1 Taylor Engineering, LLCHVAC System DesignMark Hydeman, P.E.,
FASHRAE Taylor Engineering, [email protected]
Taylor Engineering, LLCit takes 2,000 to 3,000 times the volume of
air to cool what you can with water!How do you effectively fight a
fire?With air, or with water?3 Taylor Engineering, LLCState of the
present: with air4 Taylor Engineering, LLCAir system design
overviewData center layoutAirflow configurationsDistribution:
overhead or underfloorontrol: constant or variable volumeAirflow
issues!conomi"ersHumidity control issues5 Taylor Engineering,
LLCServer airflow front to bac# or front to bac# and top are
recommended 2004, American Society of Heating, Refrigerating an
Air!"onitioning #ngineers, $nc% &www%ashrae%org'% Re(rinte )y
(ermission from ASHRA# *hermal +uielines for ,ata -rocessing
#nvironments% *his material may not )e co(ie nor istri)ute in
either (a(er or igital form without ASHRA#.s (ermission%Data center
layoutold AisleHot Aisle6 Taylor Engineering, LLCData center layout
2004, American Society of Heating, Refrigerating an Air!"onitioning
#ngineers, $nc% &www%ashrae%org'% Re(rinte )y (ermission from
ASHRA# *hermal +uielines for ,ata -rocessing #nvironments% *his
material may not )e co(ie nor istri)ute in either (a(er or igital
form without ASHRA#.s (ermission%$nderfloor Supplyold AisleHot
Aisle%nly & pressure "one for $'(7 Taylor Engineering, LLCData
center layout 2004, American Society of Heating, Refrigerating an
Air!"onitioning #ngineers, $nc% &www%ashrae%org'% Re(rinte )y
(ermission from ASHRA# *hermal +uielines for ,ata -rocessing
#nvironments% *his material may not )e co(ie nor istri)ute in
either (a(er or igital form without ASHRA#.s (ermission%%verhead
Supplyold AisleHot Aisle)ou can incorporate *A* on each branch8
Taylor Engineering, LLC!levation at a cold aisle loo#ing at
rac#s+ypical temperature profile with $' supply+oo hot +oo hot,ust
right+oo cold*here are numerous references in ASHRA#%See for
e/am(le 0% Sorell et al1 2"om(arison of 3verhea an 4nerfloor Air
,elivery Systems in a ,ata "enter #nvironment 4sing "5, 6oeling71
ASHRA# Sym(osium -a(er ,#!08!99!81 20089 Taylor Engineering,
LLC!levation at a cold aisle loo#ing at rac#s+oo warm +oo warm,ust
right+ypical temperature profile with %H supply10 Taylor
Engineering, LLCAisle capping 2004, American Society of Heating,
Refrigerating an Air!"onitioning #ngineers, $nc%
&www%ashrae%org'% Re(rinte )y (ermission from ASHRA# *hermal
+uielines for ,ata -rocessing #nvironments% *his material may not
)e co(ie nor istri)ute in either (a(er or igital form without
ASHRA#.s (ermission%old Aisle aps!nd capHot aisle lid A-" re(rinte
with (ermissionold AisleHot Aisle11 Taylor Engineering, LLCAisle
capping 2004, American Society of Heating, Refrigerating an
Air!"onitioning #ngineers, $nc% &www%ashrae%org'% Re(rinte )y
(ermission from ASHRA# *hermal +uielines for ,ata -rocessing
#nvironments% *his material may not )e co(ie nor istri)ute in
either (a(er or igital form without ASHRA#.s (ermission%old Aisle
aps:;Servers Supply HVACV V_Airflow with constant volume systems16
Taylor Engineering, LLC :ote most of these observations apply to
overhead and underfloor distributionWith constant volume fans on
the servers you can only be right at one condition of server
loading(+he solution is to employ variable speed server and
distribution fansAirflow with constant volume systems17 Taylor
Engineering, LLC7artial flow condition1est energy performance but
difficult to control >Servers Supply HVACV V_Airflow with
variable volume systems18 Taylor Engineering, LLCHow Do )ou 1alance
Airflow?Spreadsheet'D2onitoring;Site 2easurements$mage from
*ile5low
htt(=>>www%inres%com>-roucts>*ile5low>tileflow%html,
4se with (ermission from $nnovative Research, $nc% 19 Taylor
Engineering, LLC+hermal report'rom ASH9A!6s +hermal 3uidelines for
Data 7rocessing !nvironments20 Taylor Engineering, LLCWhat6s the
server airflow?S$: S$: D!00 D!00* *? ?@A> B@A>num fans = C
n;a n;atotal '2 -maD. &A> AA/BA >&,&B=@@?
