Development of a high temperature heat pump system for steam generation using medium-low temperature geothermal water.

Abstract To expand the application range of medium-low temperature geothermal water, a high temperature heat pump system with refrigerant injection technique for steam generation is developed. Four working fluids of R123, R141b, R245fa and R1234ze(Z) used in the high temperature heat pump cycle are analyzed and evaluated. Besides, the effects of evaporation temperature, injection ratio of the compressor and condensation temperature on the system performance are also discussed. The results of thermodynamic analysis indicate that the system obtains the optimal performance when uses R141b as working fluid. As the evaporation temperature is 55^oC, the condensation temperature is 125^oC and the flash evaporation temperature is 100^oC, the COP of the system reaches 3.8 and the steam mass per kWh (MkW) is 1.4 kg/kWh for R141b. [ABSTRACT FROM AUTHOR]