Assessment of the Energy Performance of an Air Source Heat Pump by Response Surface Methodology

Air source heat pumps (ASHP) are preferable to traditional heating systems because of their high efficiency and energy-saving potential. Moreover, they can be coupled with renewable energy sources. In this work the performance of a two-stage ASHP unit is presented. Experimental data were collected in winter mode. Due to the scarcity of reliable experimental data, a response surface methodology (RSM) was applied with the aim of extending the data sample. The new database was analyzed to point out the performance of the ASHP by varying the supply water temperature to the indoor terminals in different ambient conditions. It was possible to draw curves showing the relationship between ASHP performance (power consumption and COP), supply water temperature and ambient temperature. An optimal configuration of the system that minimizes the power consumption of the HP while maintaining the internal comfort was assessed to be: 30 °C for the supply water temperature and 2.4 m3h-1 for the supply water flow rate when the ambient temperature is 10 °C.