Optimization And Performance Research Of Ground Heat Exchanger Based On The Seasonal Energy Storage

Due to the use of low grade renewable energy, Ground Source Heat Pump (GSHP) which is known as the green and environmental air conditional system in the 21st century, it can meet the demand of heating and cooling for human. The core of the system is the design of buried pipe and the complex heat transfer process between surrounding soil and fluid. However, some problems are revealed in the case of the engineering, drilling depth is too big, and difference in heat transfer temperature between fluid and soil is small, which not only reducing the heat transfer per unit length, but also increasing the drilling investment; in addition, thermal conductivity of soil is small, and the heat resistance is big, which hindering the full use about soil in some distance, and wasting the soil area around buried pipe.This paper research three aspects about soil in heat insulation, heat dissipation, energy balance, build multiple pipe heat transfer optimization model based on the seasonal thermal energy storage. With the cover areas and drilling costs in conventional design as the measure of the standard, obtaining the different shallow buried depth, small spacing combination. Then, selecting the four group model for dynamic simulation to deeper study.Through the paper, using DeST to simulate the dynamic load of the office building in Nanjing. According to the selected four group models of pipe group, using FLUENT software and C language to edit function (UDF), getting the temperature change of the fluid and soil, and the correlation analysis was performed. The simulation results show that:1) it can be more effective conservation area and the corresponding drilling cost compared to the conventional design mode; 2) In optimization model, buried tube spacing is larger than lm,buried depth is more than 25m, still can effectively reduce the drilling cost and areas; 3) multiple pipes can storage more energy to be used to prepare for next season; 4) after a year of operation, unbalanced rate of soil temperature is less than 5%; 5) gradient of soil temperature at different radial distances is small, indicating that soil energy can be fully utilized.