page1School of Architecture, Center for Building Performance and Diagnostics @ CMU

Solar Absorption Cooling / Heating System for the Intelligent Workplace

Ming Qu

Sophie Masson

Dr. David Archer

IWESS Workshop Oct.4,2006

School of Architecture, Center for Building Performance and Diagnostics @ CMU Page2

CMPTK-1

Natural Gas

The initial solar heating and cooling system

Para

bolic

Tro

ugh So

lar C

ollector

s

HX-1

TO LOAD

Absorption

Chiller

Coolingtower

Cooling tower

IW solar cooling/heating system

Intelligent

Workplace

One -axis solar

trough

Introduction

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17'5"(5310mm)

12

9@15'9" (9@ 4800 mm)

15

57'7

"(1

7500

mm

)

39'4

"(12

000m

m)

Solar Collectors

Building North

Location of chiller and control box

IW Solar Field Plan

Intelligent workplaceThe Robert L. Preger

Intelligent Workplace� latitude: North 40.26◦

longitude: –79.56◦� Orientation: 15 deviation to

east from the south� area:650 m2 (7,000 ft2)

South zone � area: 245 m2 (2,637 ft2)� 9 offices and 1 conference

space� 30 people

PTSC Orientation� E-W axis

Feb.21 10:50am / 1:10pm

Dec.21 9:10am / 2:50pmJan.21 8:50am / 3:10pmFeb.21 8:00am / 3:50pm

16°

Introduction

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Parabolic trough solar collector (PTSC)

� Each module includes– parabolic trough reflector– receiver pipe, surface treated– steel support structure– single axis drive

� 4 modules, total 52.44 m2� Installed in series� Piping length:85m

Introduction

Module

12m

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Dual fired D.E absorption chiller

� 16 kW (4.55 tons)� hot water driven or natural gas fired� LiBr/H2O, sorbent; water, refrigerant� double effect� COP 1.0~1.2 at the rated condition� cooling, heating modes� heating efficiency 0.8~0.95

Introduction

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Solar cooling / heating system

� 50% in volume of propylene glycol

� constant flow

57C/50C7C/14CCHW/HW supply/return

> 130C>T_HTR

(155C)

Solar field temperature

0.4Mpa

(58psi)

0.85Mpa

(123psi)

Solar field pressure

HeatingCooling

(pressurized aqueous solutions of propylene glycol)P&ID Diagram of Solar Thermal System

P1

CMPTK-1

2

3

1

6

4

52.4 m

^2 so

lar c

ollector

field

16 kW 2E

Absorption

Chiller

Natural Gas

7

5

8

HX-1

TO LOAD

50% propylene glycol

CHW at 7.8C / HW57.2C

CHW at 14C / HW50C

Coolingwater

cooling tower

Introduction

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Design and procurement

Engineering construction draw.Equipment delivery

Preliminary designMass & Energy balance cal.

Accomplishment

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System construction and installation

Accomplishment

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PTSC mathematic model

skyoutgingfluidinaouta TTTTTTT >>>>>> ∞____

'_ gSolAbsq&

'sup_condq&

'__ skygradq&

'_ fluidconvq&

'__ garadq&

'__ gaconvq& '

_gcondq&

'_aSolAbsq&

'__ airgconvq&

'_acondq&

T (

in C

)

fluid

absorber tube

glass envelope

ambient air skyambient airsky

X

At a fixed Y

X

YAt a fixed X

T

Y

Tf

R_conv_f R_cond_a

Ta1 Ta2

Tbase

Tg1 Tg2

Tair

Tsky

R_conv_a_g

R_rad_a_g

R_cond_g

R_conv_g_air

R_rad_g_sky

R_cond_sup

The thermal network

Accomplishment

'

'

i

sthermallosopt q

q&

&−=ηη

'_

'__

'__

'bracketcondairgconvskygradsthermallos qqqq &&&& ++=

'__

'__

'_

'_ skygradairgconvgcondgSolAbs qqqq &&&& +=+

'_

'_

'_ aradaconvgcond qqq &&& +=

'_

'_

'_

'_

'_ bracketcondacondaradaconvaSolAbs qqqqq &&&&& +++=

'_

'_ fluidconvacond qq && =

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Predicted PTSC performance

Accomplishment

BROAD PTSC Efficiency vs Temp & Incident Angle

0.25

0.3

0.35

0.4

0.45

0.5

0.55

0.6

0 50 100 150 200 250 300 350 400Average Operation Temeprature Above Ambient (oC)

