new absorption chillers for high efficient solar cooling ... · pdf filenew absorption...

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New absorption chillers for high efficient solar cooling systems

Technische Universität Berlin • Institut für Energietechnik

New absorption chillers for high efficient solar cooling systemsDipl.-Ing. Stefan Petersen & Dipl.-Ing. Jan Albers

1. General Technology Overview2. Operating data3. Solar cooling system layout4. Showcase results

Foto: TU BerlinFoto: TU Berlin

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open cycles

Solar air-conditioning technologies

electrical systems thermal systems

- PV + Vapor compression chiller

- …heat transformation

processesthermomechanical

processes

- steam jet cycles

- rankine cycle + vapor compression chiller

- …

closed cycles

liquid sorbent

solid sorbent

absorption chiller

adsorption chiller

desiccant and evaporative cooling (DEC)

liquid sorbent

solid sorbent

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coolingwater

electric power

steam

steam

chilled water

vaporous refrigerant

condenser

evaporator

compressorrefrigerant throttle

liquid refrigerant

water-cooled vapor compression chiller [1]

[1] Carrier

Basics –compression chillerinner cycle

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cooling water

10 kW Phönix-absorption chiller-TU Berlin

evaporator

condenser

refrigerant

steam

Chilled water

refrigerantthrottle

steam

cooling water

diluted solution

hot water

concentrated solution

absorber

desorber

Basics – absorption chillerinner cycle

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Short general characteristic

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0

10

20

30

40

50

60

70

24 29 34 39 44 49Reject Heat Inlet Temperature [°C]

CO

P [-]

0 , 2

0 , 3

0 , 4

0 , 5

0 , 6

0 , 7

0 , 8New 50 kW Chiller

High efficient10 kW

Coo

ling

Cap

acity

[kW

]

Nominal load

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System setup – thermal system configurationHeat transformation process

Basic system configurationStorage almost inevitable

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0

10

20

30

40

50

60

70

50 60 70 80 90 100Heat Source Inlet temperature [°C]

Coo

ling

Cap

acity

[kW

]

0,9 l/s0,6 l/s

0,3 l/s

0,1 l/s

Variability Driving Heat Source I@ t_RH=30°C, V_RH=3,8kg/s, t_CW=21/16°C

dT@40kW 13K 40K

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0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0 10 20 30 40 50 60 70

Volumenstrom 0.9 l/s



Variability Driving Heat Source II @ t_RH=30°C, V_RH=3,8kg/s, t_CW=21/16°C

CO

P [-]

Cooling capacity [kW]

Volume flow

Volume flow

dt in/out < 13K@77/64…..

to.. ≈ 40K@97/57

Volume flow

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0

10

20

30

40

50

60

25 30 35 40 45

Variability Reject Heat Sink I @ t_DH=90°C, V_DH=0,9kg/s, t_CW=21/16°C

1,0 l/s

3,8 l/s

2,0 l/s

1,5 l/s

Reject Heat Inlet Temperature [°C]

Coo

ling

Cap

acity

[kW

]

Phydraulic = nominal=100%

Phydraulic = 1/64*nominal= 1.5%

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Energetic comparison including auxiliaries

0

0,5

1

1,5

2

0 0,2 0,4 0,6 0,8 1Solar fraction

auxiliary power demand pa=0

pa=10%

pa=1%

break even

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image source: Busse

SAC-System UBA Dessau

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Concept for solar cooling system

KKM

AKA

Compressionchiller

(Dry) reject heat device

Chilled waterstorage

SolarCollectors

Absorptions-chiller

Coldconsumer

Hot waterstorage

District heating

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SAC-System UBA Dessau

Temperaturetop of storage

Solardriving

temperature

Temperaturecollector outlet

Chilledwateroutlet

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Operating data and control

04:00 08:00 12:00 16:00 20:00 0

10

20

30

40

50

60

70

80

90

100

Uhrzeit am 03.09.2011

Tem

pera

tur /

°C

, Vol

umen

stro

m /

(m³/h

), S

trahl

ung

/ (10

W/m

²)

Antriebstemperatur solar

Volumenstrom Kollektorkreis

Entladevolumenstrom

Solarstrahlung horizontal

Temperatur Speicher 1 oben

Temperatur KollektoraustrittTemperature at collector outletTemperature at top of storage

Solar driving temperature

Horizontalirradiation

Flow rate in collector circuit

Driving flow rate to chiller

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Regelung und Betriebsergebnisse

04:00 08:00 12:00 16:00 20:00 0

10

20

30

40

50

60

70

80

90

100

Uhrzeit am 03.09.2011

Tem

pera

tur /

°C

, Lei

stun

g / k

W

Antriebstemperatur (Sollwert)

Temperatur Kühlwasser Eintritt

Antriebstemperatur

Temperatur Kühlwasser (Sollwert)

Kälteleistung (Sollwert)

Kälteleistung

Temperatur Kaltwasser Austritt

Driving temperature

Driving temperature(set point

Reject heat inlet temperature

Cooling load (set value)

Cooling load

Reject heat inlet temp. (set value) Chilled water temperature

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Results of first year

First yearwith new absorption chiller

Previous year with adsorption chiller

Aug. 2011 – Jul. 2012Aug. 2010 – Jul. 2011

Cold generation 59 MWh0104 MWh0

Driving heat 80 MWhth221 MWhth

Thermal efficiency 0,47 MWh0/MWhth

Electrical efficiency 4,5 MWh0/MWhel2,9 MWh0/MWhel

Water consumption 1,3 m³/MWh04,0 m³/MWh0

0,76 MWh0/MWhth +62%

+55%

68%

Change

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Control Issues: Parasitic electricity consumption

Control Strategy SEERel SEERth

Classic 12,4 0,76+Reject heat, vol.flow 17,8 0,75+Hot Water, vol.flow 13,6 0,76

+vol.flows+reject heat temp.

20,1 0,75

SEER = Seasonal Energy Efficiency Ratio

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Conclusion

Foto: TU Berlin

Development started in 2008 withcase studies and optimization:- Thermodynamic design- Manufacturing process- Cost efficiency

Final chiller concept fixed in 2009 Starting of pre-industrial manufacturing

and laboratory measurements in 2010 Installation of first prototypes

in Berlin and Dessau in 2011 Commercial launch in 2013:

- high energy efficiency (COP > 0,75)- high energy density and compactness- high cooling water temperatures > 45°C - low driving temperatures (tstart < 60°C)- low investment (~300 €/kW)

new absorption chillers for high efficient solar cooling ... · pdf filenew absorption...

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