Horizontal Ground-Coupled Heat Exchanger as a Passive Design Technique For Tropical Climates
The HorizontalGround-Coupled Heat Exchanger (GCHE) systems have been used successfully applied in many countries as a passive design technique, but due to lack of scientific findings and design specifications on its implementation in Mauritius, it is not counted as a passive design option in sustainability guidelines. Architects are skeptical about its efficacy, and to address this lack of knowledge, this paper describes the preliminary results obtained from experimental and simulation works for a horizontal ground-coupled heat exchanger prototype constructed at the university campus. A 3-D thermal model of the GCHE was developed as per the geometry of the prototype. Soil classification tests was carried to determine the thermal properties of the soil located at the test site. The Kasuda&Achembach model was used to determine the underground temperature profile at various depths. Parametric analysis on the performance of the GCHE was carried out. The pipe length was found to be the most sensitive parameter, while the pipe diameter was found to be the least sensitive one. A 50m to 60 m pipe length was found to be optimum for the surface area typically covered by houses in Mauritius, and for the pipe material, PVC was preferred over steel. Furthermore, the cooling capacity and CoP was determined for different air flow rates, and it was found that an air flow rate of 60 L/s yielded the optimum CoP.