下沉式日光温室土质墙体热特性的试验与分析

为探明下沉式日光温室土质后墙温度分布及变化规律,进而正确评价其保温性能,2009年12月-2011年6月在河南省荥阳市对下沉式日光温室的土质墙体的热特性进行了2a的连续监测,并对结果进行系统分析。结果表明:墙面温度受室内、外气温和太阳辐射的共同影响,具有与气温相同的日变化和季节变化规律;墙面温度影响墙内各深度层次的温度分布,沿墙的厚度方向由室内表面向室外表面温度递减;墙内存在热稳定层,其位置及厚度随季节而变化,厚度与墙体厚度正相关;1～3月份,热稳定层位于墙体厚度的中心位置,2m厚的墙体处没有热稳定层,3m厚的墙体处热稳定层厚30cm,4m厚的墙体处热稳定层厚70cm;4、5月份,其位置外移至距外表面100cm处,厚度也比1～3月份增加10～20cm;综合温室造价、墙体保温性及土地利用率等各方面因素,建议在河南地区下沉式日光温室土质后墙建造参数为顶宽2.5m,底厚(后墙与室外地面连接处)4.0m,后墙高度(距室外地面)不宜大于2.5m。该研究为该型温室的建造和发展提供一定的参考。

Experiment and analysis on thermal characteristics of cob wall in sunken solar greenhouse

In order to explore temperature distribution and changes regulation, further correctly evaluate thermal insulation performance of cob wall in sunken solar greenhouse, 2a consecutive test monitoring was conducted to study the thermal characteristics and heat preservation capacity from December 2009 to June 2011. The result showed that wall surface temperature was significantly affected by indoor, outdoor air temperature and solar radiation, and had the same diurnal and seasonal variation as indoor and outdoor air temperature variation. Every point of temperature inside the wall was affected by surface temperature of wall. Overall, the wall temperature declined from inner surface to outer surface at thickness direction and the thermal-stable layer existed inside wall whose location and thickness varied with season, and thickness had positive correlation with wall thickness. From January to March, the thermal-stable layer existed in the center area inside the wall, and there was no the thermal-stable layer when the wall thickness was 2 m, while the thickness of thermal-stable layer was 30 cm when the wall thickness was 3m, and the thickness of thermal-stable layer was 70 cm when the wall thickness was 4m. During April or May, the location of the thermal-stable layer moved to 100 cm away from outer surface of the wall, and it was thicker 10~20cm than that from January to March. According to construction costs, heat preservation, land availability and other factors, in Henan area of China, the parameters of soil-made back wall in sunken greenhouse were proposed with top width of 2.5 m, bottom width (the junction of back wall and outside ground) 4.0 m and back wall height from outdoor 2.5 m. This paper provides a reference for construction and development of sunken solar greenhouse.