Comparison of the Vapor Absorption System with the Vapor Compression System can be made in 9 aspects: energy input, moving part, evaporator pressure, load variation, evaporator exit, coefficient of performance, capacity, refrigerant, and lowest temperatures.
S.no |
Aspect
|
Vapor Absorption System
|
Vapor Compression System
|
---|---|---|---|
1 | Energy Input | The vapor absorption system uses low-grade energy, such as waste heat from the furnace, exhaust steam, or solar heat, for its operations. | A vapor compression system takes in high grade, such as electrical or mechanical energy, to operate the compressor used in the cycle. |
2 | Moving part | It uses a small pump as a moving part run by a small motor. | It uses a compressor driven by an electric motor or engine. |
3 | Evaporator pressure | It can operate with reduced evaporator pressure and a decrease in refrigerant capacity. | The refrigerant capacity decreases with lowered evaporator pressure. |
4 | Load variation | The performance of the vapor absorption system does not change with load variation | The performance of the vapor compressing system is very poor at partial load. |
5 | Evaporator exit | In a vapor absorption system, the liquid refrigerant leaving the evaporator does not have any bad effect on the system except to reduce the refrigerant effect. | In a vapor compression system, it is desirable to superheat vapor before leaving the evaporator so no liquid can enter the compressor. |
6 | Lowest temperature | Since water is used as a refrigerant, thus the lowest temperature attained is above 0°C. | With cascading, the temperature can be lowered to -150°C or even less. |
7 | Coefficient of Performance | The COP of the system is poor. | The COP of the system is excellent. |
8 | Capacity | It can build in capacities well above 1000 TR. | For a single compression system, having a system with more than 1000 TR capacity is impossible. |
9 | Refrigerant | Water or ammonia is used as a refrigerant. | Chlorofluorocarbons, hydrofluorocarbon, and hydrochlorofluorocarbon are used in most of the systems. |
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