Solar ventilation wall for alleviating thermal and health risks of formaldehyde and virus infection

The solar ventilation wall is a well-established passive solar system that can mitigate indoor formaldehyde pollution and virus infections, which could significantly impact health. This study introduced and evaluated a thermal purification composite ventilation wall system that utilizes solar energy to regulate indoor thermal conditions and air quality. Steady-state experiments with simulated light sources assessed its thermal efficiency and formaldehyde degradation. After 2 h of ultraviolet (UV) exposure at 300, 500 and 800 W/m², indoor temperatures rose by 2.5°C, 1.6°C and 1.0°C, with thermal efficiencies of 32.14%, 29.65% and 26.49%. Thermal catalytic oxidation reduced formaldehyde from 600 ppb to 207.1, 166.0 and 140.9 ppb, achieving degradation rates of 50.7%, 60.1% and 66.4%. Model validation showed that the root mean square deviation for temperature, formaldehyde concentration and the clean air delivery rate was below 5%, confirming reliability. Regional analysis identified solar radiation as the primary efficiency factor. From December to April, heating capacity and clean air volume across cities varied minimally, while UV disinfection of SARS-CoV-2 achieved a 96.22%–97.09% inactivation rate, demonstrating the system's potential.