Exergy optimisation of irreversible closed Brayton cycle combined cooling, heating and power plant

Abstract

AbstractA combined cooling, heating and power (CCHP) plant model composed of an irreversible closed Brayton cycle and an endoreversible four-heat-reservoir absorption refrigeration cycle is established by using finite time thermodynamics. Equations of exergy output rate and exergy efficiency of the CCHP plant are derived. Numerical examples are provided by using Powell arithmetic, and optimal heat conductance distributions among hot-, cold-, thermal consumer-, generator-, absorber-, condenser- and evaporator-side heat exchangers and compressor optimal pressure ratios are obtained by taking exergy output rate and exergy efficiency as optimisation objectives respectively. The effects of compressor and gas turbine efficiencies on the optimal exergy output rate and exergy efficiency performances are discussed. The maximum exergy output rate and exergy efficiency performances are compared with each other quantitatively. Optimal design region is obtained with considerations of exergy output rate and exergy effi...