Solar Dryer Development, Efficient and User-Friendly Aspects
Abstract
Preserving fresh food for later consumption has been, and is still today, a major problem around the world. Solar drying may be a suitable method for preserving food. One issue with dryers, depending on design is uneven drying of the produce due to different environmental conditions. Uneven drying in a solar dryer creates problems for the end user as the quality of the product will be less attractive for both storing and selling. The drying time must be kept as short as possible to avoid mold and other problems with the fruit. Avoiding long drying times is essential also for the uptake of the technology as it eases the workload put in by the end user. In this work different fan solutions are tested to mitigate this problem. Results show that using a large fan to short circuit the air in the dryer may work for this purpose. The heat exchanger efficiency was evaluated showing approximately 30 % to 40 % efficiency, which can be compared to the efficiency of the collector of approximately 50 %. However, the actual temperature rise in the heat exchanger is approximately 5 °C, which is much less compared to the temperature rise in the absorber of approximately 20 °C to 25 °C.
Keywords
solar dryer, uneven drying, fruit drying, Bhutan