. 2010, 28(22): 33-38.
Firstly, the significance of dealing with sludge and the advantages and disadvantages of the existing approaches are briefly introduced. Then, a new technique of solar greenhouse drying sludge is recommended based on the comparison among these approaches. At last, the efficiency of this technique is got by the energy-balance equation. The heat transfer of sludge material, the heat change of sludge drying bed, the heat transfer of air flow and the heat loss through greenhouse envelope structure are set as energy destination. And the solar radiation is the energy source of this system. Then, when the destination is equal to the source, energy-balance equation comes up. From the calculation, conclusion is got as below: the annual solar energy efficiency of this greenhouse could reach a rate of 46%, and in the weather conditions of Beijing, it could be get about 0.82t/m2 of water removed. In summer, this greenhouse get more water removed rather than in winter through a same time. In addition, lower outlet temperature always results in higher ventilation, which may raise the cost. Besides, good airflow organization can achieve high outlet relative humidity, which will raise the water removed. Visibility, this approach benefits economy and is practical, which deserves deep study
