Assess the benefits of ground- source-heat pumps for residential heating versus natural gas boilers in the UK

Abstract

Some basic introduction about the current background of heating in the UK and ground source heat pumps (GSHPs) and natural gas (NG) boilers was outlined in this report. Moreover, this report also provided a detailed literature-based review of previous studies of both GSHP and NG boiler, concentrating on environmental impact, costs and benefits. For the purpose, a 12kW peak heating load house which is located in London established by the IES VE have been considered as the case study. Finally, it is concluded that the coefficient of performance (COP) of GSHP should be higher than 2.2 to achieve lower carbon emissions compared with NG boilers in the current period. And under normal conditions, the efficiency of the GSHP is in the range of 2.2 to 4, so it is more environmentally friendly than the NG boiler. As for a GSHP with a COP of 4, it has been found that the carbon emissions will be reduced by about 25% in the current period, 40% in 2030 and even 90 percent in 2050 after replacing the NG boiler. Besides, the results show that using low operating temperatures will contribute to reduce carbon emissions. In the aspect of economic, it can be concluded that the installation of the GSHP is cost-effective in most cases and the higher the COP, the shorter the payback period. Under the subsidy of Renewable Heat Incentive (RHI), for a GSHP with a COP of 4, its payback period is about 20 years. However, if the COP is lower than 2.6, the capital costs cannot be fully recouped. In the end, the results and the limitations occurring in the research process have been analysed and advice on future improvements was given.