An Evaluation of Seasonal Performances Evaluation of a Vertical-type Geothermal System applied for RD and Office Building

摘要

A geothermal heat pump system of 400RT cooling capacity has been measured and evaluated 3 times through a year. Followings are the results. The inlet temperature into the GHEX (Geothermal Heat EXchanger) is lower than outlet in winter, but in summer it reversed. Even the average heat conductivity is evaluated as 3.09W/m℃, because of the heat conductivity differences between borehole #2 and # 1 (#2 is higher than #1), the temperature differences between inlet and outlet of GHEX of heat pump zone #2 is measured higher than zone #1. The maximum temperature of the 1st winter was 15℃, but it was increased to 17.5℃ at next winter, one of the major reasons is assumed that the exhausted heat might be spread less effectively and accumulated into the ground during cooling operation in summer. The geothermal system COP was calculated as 4.3 at 1stwinter measurement, 3.8 at 2nd-summer, and 3.4 at 3rd-winter.