o u n d a t i o n . The f o u n d a t i o n c o n s i s t s of a
I'D en g r a d e b e a m s u p p o r t e d every 2 m by 1 m r e i n f o r c e d c o n c r e t e
: i e r s . The end w a l l s of t h e g r e e n h o u s e a r e 2 x 4 s t u d c o n s t r u c t i o n
c o v e r e d w i t h f i b e r g l a s s . The f l o o r a r e a o f the g r e e n h o u s e is
b u i l t up to a b o u t 20 cm a b o v e g r a d e w i t h c o m p a c t e d e a r t h and is
c o v e r e d w i t h 10 cm of a g g r e g a t e . A w e e p i n g t i l e d r a i n a g e s y s t e m
and a r e f l e c t i v e p l a s t i c f l o o r c o v e r i n g a r e a l s o p r o v i d e d .
T h e d o u b l e l a y e r p l a s t i c c o v e r i n g c o n s i s t s o f a two mil
p o l y e t h y l e n e i n s i d e l a y e r and a m o r e d u r a b l e and e x p e n s i v e o u t e r
c o v e r i n g , s u c h as F a b r e n e or L o r o t e x . I n d i v i d u a l c o v e r i n a
s e c t i o n s a r e j o i n e d t o g e t h e r and to the s t r u c t u r e by P o l y - Z i p
s t r a p p i n g w h i c h f o r m s an a i r - t i g h t seal a n d h o l d s the c o v e r i n g
in p l a c e w h i l e p e r m i t t i n g a c o n t i n u o u s a i r p a s s a g e b e t w e e n the
c o v e r i n g s h e e t s . The a i r g a p b e t w e e n t h e i n n e r and o u t e r l a y e r s
- 7 1 -
i ;> m a i n t a i n e d b y l o w p r e s s u r e a i r f r o n a c::u i 1 b l o v . e r . :,
o f p o s s i b l e c o n d e n s a t i o n p r o b l e m s d u r i n g t h e w i n t e r , out.', i
i s u s e d t o p r e s s u r i z e t h e a i r g a p .
I n d i v i d u a l g r e e n h o u s e s a r e c o n n e c t e d ^o-'otln-• •• ;-,
c o r r i d o r w h i c h i s a l s o c o n s t r u c t e d o f d o u b l e l,~>yor i>l.i'.'. i'
m e t a l t u b i n g f r a m e .
A . 2 . 2 . 1 A i r C i r c u l a t i o n , H e a t i n q a n d C o o l i n g
T h e a i r c i r c u l a t i o n a n d h e a t i n n s y s t e m r u n s ; - - . '
T w o s e p a r a t e h e a t i n g c o i l s , e<.ich h a v i n g o v c - r . i i !d i m e n s i o n s o f 2 . 8 m b y 2 . 8 in a n d e a c h r o>-s t ru< 'o f 1 7 0 m o f 1 9 m m O . D . f i n n e d t u b i n o ( 1 M i s i -e a c h 9 . 5 m m i n d i a m e t e r a n d 0 . 9 m m t h i c k ) c o n : . 't o 5 c m i n l e t a n d o u t l e t h e a d e r s
F o u r a i r c i r c u l a t i o n f a n s , e a c h \)ov:-?r^d !.-y i0 . 7 5 k W t w o - s p e e d m o t o r a n d c c m a b i o o f d e ! i v < v i7 m 3 / s ( 1 5 0 0 0 S C F M ) a t 31 P a ( 1 / 8 in o h o f ••.•.•'•»•p r e s s u r e d i f f e r e n t i a l
T h r e e m o t o r i z e d air l o u v e r s y s t t ) " 1 ; f n r <• • '.>" '•a i r m o v e m e n t t h r o u g h t h e h c i s e
A t e m p e r a t u r e a n d h u m i d i t y c o n t r o l ••. V S U . T :
A p o l y e t h y l e n e a i r d u c t l o c a t e d i n , a n d ' i c c n ' y 1
t h e a t t i c a r e a o f , t h e g r e e n h o u s e s u i j u o r t o d ,:ih o r i z o n t a l g r i d s t r u c t u r e .
T h e a i r c i r c u l a t i o n a n d h e a t i r n v s t C M i h a . t < <•
s p e c i f i c a l l y d e s i g n e d t o p e r m i t u s e o f t h e c i r c u l a t i o n f.
t h e d u a l c a p a c i t y a s o n c e - t h r o u g h v e n t i l a t i o n f a r r -iri'l •<
r e c i r c u l a t i o n f a n s f o r t h e h e a t i n g s y s t e m . I n t.n< ' K M I
a i r i s d r a w n t h r o u o h t h e g r o w i n g area a n d d i .. c f-<; r M '".' :'.
a t t i c r e t u r n d u c t . C o o l a i r f l o v / s d o w n tm.- r e * :.r-i l i u c t ,
t h r o u g h a n o p e n l o u v e r l o c a t e d a b o v e t h e f i n n •• - -; •..;'. >"
t h e f i n n e d c o i l s , r e t u r n i n g t o t h e q r o w i n g a r o d . ! h ' r •
a i r t e m p e r a t u r e f r o m t h e c o i l i s c o n t r o l l e d t w ••• <' :'>
w a t e r f l o w r a t e t o t h e c o i l t o a s s u r e t h a t i mire <i :•:'.'• l /'
- 7 2 -
p l a n t s a r e n o t s u b j e c t to e x c e s s i v e h e a t s t r e s s . All f a n s a r e
i n d i v i d u a l l y c o n t r o l l e d by t h e r m o s t a t s a n d c o n s e q u e n t l y m a y be
p r o g r a m m e d t o c i r c u l a t e a i r at u p to a m a x i m u m of 2 8 m / s . At
the m a x i m u m a i r c i r c u l a t i o n r a t e , t h e f i n n e d c o i l h a s b e e n
d e s i g n e d to t r a n s f e r 1 5 3 kW ( m a x i m u m a i r t e m p e r a t u r e i n c r e a s e
a c r o s s coil of 4 . 2 ' C ) to t h e g r e e n h o u s e a i r . D e s i g n d e t a i l s of
tho coil a r e g i v e n in T a b l e A - l .
