SOLAR-POWERED COOLING, DEHUMIDIFICATION AND AIR CONDITIONING

Transcription

1 SOLAR-POWERED COOLING, DEHUMIDIFICATION AND AIR CONDITIONING Prof. Gershon Grossman Faculty of Mechanical Engineering Technion, Israel Institute of Technology Haifa 32000, ISRAEL November 2010 Solar Cooling, Dehumidification and Air Conditioning Technion Israel Institute of Technology 1

2 Demand for Air Conditioning in the World is on the rise Climate change and Global Warming Increased standard of living Demand for comfort European countries with no A/C tradition: 12 participants (national energy agencies, manufacturing experts, university labs, electric utilities) from 8 countries including the EU manufacturer s association EUROVENT gathered to identify suitable measures to transform the Central Air Conditioning market in the direction of Energy Efficiency (EU Report, 2003) Solar Cooling, Dehumidification and Air Conditioning Technion Israel Institute of Technology 2

3 Demand for A/C associated with increased demand for primary energy Solar Cooling can Alleviate the Problem Closed-cycle systems: Absorption, Adsorption, Jet-cooling. Open-cycle systems: Liquid desiccant, Solid sorption Solar Cooling, Dehumidification and Air Conditioning Technion Israel Institute of Technology 3

4 Solar Cooling System Solar Cooling, Dehumidification and Air Conditioning Technion Israel Institute of Technology 4

5 Solar Cooling/ Air Conditioning T A T H Q A2 Q H Heat Pump driven by Heat Engine Absorption/Adsorption Heat Pump Heat Pump W Heat Engine Q L Q A1 T L T A Solar Cooling, Dehumidification and Air Conditioning Technion Israel Institute of Technology 5

6 Chemical Heat Pump Principle NH 3 H 2 O H 2 O +NH NH 3 3 +NH 3 T pure = T T solution pure < T solution P pure > P P solution pure = P solution T solution -T pure =Temperature Lift Solar Cooling, Dehumidification and Air Conditioning Technion Israel Institute of Technology 6

7 Absorption Heat Pump Principle Q M1 Q H Condenser Desorber Comp W Evaporator Absorber Q L Q M2 Solar Cooling, Dehumidification and Air Conditioning Technion Israel Institute of Technology 7

8 Single-Effect LiBr-H 2 O Absorption Chiller Solar Cooling, Dehumidification and Air Conditioning Technion Israel Institute of Technology 8

9 Prototype 50 TR (175 kw) Solar Absorption Cooling System, Tadiran ASD Solar Cooling, Dehumidification and Air Conditioning Technion Israel Institute of Technology 9

10 Tadiran ASD Solar Cooling Project Solar Cooling, Dehumidification and Air Conditioning Technion Israel Institute of Technology 10

11 200 TR (700 kw) Solar Absorption Cooling System at Tel-Hashomer Hospital, Israel Solar Cooling, Dehumidification and Air Conditioning Technion Israel Institute of Technology 11

12 Absorption Working Fluid Pairs NH 3 -H 2 O H 2 O-LiBr Other absorbents for NH 3 and H 2 O Organic absorbents for CFC/HCFC Ternary mixtures Additives anti-corrosion, enhanced heat transfer Solar Cooling, Dehumidification and Air Conditioning Technion Israel Institute of Technology 12

13 Absorption Systems first cooling machines in History Chemical Heat Pumps as early as 18 th century First continuously operating refrigerators Edmond and Ferdinand Carrè ~1860 Gas-fired NH 3 -H 2 O domestic refrigerators up till ww2 Large-scale H 2 O-LiBr chillers powered by waste heat and solar Multi-effect gas-fired chillers for A/C ~1980 s and on Domestic NH 3 -H 2 O heat pump development Solar Cooling, Dehumidification and Air Conditioning Technion Israel Institute of Technology 13

