玻璃连栋温室正压通风降温系统的设计与试验

Design and experiment of the positive pressure ventilation cooling system in glass multi-span greenhouse

针对我国大型玻璃连栋温室夏季降温难度大、温度分布不均匀的问题,引入荷兰半封闭温室环境控制理念,采用正压通风降温技术,以湿帘蒸发降温提供冷源,对管道风机、送风管等关键机构进行分析计算和设计,建立连栋温室正压通风降温系统,并进行适应性生产试验。试验依托河北南和设施农业产业集群项目,以采用湿帘-风机负压降温系统的温室为对照,对采用正压通风降温系统的温室,进行降温效果对比试验。试验结果表明:1)送风管各侧孔出风风速基本一致,送风均匀性高;2)采用正压通风降温系统的温室室内温度平均高于对照温室3.7℃,极端高温时可高出6.8℃。在河北南和地区,传统湿帘-风机负压通风降温系统的降温效果优于创新设计的正压通风降温系统,正压通风降温系统的实现方式还需改进,在我国的适用性有待进一步研究。

To solve the difficulty of cooling and uneven temperature distribution in large-scale glass multi-span greenhouses in China,a positive pressure ventilation cooling system(PPVCS)was designed base on the environment control strategy of the semi-closed greenhouse in Netherlands.The system adopted positive pressure ventilation cooling technology,and used evaporation of wet pad to provide cooling source.Through the analysis and calculation of duct fan and air supply pipe,the whole system was established and tested.The experiment was conducted in Venlo-type greenhouse in Nanhe,Hebei Province.The greenhouse with pad-fan negative pressure cooling system was used as the control to compare the cooling effect with greenhouse with PPVCS.The results showed that:1)The air velocity of each side hole on each side of the air supply pipe was almost the same,and the uniformity of the air supply was good;2)The inner temperature of greenhouse with PPVCS was 3.7℃higher than that of control greenhouse on average,and the difference reached 6.8℃under extremely high temperature.In Nanhe,which located the south of Hebei Province,the cooling effect of the traditional pad-fan negative pressure cooling system was better than that of the innovative PPVCS.The PPVCS still needs to be improved to adapt China’s practical situation.