Abdul Qadir 1 , Research Assistant Peter Armstrong 2 , Associate Professor
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Abdul Qadir 1 , Research Assistant Peter Armstrong 2 , Associate Professor Mechanical Engineering Program Masdar Institute of Science and Technology Abu Dhabi, UAE IMECE2010-40571 Vancouver, BC 17 November 2010 1] [email protected] 2] [email protected] Hybrid Liquid-Air Transpired Solar Collector Model Development and Sensitivity Analysis
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Hybrid Liquid-Air Transpired Solar Collector Model Development and Sensitivity Analysis. Abdul Qadir 1 , Research Assistant Peter Armstrong 2 , Associate Professor Mechanical Engineering Program Masdar Institute of Science and Techn ology Abu Dhabi, UAE IMECE2010-40571 - PowerPoint PPT Presentation
Transcript of Abdul Qadir 1 , Research Assistant Peter Armstrong 2 , Associate Professor
Abdul Qadir1, Research AssistantPeter Armstrong2, Associate Professor
Mechanical Engineering ProgramMasdar Institute of Science and Technology
Abu Dhabi, UAE
IMECE2010-40571Vancouver, BC 17 November 2010
1] [email protected]] [email protected]
Hybrid Liquid-Air Transpired Solar CollectorModel Development and Sensitivity Analysis
Motivation: Dehumidification
UAE urban development in humid coastal regions
Abundant solar resource
Current UAE policies encourage Renewable energyEnergy efficiency
X- xx- yy
X- xx- yy
ADWEA 2008 Daily Loads (AD Island) Weather Sensitivity
Growth in Peak Demand
4,7905,180
5,910
7,735
8,735
9,705
10,600
11,46012,151
12,71113,139 13,452 13,716 14,089 14,340
0
2,000
4,000
6,000
8,000
10,000
12,000
14,000
16,000
2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020
Gro
ss M
W
Abu DhabiAl AinWestern RegionTotal System
Peak electricity demand growth estimates for Abu Dhabi (2007-2012)Recent revised estimates are significantly higher
(Ref: Abu Dhabi Water and Electricity Company, 2007)
Motivation: Dehumidification
X- xx- yy
X- xx- yy
Conventional Solar-Powered Dehumidification
Low-Cost Unglazed Solar Collector
Unglazed Hybrid Liquid-Air Collector
Heated water and air to desiccant regenerator
Transpired
air
Fan
Perforated absorber plate
Heat Balance Model
Modeling Assumptions
1. One-Dimensional Flow of Air, Water and Heat
2. Uniform Porosity to Approximate Many Small Holes
3. T(x) Can Be Modeled By Fin EquationFin Boundary Conditions: Fluid Uniform Temperatures; Uniform AbsorbedSolar Flux
4. T(y) Can Be Modeled By Non-Linear ODE
Note That (1-3) Apply to Differential Control Volume
Differential Control Volume Heat and Mass Balances
Convective Heat Transfer Relations
Convection Loss From Plate (Kutscher)Face velocity, wind speed, perforation pitch
NTU-Effectiveness Model of Perforations (Kutscher)
Convective coupling of Plate to Airstream BehindNon-uniform temperature difference: bracketing analysisPitch>>BL thickness use standard flat plat Nu=f(Re,Pr,D/L)Pitch<<BL thickness assume no coupling
Sensitivity Analysis
Ratio of Air to Total Thermal Capacitance Rate
Total Thermal Capacitance Rate
Absorber Emissivity
Back Coupling
Sensitivity Analysis
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0 0.2 0.4 0.6 0.8 1
Effici
ency
mdotcp ratio
mdotcptot=25W/m2K mdotcptot=20W/m2K mdotcptot=15W/m2K
mdotcptot=10W/m2K mdotcptot=5W/m2K
Sensitivity Analysis
0
0.1
0.2
0.3
0.4
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0 0.2 0.4 0.6 0.8 1
Effci
ency
mdotcp ratio
