太阳能谷物干燥系统的试验研究

以平板微热管阵列为核心传热元件结合复合抛物面聚光式集热器和相变蓄热器, 提出了一种以空气为传热介质的复合抛物面聚光式太阳能集蓄热一体化系统. 该系统采用复合抛物面聚光式真空管集热器为集热部件, 58#石蜡为相变储热材料, 搭接平板微热管阵列为核心热传输元件, 在室外测试了2种不同模式(先蓄后取模式和边蓄边取模式)下系统在不同空气流量下的蓄放热性能. 同时根据太阳入射光线方位角的变化, 结合聚光器入射半角θ, 确定了聚光器吸收太阳总辐射时间范围, 建立了复合抛物面聚光式太阳能集热器对太阳能辐射能的吸收计算模型. 实验结果表明: 先蓄后取模式下, 集热器吸收太阳辐照量在15 MJ左右, 一体化装置的平均蓄热效率在36%左右, 取热空气体积流量的变化对该装置日总效率影响不大, 维持在34%左右; 边蓄边取模式下, 随着空气体积流量增加, 空气有效利用量增加, 装置日总效率增大, 空气流量110 m³/h时, 空气有效利用量为7.07 MJ, 日总效率为45.6%.

Experimental study on solar energy grain drying system

A type of compound parabolic concentrator integrated collector-storage solar air heater was presented in this paper, which took flat micro heat pipe arrays as the core heat transfer element, combined with compound parabolic concentrator and latent heat storage unit. The system took compound parabolic concentrator vacuum tube collector as the heat collecting part, 58# paraffin as the latent heat storage material, and the lap joint-type flat micro heat pipe arrays as the core heat transfer element. The thermal storage and release performance of the system under two different modes (discharging after charging and charging while discharging mode) was tested outdoors. According to the change of the azimuth angle of the sun incident lights, combined with the incident half angle θ of the concentrator, the time range of the total solar radiation absorbed by the concentrator was determined, and the absorption model of the solar radiation energy by the compound parabolic concentrator was established. Results show that under the mode of charging after discharging, the solar radiation absorbed by the collector is about 15 MJ, the average heat storage efficiency is about 36%, and the change of air flow has little influence on the daily total efficiency of the device, maintaining at about 34%. Under the mode of charging while discharging, with the increase of air volume flow, the useful energy extracted increases, and the daily total efficiency of the device increases. When the air flow is 110 m³/h, the useful energy extracted is 7.07 MJ, and the daily total efficiency is 45.6%.