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.

A Review of Ground Source Heat Pump Application for Space Cooling in Southeast Asia

“…A vertical-loop GSHP was installed and connected to an experimental room with dimensions of 3 × 4.75 × 3.5 m 3 on the second floor of the Parot Racha building, Chulalongkorn University, as shown in Figure 5 [27,59]. The system included two 50-m deep boreholes with a single U-tube.…”

Optimization of Geothermal Heat Pump Systems for Sustainable Urban Development in Southeast Asia

“…Figure 3 [4] shows the geographical distribution of study on GSHP systems in the Southeast Asian region, showing a wide range of studies in Thailand [10][11][12][13][14], Indonesia [15], Malaysia [16], Singapore [17], and Vietnam. In particular, the study conducted in Kamphaeng Phet by Yasukawa et al [14] is recognized as the first investigation of GSHP technology in the region, highlighting the potential benefits of such applications at the study site.…”

“…In 2020, a collaborative study effort between Japanese and Thai academics, highlighted by the work of Shimada et al [12] was conducted at the facilities of Chulalongkorn University to conduct both experiments and simulations on an operational GSHP system. The investigation included a Thermal Response Test (TRT) to validate the simulation model within a pilot plant setup.…”

The Study of Soil Temperature Distribution for Very Low-Temperature Geothermal Energy Applications in Selected Locations of Temperate and Subtropical Climate

“…Sliwa et al [1] developed a methodology for determining the energy efficiency of borehole heat exchangers based on temperature profiling. In the case of vertical heat exchangers, the ground temperature distributions concern considerable depths as a function of the length of the boreholes [2][3][4][5][6][7]. Horizontal ground heat exchangers usually require knowledge of temperature distributions in the ground up to several meters [8][9][10][11][12].…”