14 Absorption Multi-Staging Staging required to benefit from hitemp heat source Double-effect chillers: Series and parallel connections Triple-effect systems Cascading Solar Cooling, Dehumidification and Air Conditioning Technion Israel Institute of Technology 14

15 COP Multi-Staging allows improved performance with high heat source temperatures Carnot 1-effect 2-effect 3-effect Chilled Water: 7.0 o C Cooling Water: 30.0 o C Heat Supply Temperature ( o C) Solar Cooling, Dehumidification and Air Conditioning Technion Israel Institute of Technology 15

16 Research Needs Advanced cycles Advanced fluids Heat and mass transfer in absorption/desorption System simulation Solar Cooling, Dehumidification and Air Conditioning Technion Israel Institute of Technology 16

17 ABSIM Modular Simulation Tool for Absorption and other Thermal Systems User-oriented, modular and flexible Evaluate different cycle configurations and working fluids Evaluate system performance in off-design conditions Perform preliminary design optimization Check control strategies Solar Cooling, Dehumidification and Air Conditioning Technion Israel Institute of Technology 17

18 ABSIM - Program Structure USER INPUT S OLVER 1. Condition set of equations 2. App ly constraints 3. Solve system of equations MAIN PRO GRAM 1. Interp ret inp ut 2. Form variable vector 3. Link units and form equations martix 4. Normalize 5. Activate solver OUTPUT UNIT SUBRO UTINES 1. Absorber 2. Desorber 3. Heat exchr 4. Condenser 5. Evap orator 6. Valve 7. Mixer 8. Splitter 9. Rectifier 10. Analyzer 11. Compressor 12. Pump PRO PERTY DATABAS E Solar Cooling, Dehumidification and Air Conditioning Technion Israel Institute of Technology 18

19 Desiccant System Principle Q H Two types of Desiccants Air Desiccant Adsorbent Absorbent Q L Solar Cooling, Dehumidification and Air Conditioning Technion Israel Institute of Technology 19

20 Liquid Desiccant vs. Absorption Cond Q H Q H LiBr-H 2 O Air LiCl-H 2 O Evap Q L Q L Solar Cooling, Dehumidification and Air Conditioning Technion Israel Institute of Technology 20

21 Cooling by controlled drying and wetting Ambient Temp 1 Dehumidifier Controlled wetting Solar Cooling, Dehumidification and Air Conditioning Technion Israel Institute of Technology 21

22 Cooling by controlled drying and wetting KgH O KgDryAir W 2 Saturation 100% Indirect Contact Cooling % 50% Desiccant Dehumidifica tion 6 Comfort Zone Ambient HX Wetting T ( 0 C) Solar Cooling, Dehumidification and Air Conditioning Technion Israel Institute of Technology 22

23 Schematic Description of Desiccant System Supply Air Fresh Air Blower c 15 Absorber From Solution Storage Tank Desorber 7 Blower Air/Air H.X. 6 Outlet Air C.M.1 10c 10h Fresh Air 1c 13 Drain Solution Pump Water/Solution H.X to Cooling Tower C.M.2 Cold-Water Pump Cold Water From Cooling Tower 12 3 Drain Solution Pump Water/Solution H.X. 2 1 Hot-Water Pump Hot Water From Storage Tank to Storage Tank 4 to Absorber Splitter 1h SV to Solution Storage Tank to Solution Storage Tank Solar Cooling, Dehumidification and Air Conditioning Technion Israel Institute of Technology 23

24 20-kW Solar Liquid Desiccant System at Technion, Haifa, Israel Solar Cooling, Dehumidification and Air Conditioning Technion Israel Institute of Technology 24

25 Control Unit - View of Computer Screen Solar Cooling, Dehumidification and Air Conditioning Technion Israel Institute of Technology 25

26 Solar Collector Field Solar Cooling, Dehumidification and Air Conditioning Technion Israel Institute of Technology 26

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32 The End Thank You for Your Attention! Solar Cooling, Dehumidification and Air Conditioning Technion Israel Institute of Technology 32