Experimental performance analysis of sensible heat storage in solar air collector with cherry pits/powder under the natural convection

It is important to enhance the availability of SACs either in cloudy weather or after sunset for space heating and agricultural drying process. In this context, this study aims to determine experimentally thermal performance of cherry pits as sensible heat storage material under natural convection conditions. In the first collector (Type I), powdered cherry pits (32 kg) were used as heat storage material and cherry pits (24 kg) were used in the second (Type II). The third collector (Type III) with a flat absorber plate is for comparison. Although the maximum thermal efficiencies were found 26.54% and 27.03% for Type I and Type II respectively, average thermal efficiency of Type I is higher than Type II. According to the test results, the inlet-outlet temperatures were equalized 46 min for the Type III, 200 min for Type II, and 270 min for Type I collector after sunset. As a result, it can be said that the use of cherry pits and powder as sensible heat storage material is promising.