One of the most promising applications for active solar heating worldwide is the drying of agricultural products. In a recent study, the potential amount of energy that could be displaced using solar in this market was estimated to be between 657PJ and 1530 PJ annually. The most promising market for solar drying is generally, but not always, those crops that are mechanically dried at lower temperatures.
Crops that are currently sun-dried are well suited to solar drying, but the financial resources to implement a solar drying system are often lacking. The processes that are used to dry crops at temperatures greater than 50oC could benefit from solar drying as a supplemental system, but the drying process must be re-organized. Therefore, this Task will concentrate on displacing fuel-fired dryers for crops that are dried at temperatures less than 50 degrees Celcius.
The identified potential for displacing conventional energy sources in this segment of the market is estimated to be between 300 PJ and 900 PJ. The use of solar energy for these markets is largely undeveloped. Other than open air drying, wood and conventional fossil fuels are used most extensively at present. In many countries wood is being replaced by more expensive diesel and propane fuels.
Three key barriers to increased use of solar crop drying identified by the above study are the lack of awareness, the lack of good technical information and the lack of good local practical experience.
The objective of this Task is to address these three barriers by providing technical and commercial information and experience gained from the design, construction and operation of full working demonstration systems for a variety of crops and a number of geographical regions.