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首页> 外文期刊>Turkish Journal of Agriculture & Forestry >Effect of thermal screens on the microclimate and overall heat loss coefficient in plastic tunnel greenhouses
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Effect of thermal screens on the microclimate and overall heat loss coefficient in plastic tunnel greenhouses

机译：热屏对塑料温室大棚小气候和总热损失系数的影响

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摘要

The objective of the present study was to evaluate the effects of thermal screens made of clear polyethylene (PE) and polyester material on the microclimate and overall heat loss coefficient in plastic tunnel greenhouses. The dimensions of the plastic tunnels were: width 6 m, length 20 m and height 3 m. Three different installations were used: (1) a single cover without a screen (as a control): (2) a single cover with a PE screen; and (3) a single cover with a polyester screen. The thermal screensmade of PE with UV+1R additives and polyester materials were placed at a height of 2.5 m in the plastic tunnels, and supported with wires. Air temperature, relative humidity, wind speed, solar radiation and photosynthetically active radiation (PAR) weremeasured and recorded on a data-logger. In the plastic tunnels, the overall heat loss coefficient, heat input, the control factor for air-tightness, the rate of heat loss and the thermal screen effectiveness were calculated. The results showed that the polyester and PE screens were able to keep the air temperature inside the plastic tunnels 4.8 deg C and 2.5 deg C higher than that outside, respectively. Comparison of the calculated overall heat loss coefficients shows that the differences in the valuesbetween the plastic tunnels were large. The relationships between the overall heat loss coefficient and the wind speed, and the outside temperature were modeled, including the measured and calculated values. It was found that the thermal screen effectiveness was 16 percent and 19.8 percent for the PE and polyester screens, respectively.
机译：本研究的目的是评估由透明聚乙烯（PE）和聚酯材料制成的隔热屏对塑料温室大棚的小气候和总体热损失系数的影响。塑料隧道的尺寸为：宽6 m，长20 m，高3 m。使用了三种不同的安装方式：（1）没有屏幕的单个盖子（作为控件）：（2）带有PE屏幕的单个盖子; （3）具有聚酯筛网的单个盖。将带有UV + 1R添加剂的PE热屏蔽和聚酯材料制成的热屏置于塑料通道中2.5 m的高度处，并用金属丝支撑。测量空气温度，相对湿度，风速，太阳辐射和光合有效辐射（PAR），并将其记录在数据记录仪上。在塑料隧道中，计算了总的热损失系数，热输入，气密性的控制因素，热损失率和热屏蔽效率。结果表明，聚酯和聚乙烯筛网能够使塑料隧道内部的空气温度分别比外部温度高4.8摄氏度和2.5摄氏度。计算的总热损失系数的比较表明，塑料通道之间的值差异较大。对总的热损失系数与风速以及外部温度之间的关系进行建模，包括测量值和计算值。发现PE和聚酯筛的热筛效率分别为16％和19.8％。

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