mdotcptot=25W/m2K mdotcptot=20W/m2K mdotcptot=15W/m2K
mdotcptot=10W/m2K mdotcptot=5W/m2K
Sensitivity Analysis
300
310
320
330
340
350
360
370
380
390
400
0 0.2 0.4 0.6 0.8 1
Twou
t
mdotcp ratio
mdotcptot=25W/m2K mdotcptot=20W/m2K mdotcptot=15W/m2K
mdotcptot=10W/m2K mdotcptot=5W/m2K
Sensitivity Analysis
300
310
320
330
340
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360
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380
390
400
0 0.2 0.4 0.6 0.8 1
Twou
t
mdotcp ratio
mdotcptot=25W/m2K mdotcptot=20W/m2K mdotcptot=15W/m2K
mdotcptot=10W/m2K mdotcptot=5W/m2K
Sensitivity Analysis
0
0.1
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0.3
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0.5
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0.8
0.9
0 0.02 0.04 0.06 0.08 0.1 0.12
effici
ency
(Ti-Ta)/G
e=0.1 e=0.5 e=0.9
Sensitivity Analysis
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0 0.02 0.04 0.06 0.08 0.1 0.12
effici
ency
(Ti-Ta)/G
e=0.1 e=0.5 e=0.9
Sensitivity Analysis
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
0 0.02 0.04 0.06 0.08 0.1 0.12
effici
ency
(Ti-Ta)/G
e=0.1 e=0.5 e=0.9
Sensitivity Analysis
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
0 0.02 0.04 0.06 0.08 0.1 0.12
effici
ency
(Ti-Ta)/G
e=0.1 e=0.5 e=0.9
Sensitivity Analysis
0
0.2
0.4
0.6
0.8
1
1.2
0 0.02 0.04 0.06 0.08 0.1 0.12
effici
ency
(Ti-Ta)/G
e=0.1 e=0.5 e=0.9
Sensitivity Analysis
0
0.1
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0.5
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0.7
0.8
0.9
1
0 0.02 0.04 0.06 0.08 0.1 0.12
effici
ency
(Ti-Ta)/G
e=0.1 e=0.5 e=0.9
Sensitivity Analysis
-0.6
-0.4
-0.2
0
0.2
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0.6
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1
1.2
-0.05 0 0.05 0.1 0.15 0.2
Effici
ency
(Ti-Ta)/G
Vw=5m/s Vw=3m/s Vw=0m/s Linear (Vw=5m/s) Linear (Vw=3m/s) Linear (Vw=0m/s)
Sensitivity Analysis
0
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0.9
-0.05 0 0.05 0.1 0.15 0.2
Effici
ency
(Ti-Ta)/G
Vw=5m/s Vw=3m/s Vw=0m/s Linear (Vw=5m/s) Linear (Vw=3m/s) Linear (Vw=0m/s)
Future Work
Experimental Verification
Regenerator and Absorber Models
System Optimization
Model Refinement and Collector Optimization
X
Heated water and air to desiccant regenerator
Transpired Air
Fan
Perforated absorber plate
Unglazed Transpired Air Collector(UTAC) for Desiccant RegenerationAdvisor: Dr. Peter Armstrong Student: Abdul Qadir
Research Objectives-Develop through simulation and testing, an UTAC which can deliver an outlet air temperature of 70˚C in order to regenerate a desiccant for desiccant cooling and dehumidification cycles.
- Investigate a hybrid UTAC to produce hot water & air.
- Develop an integrated model and test the performance of a desiccant cooling cycle coupled with a UTAC.
Broader Impacts- Could replace the gas burners which are
currently used to regenerate desiccants. - Cost effective way to integrate solar
technology to an existing cooling infrastructure.
- Can significantly reduce the electricity consumption by removing latent cooling load from the cooling system, especially in humid climates like Abu Dhabi’s.
Figure 2: Initial TRNSYS simulation resultsFigure 1: Schematic of the UTAC configuration
Heated air to desiccant cycle
Transpired Air
FanBuilding Roof
Perforated absorber plate
X
X- xx- yy
Heated air to desiccant cycle
Transpired Air
FanBuilding Roof
Perforated absorber plate
