Energy solution for rural household in remote cold regions: An innovative photovoltaic-based thermal energy storage system
Lijun Shi, Yanming Liu, Yanming Liu, Congrong Sun, Yingjun Guo, Dengjia Wang, Yanfeng Liu, Yanfeng Liu, Pengfei Si, Qinqing Jiang, Qiong Duan, Chunyan Wang
Abstract
Solar photovoltaic systems are crucial to solving the problem of rural energy in remote and cold areas. In the present study, an innovative off-grid photovoltaic energy supply system is proposed, which distinguishes the energy quality differences between electrical energy and thermal energy. Nighttime heating demands are primarily met by a thermal energy storage system, while domestic electricity is flexibly managed using a compact 3.12 kWh battery per building to minimize investment costs. A variable-power technology is introduced to precisely align thermal energy output with solar power generation. Research results show that, during the severe cold season, the proposed system can achieve a photovoltaic power consumption rate of 90.5 % without grid reliance, maintaining an average indoor temperature of 15.2 °C throughout the day and achieving a 100 % solar fraction. The solar thermal wall stores up to 53.25 % of solar energy, indicating its effective management in thermal energy storage and regulation. With a limited number of batteries, the solar energy guarantee rate for household electricity increases from 48.49 % in the heating season to 85.75 % in the non-heating season, thus significantly reducing user energy costs. The integration of energy-grade utilization and variable-power heat exchange technology reduces system construction and operational costs.