Design and Analysis of Concentrated Solar-energy Assisted Paddle Dryers

摘要

Paddle dryer, one kind of indirect dryers, is widely used in removing moisture content of many materials, such as brown coal, sewage sludge, and biomass. For many applications, the materials to be dried are low-valued or even wastes, so the drying energy consumption becomes the critical issue. One way to reduce the energy consumption is to introduce solar-drying technology. In this paper, firstly, we present a paddle dryer system configuration with concentrated solar energy (CSE) device, which consists of trough-type collectors, thermal storage tanks and auxiliary parts. Then a calculating model is developed to design the drying system. Examples with typical solar radiation conditions in Nanjing, China are illustrated. The energy-saving rate (η), i.e. the ratio of the provided solar energy to the total energy required by the drying process on one-day basis, is evaluated. The developed lab prototype is finally described in brief.