Abstract：Solar-earth source heat pump (SESHP) is a new type of energy saving air conditioner. In this paper, numerical simulation of the performance of a solar-earth source heat pump system (SESHPS) operated at alternate or combined mode is carried out respectively. The results indicate that a resuming-rate of 30–60% of the earth temperature near buried coil can be preferable when SESHPS is operated alternately at a period of 24 h, and the proportion of the operation time of solar-assisted heat pump (SAHP ) should be confined to 42–58%. When SESHPS is operated at combined modes 2, the energy-saving rate with and without heat storage water tank is 14.5% and 10.4%, respectively, compared with ground source heat pump (GSHP). As for the overall effect, the combined operation mode with water tank in which the heated water flows through the solar collector first and then through the buried coil is preferable. The results are significant for the engineering design, operation and management of SESHPS.

Keywords：Solar-earth source heat pump; Alternate operation; Combined operation; Earth temperature resuming-rate