Thermodynamic Analysis of a Combined Single Effect Vapour Absorption System and tc-CO2 Compression Refrigeration System
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The transcritical CO2 refrigeration system is coupled with the single effect vapour absorption with LiBr-water as a working pair, having the objective of enhancing the performance of the low temperature transcritical refrigeration system while using a natural working pair and reducing the electricity consumption to produce low temperature refrigeration. The high grade waste heat rejected in the gas cooler of the tc-CO2 compression refrigeration system (TCRS) is utilized to run the single effect vapour absorption system (SEVAR) to enhance the energy efficiency of the system. The gas cooler in the transcritical CO2 system has heat energy at a high temperature and pressure, which is utilized to run the vapour absorption system, while the other refrigerant heat exchanger provides subcooling to further enhance the performance. The combined cycle can provide refrigeration temperature at different levels, to use it for different applications. Energetic and exergetic analysis have been done to analyze the combined system to compute the performance parameters and the irreversibilities occurring in different components to further increase the performance. The combined system is optimized for various heat rejection and refrigeration temperatures. The COP of the combined system has been enhanced by 24.88% while the enhancement in exergetic efficiency (ηex) is observed at 10.14%, respectively, over tradition transcritical CO2 compression refrigeration system, with -10°C as an evaporation (TCRS cooling) temperature and the exit temperature of gas cooler T4 being 40°C.
Doi: 10.28991/HIJ-2021-02-02-02
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