A Study on the Operational Condition of a Ground Source Heat Pump in Bangkok Based on a Field Experiment and Simulation

Abstract

The deployment of highly efficient cooling equipment is expected to promote energy savings and greenhouse gas emissions reductions in the tropics. A ground source heat pump (GSHP) has high energy-savings potential for use in Bangkok, Thailand. This study aimed to elucidate the operational conditions of a GSHP when used in Bangkok which was expected to achieve a higher efficiency than an air source heat pump (ASHP) over the long term. An operational experiment on a pilot facility in Bangkok and a simulation over a three-year GSHP operation were conducted. As a result of the operational experiment and simulation, the proposed operational condition was that the 90th percentile value of the hourly heat pump (HP) inlet temperature did not exceed 5 °C above that of the hourly annual ambient temperature during the third year of operation. When a GSHP designed based on this condition was utilized for a small government building, the required number of boreholes were 24, 4, and 3 for air-conditioned areas of 200, 40, and 25 m2, respectively, which achieved 40% energy savings. Thus, a small-scale GSHP in Bangkok designed based on the proposed condition can achieve high efficiency within space limitations.