&,@A> '2;rac# -low inlet temp. &,?>>ABE
&,?B> maD load ; rac# -#W. &C &> &<
&?21 Taylor Engineering, LLC1est air delivery practicesArrange
rac#s in hot aisle;cold aisle configuration+ry to match or eDceed
server airflow by aisle3et thermal report data from 5+ if
possible7lan for worst case3et variable speed or two speed fans on
servers if possible7rovide variable airflow fans for A unit
supplyAlso consider using air handlers rather than 9As for improved
performance -to be elaborated on later.$se overhead supply where
possible7rovide aisle capping -preferably cold aisles, refer to
01:0 presentation for more details.7lug floor lea#s and provide
blan# off plates in rac#sDraw return from as high as possible$se 'D
to inform design and operation22 Taylor Engineering, LLCAirGside
economi"er23 Taylor Engineering, LLCAirGSide !conomi"er
issuesHygroscopic dust 01:0 is doing some research on thisDesign
humidity conditions See following slides24 Taylor Engineering,
LLCDesign conditions at the "one 2008, American Society of Heating,
Refrigerating an Air!"onitioning #ngineers, $nc%
&www%ashrae%org'% Re(rinte )y (ermission from ASHRA# ,esign
"onsierations for ,ata an "ommunications #?ui(ment "enters% *his
material may not )e co(ie nor istri)ute in either (a(er or igital
form without ASHRA#.s (ermission%25 Taylor Engineering, LLCSan
'ranciscoBAROMETRIC PRESSURE: 29.904 in. HGPSYCHROMETRICCHARTor!al
Te!pera"ureI#P Un$"s%& FEETWeather Hours360 to 321320 to 281280
to 241240 to 201200 to 161160 to 121120 to 8180 to 4140 to 1C>
CA AA B> BA E> EA @> @A => =A &>>D9) 1$01
+!27!9A+$9! G
H'/>>&/>>?/>>C/>>>A/>>B/>>E/>>@/>>=/>&>/>&&/>&?/>&C/>&&A/>&B/>&E/>&@/>&=/>?>Char"
'y( HA)S )O* SOFT*ARE+ ,,,-handsdo,nsof",are-.o!CA
AAB>BAE>EAH$25D5+) 9A+5% G 7%$:DS 2%5S+$9! 7!9 7%$:D D9)
A59Class%/Allo,E0S/Re.o!!endClass%/Re.o!!endSan 'rancisco limate
Data 1inswith Data enter 3uideline IonesBAROMETRIC PRESSURE: 29.904
in. HGPSYCHROMETRICCHARTor!al Te!pera"ureI#P Un$"s%& FEETChar"
'y( HA)S )O* SOFT*ARE+ ,,,-handsdo,nsof",are-.o!JDesign +arget$pper
Allowed Humidity 0imit0ower Allowed Humidity 0imit
-?>K9H.:egligible time of possible concern for humidification26
Taylor Engineering, LLC0os AngelesBAROMETRIC PRESSURE: 29.808 in.
HGPSYCHROMETRICCHARTor!al Te!pera"ureI#P Un$"s%12 FEETWeather
Hours396 to 353352 to 309308 to 265264 to 221220 to 177176 to
133132 to 8988 to 4544 to 1C> CA AA B> BA E> EA @> @A
=> =A &>>D9) 1$01 +!27!9A+$9! G
H'/>>&/>>?/>>C/>>>A/>>B/>>E/>>@/>>=/>&>/>&&/>&?/>&C/>&&A/>&B/>&E/>&@/>&=/>?>Char"
'y( HA)S )O* SOFT*ARE+ ,,,-handsdo,nsof",are-.o!CA
AAB>BAE>EAH$25D5+) 9A+5% G 7%$:DS 2%5S+$9! 7!9 7%$:D D9)
A59Class%/Allo,E0S/Re.o!!endClass%/Re.o!!end0os Angeles limate Data
1inswith Data enter 3uideline IonesBAROMETRIC PRESSURE: 29.808 in.
HGPSYCHROMETRICCHARTor!al Te!pera"ureI#P Un$"s%12 FEETChar" 'y(
HA)S )O* SOFT*ARE+ ,,,-handsdo,nsof",are-.o!JDesign +arget$pper
Allowed Humidity 0imit0ower Allowed Humidity 0imit -?>K9H.%nly a
few hours of possible concern for humidification27 Taylor
Engineering, LLCBAROMETRIC PRESSURE: 29.893 in.
HGPSYCHROMETRICCHARTor!al Te!pera"ureI#P Un$"s3& FEETWeather
Hours270 to 241240 to 211210 to 181180 to 151150 to 121120 to 9190
to 6160 to 3130 to 1C> CA AA B> BA E> EA @> @A => =A
&>>D9) 1$01 +!27!9A+$9! G
H'/>>&/>>?/>>C/>>>A/>>B/>>E/>>@/>>=/>&>/>&&/>&?/>&C/>&&A/>&B/>&E/>&@/>&=/>?>Char"
'y( HA)S )O* SOFT*ARE+ ,,,-handsdo,nsof",are-.o!CA
AAB>BAE>EAH$25D5+) 9A+5% G 7%$:DS 2%5S+$9! 7!9 7%$:D D9)
A59Class%/Allo,E0S/Re.o!!endClass%/Re.o!!endSacramento limate Data
1inswith Data enter 3uideline IonesBAROMETRIC PRESSURE: 29.893 in.
