The performance analysis of a purified PV/T-Trombe wall based on thermal catalytic oxidation process in winter

[Display omitted] •A novel purified PV/T-Trombe wall based on thermal catalytic oxidation.•Higher thermal and electrical efficiency considering formaldehyde degradation.•Linear relation of air thermal efficiency with normalized temperature difference.•High utilization on the PV cells compared with other PV/T systems. On one hand, PV/T air system is in unused condition in summer while PV/T water system exists the freezing problem in winter. On the other hand, the indoor air pollution has been gotten more and more attention. Therefore, this article proposed a purified PV/T-Trombe wall, which could produce sustainable electricity and degrade gaseous formaldehyde in whole year, realize space heating in winter and supply hot water in summer. The focus in this article was the comprehensive performance investigation in winter. Firstly, continuous six full-day experiments were conducted to investigate the thermal and electrical performance. Secondly, based on the verified system heat and mass transfer model, the formaldehyde degradation performance was investigated. Thirdly, the performance comparisons of the proposed system with other PV/T systems were conducted. Main results were: (1) The average daily electrical efficiency and air thermal efficiency were 11.9% and 36.6%, respectively. (2) The dependence between the air thermal efficiency and the modified normalized temperature difference well fitted the linear relationship under natural convection condition. (3) The clean air delivery rate was in the range of 42.5–81.6 m3/h and the daily generated volume of clean air was 202.9 m3/(m2·day). (4) The thermal and electrical efficiency considering formaldehyde degradation was 50.3%, with the increase of 3.7% due to the contribution from formaldehyde degradation. (5) The ratio of the electrical efficiency considering formaldehyde degradation to the standard PV cell efficiency approached up to 98.6%, which indicated a high utilization on the PV cells.