Integrated energy-exergy optimization of a novel micro-CCHP cycle based on MGT-ORC and steam ejector refrigerator

In the present paper a novel cycle is proposed for combined production of cooling heating and power in micro scale. The cycle comprises of a micro-gas turbine (MGT), a micro organic Rankine cycle (MORC), steam ejector refrigeration cycle (SER), and heat recovery equipments. A function called integrated energy-exergy (IEE) is proposed to optimize the cycle from energy and exergy views simultaneously by using genetic algorithm. The results show that using IEE for optimization is better than energy alone or exergy-alone optimizations. A sensitivity analyses is carried out, the cycle is most sensitive to the cooling cycle designing parameters such as the evaporator temperature, ejector compression ratio and ORC steam pressure at turbine outlet. The most exergy destructors are recuperator and combustion chamber which they count for 80% and 92% of total exergy destruction in summer and winter. In the optimum conditions the minimum pinch point temperature difference of 36 degrees C and 28 degrees C are achieved for summer and winter. The results prove energy saving of 37% and 24% for summer and winter mode working of the cycle. The overall efficiency can reach 78% in summer while at the same time the cycle exergy efficiency is 37%. Since compression energy of the cooling cycle in the winter mode is not necessary the cycle has higher exergy efficiency of 44% in winter. (C) 2016 Elsevier Ltd. All rights reserved.