Study On The Key Technology Of Mine Rock Thermal Energy Utilization

The lithosphere of underground coal mine contains substantial low-grade heat energy, which canbe applied for the refrigeration and heating of constructions after being extracted with heat pumptechnology, and it can not only effectively reduce the energy consumption of construction, but alsoimprove the utilization rate of renewable energy sources.In this paper, characteristic analysis for the rock heat energy of underground coal mine wasconducted by taking the Kailuan Tangshan Coal Mine A as an example. The heat conductivitycoefficient of lithosphere was measured through thermal response test. Secondly, numericalsimulation was conducted for factors influencing the heat performance of ground heat exchanger withFLUENT software. Finally, the operating characteristic of the rock source heat pump system wasanalyzed. According to the research result, the gross rock source heat energy of the coal mine was4.34×1012kJ, amount to1.48×105t standard coal, which was of huge development and utilization value.The heat conductivity coefficient of the lithosphere was3.72W·m-1K-1, while the single-port heatexchange amount of the instrument connection could reach6.84kW, which was stronger than the heatexchange capability of the soil. It can be learnt from the numerical simulation of the ground heatexchanger that the pipe laying depth and inflow velocity had a huge impact on the performance of theground heat exchanger, and4m gap could satisfy the demands of heat exchange. It could be learntfrom the demonstration engineering system analysis that the COP of system could reach above5.0,and the rock source heat pump system could realize the heat absorption and release equilibrium. Thestatic pressure at500m depth was4.84MPa. As a result, high pressure-bearing heat exchange devicewas developed. After the operation of rock source heat pump system, it can decrease the emission ofsubstantial pollutant and greenhouse gases, with evident environmental benefit.The rock source heat pump technology of underground coal mine provides an effective solutionfor the utilization of rock source heat energy. The research result provides new thought for theutilization of heat energy, which may provide referential basis for optimizing the rock source heatpump system.Figure25; Table25; Reference47...