| Research Abstract |
The object of this study is to devise a new solar desiccant drying method for energy savings in grain drying process and high quality grain drying using method using low humid air at ordinary temperature. We developed a solar desiccant drying system, which stores solar energy by drying the desiccant and uses the stored energy for grain drying at night or cloudy or rainy day. A stationary bed dryer for drying paddy and desiccant was installed in a green house. Artificial zeolite which is made from coal ash waste is used for desiccant, and four solar cell plates (129w*4=516W) were installed near the green house. The generated electric power is used for driving ventilation fans and a drying blower which changes the air flow direction alternately. Solar radiation, temperature and humidity were measured and transferred to computer. The ventilation fans were controlled by calculating and comparing both the equilibrium moisture content of inside and outside the green house to maintain the inside air at low humidity.
We tested the solar drying system in autumn 1995 and 1996. On sunny day, harvested high moisture grain dried into the moisture level for short term storage by solar heat in the daytime, and dried into that for long term storage by desiccant at night or next cloudy day. On cloudy day, the harvested grain dried into the moisture level for short term storage by both desiccant and solar heat. It was proved that the harvested paddy can be dried into the moisture level for the short or long term storage even on a cloudy or rainy day by the solar desiccant drying system using the same amount of zeolite as that of grain and natural energy.
|
