Research on Performance of Ground-Source Heat Pump Double U Underground Pipe Heat Exchange

Youyin Jing,Peng Yang,Jing Hou

doi:10.4236/ojmsi.2013.11001

Abstract

This paper uses FLUENT software building the three-dimensional unsteady state model of ground source heat pump single U and double U underground pipe to study on heat exchange of underground pipe system in the condition of unsteady state long-term continuous running, analyzes the change of soil temperature filed around underground pipe and performance of underground pipe heat exchange between single U and double U pipe system. The results show that double U pipe system is better than single U system, which can improve unit depth heat exchange efficiency, reduce the number of wells and reduce the initial investment.

Highlights

Ground source heat pump technology is a gradual rise of the energy saving technology along with global energy crisis and the emergence of environmental issues
This paper uses FLUENT software building the three-dimensional unsteady state model of ground source heat pump single U and double U underground pipe to study on heat exchange of underground pipe system in the condition of unsteady state long-term continuous running, analyzes the change of soil temperature filed around underground pipe and performance of underground pipe heat exchange between single U and double U pipe system
The results show that double U pipe system is better than single U system, which can improve unit depth heat exchange efficiency, reduce the number of wells and reduce the initial investment

Summary

Introduction

Ground source heat pump technology is a gradual rise of the energy saving technology along with global energy crisis and the emergence of environmental issues. Geothermal energy is a low grade energy, and a green renewable energy that human can use [1]. Conventional air conditioning high energy consumption and environmental pollution problem can be solved. The new geothermal energy could ease dependency of coal and oil in our country, and achieve the purpose of energy diversification. Some of residential districts, office buildings, hospitals and other kinds of buildings use the ground source heat pump system to heat and cool, and obtain good results. Ground source heat pump’s characteristic is high initial investment, but low operating costs than conventional air conditioning system, so reducing the initial investment is very important to ground source heat pump. Double U pipe system can improve heat exchange performance, reduce the initial investment [2]

The Theoretical Basis for Modeling

Physical Parameters

Geometric Model

Soil Temperature Distribution

Comparison of Pipe Heat Exchange

Conclusions