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Abstract In this study, a small wind turbine prototype was developed to provide electric power for a mobile cooling unit The aim of this study was to design and develop a 600-W small wind turbine that can generate electric energy to power a mobile cooling unit used for the storage of fruits and vegetables, mainly for the benefit of smallholder farmers. Smallholder farmers suffer from high postharvest losses, approximated at 50%, some of which can be avoided by using efficient low-cost cooling units, rather than open transport. Cooling slows down the metabolic rate which consequently extends the produce's shelf life and prevents spoilage, allowing farmers to provide high-quality produce to the market. This could potentially increase the farmers’ monetary returns. The study was conducted in KwaZulu-Natal on the road that stretches between Pietermaritzburg and Estcourt. The wind turbine is made of a 600-mm-diameter rotor with three PVC blades, a permanent magnet synchronous generator, a bridge rectifier, a 230-V AC inverter and a battery for energy storage. The wind turbine was tested against three vehicle speeds of 60, 80, and 100 km h −1, and the two opening levels, level 1 at 45 ^ ∘ and level 2 at 80 ^ ∘ relative to the louvre mechanism frame. The results of this study revealed that the power generated by the wind turbine is greatly influenced (p < 0. 001) by both the vehicle travelling speed and louvre opening level. The power output of 113. 4, 159. 6 and 210. 0 W per hour was observed for the vehicle speeds of 60, 80 and 100 km h −1, respectively, on louvre opening level 1. The power output of 142. 8 W h −1, 268. 8 W h −1 and 294. 0 W h −1 were observed for a wind speed of 60 km h −1, 80 km h −1, and 100 km h −1, respectively, on Louvre opening level 2. This shows that higher wind speeds (vehicle speeds) produce high-power output which accounts for the small size of the wind turbine rotor. A maximum power coefficient of 0. 49 was achieved for this study. The wind turbine can generate the power required to run a cooling technology to a limited extent, thus must have a backup power supply from the diesel engine or be used in a hybrid system.
Mthethwa et al. (Thu,) studied this question.