A Study on the Heat Transfer Performance Having Perforated Fins in Air Channel for Solar Air-water Heater using CFD

The solar air–water heater is a combined system of air-type and water-type collectors and a composite collector that can produce hot water and heated air in one system. Although it can maximize heat acquisition by transferring some of the heat lost from the absorbent plate and pipe toward the air duct, the heat acquisition is low due to the low heat capacity. To address this problem, several studies have been conducted using turbulent promoters in ducts. In this study, to improve the air-side heat transfer performance of the solar air–water heater, perforated fins on the bottom side of the absorption plate were arranged in various arrangements. Thereafter, computational fluid dynamics (CFD) was performed according to the flow conditions, and the heat transfer performance and pressure drop characteristics were analyzed. Results indicated that the heat transfer performance improved by at least 1.24 times to a maximum of 2.21 times, and that the pressure drop was in the range of 4.10 ~ 7.38 times, confirming the thermal hydraulic performance parameter (THPP). In the case of the performance coefficient, when perforated fins were attached side by side to the pipe, the highest performance coefficient was 1.18.