H u m i d i t y c o n t r o l is o b t a i n e d by e n e r g i z i n g t h e i n l e t
and e x h a u s t m o t o r i z e d l o u v e r s l o c a t e d in t h e e n d w a l l s , r e s u l t i n g
in the s i m u l t a n e o u s e j e c t i o n of h u m i d a i r a n d t h e i n f l o w o f f r e s h
o u t s i d e a i r . O n c e - t h r o u g h v e n t i l a t i o n d u r i n g p e r i o d s o f e x c e s s i v e
g r e e n h o u s e a i r t e m p e r a t u r e s is a c h i e v e d by o p e n i n g t h e i n l e t a n d
e x h a u s t l o u v e r s and c l o s i n g t h e r e c i r c u l a t i o n a i r l o u v e r l o c a t e d
a b o v e tus f i n n e d c o i l . All l o u v e r o p e n i n g s m a y be m a n u a l l y
a d j u s t e d to n a t c h s e a s o n a l t e m p e r a t u r e v a r i a t i o n s , t h e r b y
a l l o w i n g a m o r e u n i f o r m m i x i n g o f f r e s h a n d r e - c i r c u l a t i n g a i r .
D u r i n g w a r m - w e a t h e r o p e r a t i o n , w h e n p e a k d a y t i m e t e m p e r a t u r e s
e x c e e d 1 5 ° C , s u p p l e m e n t a l c o o l i n g is r e q u i r e d if g r e e n h o u s e
t e m p e r a t u r e s stre to be m a i n t a i n e d at 2 1 ° C . T h i s c o o l i n g is
a c h i e v e d by d r a w i n g o u t s i d e a i r t h r o u g h a n e v a p o r a t i v e p a d l o c a t e d
a c r o s s the e n d of t h e g r e e n h o u s e . T h e c o m m e r c i a l l y a v a i l a b l e pad
(5 cm t h i c k n e s s ) is c o m p o s e d o f a s p e n f i b e r s , a n d at a d e s i g n a i r3 2
f l o w r a t e o f 1.0 m /s p e r m of f a c e a r e a c a n cool f r e s h a i r to
w i t h i n 2 . 8 ° C o f the a m b i e n t w e t b u l b t e m p e r a t u r e ( t y p i c a l l y 1 8 ° C
d u r i n g p e a k d a y t i m e p e r i o d s ) - A w a t e r f l o w o f a p p r o x i m a t e l y
0.12 k q / s p e r m e t e r o f p a d l e n g t h m u s t b e s u p p l i e d to t h e t o p of
the nad to m a i n t a i n a c o n t i n u o u s l e v e l o f m o i s t u r e in t h e a s p e n
r i b e r s . T h i s f l o w is s u p p l i e d m o s t c o n v e n i e n t l y by a r e c i r c u l a t i n g
p u m p w h i c h d r a w s w a t e r f r o m the pad c o l l e c t i o n s u m p a n d d e l i v e r s
to <i p e r f o r a t e d h e a d e r a b o v e t h e p a d .
- 73 -
TABLE A-1,
Design Parameters and Capital Cost Summary of WarmGreenhouse Heating and Ventilation Systems
Qil0lis 1 Heat Exchanger Design
Design Heat Load (kW)
Water Inlet Temperature (CC)
Water Outlet Temperature (°C)
Air Inlet Temperature (CC)
Air Outlet Temperature (°C)
Water Flow Rate (Mg/h)
Air Flow Rate (m 3/s)
Heat Transfer Coefficient(kW/m 2.K) (Based on InsideSurface Area)
Corrected LMTD (°C)
Heat Exchange Surface Area (m )
Length of Finned Tubing (m)
Capital Cost
(Includes Installation)
Heat Exchangers (IncludingFabrication)
Fans and Support Structure
Louvers
Instrumentation and Control
Capital Cost/Greenhouse
Capital Cost per GrowingArea ($/m 2)
I n d i v i d u a l_House
153
5 4 . 0
3 7 . 0
1 3 . 3
2 2 . 5
a. i
28
0 . 4
?4 .4
1 6 . 2
340
House
i J1^
• . • • ! . ' " '
3 7 . r:
I B . •-
6 . 0
' ' ! . ' • ' " •
! • ' •
. - ' '- . ' •
i o
32Q0
3000
2200
1000
94P0
25.30
?7U')
" 0 0 ; ;
If irr.i
/ • i j
-,;_ ,
- 74 -
.\. :\ 3 Des i gn of S i n g l e R o o f G r e e n h o u s e O p e r a t i n g Un_it
The s i n g l e r o o f g r e e n h o u s e u n i t c o n s i s t s o f 4 e s s e n t i a l !
i d e n t i c a l e n d - u n i t g r e e n h o u s e s a n d 8 e s s e n t i a l l y i d e n t i c a l c e n t r a l
g r e e n h o u s e u n i t s . Each of t h e s e u n i t s c o n s i s t s of a d o u b l e p l a s t i
layer s u p p o r t e d o v e r a s e r i e s (0.91 m s p a c i n q ) o f 2.5 cm
•IJI vtinized pipe a r c h e s . The e n d s of e a c h arch of the c e n t r a l u n i t
g r e e n h o u s e s are c o n n e c t e d to a t u b u l a r r i d g e p o l e , w h i c h , in turn
i> s u p p o r t e d by a s e r i e s of c o l u m n s a t t a c h e d to a l i g h t l y
r e i n f o r c e d qre.de b e a m . For l a t e r a l r i g i d i t y , the a r c h e s are
j o i n e d by 2 x 4 r a f t e r s . The s u p p o r t a r c h e s of t h e e n d - u n i t
g r e e n h o u s e s are a t t a c h e d to end p l a t e s on a l i g h t r e i n f o r c e d g r a d e
beam and to i m m e d i a t e l y a d j a c e n t r i d g e p o l e s .
