Performance simulation research of the novel PVT-PCM-GSHP system in different climate zones

The utilization of renewable energy in buildings has become an important means to solve the problem of building energy consumption. By coupling the photovoltaic/thermal (PV/T) system with ground source heat pump (GSHP) system, energy complementarity can be realized and system performance can be improved. However, most investigated PV/T-GSHP systems before were designed for large commercial buildings thus leading to high investment. And the PV/T-GSHP system still cannot totally solve the issue that the use of solar energy is unstable and it is intermittent in the four seasons and day and night and in the region. In this study, phase change material (PCM) was coupled into the composite system to improve the heat storage capacity and reduce the operating temperature of solar cells. The composite system was designed for a typical two-storey residential building and meet the design requirements of the local climate. Moreover, the model of this novel PVT-PCM-GSHP system was built in TRNSYS software to analyse its operating performance under eight climate conditions. The PCM tank model in TRNSYS was macro-encapsulated as a component. At the same time, six operation modes were designed to reduce its operational energy consumption. In Rome, for example, the system increased the average COP of heat pump to 5.27 and the renewable power fraction (RPF) to 1.66. The COP of GSHP unit in Vladivostok obtained the highest value of 6.13. The RPF reached its highest value at 4.23 in Wellington. In the hot areas like Singapore, Bangkok or Doha, heat accumulation occurred in the system, and RPF could not exceed 1.0. Compared with the traditional PVT-GSHP, the system still improves the operating performance of the equipment, enhances the efficiency of solar cells, and realizes the triple supply of heating, cooling and electricity generation. This study provides a new solution to the building efficiency which can be a reference in the future.