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ROAD TO CLIMATE FRIENDLY CHILLERS Hydrocarbons & Absorption Chillers Systems: Development & Potential Dr. Alaa Olama Sept. 2010 , Cairo, Egypt. CONTENTS: 1- Hydrocarbon fired Absorption Chiller & Heat ratio 2- Difference between HR (COP) Abs. & COP V.C. - PowerPoint PPT Presentation
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ROAD TO CLIMATE FRIENDLY CHILLERS
Hydrocarbons & Absorption Chillers Systems: Development & Potential
Dr. Alaa Olama
Sept. 2010 , Cairo, Egypt
CONTENTS:
1- Hydrocarbon fired Absorption Chiller & Heat ratio
2- Difference between HR (COP) Abs. & COP V.C.
3- How did H.R (COP) improve dramatically.
4- Conclusion
1- Hydrocarbon Fired Absorption Chiller & Heat Ratio
COP (LP) =( Refrigeration capacity /( Gas Low calorific value * Gas consumption )
COP (HP) =( Refrigeration capacity /( Gas High calorific value * Gas consumption )
Definition of COP (HR) of Absorption Chillers
2- Difference between HR (COP) Abs. & (COP) V.C.
Overall efficiency of a power station:
S Type of Power Stations Percentage (%)
1 Best combined cycleSteam turbines carry the base load & gas turbines carry the variable load (peak load)
55
2 Steam cycle 40
3 Simple cycle 30-35
4 Transmission Losses 10
* Efficiency at Refrigeration plant boundary becomes 25 to 50 %
Comparing chillers efficiencies:
COP mvc 4 5 6
Station & transmission efficiency
25 30 35 50 25 30 35 50 25 30 35 50
COP abs 1 1.2 1.4 2 1.25 1.5 1.75 2.5 1.5 1.8 2.1 3
3- How did H.R (COP) improve dramatically
History of absorption chiller-heater
History of development for Gas direct fired absorption chiller
2005.22005.2Kyoto ProtocolKyoto Protocol
00 .. 7575 0 .80 0 .93 ~ 0.96 1.07 1.1
1.2
1.3
1.351.35
1.6 以上
H.R (COP) Improvement
Ratio of energy-saving
Low calorificvalue based COP
High calorificvalue based COP
30 energy-saving% 1.18 1.0726 energy-saving% 1.12 1.01
39 enegy-saving% 1.36 1.22
32 energy-saving% 1.22 1.1035 enegy-saving% 1.28 1.15
42 enegy-saving% 1.43 1.2845 enegy-saving% 1.45 1.35
Key technology to improve the efficiency
3.Dual absorptionDual evaporation
4.Condensed refrigerantheat-exchanger
1.Improved solutionheat-exchanger
2.RefrigerantCooler
5.High performanceheat transfer tube
RCD
6.Exhaustheat-exchanger
RFD
7.Larger Heat transferarea on ABS. EVP.
8-Efficiency improvedon High stage GEN.
RED
Internal piping flow of RFD ( chiller )
1- Improvement on efficiency of solution heat-exchanger
Shell & Tube typeheat-exchanger
• Solution heat-exchanger
High temp
Low temp.
Plate heat-exchanger
☆☆ AdvantageAdvantage
・ ・ Better heat transfer Better heat transfer performance compared to performance compared to S&TS&T
◎◎More compactMore compact
・ ・ Less solution retainedLess solution retained
☆☆ AdvantageAdvantage
・ ・ Better heat transfer Better heat transfer performance compared to performance compared to S&TS&T
◎◎More compactMore compact
・ ・ Less solution retainedLess solution retained
Key technology of improvement
2- Refrigerant cooler
↓
33℃
Key technology of improvement
Cooling down the refrigerant back from condenser, to reduce the load on Generator, to get better efficiency
Cooling down the refrigerant back from condenser, to reduce the load on Generator, to get better efficiency
Ref. cooler
EVP. (9 )℃
38℃
ABS.
Cooling W
CONDS.
Refrigerant
37℃
32℃
36.5℃
低温再生器
凝縮器
SP RP
SSPH
冷却水
35.5℃
72.3℃7.0℃
32.0℃A1=54.1%
冷水
15.0℃
37.0℃
11.1℃
【低圧】
【高圧】
再生器へ
蒸発器
蒸発器
吸収器
吸収器
Upper stage :Low pressure in ABS. / EVP.Lower stage : High pressure in ABS. / EVP.
