Solar crop dryer with thermal energy storage as backup heater

In this research work, a solar crop dryer incorporated with thermal energy storage system as backup heater was designed and constructed from locally available materials for drying sorghum. Thermal energy storage (TES) provides several opportunities for efficient energy use and conservation. In the experimental work, flake salt was used as the storage medium to store the heat energy in aluminium pipes. From the experiment conducted on the TES system, the results showed that the dryer reduced the moisture content from about 30% to 11% wet basis in 6 hours. Without the TES, the moisture content could only be reduced from 30% to 13% in 24 hours. The temperature of the TES was found to be between 110 °C and 72.2 °C which was higher than the temperature without TES (40.8 °C to 46.5 °C) for a 24-hour period. Further analysis indicated that the heat storage not only improves the drying but increases the throughput of the device as it can be used at night.