Analysis of Selection of Single or Double U-bend Pipes in a Ground Source Heat Pump System

Abstract

The ground source heat pump (GSHP) system is widely used because of its energy-saving and environmental-friendly characteristics. The buried pipes heat exchangers play an important role in the whole GSHP system design. However, in most cases, single U-bend pipes are adopted only for their simplicity in design and construction instead of high efficiency and less operation cost of the whole system. In this paper, we make a comparison between single and double U-bend pipe heat exchangers in their heat exchange rate per depth, the number of boreholes needed for the same amount of cooling load, total lengths of pipes for the two different types of heat exchangers, and seasonal overall energy efficiency of the two GSHP systems. An economic analysis method is also presented. Finally, conclusions are made for the selection of single or double U-bend pipe heat exchangers in a GSHP system after a case study using TRNSYS simulation software is carried out.