Experimental investigation of a vapor compression heat pump used for cooling and heating applications

The present work aims at evaluating the performance characteristics of a vapor compression heat pump (VCHP) for simultaneous space cooling (summer air conditioning) and hot water supply. In order to achieve this objective, a test facility was developed and experiments were performed over a wide range of evaporator water inlet temperature (14:26 °C) and condenser water inlet temperature (22:34 °C). R134a was used as a primary working fluid whereas water was adopted as a secondary heat transfer fluid at both heat source (evaporator) and heat sink (condenser) of the heat pump. Performance characteristics of the considered heat pump were characterized by outlet water temperatures, water side capacities and coefficient of performance (COP) for various operating modes namely: cooling, heating and simultaneous cooling and heating. Results showed that COP increases with the evaporator water inlet temperature while decreases as the condenser water inlet temperature increases. However, the evaporator water inlet temperature has more effect on the performance characteristics of the heat pump than that of condenser water inlet temperature. Actual COP of cooling mode between 1.9 to 3.1 and that of heating mode from 2.9 to 3.3 were obtained. Actual simultaneous COP between 3.7 and 4.9 was achieved.

► Heat pumps are used in simultaneous heating and cooling application as they can improve the overall energy utilization efficiency.
► Experiments have been performed to evaluate performance characteristics of a VCHP for cooling, heating and simultaneous cooling and heating modes.
► COP of cooling mode between 1.9 and 3.1 and that of heating mode from 2.9 to 3.3 were obtained.
► COP of simultaneous cooling and heating mode was in range of 3.7–4.9 over the considered range of operating water inlet temperatures.
► Evaporator water outlet temperature from about 4 to 13 °C and condenser water outlet temperature between 43 and 57 °C are obtained.