My Thesis Defense Presentation May 3, 2010 Department of Mechanical Engineering Middle East Technical University

1. Thesis Defense for the Degree of Master of Science
2010
MAY 3, ANKARA
NUMERICAL MODELING AND
PERFORMANCE ANALYSIS
OF SOLAR-POWERED IDEAL
ADSORPTION COOLING SYSTEMS
Department of Mechanical Engineering
Middle East Technical University

2. Presentation Outline
2
1. Motivation
2. Adsorption Cycle Descriptions
i. Simple cycle
ii. Cycle enhancements
3. Scope of the Study
4. Models
5. Conditions Analyzed
6. Results
7. Conclusions
8. Future Work
Onur TAYLAN Thesis Defense
METU May 3, 2010

3. 1. Motivation
3
 Electricity demand exceed supply in Turkey in
2016-2017 (TEIAS, 2009)
 Increasing cooling loads  Increase in electricity
demand especially on Mediterranean coast
 Many hotels use conventional AC systems in
Antalya
 Need to decrease the electricity demand for
cooling in Antalya
 Need for sustainable and renewable solutions
Onur TAYLAN Thesis Defense
METU May 3, 2010

4. 2. Adsorption Cycle Descriptions
4
 Simple Cycle
Baker and Kaftanoglu (2007)
Onur TAYLAN Thesis Defense
METU May 3, 2010

5. 2. Adsorption Cycle Descriptions
5
 Cycle Enhancements
 Heat recovery cycle
 Mass recovery cycle
 Heat and mass recovery cycle
 Thermal regeneration
 Thermal wave
 Thermal wave cycle with mass recovery
 Convectivethermal wave
 Rotary beds
Onur TAYLAN Thesis Defense
METU May 3, 2010

6. 2. Adsorption Cycle Descriptions
6
 Heat Recovery Cycle
 Two adsorbent beds
operating out of phase
 Heat transferred from
bed being cooled to
bed being heated
 Increase in COP
Wang (2001)
Onur TAYLAN Thesis Defense
METU May 3, 2010

7. 2. Adsorption Cycle Descriptions
7
 Thermal Wave Cycle
Taylan et al. (2009)
 Two beds connected via HTF
 HTF between Thot and To
 Sorption processes create dT1 and dT2
Onur TAYLAN Thesis Defense
METU May 3, 2010

8. 3. Scope of the Study
8
What was available What was needed
 Thermodynamic models  Assess the feasibility of
of using solar energy for
adsorption cooling
 Simple systems
 Heat recovery  Develop fast models to
 Thermal wave perform a large number
of parametric studies
 MATLAB models of
 Obtain basic
 Simple
performance trends as
 Heat recovery operating conditions vary
Onur TAYLAN Thesis Defense
METU May 3, 2010

9. 3. Scope of the Study
9
What has been added
 TRNSYS-compatible MATLAB model of thermal wave
cycle
 Thermodynamic models of
 Thermal wave with adiabatic mass recovery (AMR)
 Thermal wave with isothermal mass recovery (IMR)
 TRNSYS model of solar-thermal system
 Three commercial collector models (two flat plate and
one evacuated tube) integrated with the solar-thermal
system
Onur TAYLAN Thesis Defense
METU May 3, 2010

10. 3. Scope of the Study
10
What has been added (cont’d)
 Modeling five commonly-used adsorbent –
refrigerant (working) pairs using MATLAB
 Developing a normalized seasonal model
 Running steady and seasonal-transient simulations
with the integrated model
 Investigating basic trends in the cycle and system
performances as some design parameters are
varied
Onur TAYLAN Thesis Defense
METU May 3, 2010

11. 4. Models
11
 Solar Thermal System Model
TRNSYS Model MATLAB Model
Taylan et al. (2010)
Onur TAYLAN Thesis Defense
METU May 3, 2010

12. 4. Models
12
 Normalized Cooling Load
To  ti   Trfrc
q load,N  ti  =
Max To  Trfrc 
 Normalized Cooling Capacity
q F  ti × COPads  ti 
q clg,N  ti  = S×
Max  qF ×COPads 
 Normalized Match Factor
qMatch,N  ti  = qclg,N  ti   qload,N  ti 
Onur TAYLAN Thesis Defense
METU May 3, 2010

13. 4. Models
13
 Storage (qStorage,N and qStorage,max)
 Loss (qLoss,N) if qStorage,N = qStorage,max and qclg,N > qload,N
 Backup (qBackup,N) if qStorage,N = 0 and qclg,N < qload,N
 Solar Fraction ( f ) & Loss Fraction ( l )
qclg,tot q
i
clg,N  ti  qLoss,tot q
i
Loss,N  ti 
f= = l= =
qload,tot q
i
load,N  ti  qload,tot q
i
load,N  ti 
Onur TAYLAN Thesis Defense
METU May 3, 2010