The g r o w i n g s u r f a c e p r e p a r a t i o n , d o u b l e p l a s t i c c o v e r i n g
and a i r - g a p p r e s s u r i z i n g s y s t e m is i d e n t i c a l to t h a t of the s i n g l e
g r e e n h o u s e d e s i g n ( S e c t i o n A . 2 . 2 ) .
A . 2 . 3 .1 A i_r C i r c u l a t i o n , H e a t i n g and C o o l i n g S y s t e m
The air c i r c u l a t i o n and h e a t i n g s y s t e m for e a c h of the
h o u s e s in the s i n g l e r o o f g r e e n h o u s e is s i m i l a r to t h a t of the
i n d i v i d u a l g r e e n h o u s e ( S e c t i o n A . 2 . 2 . 1 ) . In the h e a t i n g m o d e , a i r
is d r a w n f r o m the g r o w i n g a r e a and d i s c h a r g e d i n t o an a t t i c
r e t u r n d u c t . This air f l o w s d o w n the r e t u r n d u c t , p a s s e s t h r o u g h
an o p e n l o u v e r l o c a t e d a b o v e the f i n n e d coil and o v e r the f i n n e d
c o i l s , r e t u r n i n g to the g r o w i n g a r e a . In the c o o l i n g m o d e , o u t -
side a i r is d r a w n t h r o u g h the g r e e n h o u s e by the c i r c u l a t i o n f a n s
and d i s c h a r g e d t h r o u g h the g r e e n h o u s e r o o f a b o v e t h e a c c e s s
c o r r i d o r .
B e c a u s e of r e d u c e d heat loss p e r u n i t g r o w i n g s u r f a c e ,
the end and central h o u s e s have l o w e r a i r c i r c u l a t i o n r a t e s and
h e a t i n g c o i l s u r f a c e a r e a s than the c o r r e s p o n d i n g s i n g l e q r e e n -
h o u s e s . K c u r c i r c u l a t i o n fans a r e e m p l o y e d in e a c h e n d h o u s e ,
- 7 5 -
b u t o n l y t h r e e f a n s i n e a c h o f t h e c e n t r a l h c . - . p • - i i ••
a r e a s a n d d e s i g n h e a t l o a d s f o r e n d a n d c e n t r a l h a u i n <u"o
i n T a b l e A -1 .
A . 2 . 4 C o m m e r c i a l Ci r e e n h o u s_e__F a c j 1 i_t_i e s
T o f a c i l i t a t e a n e c o n o m i c c o m p a r i s o n b e t w e e n " M > < _ ,
l a y o u t s , i t w a s a s s u m e d t h a t t h e m a x i m u m h e a t l o a d o f t .
r e s u l t i n g f a c i l i t i e s w a s t o b e h e l d c o n s t a n t r a t h e r t i c : l-.-.
f a c i l i t y g r o w i n g a r e a . T h e h e a t l o s s o f t h e s i n n l e r o o f <•••
u n i t is a p p r o x i m a t e l y 8 0 . " t h a t o f t h e i n d i v i d u a l h o u s e ;.»it
T h e r e f o r e , t h e f a c i l i t i e s c o n s i s t o f 1 ) 2 5 o p e r a t i n g ,.;.,r.
s i n g l e r o o f g r e e n h o u s e , a n d 2 ) 2 0 o p e r a t i n g u n i t s o f i t - i v i
g r e e n h o u s e s .
S c h e m a t i c d i a g r a m s o f t h e l a y o u t o f t h e r e s pi-,, r. i v
g r e e n h o u s e f a c i l i t i e s e r e s h o w n i n F i g u r e s A-.? a n d •'-<•.
A . 2 . 5 C a p i t a l C o s t E s t i m a t e
T h e i n s t a l l e d c o s t o f t h e c o m p o n e n t s o f t h e r e s :.•(.•<.!
g r e e n h o u s e h e a t i n g s y s t e m s i s s u m m a r i z e d i n T a b l e A - l . < , r
b e n o t e d , e v e n t h o u g h t h e h e a t l o s s p e r u n i t g r o w i n n s :J r f :<<•
l o w e r f o r t h e s i n g l e r o o f u n i t t h a n t h e i n d i v i d u a l d o s i " n , t.w2
c a p i t a l c o s t s p e r m o f g r o w i n g s u r f a c e are s i n i l a r .
T h e c a p i t a l c o s t o f t h e h e a t i n g a n d v e n t i 1 a 11 (•" *. v
f o r t h e 2 2 0 g r e e n h o u s e s i n t h e 8 h a f a c i l i t y coi:.vor. <".{- :*' s'i'ii
g r e e n h o u s e s i s a b o u t $ 2 , 0 0 0 , 0 0 0 . F o r t h e 1 0 h,* f o c i l i * / ••!•:
o f s i n g l e r o o f u n i t s , t h e e s t i m a t e d c o s t i s i?. , •. T') , fy)l] •
- 76 -
1
LIMI
TIO
NEX
CLUS
>
100 m
LEGEND
60 cm pipe
25 cm pipe
20 cm pipe
GREENHOUSE CONNECTIONSNOT SHOWN
F'lGURE A-.?. Layout of operating units and warm water distributionsystem, based on individual greenhouses.
- 77 -
MIT
t\
EXCL
USIO
I
111iIi11i
i
i
i
l
•
1
TOO m LEGEND
60 cm pipe
50 cm pipe
20 cm p ipe
5 cm p ipe
GREENHOUSE CONNECTIONS NOT SHOWN
Layout of operaling uniLb diid asystem based on single roof greenhouse.
- 78 -
DISTRIBUTION SYSTEM WITHIN THE GREENHOUSE FACILITY
A.3.1 System Description
The warm water distribution and return system withinthe two greenhouse facilities are schematically shown inFigures A-3 and A-4. As may be noted, the systems were constructedfrom various pipe sizes, and were sized to assure that t h e t o t a lsystem pressure drop did not exceed 200 kP*. A listing of thepipe diameters and lengths of supply-return line required isgiven in Table A-2.
