Exergy-analysis based comparative study of absorption refrigeration and electric compression refrigeration in CCHP systems

Abstract

Fueling with natural gas, combined cooling, heating and power (CCHP) system is expected to be widely applied in China, for its potential on energy efficiency and CO2 emissions reduction. In the design of CCHP, the choice of refrigeration system is now a hot topic because it greatly influences the performance. This paper has made a comparative study between the absorption refrigeration system and electric compression refrigeration system, in terms of exergy efficiency of refrigeration system in CCHP and energy efficiency of CCHP. A GE 9171E gas–steam combined cycle based CCHP system is chosen and analyzed as an example. The comparative study shows that the distance between power station and refrigeration station, namely the steam transport distance, has an effect on the performances of absorption refrigeration system in CCHP and CCHP based on it. As a result, under the conditions studied, absorption refrigeration is more effective when the distance is shorter than 5 km, and if longer than 9.3 km, electric compression refrigeration is a better choice. With distance between 5 and 9.3 km, the kind of refrigeration should depend on specific conditions. This paper does make important guiding significance for the choice of refrigeration system in the design of CCHP.