Are Ground Source Heat Pumps The Future Of House Heating?
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With an overall contribution of 14.25% to UK’s total greenhouse gases emissions and a jaw-dropping corresponding 94.9% of the residential sector emissions, heating certainly plays an important role in the game of carbon footprint reduction.
It’s about time we cool things down, but replacing the radiator with a warm jumper is not necessarily the only available option.
Household heating is usually powered by natural gases, infamously known around the world as a huge GHG fossil fuel, but there are at least two valid alternatives: bioenergy and electricity. The current intention to strongly foster decarbonisation of electric production implies that electrical household heating would drastically cut this sector’s emissions. Examples of simple yet effective electrical heating systems are heat pumps.
A heat pump works by transferring heat from a warmer place to a colder one, exploiting evaporation and condensation of refrigerant fluids. As it evaporates, the fluid absorbs heat, which is then released during the condensation process. There are two main types of pumps, depending on the heat source used: Air Source Heat Pump (ASHP) or Ground Source Heat Pump (GSHP). The latter seem to be the best option at the moment, as the slight changes in ground temperature, compared to the ones affecting air, guarantee a more constant efficiency throughout the year.
Although GSHPs rely on an elementary principle, their actual efficiency depends on quite a large number of requirements. First of all, maximum efficiency is only obtained if the temperature difference between the heat source and the inside system is small: a high energy expense would otherwise be needed to increase the captured heat’s temperature. This inevitably restricts the use of heat pumps in Northern countries or during hard winters. Underfloor heating is also proved to be more efficient than radiators; in case this system was not available in a building, the size of the radiators should be at least double the normal one and would still not be an excellent solution. House insulation and available space are also important factors when considering the installation of a GSHP.
Last but not least, Ground Source Heat Pumps operate best by providing a mild but continuous heating, evenly distributed in the whole space, rather than the intense and rapid one offered by the current dominant technologies. This difference could dishearten many, but a simple heat storage system would allow a better control of heat diffusion.
All these issues offer an accessible solution, as the large spread of heat pumping system in Germany and Switzerland shows. In these countries, GSHPs were found to provide an average seasonal performance factor of above 2.6, with peaks of 5.0 – the average factor for a gas boiler is 2.5. Decarbonisation of electricity will certainly puff up these numbers, making heat pumps the most efficient and at the same time environmentally friendly heat system for houses.
About the Author Giuli Cardoso
Giuli Cardoso was born and raised in Milan, Italy, but recently moved to England to study Physics and Philosophy at King’s College London. She has always been interested and passionate about sustainability and the environment and is keen to make a positive contribution towards a greener future.