Recent Development and Application of Geothermal Heat Pump Systems in Cold-Climate Regions of the US: A Further Investigation

Gaylord Olson,Louis Miller,Huojun Yang,Rui Miao,Yao Yu

doi:10.4236/eng.2017.97039

Abstract

A Geothermal Heat Pump (GHP) system is known to have enormous potential for building energy savings and the reduction of associated greenhouse gas emissions, due to its high Coefficient Of Performance (COP). The use of a GHP system in cold-climate regions is more attractive owing to its higher COP for heating compared to conventional heating devices, such as furnaces or boilers. Many factors, however, determine the operational performance of an existing GHP system, such as control strategy, part/full-load efficiency, the age of the system, defective parts, and whether or not regular maintenance services are provided. The omitting of any of these factors in design and operation stages could have significant impacts on the normal operation of GHP systems. Therefore, the objectives of this paper are to further investigate and study the existing GHP systems currently used in buildings located in cold-climate regions of the US, in terms of system operational performance, potential energy and energy cost savings, system cost information, the reasons for installing geothermal systems, current operating difficulties, and owner satisfaction to date. After the comprehensive investigation and in-depth analysis of 24 buildings, the results indicate that for these buildings, about 75% of the building owners are very satisfied with their GHP systems in terms of noise, cost, and indoor comfort. About 71% of the investigated GHP systems have not had serious operating difficulties, and about 85% of the respondents (building owners) would suggest this type of system to other people. Compared to the national median of energy use and energy cost of typical buildings of the same type nationwide, the overall performance of the actual GHP systems used in the cold-climate regions is slightly better, i.e. about 7.2% energy savings and 6.1% energy cost savings on average.

Highlights

According to the Buildings Energy Data Book [1], the US consumes approximately 19% of the total energy of the world, in which buildings account for 41% of the US energy consumption
The use of a Geothermal Heat Pump (GHP) system in cold-climate regions is more attractive owing to its higher Coefficient Of Performance (COP) for heating compared to conventional heating devices, such as furnaces or boilers
After the comprehensive investigation and in-depth analysis of 24 buildings, the results indicate that for these buildings, about 75% of the building owners are very satisfied with their GHP systems in terms of noise, cost, and indoor comfort

Summary

Introduction

According to the Buildings Energy Data Book [1], the US consumes approximately 19% of the total energy of the world, in which buildings (commercial and residential) account for 41% of the US energy consumption. It has been well known that a GHP system has enormous potential for building energy savings and the reduction of associated greenhouse gas emissions, due to its high operational efficiency. This type of system takes advantage of the nearly stable underground temperatures to reject/extract heat to/from underground regions. An energy and exergy flow analysis was performed by Lohani and Schmidt [6] in 2010 considering different heating options, including fossil fuels, ground and air source heat pump systems. GHP systems can be used for snow melting on pavements and bridge decks [22] [23] [24] [25] [26]

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