Amirkabir University of Technology Amirkabir Journal of Mechanical Engineering 2008-6032 53 7 2021 09 23 Comparison of axial and radial soil temperature distribution in U-tube and coaxial borehole heat exchangers Comparison of axial and radial soil temperature distribution in U-tube and coaxial borehole heat exchangers 4361 4378 4185 10.22060/mej.2020.18276.6799 FA Sepehr Sanaye Professor of departement of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran Fateme Mousavi Department of mechanical engineering, Iran university of science and technology Journal Article 2020 04 27 Dynamic variation of surrounding soil temperature in axial (depth) and radial directions of vertical type geothermal heat pump (heat exchangers are investigated here. This soil temperature distribution for borehole heat exchangers plays an important role in thermal operation, electricity consumption and coefficient of performance of geothermal heat pump. Thus the transient 3-dimensional numerical modeling of U-tube and coaxial borehole heat exchangers are investigated to find the temperature distribution around the buried pipes. The simulation is performed using ANSYS FLUENT 16.0 software based on the finite volume method. The effects of various parameters are studied and modeling results for the cooling application of heat pump are obtained for different mass flow rates of condenser cooling water. Results show that the injection heat transfer rate to the ground in summer, in the coaxial borehole heat exchanger at mass flow rates of 0.8, 1, 1.2 kg/s are 5.34%, 11.9%, 16.5% higher than U-tube borehole heat exchanger respectively. Moreover, after 93 days, the vertical temperature distribution of the soil for U-tube heat exchanger shows a significant variation mainly at depths less than 36.6 meters while the coaxial heat exchanger greatly affects the soil temperature distribution even in higher depths. Dynamic variation of surrounding soil temperature in axial (depth) and radial directions of vertical type geothermal heat pump (heat exchangers are investigated here. This soil temperature distribution for borehole heat exchangers plays an important role in thermal operation, electricity consumption and coefficient of performance of geothermal heat pump. Thus the transient 3-dimensional numerical modeling of U-tube and coaxial borehole heat exchangers are investigated to find the temperature distribution around the buried pipes. The simulation is performed using ANSYS FLUENT 16.0 software based on the finite volume method. The effects of various parameters are studied and modeling results for the cooling application of heat pump are obtained for different mass flow rates of condenser cooling water. Results show that the injection heat transfer rate to the ground in summer, in the coaxial borehole heat exchanger at mass flow rates of 0.8, 1, 1.2 kg/s are 5.34%, 11.9%, 16.5% higher than U-tube borehole heat exchanger respectively. Moreover, after 93 days, the vertical temperature distribution of the soil for U-tube heat exchanger shows a significant variation mainly at depths less than 36.6 meters while the coaxial heat exchanger greatly affects the soil temperature distribution even in higher depths. https://mej.aut.ac.ir/article_4185_b207f5c56605a9d1a22e1e134fe95ba9.pdf