Research on the Performance of Solar and Air-Source Heat Pump Combined Heating Systems

A solar and air-source heat pump combined heating system for experimental research is setup, the efficiency of the solar collectors and the COP of the air-source heat pump is tested by experiments. Hourly simulations during a whole year are conducted based on the performance data obtained from experiments, several conclusions are drawn: (1) The solar and air-source heat pump combined heating system can save electricity up to 50-70% compared to solar system assisted by electrical resistance heater, when located in places with not very cold winter; (2)The solar and air-source heat pump combined systems is more sensitive to supply water temperature and its percentage of electricity saving is reducing with the rising supply water temperature compared to auxiliary heating by electrical resistance. (3) The life-cycle cost of the combined system is not very sensitive to solar fraction when solar fraction ranges from 30% to 70%, and it is lowest when the solar fraction is near 50%.