Abstract: A solar seasonal heat storage and heating （SSSH） system for an office building in a severe cold area of Zhangjiakou is studied，to promote the application of SSSH system. The start/stop control conditions of heat collection （heat storage），heating performance and ground temperature variation are analyzed by taking experiments and TRNSYS dynamic simulation. The experiment results show that the heat collection efficiency decreases with the increase of the start/ stop temperature difference，and the heat collection efficiency and storage efficiency decrease with the increase of start-up temperature of heat storage. The simulation results show that with the increase of start-up temperature，stop temperature or start /stop temperature difference of heat collection and the heat collection（heat storage）efficiency will decrease，while energy efficiency ratio of heat collection（heat storage）cycle will increase. Every 1 ℃ increase of heat storage starting temperature will lead to a 0.7% decrease and a 0.3% decrease in heat collection and heat storage efficiencies on average. And every 1 ℃ increase of the start/stop temperature difference will reduce the heat collection efficiency by 1.7%，while increase the energy efficiency ratio of heat collection cycle by 2.0%. The COP of the heat pump and the system are 3.4 and 3.1 in heating seasons，respectively. Completing the cycle of heat storage and heating，the ground temperature rises from 6.12 ℃ to 6.91 ℃，which meets the requirements of long-term stable operation of the system.

Key words: GSHP, solar energy, clean heating, heat storage across seasons, operating performance, TRNSYS, storage efficiency, heat collection efficiency, ground temperature