Solar drying in Thailand

Research and development work in solar drying conducted in Thailand during the past 15 years is reviewed. Technical and economic results indicate that solar drying for some crops such as paddy, multiple crops and fruit is feasible. However, both the farmers who accept solar drying and the places where it is accepted are still very few. This may be due to the long payback period and high initial investment cost. Research and development work on solar air heaters is also reviewed. Most of the solar air heaters developed in Thailand have used modifications to the roofs of buildings. Both bare and glass-covered solar air heaters have been found technically and economically feasible when compared to electricity but have not been able to compete with fuel oil. Further research and development work should be continued in order to reduce costs. A standard test for solar air heaters should also be developed.