Performance and viability of transpired solar collectors for pre-heating ventilation air

• Solar air heating reduced ventilation heating demand in a large educational building. • Real operating conditions showed stable performance across a full heating season. • Solar air heating system reduced annual heating energy use and emissions by 24%. • Results demonstrated potential for advancing building-sector decarbonisation. Reducing heating-related energy demand in buildings is a critical step toward decarbonisation. This study investigates the feasibility of using unglazed transpired solar collectors to pre-heat ventilation air. It is hypothesised that such systems can significantly lower energy use and carbon emissions while offering economic benefits. An experimental unglazed transpired solar collectors system was installed in a university building in Cork, Ireland, and its performance was evaluated through real-time measurements and validated against simulations using the “RETScreen Expert” tool. The validated model was then scaled to a full-facade application (163 m 2 ), estimating a 24% reduction in annual heating energy use and a 23.4% decrease in greenhouse gas emissions. The system demonstrated a simple payback period of 10.3 years and an internal rate of return of 12.2% on equity. However, the financial outcomes remain closely linked to future heating fuel price trends, and the exclusion of auxiliary equipment costs (e.g., ducts, fans, filters) reflects a focus on core system performance based on reliably available data. These findings highlight the potential of unglazed transpired solar collectors for energy savings and emissions reduction, while also identifying areas for further research and detailed cost modelling.