Operation Performance And Surrounding Soil Temperature Field Research Of Library Gshp In Donghua University

There are still few project examples of its operating performance and the monitoring of its surrounding soil temperature field, especially lacking long-term actual operating data. Therefore, it is of great practical significance to research ground source heat pump operating performance and its surrounding soil temperature field by combing the actual case.This essay set the ground source heat pump system of Donghua University library in Shanghai as the background. It establishes the heat transfer models and accomplishes numerical simulation during the research with the experimental tests and theoretical analysis.First of all, this essay makes a introduction about the overview of the ground source heat pump air conditioning system of the library, including device configuration, data collection system and automatic control system. Secondly, with the experiments, it analyses the operating performance of the GSHP system in summer and winter during the second year of operation. The emphasis will be put on the variation of energy efficiency coefficient of the units and system in the intermittent mode and the operating performance of the whole system. Moreover, the analysis of the load characteristics of the gains and losses of heat in the soil around the tube group is taken. This paper considers that the unique intermittent operation mode, which contains the summer and winter, makes a good recovery of temperature in the soil without heat accumulate. Finally, in order to test the heat exchange of the buried pipeline under dynamic load and analyse the influence of heat exchange on the soil temperature field, the author establishes a single U-tube three-dimensional non-steady-state heat transfer model with CFD software. It proved the accuracy of the model with the experiment data. Then, the influence of different speed of the liquid in tube and different backfill material on the heat exchange of buried pipelines is studied.On the analysis of the heat flux on depth direction in backfill area, the method, the analysis of heat flux of buried pipelines wall, are used to study surrounding soil temperature field. By establishing three-dimensional heat transfer model of the tube group, the surrounding soil thermal diffusivity is simulated. The result suggests that space between tube is reasonable, and the intermittent operation mode makes a good recovery of temperature in the soil. Due to the fact that there is few heat transfer along the buried depth direction, it is convenient to use two-dimensional model to simulate and analyse the soil temperature field.