• Abdeen Mustafa Omer Energy Research Institute
Keywords: Geothermal heat pumps, direct expansion, ground heat exchanger, heating and cooling


In the recent attempts to stimulate alternative energy sources for heating and cooling of buildings,
emphasise has been put on utilisation of the ambient energy from ground source heat pump
systems (GSHPs) and other renewable energy sources. Exploitation of renewable energy sources
and particularly ground heat in buildings can significantly contribute towards reducing
dependency on fossil fuels. Geothermal heat pumps (GSHPs), or direct expansion (DX) ground source
heat pumps, are a highly efficient renewable energy technology, which uses the earth, groundwater or
surface water as a heat source when operating in heating mode or as a heat sink when operating in a cooling
mode. It is receiving increasing interest because of its potential to reduce primary energy consumption and
thus reduce emissions of the greenhouse gases (GHGs). The main concept of this technology is that it
utilises the lower temperature of the ground (approximately <32°C), which remains relatively stable
throughout the year, to provide space heating, cooling and domestic hot water inside the building area. The
main goal of this study is to stimulate the uptake of the GSHPs. Recent attempts to stimulate alternative
energy sources for heating and cooling of buildings has emphasised the utilisation of the ambient energy
from ground source and other renewable energy sources. The purpose of this study, however, is to examine
the means of reduction of energy consumption in buildings, identify GSHPs as an environmental friendly
technology able to provide efficient utilisation of energy in the buildings sector, promote using GSHPs
applications as an optimum means of heating and cooling, and to present typical applications and recent
advances of the DX GSHPs. The study highlighted the potential energy saving that could be achieved
through the use of ground energy sources. It also focuses on the optimisation and improvement of the
operation conditions of the heat cycle and performance of the DX GSHP. It is concluded that the direct
expansion of the GSHP, combined with the ground heat exchanger in foundation piles and the seasonal
thermal energy storage from solar thermal collectors, is extendable to more comprehensive applications

Author Biography

Abdeen Mustafa Omer, Energy Research Institute

Energy Research Institute (ERI), Nottingham, United Kingdom