PERFORMANCE-CHARACTERISTICS OF A HIGH-TEMPERATURE WATER-TO-WATER HEAT-PUMP

A simulation model is utilized to predict the performance of a high temperature water-to-water heat pump, running on Refrigerant 11, over a range of evaporator and condenser water temperature (10 to 40°C and 40 to 70°C) and compressor speeds (500 to 3000 r.p.m.). It is shown that heat pump power output can be effectively controlled by varying compressor speed. Effects of compressor speed, heat source and heat sink (end-use) temperature on the heat pump efficiency are presented. Special attention is devoted to the values of predicted refrigerant temperature at the compressor discharge. These are compared with the thermal limit of the refrigerant. Modifications to the system, to reduce refrigerant maximum temperature, are also discussed.