The commercial greenhouse is one of the most effective cultivation methods with a yield per cultivated area up to 10 times more than free land cultivation but the use of fossil fuels in this production field is very h...The commercial greenhouse is one of the most effective cultivation methods with a yield per cultivated area up to 10 times more than free land cultivation but the use of fossil fuels in this production field is very high.The objectives of this paper are to modeling and experimental evaluation of heat and mass transfer functions in an innovative solar greenhouse with thermal screen.For this propose,a semi-solar greenhouse was designed and constructed at the North-West of Iran in Azerbaijan Province(38100N and 46180E with elevation of 1364 m above the sea level).The inside environment factors include inside air temperature below screen(Ta),inside air temperature above screen(Tas),crop temperature(Tc),inside soil temperature(Ts),cover temperature(Tri)and thermal screen temperature(Tsc)were collected as the experimental data samples.The dynamic heat and mass transfer model used to estimate the temperature in six different points of the semi-solar greenhouse with initial values and consider the crop evapotranspiration.The results showed that dynamic model can predict the inside temperatures in four different points(Ta,Tc,Tri,Ts)with MAPE,RMSE and EF about 5-7%,1-2℃ and 80-91%for greenhouse without thermal screen and about 3-7%,0.6-1.8C and 89-96%for six different points of greenhouse with thermal screen(Ta,Tc,Tri,Ts,Tas,Tsc),respectively.The results of using thermal screen at night(12 h)in autumn showed that this method can decrease the use of fossil fuels up to 58%and so decrease the final cost and air pollution.This movable insulation caused about 15℃ difference between outside and inside air temperature and also made about 6℃ difference between Ta and Tas.The experimental results showed that inside thermal screen can decrease the crop temperature fluctuation at night.展开更多
Greenhouses are one of the most effective cultivation methods with a yield per cultivated area up to 10 times more than free land cultivation but the use of fossil fuels in this production field is very high.The green...Greenhouses are one of the most effective cultivation methods with a yield per cultivated area up to 10 times more than free land cultivation but the use of fossil fuels in this production field is very high.The greenhouse environment is an uncertain nonlinear system which classical modeling methods have some problems to solve it.There are many control methods,such as adaptive,feedback and intelligent control and they require a precise model.Therefore,many modeling methods have been proposed for this purpose;including physical,transfer function and black-box modeling.The objective of this paper is to modeling and experimental validation of some inside environment variables in an innovative greenhouse structure(semi-solar greenhouse).For this propose,a semi-solar greenhouse was designed and constructed at the North-West of Iran in Azerbaijan Province(38°10′N and 46°18′E with elevation of 1364 mabove the sea level).The main inside environment factors include inside air temperature(Ta)and inside soil temperature(Ts)were collected as the experimental data samples.The dynamic heat transfer model used to estimate the temperature in two different points of semi-solar greenhouse with initial values.The results showed that dynamic model can predict the inside temperatures in two different points(Ta and Ts)with RMSE,MAPE and EF about 5.3C,10.2% and 0.78% and 3.45C,7.7%and 0.86%,respectively.展开更多
基金This study was supported by a grant from Tabriz University,Iran.The authors are grateful for the support provided by Tabriz University.
文摘The commercial greenhouse is one of the most effective cultivation methods with a yield per cultivated area up to 10 times more than free land cultivation but the use of fossil fuels in this production field is very high.The objectives of this paper are to modeling and experimental evaluation of heat and mass transfer functions in an innovative solar greenhouse with thermal screen.For this propose,a semi-solar greenhouse was designed and constructed at the North-West of Iran in Azerbaijan Province(38100N and 46180E with elevation of 1364 m above the sea level).The inside environment factors include inside air temperature below screen(Ta),inside air temperature above screen(Tas),crop temperature(Tc),inside soil temperature(Ts),cover temperature(Tri)and thermal screen temperature(Tsc)were collected as the experimental data samples.The dynamic heat and mass transfer model used to estimate the temperature in six different points of the semi-solar greenhouse with initial values and consider the crop evapotranspiration.The results showed that dynamic model can predict the inside temperatures in four different points(Ta,Tc,Tri,Ts)with MAPE,RMSE and EF about 5-7%,1-2℃ and 80-91%for greenhouse without thermal screen and about 3-7%,0.6-1.8C and 89-96%for six different points of greenhouse with thermal screen(Ta,Tc,Tri,Ts,Tas,Tsc),respectively.The results of using thermal screen at night(12 h)in autumn showed that this method can decrease the use of fossil fuels up to 58%and so decrease the final cost and air pollution.This movable insulation caused about 15℃ difference between outside and inside air temperature and also made about 6℃ difference between Ta and Tas.The experimental results showed that inside thermal screen can decrease the crop temperature fluctuation at night.
文摘Greenhouses are one of the most effective cultivation methods with a yield per cultivated area up to 10 times more than free land cultivation but the use of fossil fuels in this production field is very high.The greenhouse environment is an uncertain nonlinear system which classical modeling methods have some problems to solve it.There are many control methods,such as adaptive,feedback and intelligent control and they require a precise model.Therefore,many modeling methods have been proposed for this purpose;including physical,transfer function and black-box modeling.The objective of this paper is to modeling and experimental validation of some inside environment variables in an innovative greenhouse structure(semi-solar greenhouse).For this propose,a semi-solar greenhouse was designed and constructed at the North-West of Iran in Azerbaijan Province(38°10′N and 46°18′E with elevation of 1364 mabove the sea level).The main inside environment factors include inside air temperature(Ta)and inside soil temperature(Ts)were collected as the experimental data samples.The dynamic heat transfer model used to estimate the temperature in two different points of semi-solar greenhouse with initial values.The results showed that dynamic model can predict the inside temperatures in two different points(Ta and Ts)with RMSE,MAPE and EF about 5.3C,10.2% and 0.78% and 3.45C,7.7%and 0.86%,respectively.
