Experimental investigation and performance analysis of a ground-coupled heat pump system

• We designed a ground-coupled heat pump system with heat recovery technology for a cooling-dominated building.
• Experiments of heat transfer between the ground heat exchanger and the soil under typical working conditions were carried out.
• The variations in soil temperature after long-term operation were predicted.
• Some suggestions on the design of such systems were given.

A ground-coupled heat pump system using heat recovery technology was developed for a cooling-dominated building. According to experimental results, an increment in soil temperature of about 0.5 °C was observed after one year of operation. The long-term performance analysis shows that the increase in soil temperature is one third of that without heat recovery. The higher the set value of indoor temperature, the lower is the increase in soil temperature after long-term operation. The distance between the boreholes is suggested to be 4–5 m in urban areas with limited space for the installation of ground heat exchangers.