Australian Solar Cooling Interest Group (ausSCIG) Conference 2013
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Institute of Air-handling and Refrigeration (ILK Dresden)
Component development and first test results of a
directly air-cooled water/LiBr absorption chiller
Australian Solar Cooling 2013 Conference, Sydney 2013
Day 2 – Solar Cooling Conference - 12/04/2013
Venue: CSIRO, North Ryde, Sydney
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Australian Solar Cooling Interest Group (ausSCIG) Conference 2013
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ILK Dresden – R&D company
Founded in 1964
Re-established as independent
research institute in 1991
Employees: 145
Academics: 72 %
mean age: ~44
Laboratory area: ~3000 m²
Test rigs: ~56
Phys. / Chem. Laboratories: 25
12.04.2013
Day 2 – Solar Cooling Conference - 12/04/2013
Venue: CSIRO, North Ryde, Sydney
Directly air-cooled absorption chiller - Australian Solar Cooling 2013 Conference - M. Safarik
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Background and goal of the development
Problems in systems with small scale chillers
Complexity of the systems
Interface problems because of different crafts (might be) involved
Possibly high error rate during installation
Auxiliary energy demand of the system
Limited applicability of evaporative systems but high re-cooling
sensibility of the cycle
12.04.2013
Directly air-cooled absorption chiller - Australian Solar Cooling 2013 Conference - M. Safarik
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Day 2 – Solar Cooling Conference - 12/04/2013
Venue: CSIRO, North Ryde, Sydney
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Challenges
Avoiding of an intermediate circuit:
- to minimize the auxiliary energy demand (as re-cooling circuit pump
usually consumes a lot)
- for a better approach of external and internal temperatures since
temperature lift is limited
Air-cooled absorber needed
Water as refrigerant -> big free section needed
?
Air as heat transfer media -> big free section needed
12.04.2013
Day 2 – Solar Cooling Conference - 12/04/2013
Venue: CSIRO, North Ryde, Sydney
Directly air-cooled absorption chiller - Australian Solar Cooling 2013 Conference - M. Safarik
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Distribution of the auxiliary energy demand
of a small scale water cooled absorption chiller
35 %
25 %
22 %
Nominal cooling capacity: 19,4 kW
12.04.2013
%-numbers: pump efficiency
Directly air-cooled absorption chiller - Australian Solar Cooling 2013 Conference - M. Safarik
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Day 2 – Solar Cooling Conference - 12/04/2013
Venue: CSIRO, North Ryde, Sydney
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Australian Solar Cooling Interest Group (ausSCIG) Conference 2013
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Auxiliary energy demand of the system
Auxiliary energy demand of the system with constant
speed pumps/fans as a function the cooling capacity
12.04.2013
Day 2 – Solar Cooling Conference - 12/04/2013
Venue: CSIRO, North Ryde, Sydney
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Distribution of auxiliary energy demand
12.04.2013
Directly air-cooled absorption chiller - Australian Solar Cooling 2013 Conference - M. Safarik
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Day 2 – Solar Cooling Conference - 12/04/2013
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Australian Solar Cooling Interest Group (ausSCIG) Conference 2013
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Examples of air-cooled absorption chillers
Source Helioplus
Source: Rotartica
H2O/LiBr, rotating HX,
NH3/H2O -> high working pressure!
