Development of High Quality Grin Drying Method using Solar Battery Ventilation and Solar Desiccant System

本研究的目的是设计一种新的太阳能除湿干燥方法，以节省粮食干燥过程中的能源和高品质的粮食干燥方法，使用低湿空气在常温下。研制了一种太阳能除湿干燥系统，通过干燥干燥剂来储存太阳能，利用储存的能量在夜间或阴雨天进行粮食干燥。在绿色温室内安装了固定床干燥机，用于干燥稻谷和干燥剂。以粉煤灰废弃物为原料制成的人造沸石作为干燥剂，在绿色住宅附近安装4块129W*4=516W的太阳能电池板。所产生的电力用于驱动通风风扇和干燥鼓风机，其交替地改变空气流动方向。测量太阳辐射、温度和湿度，并将其传输到计算机。通过计算和比较绿色房内外的平衡含水率来控制通风机，以保持室内空气处于低湿度。晴天收获的高水分粮食，白天利用太阳热将其干燥至短期储藏的水分水平，夜间或次日阴天利用干燥剂将其干燥至长期储藏的水分水平。在阴天，收获的谷物通过干燥剂和太阳能热干燥到短期储存的水分水平。试验证明，采用与粮食等量的沸石粉和自然能源，利用太阳能干燥系统，即使在阴雨天，也能将收获的稻谷干燥至短期或长期储存的水分水平。

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.