Study On The Engineering Application Of Ground Source Heat Pump

The ground source heat pump, which uses the ground as its heating and cooling source, is a renewable energy technology. It uses the ground as its thermal storage medium, which realizes the concept of cross-quarter usage of resources. In summer the ground heat exchangers transfer the cold energy which had been stored in winter to buildings, therefore the heat energy is stored simultaneously. The process in winter is inverse to that in summer. Owing to this operation mechanism, the energy efficiency of ground source heat pump is higher than conventional system, because it has lower condensing temperature and higher evaporation temperature. The application of GSHP has great significance in energy saving and emission reduction as well as low-carbon city development.The underground heat exchange of GSHP is a long-term non-steady-state process whose long-term performance is not only determined by the undisturbed ground temperature and the ground thermal properties, but also the load distribution and its amount.Focus on the engineering applications of GSHP, three aspects of GSHP is analyzed:1) The underground heat transfer model. The existing analytical models for underground heat transfer are compared. It is found that the Infinite-Length Linear Heat-source Model has the simplest formula which is convenient to use and its accuracy is high for the engineering applications.2) The thermal response test. According to the latest technical code for ground-source heat pump system, a high-precision thermal response test device has been developed and the Matlab code which is used for the parameter estimation is given.3) The long-term performance of ground heat exchanger. Based on the principle of superposition, the Infinite-Linear Heat-source model is used to analyze the long-term performance of single bore and bore group, whose results are compared with that obtained by GeoStar V3.0. It is suggested that the Infinite-Length Linear Heat-source Model can be applied to the design and operating performance analysis of GSHP. It can provide us with hourly operating performance and its calculation speed is fast.