Although there is abundant geothermal energy in deep reservoirs, to effectively extract the heat rather than the geofluid is still a challenge. This study investigated the heat extraction performance of a coaxial double-pipe heat exchanger in a deep geothermal well with particular reference to geothermal heating. A numerical simulation model is established and the heat extraction rates (geothermal energy production rates) and their changes with the time of production are analyzed in detail. As a result, either the heat-carrier mass flowrate of 1.5 kg/s for direct heating utilization or 4 kg/s for heating with use of heat pump system has shown a sound performance. Results obtained are useful for better understanding of such geothermal heat extraction technology.
Keywords geothermal energy production rates, coaxial double-pipe heat exchanger, heating, heat pump