Performance comparison of capillary mat radiant and floor radiant heating systems assisted by an air source heat pump in a residential building

Abstract

The radiant heating system assisted by an air source heat pump has been widely applied in China for its effective energy conservation, high comfort performance and flexible utilization. Because the coefficient of performance of the system is strictly controlled by the supply water temperature heated by the air source heat pump, an efficient radiant terminal with low-temperature supply water is of significance to the coefficient of performance. In this research, the energy-saving feature of the capillary mat radiant heating system was first proved theoretically based on the influence of the heat transfer temperature difference on the coefficient of performance of the air source heat pump. In order to compare the performances of the capillary mat radiant and floor radiant heating systems, an experiment platform of two different radiant terminals assisted by an air source heat pump was established in a residential building in Xi’an, China. Experimental results showed that, to satisfy the indoor heating requirements, the supply and return water temperatures ought to be 35.0℃ and 30.9℃, respectively, and for the capillary mat radiant heating system, 43.9℃ and 38.8℃, respectively, for the floor radiant heating system. However, the electricity consumption of the capillary mat radiant heating system is 45% less than that of the floor radiant heating system. Thus, our study validated the energy-saving potential of the capillary mat radiant heating system assisted by an air source heat pump.