## 2 Materials and Methods
### BES Modeling
#### 2.2.2 Model Creation  
The model was created using Simulation Studio, which is the main interface of the TRNSYS-18 program. TRNSYS-18 is a component-based program, and the simulation studio allows for the connection of all the components of the simulation together to create a model. The TRNSYS-18 Simulation studio for multi-span greenhouse model is presented in Figure 6 with the types used and their interconnections of this specific multi-span greenhouse BES model. Type-56 is first used to build the model component an interface is called TRNBuild. This is followed by the importation of IDF file for the 3-D model created by Transys3d of the multi-span greenhouse with DOE-2 files for all the cover and screen materials into TRNBuild. Application of the prepared materials into the 3-D TRNBuild is next. The TRNBuild deals with all the parameters and calculations of the greenhouse model, including solar radiation calculation on each surface of the greenhouse, convective, conductive, and radiative heat exchanges, heating and cooling set-points. The greenhouse ground properties, thermal conductivity, capacitance, and density were, 1.89 kJ\(\cdot\)h\({}^{-1}\cdot\)m\({}^{-1}\cdot\)K\({}^{-1}\), 1.5 kJ\(\cdot\)kg\({}^{-1}\cdot\)K\({}^{-1}\), and 2000 kg\(\cdot\)m\({}^{-3}\), respectively, were also added in TRNBuild. The TRNFLOW, a tool for the calculation of the natural ventilation of the greenhouse, is also included in the TRNBuild interface. TRNBuild combines the thermal and ventilation model of the greenhouse. In simulation studio, the weather data is connected to Type-56 for the simulation of the greenhouse in the real situation. In the simulation studio different types were used to process the weather data and controllers for the dynamic day/night and seasonal control of natural events opening and closing with inside temperature, screens control with outside solar radiations and heating and cooling set-points. A detailed description of all the specific components (Types) used in this modeling process is presented in Table 4. \begin{table}
\begin{tabular}{l c c c c c} \hline \hline \multirow{2}{*}{**Cover Characteristics**} & \multicolumn{5}{c}{**Greenhouse Materials**} \\ \cline{2-6}  & **Ph-77** & **Ph-Super** & **Polyester** & **Luxous** & **Tempa** \\ \hline \multicolumn{6}{c}{**Solar radiation (300–2500 nm)**} \\ \hline Transmittance front & 0.17 & - & - & - & - \\ Transmittance back & 0.17 & - & - & - & - \\ Reflectance front & 0.59 & - & - & - & - \\ Reflectance back & 0.51 & - & - & - & - \\ \hline \multicolumn{6}{c}{**Visible radiation (380–760 nm)**} \\ \hline Transmittance front & 0.17 & - & - & - & - \\ Transmittance back & 0.17 & - & - & - & - \\ Reflectance front & 0.59 & - & - & - & - \\ Reflectance back & 0.51 & - & - & - & - \\ \hline \multicolumn{6}{c}{**Thermal radiation (2500–40,000 nm)**} \\ \hline Transmittance & 0.20 & 0.38 & 0.02 & 0.38 & 0.01 \\ Emmittance front & 0.38 & 0.60 & 0.94 & 0.44 & 0.67 \\ Emmittance back & 0.48 & 0.60 & 0.94 & 0.44 & 0.67 \\ \hline Conductivity (W\(\cdot\)m\({}^{-1}\cdot\)K\({}^{-1}\)) & 0.59 & 0.08 & 0.05 & 0.04 & 0.21 \\ Thickness (mm) & 0.40 & 0.30 & 0.40 & 0.22 & 0.25 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Physical, optical, and thermal properties of the screens.