Case study of a groundwater source heat pump at a coastal aquifer

A groundwater source heat pump (GWHP) system for heating and cooling of building is a proven technology which has been adapted worldwide. This system is located at a coastal aquifer consisted of sand and gravel sedimentary layers. The groundwater flow direction towards to coastline and the aquifer thickness is around 24m which is the same depth of pumping and injection wells. The purpose of the GWHP is water heating for a commercial bath facility and the installed heat pump capacity is 396 kW. The groundwater pumping rate is around 1000 m³/day at three wells and the thermally wasted water through heat exchanger reinjects to three injection wells. The pumping tests were conducted to calculate hydraulic parameters. The system operates 6 hours per day with a break of once a month period, and we analyzed the monitoring data of more than one year. At the pumping well the entering water temperatures ranges from 6.0 to 14.7°C, and the groundwater temperature range of injection well is between 2.0 and 8.3°C. From the assumed hydraulic parameters, boundary conditions of operation time, and water levels measured during pumping tests, the groundwater flow and thermal diffusion were simulated by FEFLOW numerical modeling. The simulation model could represent the area of thermal diffusion according to the operation time.  

Acknowledgment: This study is conducted by KIGAM basic project ‘Development for Climate Change Adaptation Technologies for Securing and Utilization Large-Scale Groundwater Resources (23-3411)’