Working fluids for high temperature heat pumps

Abstract

The suitability of working fluids for use in high temperature heat pump systems has been considered on the basis of their volumetric and other thremodynamic properties. The change of thermodynamic properties with temperature has been graphically illustrated. It is shwon that water becomes increasingly attractive as a working fluid as the delivery temperature approaches 200°C. A heat pump using water as the fluid is capable of an actual coefficient of performance of five and a gross temperature lift of 70°C for a condensation temperature of 200°C.