All pipe employed was assumed to be carbon steel. Wherepossible, the most inexpensive pipe which would match the maximumpressure requirements (620 kPa) of the system was specified. Forexample, Schedule 10 pipe was specified for the 60 cm main rupply1i nes.
A.3.2 Capital Cost
A summary of the estimated capital cost of the distribu-tion systems for the two greenhouse facilities is given inTable A-2. Installed pipe costs include excavation costs (2 meterdepth), yard handling, welding and installation, pipe costs (at$1.40/kg of steel), sand cover and backfilling, but do not includeprovision for expansion loops or insulation. The most appropriateinsulation, if in fact insulation is necessary, has yet to bedetermined.
for the 60 cm line, the cost of pipe accounts forapproximately 70 percent of installed cost, indicating that,substantial savings could be made if a cheaper pipe material withcorresponding cheaper installation costs could be specified.
- 79 -
TABLE A - 2
Sys tems S p e c i f i c a t i o n s a n d C a p i t a l C o s t Summary fitG r e e n h o u s e Warm W a t e r D i s t r i b u t i o n S y s t e m ' /
Ind i v i dua 1_ 1°_4.1eJ
System Specifications
Maximum Flow at Design Conditions (kq/h) 1.8 x 10
Maximum System Pressure Droo (kPa) ~ 7 0
Maximum Design Pressure (kPa) 620
Capital Cost
P i p i n g
PipeDi a m e t e r
(cm)
60542520155
S u m m a r y
I n s t a ] l e dC o s t ( a )
( $ / « )
39536024518716482
(m)
460
9751460
550
Sub-total
Valves, Manholes, e tc.(at 252 of Installed Piping Cost)
TOTAL
Cosill180,
240,273,
45,
738,
185,
923,
t
000
000000
"00
ooo
, o o o
,000
(tint
• : . ; o' f. I ;.
(a) Per m e t e r of i n s t a l l e d return and supply line.
(b) Meters of i n s t a l l e d supply-«-eturn line.
- 80 -
A.4 MODERATOR HEAT EXCHANGE AND WARM WATER SUPPLY SYSTEMS
The warm water supply and moderator heat exchange systemswere designed to supply up to 1.8 x 10 kg/h of warm water at54°C to the respective greenhouse facilities. To supply this warmwater, two heat supply systems were assessed: 1) the moderatorneat exchange system of a single reactor was modified, and 2) themoderator heat exchange systems of two separate reactors weremodified. ,
A.4.1 System Design
The moderator heat exchange system of a G-2 CANDUreactor is designed to cool 0.94 m /s of heavy water from an inlettemperature of 71°C to a return temperature of 43°C. To achievethis cooling, two heat exchangers, each transferring 60 MW of heat,are connected in parallel flow circuits (Fig. A-5).
Modification of a moderator heat exchange system depends,in part, on the requirement for standby heating capability for thegreenhouse facility during a reactor shutdown. For a facilitylocated at a single reactor power station, standby capability wasassumed to be provided by an oil-fired hot water system (Fig. A-6).At a multi-unit station, it was assumed that standby capabilitycould be provided from a modified moderator circuit in anadjacent reactor (Fig. A-7). As discussed below, standby heatingcapability influenced the design of the modified heat exchangesystems.
The oil-fired standby system associated with a singlereactor installation was assumed to provide the standby designheat load of 26 MW and to be available as a supplementary heatsource during those periods when greenhouse load demand exceededthe normal requirement for 23 MW. Consequently, the moderator
- 81 -
CALANDRIA
71 °C
36°C
2 0 °C COOLING WATER
43°C
FIGURE A-5. Existing moderator heat exchange .••/. \ • ••:,. 'CANDU reactors: desi gn temper at •;; ;.•:_, \i. ,v;:..
- 82 -
43 °C CALANDRIA
71 °C
I
COOLING WATER
-J
49 °C
37 °C
STANDBYHEATING
PUMPHOUSE
i I
s;
FIGURE A-6. Modified moderator heat exchange system and warmwater supply system for single unit station.
- 83 -
UNIT ONE
CALANDRIA
COOLING MATER
54»C
37°C
T
PUMPHOUSE
i. _ _ _ _ _ _
UNIT TWO
.71 °C
.63 °C
I
i
CALANDRIA
FIGURE A - 7 . M o d i f i e d m o d e r a t o r h e a t e x c h a n g e an-', warm v . i ' 's u p p l y s y s t e m f o r m u l t i - u n i t power' s t a t i o n .
- 84 -
heat exchangers for a single unit station were designed torecover only 23 MW of heat* resulting in a reduced capital costin the moderator heat exchange system. During periods of peakdemand (up to 35 MW) it was assumed that the necessary additionalheat (12 MW) was added to the light water flowing to the green-house facility at the pumphouse. Consequently, the designoutlet temperature of the light water stream from a single reactorstation is lower than the corresponding temperature from amulti-unit heat exchange system (Table A - 3 ) .
Wr.en a multi-unit station is modified, the exchangersin each of two reactors must be modified to provide 17.5 MW atpeak demand and 26 MW during shutdown of one of the reactors.Both requirements can be met by designing each exchanger to meetits peak demand of 17.5 MW. This is possible since the temperatureof the light water supplied to the greenhouse facility may bereduced from 54°C to 35°C and still maintain the greenhouses attheir standby temperature of 7°C, if the flow of light water ismaintained to the facility. Thus, by allowing the return watertemperature from the greenhouse facility to drop to 24°C, andby increasing the flow through the remaining on-line reactorheat exchange system from 0.9 to 1.35 x 10 kq/h, the heat recoverycapability of the on-line heat exchanger increases from 17.5 to26 MW. The c ^ i e t water from the exchanger (at 41°C) is mixedwith the remaining 0.45 x 10 kg/h of light water bypassed at thepumphouse to produce a return stream of 1.8 x 10 kg/h of lightwater at 35°C for the greenhouse facility.
