Professor Kim Choon NG , Mechanical Engineering, National University of Singapore, and Visiting Solar powered adsorption cooling cum desalination
Feb 22, 2016
Professor Kim Choon NG, Mechanical Engineering, National University of Singapore, and Visiting Professor Water Desalination and Reuse Centre, KAUST, SA Email: [email protected] [email protected]
Solar powered adsorption cooling cum desalination
Adsorption-triggered-evaporation Desorption-activated-condensation
25-33°C
28-36°C
55-85°C, from Solaror waste heat
45-75°C25-30°C28-33°C
7-28°C12-33°C
Mesoporous adsorbent
SiO3.nH2 O , 800m2/g
Cooling power, Tchilled = 7-20°C, 25- 32 Rtons/tonne
Potable water TDS <10ppm, pH =7.3,±0.15 to 12 m3/tonne.day
Advantages:-Produce two useful effects with low-temperature heat input,-low specific energy (electric) consumption (1.38kWh/m3), -no major moving part, inexpensive materials for construction
• The daily average radiation in Thuwal (KAUST) is about 22 MJ/m2.day (latitude λ=22o , sunshine hours from 9 to 13 h/day)
• Estimated thermal rating is 1300 kWh/m 2.year, as compared with 925 kWh/m 2.year @ 65o C in Singapore .
• Recommend to use tube collectors because (i) it is easy to handle, (ii) it reduces the dust accumulation – dust particles will slide over the tube curvature whilst those accumulated on top could be blown over by strong wind.
Provide shading that reduces heat stress in green houses.
5
Exhaust Gas
Why Co-Generation ?
Electricity (- max at 1.3 MW)
Steam (4800 kg/h)
• Cooling (7o C and 15-18
0C)• Water
(5 l/m2 .day)
Electricity from grid ( )42.0th
“Kettle” Boiler (8 bar)
Electrically-operated decicant dehumidifier
Gas Turbines x 2 units of 700 kW
Temperature cascaded utilization of exhaust energy with AB_AD chillers
Waste heat operated boiler (8 bar)
Steam driven AB/AD chillers
375 to 500oC
125o C
Primary fuel, (Town gas)
TriGen EUF =0.85- Thermally-driven design
Conventional EUF=0.52
DARI’s energy needs
Conventional approach
Co-generation cum solar
Primary fuel
diesel
electricity
7
Grid of KAUST
Electric chillers (400 Rtons)
CWS =7 C
Gas Turbines (2x 700 kW)
360 kW1000 to 1200 kW
Steam(177 C, 8.3 bar)
AB chillers (COP 0.9 to 1.1) giving 800 to 1000 Rtons
AD Chillers (COP =0.5 to 0.65) giving 120 to 150 Rtons
500-600 kW for use in DARI
CWS = 9-10 C
CWS = 14 to 18 CWater production75 m /day
Further waste heat recovery
50-60 kW 20 to 25 kW
Seawater Cooling Towers (1200 Rtons)
40 – 55 kW
Exhaust leaving at < 125 C
8
Sea Water Tank
Pre-treatment sea water tank
Sea water feeding line
9
Reactor Bed Condensate drainage
Collection tank
Release Valve
Condenser
11
Pretreatment
tank
Hot water
storage Waste heat recovery
from exhaust Fresh water
storage
Post treatme n t
tank
Sea water
Silo-type adsorber-desorber beds
Condenser and evaporator Cooling water system
valves
E x haust gas
2 0 0 to 25 0 C
12
Reaction bed tower
Evaporator
Condenser
Purified water
storage tank Reaction bed tower
1
2 3
4
5
d d
H
Can the AD cycle scale to a commercial size ? – to work closely with industry partners of KAUST
14
15