Schematic view of experimental set-up
Experimental set up
Two solar air heaters (s1 and s2) of same specific dimensions have been designed and fabricated to supply hot air for drying and space heating. Both air heaters were experimentally tested individually for their thermal performance on different configurations.
Plywood of 1 cm thickness was used for the fabrication of both solar air heaters
The specific area of absorber tray was
151 53 cm2 which has been made of by using a
0.5 mm thick
22 SWG Al sheet. The absorber tray was painted dull black to store the maximum amount of solar energy for s1. To reduce the heat losses, a 2 cm thick layer of glass-wool was placed between the absorber tray and outer cabinet. A single pane transparent float glass of 0.3 cm thickness and 151 70 cm2 was used for glazing to allow the solar radiation inside the SAH. The single glazing has been considered
effecting elements of the system like as halogen lights, inside wall of ducts for good reflection, and mainly the absorber tray are required to be very clean while performing (a float glass, beneath which the granular carbon is spread of heat storing for long hours) and for efficient working in good and poor ambient conditions.
Dusty transparent glass over storage media and dusty reflective walls will be resulted in lower efficiency of the system. Double glazing makes the system a little bit complicated in comparison of discussing system and more maintenance and attention will be required
The distance between glazing and absorber tray was 10 cm for
both heaters. A layer of granular powder of 1 mm was spread on
the absorber tray and sealed by 2 mm float glass for s2 (Fig. 2).
The side walls of SAH were tilted at 115o angle because of receiving
good amount of solar radiation through its exposed area. For air
supply two similar high velocity table fans