The increased pressure drop resulting from an increasedflow through the exchanger of a single unit is compensated, inpart, by the reduced pressure drop associated with a reduced flowfrom the pumphouse to and from the moderator heat exchange system.
A summary of the design data for the two moderator heatexchange and water supply systems is given in Tables A-3 and A-4.
- 85 -
TABLE A-3
Design Parameters and Capital Cost Summaryof Moderator Heat Exchange Systems
Single-Unit Station Two-Unit Station
Exchanger Design Parameters
(Two Heat Exchangers/System)
Design Heat Load (MW)
[)2O Inlet Temperature (°C)
D2O Outlet Temperature (°C)
Light WaterInlet Temperature (°C)
Light WaterOutlet Temperature (°C)
D2O Flow Rate (kg/h)
Light WaterFlow Rate (kg/h)
Heat Transfer ?Coefficient (kW/m.K)
Corrected LMTO (°C)
Heat ExchangeSurface Area (mz)
Capital Cost Summary
StandbySystem
11.5
71 .0
65.6
37. 0
49.0
1.8 x 10 6
0.9 x 10 6
1 .71
23.0
290
PeakingSystem
8.6
71 .0
67.0
37.0
49 .0
1.8 x 106
0.7 x 106
1 .71
23.0
215
Dcsi
1 7.
71 .
63.
37 .
54
1 . 8 v
0 . 9 x
1
i *;
555
iLn.
5
0
r,
.i
1 L!C
i:-
.71
.4
V. ij r 1
Stan0>U'/a
[••'
r•y.>
41
l .;' >
1 .4 X
t .
^ ;
' " I'.) i • V
1 ;l
1 11
71
Modified System Cost ($) 640.000 475,000
- 86 -
TABLE A-4
Design Parameters and Capital Cost Summary of Main SupplyPiping, Pumphouse, and Standby Heating Systems
Main Supply Piping System
Design Data
Maximum Flow Rate (kg/h)Maximum System Pressure (kPa)Piping Network
Pipe Diameter (cm)Pipe Length (m)
System Pressure DropPiping (kPa)Moderator Heat Exchanger (kPa)
Capital Cost
Installed Cost ($'m)Total Cost (S)
Single-Unit Station
Standby Peaking
Two-UnitStation
1.8 x 106i>0
541220
34070
360440,000
1.4 x I620
451220
34050
330400,000
1 .8 x 10c
620
601220
165100
395480,000
Pumphouse
Capital Cost (S)
Pumps (4 x 75 kW)Piping, Electrical and ControlsBui 1di ng
TOTAL
405010
,000,000,000
405010
,000,000,000
405010
,000,000,000
100,000 100,000 100,000
Standby Heating System
Design Heat Load (MM)
Capital Cost ($)
Boilers, including sparesOil Storage TanksPlumbing and ElectricalInstal lationBuildingContingenci es
26
237,00060,00074,00030,00037,00092,000
26
237,00060,00074,00030,00037,00092,000
TOTAL 530,000 530,000
- 87 -
At m a x i m u m f l o w , the anticipated system
(greenhouse d i s t r i b u t i o n , m o d e r a t o r heat e x c h a n g e and supply
s y s t e m s ) is less than the m a x i m u m design pressure of 020 i.To.
This flow may be delivered by 4 pumps operated in p a r a l l e l , em-
p o w e r e d by a 75 kW m o t o r and c a p a b l e of a net d e l i v e r y presvj-
of 520 kPa. The pumps would be actuated a u t o m a t i c a l l y by
p r e s s u r e c o n t r o l , and are located in a pumphouse adjacent to
the q r e e n h o u s e f a c i l i t y .
A.4.2 Capital Cost of Heat Supply Systems
The capital cost of the heat supply systems include, 'r,
cost of modifying the moderator heat exchange s y s t e m , construction
of the supply l i n e s , pumps and pumphouse and of the stan'oy h"^ t.t ••'
s y s t e m . Individual costs of each item are p r e s e n t e d in Tab!.- • :
and A - 4 .
Costs of modifying the moderator heat exchange <ry.t(i
were based on data supplied by R e n s h a w (Appendix C ) . The2
e s t i m a t e d cost of $1100/m of exchanger surface includes fabrica-
tion and i n s t a l l a t i o n of the e x c h a n g e r , piping modification.-,.
c o n t r o l s and additional heavy w a t e r holdup in the exchanger.
A.S NATURAL GAS GREENHOUSE HEATING SYSTEM
To assess the relative economics of the proposed w> ,tt
heat recovery s y s t e m for g r e e n h o u s e s , it was necessary to ev^lud
the capital and o p e r a t i n g costs of a competitive fossil fired
h e a t i n g system. The fossil-fired system chosen for evaluation W
a natural gas heated system in a single roof g r e e n h o u s e facility
of 10 ha.
- 88 -
A. 5.1 Description
The natural gas heating system chosen is commerciallyavailable and referred to as the Fan Jet system. It consists ofan axial flow air circulation fan (0.75 kW motor) mounted near theroof at one end of a greenhouse unit. A perforated, one meterdiameter, polyethylene film air duct is attached to the dischargeside of the fan and extends the length of the greenhouse. Thetwo-speed fan operates continuously, inflating the tube andrecirculating air throughout the greenhouse.
Two natural gas furnaces are mounted adjacent to, andon either side of, the main air circulation fan. Each furnace isequipped with a fan (0.25 kW motor) which draws air from thegreenhouse and discharges heated air directly into the intakeside of the main circulation fan. The operation of the furnaceand furnace fans is controlled by thermostats.
When either the greenhouse temperature or humiditybecome too high, a motorized louver is energized at one end ofthe greenhouse. Simultaneously, two exhaust fans (each with a0.75 kW motor) at the opposite end of the greenhouse are energized,and fresh air is drawn through the greenhouse. The exhaust fansoperate against a gravity-controlled discharge louver.
