A solar drier supplemented with auxiliary heating systems for continuous operation

Abstract A prototype solar fruit and vegetable drier was developed. This comprises a glass covered flat plate collector containing metal chips, a drier with translucent walls, and an insulated tunnel, joining the two. Bell peppers and sultana grapes were dried to commercially acceptable moisture levels in various kinds of weather conditions and at various air velocities. The quality of the dried product as well as the drying times were found to be in favor of the solar drier as compared with open-air drying. Likewise, an economic analysis was undertaken to investigate the possibility of using various heat sources for an auxiliary heating system. Such a system is being developed and will be coupled to the prototype to enable all-weather operation.