Eff

icie

ncy

Incident angle = 0Incident angle = 10INcident angle = 20Incident angle = 30Incident angle = 40Incident angle = 50

Syltherm 800Direct normal solar radiaiton I_dn=900W/m^2

BROAD PTSC Efficiency vs Temp & Insolation at 0 Incident Angle

0.25

0.3

0.35

0.4

0.45

0.5

0.55

0.6

0 50 100 150 200 250 300 350 400

Average Operation Temeprature Above Ambient (oC)

Eff

icie

ncy

insolation 1100 W/m^2

insolation 1000 W/m^2

insolation 900 W/m^2

insolation 800 W/m^2

insolation 700 W/m^2

insolation 600 W/m^2

insolation 500 W/m^2

insolation 400 W/m^2

Syltherm 800Incident Angle =0

Solar collector efficiency & air in the annular space

0.4

0.45

0.5

0.55

0.6

0.65

0 50 100 150 200 250 300 350 400

Average Operation Temperature Above Ambient (oC)

Per

cen

t o

f en

erg

y to

to

tal c

olle

cted

Optical losses

vacuum

Air

Insolation = 900 W/m^2Incident angle =0

0.49

0.51

0.53

0.55

0.57

0.59

0 50 100 150 200 250 300 350 400

Average Operation Temeprature Above Ambient (oC)

Eff

icie

ncy 6 m^3/H

7 m^3/H

8 m^3/H

9 m^3/H

10 m^3/H

11 m^3/H

12 m^3/H

13 m^3/H

Syltherm 800Incident Angle =0Direct normal solar radition 900 W/m^2

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Predicted energy accounting by model

Accomplishment

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Preliminary system simulation

Accomplishment

hot heat transfer fluid

SOLAR ENERGY SUPPLY SYSTEM SIMULATION

BUILDING SIMULATION

LOAD LOOPSOLAR COLLECTION

LOOP

IW heating /

cooling loads

SEMCO air units

Weather data

Occupancy schedule

Equipment schedule

Lighting schedule

Season schedule

Cooling set point T,RH

Heating set point T,RHIntelligent Workplace

Conditioned fresh air

T, RH, air change rate

IW T, RH

IIW sensible heating /

cooling loads

One -axis solar

trough

Pump_solar

Pressure relife valve

Dual 2E

abs.

chiller

weather in Pittsburgh

Heat from burned gas

diverter

mixerPump_load

control

Information flow of TRNSYS simulation

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Estimated IW solar system performance by system simulation

IW solar cooling and heating system

might cover 39-50% of cooling load and 5-30% heating based on the system simulation.

Accomplishment

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System also designed for experiments

Installed HX-2 to

� Validate PTSC model

� Evaluate system simulations

� Compare absorption chiller vs HX for space heatingPump

S5

Heat

exchanger HX-2

Pump S4

CMPTK-1

Natural Gas

Para

bolic

Tro

ugh So

lar C

ollector

s

HX-1

TO LOAD

Absorption

Chiller

Cooling tower

Cooling water

Accomplishment

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� Integration with cooling and heating devices� Integration of energy supply systems like solar energy, bio-diesel energy

supply system� System simulation including the integration of various energy supply

systems to help design.� Economic of solar cooling and heating� System design, evaluation of a given application

suggestions

Where are we?

Where are we going ?

� Completed system installation� Commissioned the system, solar field has be operated at above 150C

driving 16kW D.E absorption chiller.

Questions?

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Experiments to validate PTSC model

Measure PTSC efficiency� optical efficiency � (no thermal loss)� at various elevated temperature� at different incidence angle

Thermal loss

� at various elevated temperature

� through piping

Heat capacity

V10 V3 V4

HX2 HX1

connect to CHW grid

T1

F1 F3 F4

Accomplishment

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Experiments to evaluate system simulation

Measure system performance for daily or seasonal operation� Different load profile� Solar radiation� control strategy

V10 V3 V4

HX2, chiller

HX1 Connect to CHW gridLoad=F4*Cp*(T7-T8)

F1 F3 F4

T8

T7

Time

Load16 kW

GIVEN

Accomplishment