Energy, exergy, and economic analysis of indirect solar dryer integrated phase change material cans

Abstract

The efficiency of solar dryers fluctuates as the solar radiation declines, influencing the removed water content from products. Therefore, continuous heat delivery with a stable temperature range for a longer time using energy storage materials is an efficient way to enhance the drying process from energy and exergy prospects. To this aim, a solar dryer integrated with phase change material (PCM) was designed and examined in harsh weather conditions. The solar dryer performance with 1 and 2 kg of PCM (equipped in 6 and 12 cans, respectively) was analyzed against an identical reference dryer assessing numerous energy, exergy, and economic parameters. Research outcomes revealed that PCM cans have sustained the drying process, stabilized drying temperature and functioned as an extra heat source during the daytime. Furthermore, the modified solar dryer achieved an average moisture content removal of 86.5 % and 89.7 % by employing 6 and 12 PCM cans, compared to 82.5 % in the reference dryer. Energy analysis displayed that the useful heat gain was maximized by up to 3.9 % and 9.5 % integrating 6 and 12 PCM cans, respectively. Moreover, the thermal efficiency achieved by the modified dryers was about 2.5 % and 6.8 %, respectively. Exergy analysis indicated remarkable exergy gain, exergy efficiency, and sustainability index for the solar dryer modified with 12 PCM cans, achieving a maximum of 593 W, 20 %, and 46 %. Economic analysis exhibited that the solar dryer energy payback period with 6 and 12 PCM cans was shorter than that of the reference dryer by 33.7 % and 35.1 %, respectively.