Design and Development of a Solar PV Based Evaporative Cooled Transit Storage Unit for Horticultural Products

Abstract

Adequate cold storage facility for Horticultural products is critical due to their perishable nature. Green energy based evaporative cooling storage unit is a sustainable and efficient solution for small scale farmers and vegetable vendors in hot and dry climates who need to store their produce. Solar power operated evaporative cooling structures are low cost and efficient in reducing ambient temperature and increasing relative humidity, which increases the shelf-life of vegetables. A green energy-based evaporative cooling transit storage unit of 0.63m3 capacity was designed and fabricated. The transit unit was designed and operated as a a tricycle. Two suction fans (15.6W), submersible water pump (12W) and LED light (2.88Wp) were powered through two 100-Wp solar panels. Two batteries, 7Ah each were also used to store energy. The storage unit was made up of MS sheets of 1.2mm thick while a side of the system was made up of GI wire mesh with honeycomb pad. To test the performance of the developed unit tomato, spinach and radish were used. Results revealed that there was a significant difference (P=0.05) in PLW, firmness, TSS, and colour values of the vegetables when stored inside the unit compared to vegetables stored in ambient condition. The ambient temperature during the study was 32.2-43.4°C and RH was 21.1- 46%. The drop-in temperature was 7.8 to 14.8°C as compared to ambient conditions, while RH in the cooling chamber increased considerably to 84%.  The average cooling efficiency obtained was 84.12%.  The shelf life of stored vegetables inside the unit was 2-5 days higher than those kept under ambient conditions.