A novel solar PV/T driven air purification system based on heterogeneous photocatalytic reaction principles: A short review and preliminary investigation

This article aims to propose a novel high-efficient, autonomous, hybrid solar air purification, electrical generation and thermal recovery system, and conduct a preliminary feasibility analysis on the proposed system. The main works involve: (1) a short review on PV/T driven purification technology, (2) the introduction on the PV/T driven air purification system based on the heterogeneous photocatalytic reaction principles, (3) the effect of TiO2 concentration on the system solar spectra characteristics, electrical performance, and the solubility of formaldehyde, (4) and the formaldehyde photocatalytic degradation performance under different formaldehyde concentrations in TiO2 nanofluids. The main results are: (1) PV/T technology has huge application potential on the integration with the water or air purification systems. (2) As the increase of TiO2 concentration (0.05-0.12 g/L), the value of short-circuit current presents an obvious decreasing trend. The light transmittance loss of the TiO2 nanofluids layer basically has a little change in the TiO2 concentration range of 0.05-0.08 g/L, while a large decrease when the TiO2 concentration is more than 0.08 g/L. (3) As the increase of TiO2 concentration, the solubility of formaldehyde diminishes except the concentration of 0.05 g/L, which shows that a certain concentration of TiO2 can improve the formaldehyde solubility because the TiO2 particles have abundant hydrophilic groups on the surface. (4) The formaldehyde photocatalytic degradation rate decreases with the formaldehyde concentration in TiO2 nanofluids in the range of formaldehyde concentration of 0.05-0.15 mg/L. The degradation process can be divided into three stages.