Hybrid solar Chimneys: Enhancing thermal comfort and Alleviating indoor air pollutants − A comprehensive review

Abstract

Indoor air pollution (IP) remains underrecognized compared to outdoor pollution, despite extensive research on environmental contamination and outdoor air quality. Individuals of all age groups spend the majority of their time indoors—often over 90%—placing them at continuous risk of exposure to indoor pollutants and potential harm to both individual and public health. In this context, hybrid solar chimney (SC) systems have emerged as a promising strategy to enhance thermal comfort and mitigate indoor pollution levels. These systems employ thermal buoyancy for natural ventilation, thus improving indoor comfort and indoor air quality (IQ). Researchers have investigated several modifications to hybrid systems, such as integrating Photovoltaic cells (PV), Phase Change Materials (PCMs), evaporative cooling, and Earth-air heat exchangers (EAHE), to improve their efficiency, these studies have primarily focused on the thermal comfort benefits. However, a notable gap remains in addressing indoor pollutants. In response, this review examines the potential of integrating a photocatalytic reactor into hybrid solar chimneys to target airborne contaminants while maintaining desirable indoor temperatures. The findings underscore the need for future advancements in hybrid Solar Chimney technology, particularly in optimizing multi-technology integration, enhancing photocatalytic materials, and establishing standardized performance metrics to evaluate both thermal comfort and air quality. Lastly, the review highlights the challenges facing these systems and proposes directions for future investigation.