Assessment and Utilization of Shallow Geothermal Energy Resources in Tianjin Area

Abstract

Based on investigation of the shallow geothermal energy in Tianjin, the shallow geothermal occurrence characteristics is closely linked with the Quaternary .The quaternary lithology is mainly composed of clay, silty clay, silt, fine sand and coarse sand, geological structure is clay, silty clay, silt, fine sand, coarse sand and mutual layer, thermal conductivity of rock and soil is 1.23 ~ 1.58W/ (m• ℃), the specific heat capacity is 1898.52 ~ 2201.70 W/ (m ℃), underground water is 100 ~ 3000 (m3/d), coefficient of hydraulic conductivity 50 ~ 300 (m2/d), groundwater recharge is 30 ~ 80m3/h, the single well recharge is 30 ~ 50% of output yield, The recharge is below 50 m3/h, formation heat exhaustion is 32.32 ～ 126.1. the heat absorption is 17.73 ~ 66.8 (w/m).Based on the the investigation of shallow geothermal energy and suitability evaluation in Binhai New Area, combing with the corrected ground thermal properties, we evaluate the the shallow geothermal resources of the suitable area , including the evaluation of shallow layer soil and groundwater heat capacity and heat power. The method of reduction groundwater source is used in heat pump heat power calculation , The new calcaulation system of buried vertical tube heat power is created with FLUENT and EED software At the same time, we analyze the problems and influence factors existing in the shallow geothermal development and utilization process, then put forward suggestions. provide a reliable basis for the development and protection of the shallow geothermal energy resources.