Energy efficient achievement of indoor air quality and thermal comfort using mechanical ventilation heat recovery and solar-energy pre-heating

Transpired solar collectors (TSCs) are recognized as an efficient lower-temperature air-heating solar thermal conversion technology; However their influence on internal thermal comfort and indoor air quality (IAQ) have seldom been assessed. This study evaluates a TSC integrated with a mechanical ventilation heat recovery (MVHR) system for pre-heating ventilation air in a university classroom located in Cork, Ireland. Additionally, the study examines the overall system's ability to maintain IAQ and its energy savings. A TSC connected to an MVHR system was experimentally monitored in different modes during spring 2024. The effects of wind, flow rate, temperature rise and radiation on TSC thermal performance were examined and the results were compared with existing literature. Changes in CO₂ concentration, air temperature and the MVHR system energy consumption were compared across scenarios with and without collectors or heat recovery. Findings suggest that key factors influencing TSC thermal performance include wind speed, mass flow rate and temperature rise. The TSC requires higher MVHR fan energy use and it lowers MVHR heat exchanger efficiency. However, the total heating energy demand was reduced by more than 20%.