☆☆AdvantageAdvantageBigger concentration difference of solution, by separating ABS. & EVP. to 2 stages
Enable to reduce circulating flow
Less heating calorie at Less heating calorie at Generator,Generator,thus better efficiencythus better efficiency
Less heating calorie at Less heating calorie at Generator,Generator,thus better efficiencythus better efficiency
3- Dual Absorption, Dual Evaporation Cycle
Key technology of improvement
4- Condensed refrigerant heat-exchanger
Key technology of improvement
Weak solution
Condenser ( 38℃ )
Low temp. H-exchanger
Low stage GEN.
High temp. H-exchanger
S.P.
Heat recovery on High High temp. Refrigerant back temp. Refrigerant back from low GEN. and from low GEN. and weak solution, weak solution, to get better efficiency
Heat recovery on High High temp. Refrigerant back temp. Refrigerant back from low GEN. and from low GEN. and weak solution, weak solution, to get better efficiency
44℃
Con
den
sedrefrigeran
t
Condensed refrigerantCondensed refrigerantheat-Exchangerheat-Exchanger
90℃Heat from Low GEN.⇒Steam from High GEN.
78℃
36℃
5- High Performance heat transfer tube
Key technology of improvement
Exhaust
Natural Gas
Air supply20℃
High GEN.
The gas consumption reduced by pre-heating pre-heating the air supply to the the air supply to the Burner.Burner.
The gas consumption reduced by pre-heating pre-heating the air supply to the the air supply to the Burner.Burner.
6- Exhaust heat-exchanger( Air pre-heater )
Key technology of improvement
165℃
75℃
155℃
Air Pre-Air Pre-heaterheater
Key technology of improvement
7- Larger Heat transfer area on ABS. EVP.
Key technology of improvement
8- Efficiency improved on High stage GEN.
Improved solution heat-Improved solution heat-exchangerexchanger
ExhaustExhaustheat-exchangerheat-exchanger
increased KA increased KA value, on CND. value, on CND. ABS.ABS.
Refrigerant Refrigerant coolercooler
COP1.22
COP1.00
Solution flow Solution flow regulationregulation
RED
Improved solutionImproved solutionheat-exchangerheat-exchanger
+0.085
+0.015
RFD
+0.04 +0.015
+0.02
Dual ABS. / Dual ABS. / EVA.EVA.
+0.02
Large head of chilled Large head of chilled water water (( Δ8℃Δ8℃ ))
Condensed Condensed ref. heat-ref. heat-exchangerexchanger
+0.05
+
+0.035
Efficiency Efficiency improved High improved High
GEN.GEN.
COPCOP1.291.29
Designed based on COP1.29 COP1.29 machine
COPCOP1.351.35
ExhaustExhaustheat-exchangerheat-exchanger
+0.06
Reached COP1.35 COP1.35 with Exhaust heat-Exhaust heat-exchangerexchanger
Key technology of improvement
Improvement of COP by each technology
4- Conclusions
Conclusions:-
1- When comparing The overall thermal efficiencies ,it is important to compare the
efficiency of mechanical vapour compression systems (electric chillers) to the
efficiencies of vapour compression systems ( absorption chillers) , starting at the
boundary of supply to the power station(natural gas ) and the boundary of supply of
natural gas at the absorption chillers burner, otherwise the comparison cannot be
fair.
2- When this is done ,the difference in efficiencies is then quite close , taking into
consideration that few power stations in Egypt have high thermal efficiencies.
3- Therefore the use of natural gas in large central air conditioning projects is
economically sound since the saving in investment cost for power plant is
considerable.
(1)
Conclusions(Cont.):-
4- Shaving electrical peak loads in summer can only be achieved by the use of
natural gas fired air conditioning system.
5- legislation exists in many countries that prohibit the use of electrical energy in air
conditioning over a certain refrigeration tonnages (over about 1000 TR) This is the
case in Japan , South Korea & lately the United Arab Emirates.
The aim of the legislation is to preserve electric power for applications where there
are not other alternative sources of energy .
(2)