Small wind turbine blade optimisation and design using QBlade for integration into a low-cost fresh produce preservation technology

Smallholder farmers (SF) experience about 23% postharvest fruit and vegetables (FV) losses during transportation due to unfavourable environmental conditions. This is because SF cannot afford available mobile cooling technologies since they are energy-intensive and consequently expensive. Instead, SF resort to utilising personal vehicles to transport fresh produce, with the storage environment mainly characterised by high temperature and low relative humidity. Power supply is a great challenge for mobile cooling technologies. Mobile cooling technologies use petrol and diesel to power their system as the main energy source. These sources are costly, rapidly depleting, and detrimental to the atmosphere. Renewable energy sources (RES) such as biomass, solar and wind energy are promising technologies to substitute fossil fuels for powering cooling technologies. This paper is part of a study to develop a wind turbine blade for incorporation in a mobile evaporative cooling unit. In this paper, QBlade is used to model the small wind speed with a power output rated around 600 W. The Blade Element Momentum theory is embedded in the software and is used to optimise the blade design. The SG6043 airfoil section was used to design the blades. Furthermore, the comparison is made between QBlade and MATLAB Simulink as models. The important design parameters considered include air density, wind speed, rotor diameter, pitch and twist angle. The case study uses a small horizontal axis wind turbine (HAWT) driven by a permanent magnet synchronous generator (PMSG). QBlade modelling showed that a small wind turbine (SWT) with a rotor diameter of 600 mm, a design tip speed ratio (TSR) of 6 running at 19 m s^‑1 can generate electrical energy of 0.6 kWh at a rotor rotational speed of 3200 rev min^‑1, whereas the power coefficient was found at 0.45. QBlade and MATLAB Simulink are both appropriate for SWT design.