Evaluating the energy and cost impacts of ground source heat pumps and photovoltaics in a Finnish detached house : current climate versus 2050 climate projections

Abstract

This study investigates the impact of adding a ground source heat pump(GSHP) and building-integrated photovoltaics(PV) on an old(built in 1985) Finnish single-family house's energy consumption and overall CO2 emissions. The reference building was modeled via IDA Indoor Climate and Energy (IDA ICE) simulation according to the thermal and energy standards of the old Finnish buildings. The energy performance was simulated in five different scenarios regarding the climate conditions of both present and 2050 weather in Hämeenlinna. The study aims to assess the contribution of ground source heat pumps and building-integrated photovoltaics systems to fulfilling the energy needs of the building in terms of electricity, space heating, and domestic hot water supply. Results showed that the GSHPs could potentially reduce energy consumption by 37% at best. Similarly, CO2 emissions could be drastically reduced, with 23% achieved under present conditions and as high as 33% reduction based on climate of future projections. However, the study finally points to a critical barrier against the widespread adoption of these technologies high installation costs. The payback period was found to be nearly 25-30 years in the case of GSHP installation, thus rendering the investment uneconomic for a large part of the pool of homeowners. Subsidies, or low-interest loans, may be needed if these technologies are to be made more widely accessible, the research indicated. Besides, the structural dysfunctions of older buildings need to be treated before putting in place the advanced energy systems, as the improvement of thermal performance through the use of insulation and current window types will maximize the benefits of GSHPs and PVs and will lead to more energy savings and emission reductions. This finding agrees with the Finnish environmental policy.