State of the Art, Perspective and Obstacles of Ground-Source Heat Pump Technology in the European Building Sector: A Review

Abstract

In the European Union, 40% of the overall final energy consumption is attributable to the buildings sector. A reason for such data may be found considering that the great majority of the building stock is more than 40 years old. According to the European Commission, an interesting potential lies in the refurbishment of the building sector, and heat pump technology has been recognized as one of the most cost-effective solutions to tackle the environmental issue of this sector. Regarding heat pump technology, ground-source heat pumps (GSHPs) have been proven to be the most efficient solution on equal boundary conditions. Despite this, in most EU states’ markets, GSHPs hold only a small market share with respect to air-source heat pumps. In this paper, the state of art and possible future developments of GSHP technology have been reviewed together with a focus on the potential of such technology, most of all on the refurbishment of existing buildings, and on the obstacles to its spread. The state of art of borehole heat exchangers has been studied, focusing on the parameters characterizing the outside pipe and the pipe itself, i.e., pipe and grout materials. Moreover, an overview on the last developments involving refrigerants and secondary fluids is given. Finally, the design and control strategies of GSHPs have been reviewed.

A Review of Groundwater Heat Pump Systems in the Italian Framework: Technological Potential and Environmental Limits

“…As [22] reports, a significant portion of building energy consumption in the EU, approximately 60-80%, is attributed to space heating. This may be because 64% of EU buildings are more than 40 years old [4].…”

Groundwater Microbiology of an Urban Open‐Loop Ground Source Heat Pump with High Methane

“…30-80°C) for space heating of buildings and hot water. The submersible well pump and heat pump unit are usually powered by electricity, providing three to four units of heat output for one unit of electrical input, and has 15 to 77% lower CO2 emissions than gas boilers, which reduces to zero net CO2 emissions once the grid is supplied with 100% renewable energy (Menegazzo et al 2022). This renewable heating technology is likely to become dominant for domestic and nondomestic heating as the UK government is due to phase out installation of new domestic gas boilers by 2035 (BEIS 2021) and to reach NetZero emissions by 2050 and has set a target to install 600,000 heat pumps per year by 2028.…”

“…The heat exchanger transfers a small proportion of heat from the groundwater to a separate network of "clean" water which is passed through a heat pump that concentrates the temperature to a suitable temperature (e.g., 30-80 • C) for space heating of buildings and hot water. The submersible well pump and heat pump unit are usually powered by electricity, providing 3-4 units of heat output for one unit of electrical input, and have 15-77% lower CO 2 emissions than gas boilers, which reduces to zero net CO 2 emissions once the grid is supplied with 100% renewable energy (Menegazzo et al 2022). This renewable heating technology is likely to become dominant for domestic and non-domestic heating as the UK government is due to phase out installation of new domestic gas boilers by 2035 (BEIS and E. A. I. S. Business 2021).…”

Numerical Simulation of Heat Extraction by a Coaxial Ground Heat Exchanger Under Freezing Conditions

“…Ground source heat pump (GSHP) is a highly efficient renewable energy technology which allows sufficient reduction in energy consumption for building heating and cooling [1]. An important part of each GSHP system is a ground heat exchanger (GHE) installed in a vertical borehole or horizontal trench.…”