14. 4. Models
14
 Normalized Collector Area
q clg,N  ti 
Acoll , N =
G  ti 
× COPsys  ti 
Grfrc
 Normalized Mass of Adsorbent
 Max  X  
-1
mads,N = 
 X base 
Onur TAYLAN Thesis Defense
METU May 3, 2010

15. 5. Conditions Analyzed
15
 Adsorption cycle types
 Reversible (Rev)
 Simple
 Heat recovery with two spatially isothermal beds (HRec)
 Thermal wave with no mass recovery (NMR)
 Thermal wave with adiabatic mass recovery (AMR)
 Thermal wave with isothermal mass recovery (IMR)
 Adsorbent – Refrigerant (working) pairs
 Zeolite NaX – Water (Z1)
 Zeolite X13 – Water (ZW)
 Silica Gel – Water (SG)
 Activated Carbon – Ammonia (CA)
 Activated Carbon – Methanol (CM)
Onur TAYLAN Thesis Defense
METU May 3, 2010

16. 5. Conditions Analyzed
16
 Collector types
 Flat plate collector (FP)
 Evacuated tube collector (ET)
 Cooling tower types or condensation temperature Tcond
 Dry cooling tower
 Wet cooling tower
 Evaporation temperature Tevap
 Excess bed temperature Texcess  To  Tcond
 Heat capacity ratio R   mshell cshell  mHTF cHTF  mads cads  1
 Maximum bed temperature Thot
Onur TAYLAN Thesis Defense
METU May 3, 2010

17. 6. Results
17
 Comparison of different adsorption cycles
5.0
4.5
4.0 Reversible
3.5 NMR with bypass
3.0 NMR without bypass
COPads
2.5 AMR with bypass
2.0 AMR without bypass
1.5 IMR with bypass
1.0 IMR without bypass
0.5 Heat Recovery
0.0 Simple
90 100 110 120 130 140 150 160 170 180
Maximum Bed Temperature, Thot (oC)
Base Case: Z1 pair, Tcond = 30oC, Tevap = 10oC, R = 10 and Texcess = 0oC
Onur TAYLAN Thesis Defense
METU May 3, 2010

18. 6. Results
18
 Comparison of working pairs
1.4
1.2
1.0
Rev
COPsys,clg
0.8 Z1
ZW
0.6
SG
0.4 CA
0.2 CM
0.0
80 90 100 110 120 130 140 150 160 170 180 190
Maximum Bed Temperature, Thot (oC)
Base Case: NMR, Tcond = 30oC, Tevap = 10oC, R = 10 and Texcess = 0oC
Onur TAYLAN Thesis Defense
METU May 3, 2010

19. 6. Results
19
 Comparison of collectors and solar radiation levels
0.14
0.12
0.10
FP,500
COPsys
0.08 FP,750
0.06 FP,1000
ET,500
0.04 ET,750
0.02 ET,1000
0.00
90 100 110 120 130 140 150
Maximum Bed Temperature, Thot (oC)
Base Case: Z1 pair, Tcond = 20oC, Tamb = 35oC, Tevap = 10oC, R = 10 and Texcess = 10oC
Onur TAYLAN Thesis Defense
METU May 3, 2010

20. 6. Results
20
 Comparison of cooling towers and Tevap
0.16
0.14
0.12 Simple,Dry
0.10 HRec,Dry
COPsys,clg
Simple,Wet
0.08
HRec,Wet
0.06 Simple,5
0.04 Simple,15
0.02 HRec,5
HRec,15
0.00
90 100 110 120 130 140 150 160 170 180 190
Maximum Bed Temperature, Thot (oC)
Base Case: Z1 pair, Tcond = 30oC, Tevap = 10oC, R = 10 and Texcess = 10oC
Onur TAYLAN Thesis Defense
METU May 3, 2010

21. 6. Results
21
 Comparison of Texcess and R
0.30
0.25
Simple,DTexcess=0
COPsys,clg
0.20 Simple,DTexcess=10
HRec,DTexcess=0
0.15 HRec,DTexcess=10
Simple,R=0
0.10 Simple,R=3
HRec,R=0
0.05
HRec,R=3
0.00
80 90 100 110 120 130 140 150
Maximum Bed Temperature, Thot (oC)
Base Case: CA pair, Tcond = 30oC, Tevap = 10oC, R = 10 and Texcess = 10oC
Onur TAYLAN Thesis Defense
METU May 3, 2010

