Thermal Performance Evaluation of a Double Tube Ground Coupled Heat Exchanger in the Climate of Bangladesh

The ground-coupled heat exchanger (GCHE) is used in space heating and cooling systems to exchange heat with ground soil as a heat source/sink to reduce energy consumption. An experimental investigation is performed in this work to assess the thermal performance of a double tube ground coupled heat exchanger in the climate condition of Bangladesh. A double tube heat exchanger is fabricated using two PVC pipes of different diameter and inserted into 9.14 m depth of the ground. To measure the performance of the heat exchanger, water is circulated through the heat exchanger and temperatures and flow rate of the circulated water are measured. By altering the flow rate, the heat exchanger's rate of heat transfer can be determined. For a period of 12 hours, the water flow rates were 3 lit/min and 5 lit/min. The experiment shows that a flow rate of 3 lit/min gives a higher heat transfer rate per unit length than a flow rate of 5 lit/min. The average rate of heat transfer for the double tube GCHE was 82.36 W/m and 93.28 W/m for the flow rate of 5 lit/min and 3 lit/min, respectively, for the duration of 12 hours.