Preliminary conceptual design and thermo-economic analysis of a combined cooling, heating and power system based on supercritical carbon dioxide cycle

Abstract

Application of the supercritical carbon dioxide (sCO2) cycle to advanced nuclear reactors have confirmed a number of benefits. However, abundant low-level cooling heat is wasted in the gas cooler. A combined cooling, heating and power (CCHP) system, which integrates a sCO2 cycle with an Organic Rankine cycle (ORC) and an ejector refrigeration cycle (ERC), is proposed to realize the energy cascade utilization for nuclear power. The thermodynamic and exergoeconomic models of the novel CCHP system are established for system simulations under steady-state conditions. Parametric analysis results show that the decrease of ORC turbine back pressure or the increase of sCO2 turbine inlet temperature and ERC evaporation temperature contribute to both design thermodynamic and exergoeconomic performance. In addition, there exist optimal values of the sCO2 compressor pressure ratio and the bottoming cycle turbine inlet pressure to minimize the total product unit cost and maximize the exergetic efficiency. Furthermore, multi-objective optimization by means of a genetic algorithm is carried out to obtain the optimal design performance. The CCHP system can gain an improvement by 9.17% for the exergetic efficiency and a decrement by 5.05% for the total product unit cost compared with the stand-alone sCO2 system under the optimal condition.