Advanced, extended and combined extended-advanced exergy analyses of a novel geothermal powered combined cooling, heating and power (CCHP) system

Abstract

In this study, not only conventional and advanced exergies, but also advanced exergoeconomic, extended exergy and combined extended-advanced exergy analyses are firstly applied to the novel ejector-based CO2 transcritical Combined Cooling, Heating and Power (CCHP) system powered by geothermal energy. It is found that the evaporator and domestic water heater (DWH) components should be focused to increase system efficiency. For the vapor generator (VG), evaporator (EV) and DWH, avoidable exergy destruction rates are found as 26.334 kW, 0.323 kW and 8.288 kW, while their unavoidable exergy destruction rates are 11.206 kW, 0.276 kW and 1.410 kW, respectively. The extended avoidable exergy destruction rates are determined as 89.068 kW, 5.174 kW and 12.385 kW, while their unavoidable exergy destruction rates are 36.846 kW, 3.079 kW and 1.992 kW for the VG, EV and DWH, respectively. Improvement potential of VG, EV and DWH are endogenous, it means they should be focused on these components themselves. DWH is strongly connected to condenser which has important role on exergy destructions of it and condenser should be focused on improving DWH. According to mexogenous exergy destruction results, the condenser's exergy destruction is equal to −0.468, which means DWH's exergy destruction can be reduced.