Additional cooling may be obtained by installation ofan evaporative cooling pad adjacent to the inlet louver.
A.5.2 Capital Cost
The estimated capital cost of the components of the FanJet natural gar heating and ventilation system are listed inTable A-5. As may be noted, it was assumed that the capital costof the system for an end-unit and a central-unit greenhouse wereidentical .
- 89 -
TABLE A-5
Capital Cost Summary of Natural Gas Heatinoand Ventilation Systems
Heating System
Furnaces
Distribution Fans
($/Greenhouse)
800
(1 x 0.75 kW; 2 x
Ducting
Instrumentation
Installation
0.25
Sub-
kW)
total
700
100
250
500
2350 705,000
Ventilation and Air Circulation
Louvers (1 motorized; 1 gravity)
Exhaust fans (2 x 0.75 kW)
Control and Instrumentation
Installation
Sub-total
TOTAL (300 Greenhouses)
1200
100C
250
_300
2750 825,000
1 ,530,000
- 90 -
A. 6 MAINTENANCE AND OPERATING COST SUMMARY
The yearly maintenance costs of the heating systemcomponents were estimated as a percentage of Installed capitalcost. A listing of the capital cost percentages assumed forthe respective components, together with the resultinq estimatedyearly maintenance costs are given in Table A-6.
The yearly operating costs of the heatinq systemcomponents are listed in Table A-7. The only utility consumptionconsidered was electricity. To obtain electrical consumption(kWh/a), the estimated yearly load factor of the component wasmultiplied by its rated yearly consumption. Electricity wasassumed to cost 15 m$/kWh.
- 91 -
TABLE A-6
Maintenance Cost Summary
Moderator_Wa_st_e Heat_ Del i very System1;
l n - R p a c t o r Heat F.xcharuie SystemM.iin Supply Syr. teni Pi pi noPumphouse
PumpsPi pi ni) and e l e c t r i c a lC o n t r o l sBuildinq
S t a n d b y H e a t i n a
TOTAL
C a p i t a l
10
__Do
One U n i t
'. ta nd! yHe a t inn
19 ,
4 ,
i] ,
26_.
60
,200,80-'
,00060'!("• *\ C\
?oo,5 00
,300
l_1d_r_s_
_S_td_t
P e a k
14,
»1 %
1 Of")
i nq
.bO
or-;!'!! 'i
b'-
I i •
?00b i ^
b b:)
u<• t ,,t i
• ' •
4 .•;
t
! .''
b •'. . •'•
Greenhouse Heatina System
Do 1 U r s
Warm Water Heating SystemHeat Exchanger and PipingFans, LouversInstrumentation and ControlsFan Support StructureWater Distribution System
TOTAL
C a a i t a lL 0 S
255Ci
I ndi vH o u s e
14,53,11 ,
96,
idTs_U
060000onn
_b_00
b60 1 1 3 . -,'.y
Natural Gas Heating SystemHeatinq and VentilationGas Distribution
TOTAL
(a) 8 hectare growing surface(b) 10 hectare growing surface
; » . - . • : • )
7 7 .
- 92 -
TABLE A-7
U t i l i t y Operating Cost Summary
_*iJLe_Jif-AL I'e l i v e r y System
L i q h t Water Pumping(4 x 75 kU pumps)
3,3 Pumping
Assumed AnnualLoad Factor
0.52
ElectricalConsumption
kWh/a
1.35 x 10c
OperatingCost(j/a)
20.250
20,000
Greenhouse Heating and Ventilation
Harm Hater System
Individual Houses (8 ha)
Heating System Fans(880 x 0.75 kW)
Ventilation System Fans(880 x 0.75 kW)
Block Houses (10 ha)
Heating System Fans(1000 x 0.75 kW)
Ventilation System Fans(1000 x 0.75 kW)
0.50
0.18
0.50
0.18
2.9 x 10s
1 .0 x 10v
3.28 x 10°
1.21 x 10c
43,500
15,000
49,200
18,150
..atural Gas Heating System (10 ha)
Heating System Fans(300 x 0.75 kW;600 x 0.25 kW)
Ventilation System Fans(1000 x 0.75 kU)
0 .
0.
50
18
1
1
.64
.21
X
X
1 0 '
10 6
24
18
,600
,150
- 9 3 -
A P P E N D I X B
S T R U C T U R E O F W A S T E H E A T G R E E N H O U S E I f i D U S T k Y
A g r e e n h o u s e i n d u s t r y b a s e d o n t h e u t i l i z a t i o n o f w a ^ t , .
h e a t w o u l d n e c e s s a r i l y i n v o l v e c o o p e r a t i o n b e t w e e n s e v e r a l ' e v e l
o f g o v e r n m e n t , a h y d r o - e l e c t r i c u t i l i t y , a n d t h e q r o w e r s . 1'. 's
n o t t h e o b j e c t i v e o f t h i s A p p e n d i x t o d e s c r i b e h o w lnn i n d u s . i ' '
w o u l d b e b u i l t a n d o p e r a t e d , b u t s i m p l y t o p o i n t o u t s o m e o f ttu
p r o b l e m s a n d t h e i r p o s s i b l e s o l u t i o n s a s a b a s i s f o r fwt'jre
di s c u s s i o n .
T r a d i t i o n a l l y t h e g r e e n h o j s e v e g e t a b l e i n d u s t r y in
C a n a d a h a s b e e n c o m p o s e d o f a l a r g e n u m b e r o f i n d i v i d u a l h o i o i ; <r-
v a r y i n g i n s i z e f r o m " p a r t - t i m e " o p e r a t i o n s o f a f e w h u n d r e d
s q u a r e m e t e r s u p t o a m a x i m u m o f p e r h a p s 4 h a , w i t h tl>e a v e r a a e
s i z e b e i n g a b o u t 0 . 4 h a . It h a s b e e n p o s s i b l e f o r a n i n d i v i ci - < i
t o e n t e r t h e g r e e n h o u s e b u s i n e s s , o r e x p a n d h i s g r e e n h o u s e area,
o n t h e b a s i s o f h i s p e r s o n a l d e c i s i o n . It ha<; a l s o b e e n ^ o s s i b ! "
f o r m a n y g r e e n h o u s e o p e r a t o r s t o b e e n q a q e d i n m i x e d f a r m i nq-.
w i t h o r c h a r d s , v i n e y a r d s o r f i e l d c r o p s o f v e q e t a h l e s in ai'.<.' i t i o n
t o g r e e n h o u s e s .
