Experimental Studies on a Solar Air Heater Having V-Corrugated Absorber Plate with Obstacles Bent Vertically

A solar air heater (SAH) is a simple heater using solar radiation that is useful for drying or space
heating. Unfortunately, heat transfer from the absorber plate to the air inside the solar air heater is
low. Some researchers reported that obstacles are able to improve the heat transfer in a flat plate solar
air collector and others found that a v-corrugated absorber plate gives better heat transfer than a flat
plate. Yet, no work of combining these two findings is found.
This paper describes the result of experimental study on a SAH with v-corrugated absorber plate
and obstacles bent vertically started from 80o to 0o with interval 10o on its bottom plate. Experiments
were conducted indoor at five different Reynolds numbers (1447 #8804 Re #8804 7237) and three different
radiation intensities (430, 573, and 716 W/m2).
It is found that the obstacles improve SAH performance. Both the air temperature rise and
efficiency increase with inserting obstacles bent at any angle vertically. Unfortunately, the air
pressure drop is increasing, too. Obstacles bent vertically at smaller angle (means more straight) give
higher air temperature rise and efficiency. However, the optimum angle is found 30o. The air
temperature rise and efficiency will be 5.3 lower when the obstacles bent 30o instead of 0o, but the
pressure drop will be 17.2 lower.