Laboratory experiment to study the effect of aspect ratio on thermal and purification performance of photocatalytic-Trombe wall

• Published in: Energy (Oxford) Vol. 332; p. 137152
• Main Authors: Wu, Shuang-Ying, Zhao, Yi-Min, Xiao, Lan
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 30.09.2025
• Subjects: Aspect ratio; Equivalent solar radiation intensity; Photocatalytic-Trombe wall; Purification performance; Thermal performance; Equivalent solar radiation intensity; Photocatalytic-Trombe wall; Aspect ratio; Purification performance; Thermal performance
• ISSN: 0360-5442
• DOI: 10.1016/j.energy.2025.137152

The unique "C" structure of photocatalytic-Trombe wall (PC-TW) channel means that changes in aspect ratio significantly affect its performance. This study constructed an experimental platform in a laboratory to measure the temperature of each component in PC-TW channel, as well as the air temperature and formaldehyde concentration at both the inlet and outlet. The influence of equivalent solar radiation intensity Ieq and aspect ratio w1/H1 on PC-TW performance was investigated. The main findings are as follows: The increase in Ieq contributes to all efficiencies of PC-TW, and the lower the Ieq, the more significant the improvement in all efficiencies. There exists an optimal aspect ratio of w1/H1 = 0.05 allowing the thermal efficiency ηth and total efficiency ηtotal to reach their maximums, while the purification efficiency ηHCHO shows varying trends with Ieq. The impact of w1/H1 on the overall natural convective heat (ha) and mass (hm) transfer coefficients is very different. ha reaches its maximum at w1/H1 of 0.05, while hm generally presents a decreasing trend as w1/H1 increases. Considering the performance and practical application, the recommended aspect ratio of PC-TW is 0.05. Under Ieq = 700W/m2, ηth can reach 42.57 %, while ηHCHO is only 0.88 %. In view of the poor percentage of ultraviolet radiation in solar radiation, how to improve the purification efficiency without compromising the thermal efficiency is a crucial topic for in-depth exploration in PC-TW. •Experimental platform for photocatalytic-Trombe wall under laboratory conditions.•Effect of aspect ratio and equivalent solar radiation intensity on the performance.•Natural convective heat and mass transfer coefficients exert different trends.•The purification performance is very limited and is the key to enhancement.•The recommended aspect ratio for the performance and practical application is 0.05.