intermediate circuit
Gas driven -> high temperature
12.04.2013
Day 2 – Solar Cooling Conference - 12/04/2013
Venue: CSIRO, North Ryde, Sydney
Directly air-cooled absorption chiller - Australian Solar Cooling 2013 Conference - M. Safarik
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Australian Solar Cooling Interest Group (ausSCIG) Conference 2013
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Examples of air-cooled absorption chillers
Source: Broad
H2O/LiBr, gas driven, intermediate
circuit
Q0=23 kW; zetta=1,1, Pel=1,8kW
Source: Broad
12.04.2013
(COPel=12,7)
Directly air-cooled absorption chiller - Australian Solar Cooling 2013 Conference - M. Safarik
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Day 2 – Solar Cooling Conference - 12/04/2013
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Balancing Single Lift vs. Double Dift
0,8
125
0,75
120
0,7
115
0,65
110
0,6
105
0,55
100
0,5
95
0,45
90
0,4
85
0,35
80
0,3
75
0,25
70
0,2
65
0,15
60
ζreal [-]
tHW,e [°C]
durchgezogen
- Double
/ gestrichelt - Single Lift lift
Solid lines – single effect/double
lift; dashed
linesLift
– single-effect/single
130
0,1
20
25
30
35
40
45
50
tL,e [°C]
For chilled water out: 13 °C
12.04.2013
Day 2 – Solar Cooling Conference - 12/04/2013
Venue: CSIRO, North Ryde, Sydney
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Aimed specifications for the component development
External Fluid
Nominal Condition
Operating Range
Chilled water temperature
18 °C / 13 °C (in/out)
(water w. 20 % Glycol)
6 °C … 20 °C (out)
Heating water temperature
95 °C / 87 °C (in/out)
(water w. 20 % Glycol)
75 °C … 105 °C (in)
Ambient air (for recooling)
32 °C / 42 °C (in/out)
10 °C … 32°C (in)
Cooling capacity
8 kW
Condenser and Absorber directly air-cooled
Outdoor installation, frost save
Auxiliary energy consumption at nominal conditions < 60 Wel/kW0 („EER“ > 16)
Single effect / single lift
12.04.2013
Directly air-cooled absorption chiller - Australian Solar Cooling 2013 Conference - M. Safarik
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Calculated cooling capacities for different
temperatures
tAL [°C] - t KT ,a [°C]
25
32 - 18
20
Θ o [kW o ]
32 - 14
15
32 - 10
37 - 18
10
32 - 6
37 - 14
40 - 18
5
0
80
85
90
95
100
105
110
tHW,e [°C]
12.04.2013
Day 2 – Solar Cooling Conference - 12/04/2013
Venue: CSIRO, North Ryde, Sydney
Directly air-cooled absorption chiller - Australian Solar Cooling 2013 Conference - M. Safarik
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Australian Solar Cooling Interest Group (ausSCIG) Conference 2013
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Design and testing of components (Samples)
Even and permanent distribution of the solution onto vertical absorber tubes
Good wetting inside the tubes over the whole lenght
Increase of HX area on air side
Efficiency of the fan vs. cost
Model
ηFan [-]
cost [€]
Arial 1
0,354
752
Axial 2
0,375
817
Axial 3
0,395
826
Radial 1
0,480
995
Radial 2
0,570
1222
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Directly air-cooled absorption chiller - Australian Solar Cooling 2013 Conference - M. Safarik
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Day 2 – Solar Cooling Conference - 12/04/2013
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Australian Solar Cooling Interest Group (ausSCIG) Conference 2013
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Test of components within functional model
12.04.2013
Day 2 – Solar Cooling Conference - 12/04/2013
Venue: CSIRO, North Ryde, Sydney
Directly air-cooled absorption chiller - Australian Solar Cooling 2013 Conference - M. Safarik
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First Results
Criteria
Design target
Cooling capacity
8 kW
7,7 kW
with inlet temperatures: with inlet temperatures:
95 °C; 32 °C; 18 °C
95 °C; 29,5 °C; 18 °C
Thermal EER
0,71
0,72
Auxiliary energy demand
(“electrical EER”)
0,50 kW
62,5 Wel/kW0
EERel: > 16
0,64 kW
85 Wel/kW0
EERel: > 12
12.04.2013
Reached so far
Directly air-cooled absorption chiller - Australian Solar Cooling 2013 Conference - M. Safarik
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First Results
1,0
7,5
0,9
7,0
0,8
6,5
0,7
6,0
0,6
5,5
0,5
5,0
0,4
4,5
0,3
4,0
0,2
3,5
0,1
3,0
0
50
100
150
200
ς
12.04.2013
Day 2 – Solar Cooling Conference - 12/04/2013
Venue: CSIRO, North Ryde, Sydney
rL
250
300
ζ [-]
Θ o [kW]
MP 95/30/13 (t HW,e/t L,e/t KT,a) Ventilator n=1
8,0
0,0
350
[l/h]
Directly air-cooled absorption chiller - Australian Solar Cooling 2013 Conference - M. Safarik
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Outlook
Optimisation
Decrease of air side pressure drop
Prevention of air bypass
Improvement of design and alignment of components
Avoidance of solution displacement
=> Design and construction of an optimised prototype
Build-up of an adapted testing infrastructure
More detailed laboratory testing
Monitoring and evaluation of two prototypes in field tests
12.04.2013
Directly air-cooled absorption chiller - Australian Solar Cooling 2013 Conference - M. Safarik
Day 2 – Solar Cooling Conference - 12/04/2013
Venue: CSIRO, North Ryde, Sydney
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ILK Dresden
Thanks for your attention!
Department of Applied Energy Engineering
Bertolt-Brecht-Allee 20; 01309 Dresden; Germany
Dr.-Ing. Mathias Safarik
Tel.:
E-Mail:
Day 2 – Solar Cooling Conference - 12/04/2013
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+49 351 4081-700
[email protected]
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