22. 6. Results
22
 Comparison of investigated operating conditions
9.0
8.0
7.0 base
Tcond=20
6.0
Tcond=40
COPads
5.0
Tevap=5
4.0 Tevap=15
3.0 DTexcess=0
2.0 DTexcess=10
1.0 Tcond=20, R=0
0.0 Tcond=20, R=10
90 100 110 120 130 140 150 160 170 180
Maximum Bed Temperature, Thot (oC)
Base Case: IMR with Z1 pair, Tcond = 30oC, Tevap = 10oC, R = 3 and Texcess = 5oC
Onur TAYLAN Thesis Defense
METU May 3, 2010

23. 6. Results
23
 Normalized Results (Solar and Loss Fractions)
f and l not affected by cycle type
 Using ET increases both f and l
 Using wet cooling tower increases f and l for FP and
decreases l for ET
 Decreasing Texcess or R or increasing S increases f and
decreases l
 As Thot increases f and l decrease
 1 – f proportional to qBackup
Onur TAYLAN Thesis Defense
METU May 3, 2010

24. 6. Results
24
 Normalized Results (Required Collector Area)
1000
Normalized Collector Area, Acoll,N
FP,Simple,Dry,R=10
100 FP,Simple,Wet,R=10
FP,HRec,Dry,R=10
FP,HRec,Wet,R=10
FP,Simple,Dry,R=0
10
FP,HRec,Wet,R=0
ET,Simple,Dry,R=10
ET,HRec,Dry,R=10
1
90 120 150 180
Maximum Bed Temperature, Thot (oC)
Onur TAYLAN Thesis Defense
METU May 3, 2010

25. 6. Results
25
 Normalized Results (Required Adsorbent Mass)
2.5
Normalized Adsorbent Mass
2.0
Dry+10degC
1.5
Dry+5degC
mads,N
Dry
1.0 Wet+10degC
Wet+5degC
0.5 Wet
0.0
90 120 150 180
Maximum Bed Temperature, Thot (oC)
Onur TAYLAN Thesis Defense
METU May 3, 2010

26. 7. Conclusions
26
 Suggested configuration
 Thermal wave cycle
 Evacuated tube collector
 Wet cooling tower
 High evaporation temperature
 Low excess bed temperature
 Low heat capacity ratio for simple and heat recovery
cycles
 High storage capacity
 Other parameters vary between analyzed cases
Onur TAYLAN Thesis Defense
METU May 3, 2010

27. 7. Conclusions
27
 Working pair selection depends on the available
maximum bed temperature
 Implementing heat recovery increases the
performance of simple cycle
 Implementing mass recovery to thermal wave cycles
does not increase the performance significantly,
although it increases the complexity of the system
 Backup power needed for Antalya
Onur TAYLAN Thesis Defense
METU May 3, 2010

28. 8. Future Work
28
 Implementing heat and mass transfer and diffusion
equations based on the specific thermal design of
the adsorbent bed
 Extending the current analysis with exergy analysis
 Modeling some other kinds of thermal wave
 Modeling heat recovery cycle with infinite number
of beds and comparing with thermal wave cycle
 Introducing new adsorbent – refrigerant pairs
 Verifying the results of the present study
experimentally, especially the thermal wave cycle
Onur TAYLAN Thesis Defense
METU May 3, 2010

29. References
29
 Baker, D. K., and Kaftanoglu, B., "Limits to the Thermodynamic Performance of a
Thermal Wave Adsorption Cooling Cycle," Proceedings of HEFAT 2007, pp. 6, Sun
City, South Africa, 2007.
 Taylan, O., Baker, D. K., and Kaftanoglu, B., "Parametric Study and Seasonal
Simulations of a Solar Powered Adsorption Cooling System," Proceedings of ECOS
2009, pp. 833 - 842, Foz do Iguacu, Parana, Brazil, 2009.
 Taylan, O., Baker, D. K., and Kaftanoglu, B., "COP Trends for Ideal Thermal Wave
Adsorption Cooling Cycles with Enhancements," Int. J. of Refrigeration: Under
Review, 2009.
 Taylan, O., Baker, D. K., and Kaftanoglu, B., "Adsorbent – Refrigerant Comparison
for a Solar Powered Adsorption Cooling System Using Seasonal Simulations,"
Proceedings of 10th REHVA World Congress, Antalya, Turkey, 2010.
 "Turkish Electrical Energy 10-Year Generation Capacity Projection," Turkish
Electricity Transmission Co. (TEIAS), Ankara, 2009.
 Wang, R. Z., "Performance Improvement of Adsorption Cooling by Heat and Mass
Recovery Operation," Int. J. of Refrigeration, vol. 24, no. 7, pp. 602-611, 2001.
Onur TAYLAN Thesis Defense
METU May 3, 2010

30. Thank you!
Onur TAYLAN
M.Sc. Candidate
Department of Mechanical Engineering Thesis Defense
Middle East Technical University May 3, 2010