Development and Preliminary Analysis of a Solar Dryer for Flour Dehydration

Until now, drying flour in full sunlight has been the technique most widely used in Burkina Faso. This method exposes the flour to numerous risks of poisoning, pollution, soiling and destruction of nutritional qualities. Despite this, there are very few documented solutions to the problem. This has prompted this work on the design and preliminary study of a solar dryer for drying flour. To this end, the design approach based on unfavourable periods was used to dimension the solar collector elements. The initial studies were carried out experimentally, starting with a no-load study and then a load study. As a result of this work, a two-in-one solar dryer was designed and built. It was able to heat the drying air to 65°C in unfavourable weather conditions. During drying, the temperature reached 58°C in forced convection. However, the average drying temperature was below the predefined drying temperature range (45-55°C). The drying speed was less than half that predicted. As a result, the drying time was 10 hours 20 minutes instead of the planned 4 hours. The water content lost through the flour reached 31.14% on rack 1, whereas it was assumed to be 25%.