Thermodynamic analysis and optimization of a novel dual-evaporator system powered by electrical and solar energy sources

A novel dual-evaporator system with dual-source (renewable and electrical energies) is proposed to provide negative and positive evaporator temperatures. The system is a combination of the generator -absorber heat exchange (GAX), ejector-expansion transcritical CO2 refrigeration (EETC), Organic Rankin Cycle (ORC) and supercritical CO2 power cycles. The system is analyzed and optimized thermodynamically in detail. It is found that allocating the lower temperatures (-25 to -45 degrees C) for EETC evaporator and higher temperatures (5-10 degrees C) for GAX evaporator is more suitable. Detailed exergy analyses reveal that 19.89% and 5.92% of total input exergy, are useful in EETC evaporator and GAX evaporator, respectively. The ejector is found to be the highest source of irreversibility in the system. Moreover, the system performs better than dual-evaporator systems recently reported in literature. (C) 2013 Elsevier Ltd. All rights reserved.