Study on an advanced borehole heat exchanger for ground source heat pump operating in volcanic island: Case study of Jeju island, South Korea

Abstract

This paper presents an advanced borehole heat exchanger that has been developed in order to apply a ground source heat pump to a volcanic island where the existing borehole heat exchangers are inapplicable by local ordinance. The advanced borehole heat exchanger was fabricated and installed at a verification-test site to evaluate its heat capacity in terms of refrigeration ton (RT). The proposed heat exchanger was also compared with the conventional heat exchanger that was made of high-density polyethylene (HDPE) heat exchanger. The thermal response test was carried out by flowing water at various temperatures into the heat exchangers at the fixed flow rate of 180 L/min. The results revealed that the maximum heat capacity for the developed heat exchanger was measured at 63.9 kW, which is 160% higher than that of the high-density polyethylene heat exchanger (39.9 kW). It was also found that the developed HX has the highest heat gain achieving 94 kW as compare to 21 kW for high-density polyethylene-Hx.

Analyzing the Performance of Double Spiral Tube Ground Heat Exchangers in a Zero-Energy Building Using Measurement Data

“…Luo et al [23] analyzed the thermal load of a BHE installed in a GSHP with three borehole diameters and revealed that an increase in the borehole diameter could slightly improve the thermal performance of the BHE. Kim et al [24] developed a stainless-steel BHE and elucidated that it has a 160% and four times higher maximum heat capacity and gain (kW), respectively, when compared with conventional GHEs made of high-density polyethylene, implying a high heat extraction capacity from the ground. Zou et al [25] developed a three-dimensional heat transfer model for three types of horizontal GHEs (HGHEs) and demonstrated that spiral-coil HGHEs exhibit the best performance with respect to the COP and heat transfer rate (W/m).…”