U t i l i z a t i o n o f w a s t e h e a t w i l l r e q u i r e a c h a n n e f r o n t h e
t r a d i t i o n a l o r g a n i z a t i o n d e s c r i b e d a b o v e . S o m e o f t h e f a c t o r ' ,
w h i c h w i l l i n f l u e n c e t h e n e w o r g a n i z a t i o n a r e :
1 . A d a p t a t i o n o f t h e n u c l e a r s t a t i o n t o a l l o w w a ^ t eh e a t t o b e u t i l i z e d w i l l b e r e c u i r e d w h ^ i i^n
n u c l e a r s t a t i o n is b u i l t .
2 . C a p i t a l i n v e s t m e n t i n t h e m o d i f i c a t i o n s to t h en u c l e a r s t a t i o n a n d d i s t r i b u t i o n s y s t e m w i l l l er e q u i r e d b e f o r e g r e e n h o u s e p r o d u c t i o n b e o i n s .
3 . T h e g r e e n h o u s e i n d u s t r y w i l l b e r e q u i r e d t o l o - a t en e a r t h e n u c l e a r s t a t i o n w h i c h m a y i n v o l v e p o o rs o i l s a n d h i g h l a n d v a l u e s o r t a x e s .
4. distribution costs will require that the green-houses be built close together (high density)y;iic^ may preclude mixed farming.
5. Since most of the capital costs will be incurredbefore any greenhouses can be heated, it will benecessary that most of the greenhouses beginoperation as soon as the distribution system iscompleted. When all available heat has beenutilized, further expansion by individuals willnot be possible.
Five possible structures for the waste heat greenhouseindustry are shown in Table B-1. Ownership and operation by ahydro-electric utility (hydro), is probably not a viable optionsince operation of agricultural enterprises would be consideredto be outside the mandate of most such utilities. Hydro asowner and leaser would also almost certainly be outside theutilities mandate. This organization would put the leasee in theposition of tenant rather than owner, a position which is notpalatable to most farmers.
Ownership and operation by a large corporation wouldhave the advantage that the corooration would have the financial,organizational and engineering capabilities required to carryout a large project. It is probable, however, that grantingexclusive rights to waste heat to a large corporation would be apolitically difficult decision. It would be opposed by theexisting greenhouse industry, since they would consider thecompetition to be unfair. Operation of 4 to 8 ha as a singleblock might also encounter "negative economics of scale" as havebeen noted in the greenhouse industry.
The final two possibilities are similar in that theyenvisage either hydro or a growers co-operative acting as autility. This utility would be responsible for acquiring, anddistributing the heat. It would recover its cost by charging a
TABLE B-l
Five Possible Organizations of an Industry Utilizirg WasteHeat for Greenhouse Vegetable Production
Ownership ofmodifications tonuclear station
Ownership ofdi stributionsystem
Operation ofdistributionsystem
Ownersrtip ofgreenhouses
Cost recovery ofheat -s J ppl y s v:. te:r
Ownedand operated
by hydro
hydro
hydro
hydro
h / d r o
;a ies ofv e g e t a b l er.roduce by
h y d r o
Owned Dy hydro ;leased tooperator
hydro
fiydro
hydro
leased l.yhydro tooneratcr
1 eL.se rharqeand month'1/
Owned andoperated by
large corporation
hydro orcorporation
corporati on
corpora ti on
corporati on
fixed anrHict 1fee or
k?at charge
Heat supply fromqrov.ers
co-operative asa uti1lty
hydro orqrowers C O - O D
qrowers C O - O D
arowers co-op
individualopera tors
hydro tyf i xed anr ua1fee or heat
c h a r o e ." r o w e r ; c c - ^ n
i t;.i t (. "ia r q e .
Heat supplyfrom hydro
as a utility
hydro
hydro
hvdro
i ndi v i dualoperators
hook-up feeand
n e 3 t c 'i a r o e
10en
- 96 -
hcok-up fee (dependent on distance from the distribution point andon capacity) and a heat-use charge. It would be advantageous fornydro to act as the utility since design, construction and opera-tion of the distribution system would be simple for them butwould be relatively more difficult and expensive for a growersco-operative. Thus, for the purposes of thi study, we haveassumed that hydro would act as the utility and the division ofresponsibility would be:
1. Hydro would be respon:-ible for traditionalutility responsibilities:a) in-reactor modifications to heat exchangerb) pump house, controls and supply pressure
in primary linesc) layout of distribution grid and primary
feeder linesd) metering heat suDplied to greenhouse unitse) electrical, domestic water, sewer and storm
sewer systems and also roads.
2. Greenhouse operator would be responsible for:a) heat exchange equipment within greenhouseb) return and leakage within greenhousec) operations withinthe property line.
The question of land costs and taxes is of particularimportance if the nuclear power station is near a major city.Since land prices, zoning or taxation policies could make wasteheat utilization in greenhouses economically impossible near agiven nuclear power station, the question might arise "is suchutilization desirable?". It will be necessary, therefore, thatdata to make rational decisions be available.
Although the organization of this greenhouse industrywill require creative problem solving, there are advantages thatshould accrue from use of the waste heat system:
- 97 -
1. A f t e r c o n s t r u c t i o n , the h e a t i n q c o s t s of the w a s t eheat s y s t e m will e s c a l a t e at r o u g h l y the same rateas the c o s t of e l e c t r i c i t y . S i n c e e l e c t r i c i t y c o s tm a y well e s c a l a t e at a l o w e r rate than fossil fuelc o s t , w a s t e heat s y s t e m s may gain a c o m p e t i t i v ea d v a n t a g e in the f u t u r e .
