Performances and compactness of a cooling system powered with PEMFC thermal effluent

The thermodynamic study of a small scale cooling system combining an ORC cycle and a refrigeration cycle is carried out. The system includes the same components as those used for ejection cycles except that a combination of a vane compressor and a vane expander replaces the usual ejector. Real fluids properties, efficiencies of the pump, the compressor and the expender and pressure drops are considered. The isentropic efficiency of the expander was measured experimentally and the data were used in the thermodynamic model to simulate the complete system in steady state. The system is designed for operating with a 2 kW heating source at 65 °C corresponding to the heat rejected by a domestic PEMFC-type cell and a parametric study assess its performance, compactness and sensitivity when operating at off design. The evaporating temperature varies from −9.5 °C to +10.5 °C and the condensing temperature varies from 20.1 to 40.1 °C. Over the 12 fluids tested here, R1270 appears to be the most promising fluid, providing high performance, good compactness, low environmental nuisance and low off design sensitivity.