Long-term thermal performance of active-passive solar system integrated with solar louver

Traditional active-passive solar heating system face the problem of unsatisfactory installing space in densely built urban areas. Promoting solar louver for improving solar energy utilization has attracted enormous interest owing to its convenience and high efficiency. However, our understanding of thermal performance of solar louver as a passive heating method to enhance solar heat gain is limited. The aim of present study was to investigate the long-term thermal performance of active-passive solar system where solar collector heating system integrated with solar louver. In this work, both an in-situ experiment and a system model in TRNSYS-MATLAB were established to analyze the heat capacity and heating supply efficiency under comparative conditions. The results demonstrated that solar louver could effectively capture more solar energy into room, leading to higher indoor temperature and narrowing active solar heating supply by 33.8 % when compared to that of non-coupled solar louver condition. Solar radiation duration had more significant impact on heat collection capacity. Throughout 1 year heating period, the average daily heat gain from solar louver and solar collector heating system was 1.397 kW/d and 17.68 kW/d, respectively. The solar louver & solar collector heating system method could meet 65.8 % heating time with indoor temperature more than 18 °C. For practical economic-energy-saving application of this active-passive solar heating system, the suggested minimum load undertaken proportion of solar louver and solar collectors was 29.42 % and 41.96 % under the benchmark condition. These findings provide the theoretical basis of performance optimization and practical implementation of active-passive solar heating system in buildings.