2. From the p o i n t of v i e w of the i n d i v i d u a l g r e e n h o u s eo p e r a t o r , the w a s t e h e a t system will be s i m p l e rs i n c e he will not h a v e to o p e r a t e and m a i n t a i nb o i l e r s . D i s c u s s i o n s w i t h g r o w e r s in the L e a m i n g t o narea i n d i c a t e that t h i s is a m a j o r a d v a n t a g e .
3. The high d e n s i t y of g r e e n h o u s e s in a g i v e n a r e a , amithe r e q u i r e d g r o w e r s o r g a n i z a t i o n s h o u l d m a k e p o s s i b l ec o - o p e r a t i v e b u y i n g , g r a d i n g , p a c k i n g and s h i p D i n g .I n c r e a s e d s p e c i a l i z a t i o n is also p o s s i b l e , as wellas » m o r e a g g r e s s i v e and forward l o o k i n g a t t i t u d eon the p a r t of the g r o w e r s .
4. The e x i s t e n c e of a p r i m a r y user of w a s t e heat (theg r e e n h o u s e s ) may a l l o w the d e v e l o p m e n t of s e c o n d a r yu s e r s . T h e s e m i g h t i n c l u d e use of g r e e n h o u s e e f f l u e n tas the s o u r c e for h e a t pumps in the o p e r a t o r s h o u s e s ,p a c k i n g s h e d s and g r o w i n g rooms or the use of r e t u r nw a t e r f o r soil h e a t i n g or in t e m p o r a r y crop s h e l t e r s .
5. I n t a n g i b l e s , such as the s u b s t i t u t i o n of a w a s t ep r o d u c t ( h e a t ) for a n o n - r e n e w a b l e r e s o u r c e ( p e t r o l e u m ) ,the d e v e l o p m e n t of g r e a t e r C a n a d i a n s e l f - s u f f i c i e n c yin food p r o d u c t i o n , and the d e m o n s t r a t i o n of am o d i f i c a t i o n to the C A N D U r e a c t o r s y s t e m which m a y beof i n t e r e s t to d e v e l o p i n g c o u n t r i e s , are a d d i t i o n a la d v a n t a g e s w h i c h m e r i t c o n s i d e r a t i o n .
- 98 -
APPENDIX C
HEAT EXCHANGER COSTS FOR THE MODIFIED MODERATOR CIRCUIT
Costs of modifying the moderator heat exchange system
were based on data supplied in a memorandum from R. H. Renshaw
(Division Manager of Process Engineering, Atomic Energy of Canada
Limited, Power Projects at Sheridan P a r k ) .
It should be noted that the nuclear station referred
to (Bruce A) is not a G-2 CANDU reactor station, and therefore,
heavy water flows and temperatures quoted are different than
in the G-2 moderator system. Further, since the heat exchangers
are designed for full flow continuous operation, operating costs
(essentially heavy water pumping costs) are significantly greater
than in the heat recovery system proposed in this report.
The pertinent sections of the memorandum follow:
g'ARM WATER FROM MOVSRATOR COOLING
We have '/put fieoaest ton data on mode-tatoi heat fiZCovzMj
at 140'f.
We do not have, fieady nu.mbe.fih. In Heiponse. to ijou.fi
\equzAt, %'e. have calculated a comparison between Bnuce A, not
uptatzd and pnoducina H2O at 9S°F, and Biuce A, not upKated and
\t-optimized to pioduce H2O at 140"F.
Thii ttiofik <t'a<j donz with a hzat zxchanqzK optimization
computtfi pxogfian dtblqnzd ^01 8iuce A.
A4 ijou anticipate., thtfie. anz design di^icaltizi,. We
have, uncovered iowe 0^ them in designing $on vziy watm salt
coofinn situations in which an intoxmediatz fifizsh wate.fi
- 99 -
(oup -ii iliquified. The i,oKt o^ optimization that c.'c have ifctshete molt oft lehi, ignofiei the&e, on aitumei than a-ie. ici'.ubUei.e.. that ultimate heat iink \equifiementi> axe net, thcttempefiatufte coe^icienti an.e tolenable OK negative, thatend-ikield deiign it, not a^ected, and AO (,01th.
A iub&tantiat aid if, in the viing.% in the ionm <•:' 'ii.evident and fowet holdup heat exchange*.*. ('e an.e picpativdetailed data at pn.ei>ent, but toe do not include it in thepieient iooik.
- 100 -
TABLE C-1
design Specifications and Calculated Costs forModerator Heat Exchanger
A s s
CosCosCosCosHea0?0D2OH?0H20
j in •.• t i
t oft oft oft oft re::itemotemptemptemp
ons
tubing ( I nco10 v)D2O oumpinqH2O "Dumpingoved. from calandria. to calandria. from lake. to lake
Reference
$125/kg$2.25/ft$420/kw$420/kw75MW(th)187.8°F105°F68°F98 °F
New
$125/kg$2.26/ft$420/kw$420/kw7 5MW(th)187.8°F127°F68°F140°F
Results Reference New
L.2O costH/X system pioinq costHeat Exch. costOther capital
504,06956,806
751 ,867
Total Capital: $1,312,742
Total Operating: $ 202,119
$ 906,27067,532
1,392,720
$2,366,522
j 195.732
D2O flowH2O flowHeat Tx surfaceLMTO (corrected)
3,120,914 lb /h8,530,500 1b /h
13,311 sq ft50.680
4,265,250 lb /h3,554,375 lb /h
26,210 sq ft30.670
The International Standard Serial Number
ISSN 0067-0367
has been assigned to this series of reports.
To identify individual documents in the series
we have assigned an AECL—number.
Please refer to the AECL—number when
requesting additional copies of this document
from
Scientific Document Distribution Office
Atomic Energy of Canada Limited
Chalk River, Ontario, Canada
KOJ I JO
Price S7.00 per copy
2650-76
Recommended