Integrated Thermal Energy Storage for Enhanced Performance in Indirect Solar Drying Systems

Abstract

An indirect, active-type, low-cost solar drier with latent heat thermal energy storage was built utilising affordable, locally accessible materials to dry agricultural products.

The dryer is made up of a drying chamber, a solar flat plate collector with thermal energy storage material, and a blower to create the necessary air flow in the system. The crop selected for the experiment is ginger since it has a high yield and significant losses in India. Dried ginger is also a necessary part of a diet because of its high nutritional and medicinal value. In this studies multiple PCM with different melting temperature was filled in the baffles of solar collector so that it can be easily melt in day time and release heat in off sun shine hours. In these experiments, the final moisture content is obtained in seven hours in an indirect solar dryer with thermal energy storage, eight hours in a direct solar dryer, and eleven hours in an open sun dryer. The average efficiency of collector was found to be 85 %, whereas the efficiency of dryer was found to be 47 %. The dryer runs effectively for the next three to four hours after sunset, maintaining a temperature inside the drying chamber that is eight degrees celsius greater than the atmospheric air. The dryer's effectiveness is further enhanced by placing a liquid or solid sensible heat-storage material in the drying chamber's bottom.