Influence of Roof Ventilation of Solar Greenhouse on Temperature and Humidity and Carbon Dioxide Level in Cold and Arid Regions
In order to study the influence of the indoor temperature,humidity and carbon dioxide level in a solar greenhouse in cold and arid areas under the ventilation mode of opening the top vent on,the environmental monitoring system of the greenhouse was built by means of RS-485,and the data of temperature,humidity and carbon dioxide content at 20,80 and 180 cm above the ground in the greenhouse during the ventilation period were collected and analyzed.On this basis,the least square method was used to establish the regression model of temperature,humidity and carbon dioxide content in the crop area at 20 cm height above the ground before and after ventilation,and the regression model of indoor temperature,humidity and carbon dioxide content change after ventilation for 0.5 h.The results showed that closing the vent before 14:30 could make the indoor temperature rise again,opening the top vent ventilation made the indoor temperature,relative humidity and carbon dioxide content close to the outdoor.The distribution of environmental factors in different positions in the greenhouse before and after ventilation was non-uniform,with the maximum difference of temperature 11.6℃,relative humidity 11.8%and carbon dioxide content 68 μmol·mol-1.The coefficients of determination of the regression models were above 0.567,indicating that the independent variables in each model had a certain correlation with the dependent variables.It was possible to estimate the temperature,humidity and carbon dioxide content in the crop area at 20 cm height above the ground and the temperature,humidity and carbon dioxide content change after ventilation for 0.5 h through the data of a few sensors.Above results provided theoretical basis and technical reference for precise control of environmental factors of solar greenhouse in the northern cold and dry areas.
solar greenhouseroof ventilationtemperature and humiditycarbon dioxide levelregression
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