HGPSYCHROMETRICCHARTor!al Te!pera"ureI#P Un$"s3& FEETChar" 'y(
HA)S )O* SOFT*ARE+ ,,,-handsdo,nsof",are-.o!SacramentoJDesign
+arget$pper Allowed Humidity 0imit0ower Allowed Humidity 0imit
-?>K9H.:egligible time of possible concern for humidification28
Taylor Engineering, LLC0ower humidity limit2itigate electrostatic
discharge -!SD.9ecommended procedures7ersonnel groundingable
grounding9ecommended e8uipment3rounding wrist straps on
rac#s3rounded plate for cables3rounded flooringServers rated for
!SD resistance5ndustry practices+elecom industry has no lower
limit+he !lectrostatic Discharge Association has removed humidity
control as a primary !SD control measure in their !SD;A:S5
S?>/?> standardHumidity controls are a point of failure and
are hard to maintain2any data centers operate without
humidification+his needs more researchAnd for some physical media
-tape storage, printing and bursting.%ld technology not found in
most data centers5t is best to segregate these items rather than
humidify the entire data center29 Taylor Engineering, LLC!SD
control: floor grounding$mage from -anuit, re(rinte with
(ermissionWater-Side EconomizerWater-Side Economizer5ntegratedHea"
E4.han5er $n ser$es ,$"h .h$llers on CH* s$de31 Taylor Engineering,
LLC!conomi"er SummaryAirGSide !conomi"ers7rovides free cooling when
dryGbulb temperatures are below E@H'G@>H'/2ay increase
particulates -01:0 research indicates this is of little
concern./Should be integrated to be most effective/5mproves plant
redundancy(an wor# in con4unction with waterGside economi"ers on
data centers(:eed to incorporate relief/WaterGSide
!conomi"ers7rovides low energy cooling when wetGbulb temperatures
are below AAH'GB>H'/Avoids increased particulates -and low
humidity if that concerns you./Should be integrated to be most
effective -see previous slide./5mproves plant redundancy(an wor# in
con4unction with airGside economi"ers on data centers(1oth are
proven technologies on data centers(32 Taylor Engineering, LLCA
case study of two designsollocation facility in the 1ay AreaSide by
side designs in same facility over two phases2otivation for the
second design was to reduce costase study was developed by 0awrence
1er#eley :ational 0aboratory -01:0.Data enters @/& and @/?1oth
sections at LC>K buildGout during monitoring33 Taylor
Engineering, LLCA tale of two designs: overviewPhase % )a"a Cen"er
(6-%)?B,?>> ft??E W;ft? design+raditional underGfloor design
with 9A unitsAirGcooled DJHumidity controls ->> ft?A>
W;ft? design$nderGfloor supply from central AH$s with HW
coilsWaterGcooled plantAirGside economi"ers:o humidity controls34
Taylor Engineering, LLCA tale of two designs: a closer
loo#:ormali"ed efficiency metric:serverssystems
coolingcoolingkWkW_= Data normali"ed to computer loadsL&;<
of the normali"ed energyPhase % )a"a Cen"er (6-%)Phase 3 )a"a
Cen"er (6-3)35 Taylor Engineering, LLCA tale of two designs:
resultsPhase % )a"a Cen"er (6-%)Around ?D the H*A installed cost
-M;ft?.Around >> M>> M:umber of units ?& &C
< net total cooling -btuh. ,>>>@>>net sensible
-btuh. C=E,>C==,>>>@&@,>>>sensible -tons.
CC/&CC/CB@/?'2
&B,A>>?A,>>>A>,>>>SA+
A=/C>A=/>>airside d+
?A/&>&A/E>&B/>>5nternal S7 ? >/@ >/@
&/@ &/@no/ fans C C ?fan type entrifugal 7lenum 7lenumno/
motors & C ?H7;motor &A A &Atotal H7 &A &A
C>1H7;motor &A >w;sf.Air delivery limitations9eal estate
Wor#ing conditionsHot aisles are approaching %SHA limitsostly
infrastructureHigh energy costs2anagement over time9eliability0oss
of power recovery7articulates41 Taylor Engineering, LLC+a#e
Aways$se airG or waterGside economi"ers where possibleonsider
personal grounding in lieu of humidificationonsider AH$s as an
alternative to 9Asonsider *SDs on fans, pumps, chillers and
towers9efer to ASH9A!, 01:0 and $ptime 5nstitute for more
recommendations42 Taylor Engineering, LLCState of the future:
cooling with li8uid
