Investigations On Heat Flow Characteristics Of The Aquifer For Groundwater Heat Pump (Gwhp) Composed Of Different Well Types

Shallow geothermal utilization involves complex underground heat and mass transfer. Through the numerical computation method, this paper presents two methods to increase the utilization of geothermal energy by simulating thermal interaction and thermal breakthrough in the aquifer. One is to increase the number of extraction-injection wells to reduce the flow rate of every well, and the other is to increase the distance between the extraction and injection wells to lengthen the heat exchange time of injection water to the aquifer. The results show that the two methods can alleviate thermal breakthrough, but meanwhile increase the project investment. Therefore, an improved extraction-injection well structure, namely semi-filter well (SFW), has been put forward to enhance the utilization of geothermal energy by changing the direction of groundwater flow. Comparisons of simulations between the SFWs and the traditional wells reveal that if the extraction wells are SFWs, it can lighten thermal breakthrough and improve coefficient of performance. A test table of ground heat exchanger system has been built to validate the simulations. The average error between the experimental data and the simulation data was 5.5%.