Integrated PV-PCM electric film used in building envelope for solar heating: modelling, testing and application in Qinghai-Tibet Plateau

The Qinghai-Tibet Plateau, characterized by a cold climate and prolonged heating periods, presents an opportunity for energy conservation through the implementation of a multi-energy complementary system that primarily utilizes solar energy, supplemented by electric heating. Despite the region's abundant solar resources, challenges such as uneven spatial and temporal distribution of solar energy, supply-demand mismatches, and complex control strategies persist. Moreover, existing research lacks long-term evaluations of heating systems' operational effectiveness in this area. To address these issues, this paper proposes a household energy system that meets heating, lighting, and hot water needs for remote rural households, using a photovoltaic (PV) and electric heating phase change thermal storage wall. An experimental platform in the Lhasa area enables measurements during the heating season, facilitating the development of a control strategy and an energy efficiency evaluation method. The assessment reveals that the system can achieve an operational efficiency of 71.4 %, with solar energy contributing 100 % to the heating branch, thus eliminating grid electricity consumption for heating. Additionally, the system reaches working and overall conversion efficiencies of 16.6 % and 84.1 %, respectively, while optimizing the thermal storage layer to about 2 cm to reduce investment costs. This research offers valuable insights for promoting energy-saving practices in buildings across the Qinghai-Tibet Plateau.