越冬期日光温室土质墙体温度变化特性研究

Study on Temperature Variation Characteristics of Cob Wall in Solar Greenhouse in Winter

对日光温室土质墙体的分层温度、温室内地面土壤的分层温度、室内外气温进行了监测,研究了日光温室墙体的分层温度变化特征及影响温度分布的原因。结果表明:土质墙体的分层温度以一定的周期呈正弦或余弦的变化,土质墙体表层温度对气温的变化响应较明显,深层温度对气温的变化响应不明显。随着距离外墙表面的深度增大,温度波的振幅逐渐减小,最大值最小值出现的时间也出现了滞后现象,墙体中有约120cm的土壤温度基本不变,温度波的振幅很小,说明土质墙体中有恒温层的存在。墙体温度波的振幅大于同层次土壤的振幅。温度也高于同层次的土壤。这是因为分层土壤的热扩散率不同所导致。土质墙体在整日内都是吸热体,起到了良好的蓄热作用;而地面土壤在夜间的某个时段内是放热体,起到了保持室内温度的作用。土质墙体整日内不同时刻的温度分布规律是随着距内墙表面距离的增大而缓慢递减。

The stratification temperature of cob wall, stratification temperature of ground soil in solar greenhouse and air temperature inside and outside the solar greenhouse were determined, temperature variation characteristics of cob wall and reason of influence on temperature distribution were analyzed. The results showed that stratification temperature of cob wall changes period in sine or cosine within a certain. Responses of skin layer of cob wall to air temperature were obvious;on the contrary,responses of deep layer of cob wall to air temperature were not obvious. With the increase of distance to the cob wall surface, amplitude of temperature wave gradually decreased. The lag phenomenon appeared like occurrence time of the minimum and maximum value. The temperature of about 120 cm soil within the cob wall remained unchanged and amplitude of temperature wave was minimal, which illustrated that there was constant temperature layer within the cob wall. The amplitude of temperature wave in the cob wall was larger than that of the same layer in the soil of the same layer and the temperature in the cob wall was higher than in the same layer, which was resulted in the differences of thermal diffusivity. Cob wall was heat receiver in the whole day and played a good role of heat storage~ the ground soil in a certain period of night was heat releaser, and played a role of keeping the indoor temperature. The temperature distribution rule of cob wall in the different period of the whole day was that with the increase of distance to the interior surface of the cob wall, the temperature decreased progressively.