日光温室墙体上强制通风对室内温度和湿度的影响

Effect of the Wall of Solar Greenhouse with Forced Ventilation on the Indoor Temperature and Humidity

为了增强日光温室的环境调控能力,在日光温室后墙墙体上(1.5 m高度)设置风机(550 W)进行强制通风,测定不同通风方式(顶部通风、底部通风、顶部通风+底部通风、全封闭状态)下温度和湿度的变化。结果表明,春夏季后墙设置风机强制通风,能有效降低室内温度,改善相对湿度和CO_2供给,与自然通风(温室顶部+底部通风)相配合,可以使温室内温度降低7~8℃,且不同部位效果不同,即前部和后部的温度从40℃降低到31℃,中部位置的温度从40℃降到35℃,相对湿度从29%提高到36%;在全封闭状态下,强制通风使温室内前部、中部温度降低4~5℃,相对湿度从80%降低到70%;秋季在底部通风状态下,强制通风能使温室内的温度降低3℃左右,相对湿度变化较小;在顶部通风状态下,强制通风不仅没有降低室内温度,反而使温室内温度略有升高,前部位置温度从31℃提高到37℃,中部和后部位置温度从31℃分别提高到35,32℃,相对湿度从44%提高到51%,这是由于顶部通风面积偏小,难以将热量散出。

To enhance the effect of environmental regulation ability,forced ventilation with fans（550 W）on the wall of back wall（1.5 m height）of solar greenhouse,environmental changes under different ventilation modes（top ventilation,bottom ventilation,closed,top bottom ventilation）were measured.The experimental results showed that in the spring and summer season with the fan forced ventilation at back wall,it could reduce indoor temperature effectively,improve humidity and CO_2 supply.Matching with natural ventilation（top bottom ventilation）,the temperature in greenhouse could be reduced by 7-8 ℃,and the effect of different parts was different,both of the front and back indoor temperatures decreased from 40 ℃ to 31 ℃ and the range was about 9 ℃,the temperature of the middle in greenhouse fell from 40 ℃ to 35 ℃,the relative humidity increased from 29% to 36%.In the fully closed state,the temperature of front and middle position in the greenhouse fell from 4 ℃ to 5 ℃,the relative humidity dropped from 80% to 70%.With the bottom-ventilation-only condition in autumn,forced ventilation could reduce the temperature of greenhouse by about 3 ℃,and the relative humidity changed little.However,in the top ventilation condition,back wall forced ventilation didn＇t reduce the indoor temperature,while the indoor temperature increased slightly,the temperature of the front position increased from 31℃ to 37 ℃,the middle and back increased from 31 ℃ to 35 ℃ and 32 ℃,respectively,and the relative humidity increased from 44% to 51%.This is due to the top of the ventilation area is small,it is difficult to radiate heat.