By Josh Perry, Editor
European researchers have collaborated on a novel, geothermal, dual-source heat pump (DSHP) that provides cost-effective, energy-efficient heating and cooling of buildings, as part of the European Union GEOTeCH project.
The pump is put into practice at De Montfort University in Leicester.
(De Montfort University)
The research was announced by the EU Community Research and Development Information Service (CORDIS).
“The innovative DSHP takes advantage of either air or ground heat sources, depending on operating and climatic conditions,” the announcement explained. “It’s able to select the most favorable heat source or heat sink (for heating or cooling, respectively) in a way that allows it to operate as an air-to-water or brine-to-water heat pump.”
This design allows for air or the brine from the ground to act as heat sources in the winter or as heat sinks for cooling during the summer. It also provides year-round warm water.
The pump is being displayed at four European sites, including De Montfort University in Leicester (U.K.).
The article noted, “Five boreholes have been drilled at DMU in locations where there was enough soft ground to drill down at least 10 m. Heat exchangers have been installed in four of the boreholes. In the fifth hole, temperature sensors have been set up to record data on changes in ground temperature. Data is also being recorded on energy consumption and comfort levels in the demonstration site, which replicates a small domestic building.”
In an article on the university site, Professor Rick Greenough, who is leading the research group, said, “Geothermal energy is the future – it’s a clean and sustainable source of power. It does not produce greenhouse gases that can be harmful to the atmosphere…Most people rely on gas but there is a limited supply of fossil fuels, whereas geothermal heat pumps can make use of the practically limitless heat from the sun that falls on the ground and warms the air around us.”
The research was recently published by the International Journal of Low-Carbon Technologies. The abstract stated:
“This article presents the characteristics and performance of an innovative dual source heat pump (DSHP) for heating, cooling and domestic hot water (DHW) production. The research work was carried out in the framework of the H2020 European project: Geot€ch ‘GEOthermal Technology for economic Cooling and Heating’.
“The DSHP is able to choose the most favourable source/sink in such a way that it can work as an air-to-water heat pump using the air as a source/sink, or as a brine-to-water heat pump coupled to the ground. The DSHP is manufactured as an outdoor ‘plug & play’ unit, working with R32 refrigerant and including a variable speed compressor, which gives full capabilities for an efficient modulating operation.
“The DSHP was fully characterized in steady state conditions at the IUIIE laboratory. In order to assess its dynamic performance and to identify key control strategies to optimize its annual operation, a complete integrated model of the DSHP system in TRNSYS including the DSHP and all the other system components was developed. A first energy assessment, carried out for an office building located in the Netherlands, proves that the DSHP system would be able to reach a similar efficiency than a pure ground source heat pump (GSHP) system with half the ground source heat exchanger area needed.
“Therefore, the DSHP system could become a cost-effective alternative solution for heating, cooling and DHW production in buildings, as the initial investment would be significantly reduced compared to GSHPs, with similar or even higher energy efficiency.”