Research of direct expansion type ground source heat pump using steel pipe pile for house

Abstract

The purpose of this paper is to clarify the heating performance of a direct expansion type ground source heat pump using steel pipe pile for house. The ground source heat exchanger consisted of one copper tube with an outer diameter of 4.0 mm and an inner diameter of 3.2 mm, and two similar copper tubes connected in a U-tube at the bottom. Experiments were conducted at a set of 22.5°C for 8 hours and 23°C for 144 hours. Consequently, the average heat gain for 8 hours was 3.8 kW and COP was 4.1, and it for 144 hours was 5.3 kW and COP was 2.0.