Experimental study of the effect of slit width and slit spacing on the thermal performance of slit-glazed collectors

Abstract

An experimental study on the thermal performance of slit-glazed collectors was conducted. Here, glass panes were used as slit glazing cover, and the air was blown continuously through the gaps between them by fan (slit glazing is an uncomplicated and economical process compared to glass perforation). In this study, the effect of the width of glass panes, the distance between the slits, and mass flow rates were studied on three slit-glazed collectors. A glass pane with the length of 131 cm and thickness 0.4 cm was studied for three different slit widths: 6, 5, and 4 cm. The experiments are conducted with four different gap distances between the glass panes (0.5, 1, 2, and 3 mm) and three air mass flow rates (0.014, 0.022, and 0.029 kg/s). The experimental results indicated that the maximum thermal efficiency of 75% was obtained when the gap distance was 0.5 mm, slit width was 4 cm, and the mass flow rate was 0.029 kg/s. The maximum rise in air temperature was noted as 28°C when the gap distance and slit widths were 0.5 mm and 5 cm, respectively. Hence, the best thermal performance was achieved with the smallest slit width and gap distance parameter values.