Thermal analysis of PV system and solar collector integrated with greenhouse dryer for drying tomatoes

Abstract

This work aims to develop a standalone hybrid solar greenhouse dryer (GD) integrated with a PV system and solar collector for smallholder processors of tomatoes postharvest. Evaluate the thermal performance of forced convection mixed-mode GD using a mathematical model. Investigate different pretreatments on fresh tomatoes (full, halves, slices, with and without blanching, with and without sugar) before drying, identify the best pretreatment and compare the quality of final product with open sun drying. Blanching tomatoes in hot water for 15 min before drying showed a higher initial drying rate compared to non-blanching treatments. Based on thermal energy analysis of the hybrid GD, the useful heat gain ranged from 6.45 to 26.62% of insolation available over the GD. The daily average heat gain that was used for drying tomatoes inside the GD reduced from 60% at the beginning to 5% at the end of the drying process. The average overall efficiency of the hybrid GD reached up to 17.96%.