| Facility agriculture is the use of certain artificial facilities,advanced science and technology to improve or create environmental meteorological factors,In order to provide appropriate environmental conditions for the growth and development of animals and plants,effective specialized,intensive and large-scale agricultural production is carried out,It is an important direction of development of modern agriculture.At present,the efficiency of facility agriculture in Chongqing is relatively low,and the new agricultural industry supported by facility agriculture has not yet formed.In facility agriculture equipment in Chongqing area,which is a simple plastic small arch,plastic greenhouse,and a small amount of scientific research,tourism modern intelligent greenhouse.Under certain cultivation conditions,the microclimate is an important factor affecting the growth and quality of the crops in the plastic greenhouse.Therefore,a systematic study of the characteristics of microclimate in the facilities and the establishment of microclimate prediction models in plastic greenhouse can provide a scientific basis for environmental control and cultivation management of facility agriculture.Taking the plastic shed of the agricultural test station of Jiangjin District of Chongqing as an example.Based on the theory of energy balance and heat transfer,the environmental factors that affect indoor air temperature and humidity in plastic greenhouse were analyzed in detail.The unsteady state energy balance equation of covering layer,crop canopy,soil layer and air layer and the unsteady equilibrium equation of air layer were established.The outdoor environment parameters,physical parameters,crop characteristic parameters as input variables,the first order assignment,trial and other mathematical methods to nonlinear equations for the higher-order programming of equations by Computer software software,Finally the indoor temperature and relative humidity output at any time.In the plastic shed of the agricultural test station of Jiangjin District of Chongqing City,two stages were tested.The first stage was to test three single plastic sheds with plants in different growth stages.The second stage was aimed at three weather conditions in spring,sunny,cloudy and rain in the single plastic shed in Chongqing.The test content mainly included the strong solar radiation inside and outside the room.Degree,gate wind speed,outdoor wind speed,indoor and outdoor air temperature,indoor and outdoor air relative humidity,indoor and outdoor soil surface temperature,and indoor and outdoor air temperature,relative humidity,solar radiation intensity,gate wind speed and outdoor effective wind speed,indoor temperature and humidity at different heights and different positions of indoor temperature and humidity were compared and analyzed.In the calculation of the mechanism model,combined with the optimization method and the characteristics of the plastic greenhouse in Chongqing,the value of the convection heat transfer coefficient is determined according to the measured values,and the prediction accuracy of temperature and humidity is improved.The results showed that three kinds of sunny and rainy days,cloudy weather,the standard error of the indoor air temperature measured and simulated values were 1.28,0.72,0.93 degrees,relative errors were 0.06,0.04,0.03,coefficients are respectively 0.76,0.74,0.81,indoor air relative humidity measurement and model error value for quasi standard 0.08,0.09,0.06,the relative error were 0.13,0.1,0.09,coefficients are respectively 0.81,0.55,1.16?Compared with the mechanism model,This paper uses the observation data at the same time,the outdoor air temperature,relative humidity,wind speed,solar radiation intensity as independent variables and the dependent variable of indoor air temperature,relative humidity,using the method of stepwise linear regression,successive construction of indoor temperature and humidity during the day and night prediction model,and verified the model. |
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