# Cumulative Energy Demand and Carbon Footprint of the Greenhouse Cultivation System
## 2 Materials and Methods
The first of them, DGT Volmatic, records the outside air and greenhouse air temperature, solar radiation, air humidity, the position of thermal screens and vents, as well as the operating time of circulation pumps. The second one, Aqutherm, measures the heat consumption in the greenhouse and in the supply manifold as well as the temperature and flow of the heating medium in the greenhouse and in the boiler. Regardless of the heat from coal combustion, the study has taken into account the auxiliary energy necessary to keep the heating systems operational, the GH technical equipment and the heat source. Auxiliary electricity consumed in the heat source, which was included in the calculations, was calculated as the share identical to the share of the tested GH area in the total area of the facility. Scenario 1 (reference) is a coal combustion scenario that reflects the real state of the measurement site. Scenarios 2 to 4 are variants that assume that the heat source will burn fuel other than coal while the GH operating system will remain unchanged. It is assumed that coal-fired boilers will be replaced in scenario 2 by gas-fired boilers, while in scenarios 3 and 4--biomass will be burnt; wood pellets and wood chips, respectively. It was assumed that the annual average values of heat generation efficiency are consistent with the methodology for determining the energy performance of buildings [31]. The scenarios are intended to demonstrate the impact of fuel choice on final energy demand, fuel quantity and the environment. Based on the measurement results, and in accordance with the national methodology for calculating the energy performance of buildings [31], efficiency values were established \begin{table}
\begin{tabular}{c c c} \hline \hline
**Description** & **Value** & **Units** \\ \hline floor area & 1250 & m\({}^{2}\) \\ width (W) & 20.0 & m \\ roof height (H\({}_{\text{R}}\)) & 7.7 & m \\ sidewall height (H\({}_{\text{S}}\)) & 2.2 & m \\ length (L) & 62.5 & m \\ cubage undercover & 6188 & m\({}^{3}\) \\ overall heat transfer coefficient without a & 6.68 & W\(\cdot\)m\({}^{-2}\)K\({}^{-1}\) \\ thermal screen & 4.66 & W\(\cdot\)m\({}^{-2}\)K\({}^{-1}\) \\ overall heat transfer coefficient with a & 4.66 & W\(\cdot\)m\({}^{-2}\)K\({}^{-1}\) \\ thermal screen & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Characteristics of the GH under study. for heat generation and distribution systems, in order to determine the annual final energy consumption, by following Equation (1):  
\[\mathrm{Q_{F}=Q_{U}/\eta_{tot}}, \tag{1}\]  
where  
\(\mathrm{Q_{U}}\)--heat consumption in the heating system of the greenhouse, \(\mathrm{MWh\cdot y^{-1}}\);  
\(\mathrm{\eta_{tot}}\)--average seasonal total efficiency of the GH heating system--from generating heat to transferring it to the interior of the greenhouse, calculated according to Equation (2):  
\[\mathrm{\eta_{tot}=\eta_{g}\cdot\eta_{s}\cdot\eta_{d}\cdot\eta_{e}}, \tag{2}\]  
where  
\(\mathrm{\eta_{g}}\)--average seasonal efficiency of energy carrier generation from the energy supplied to greenhouse's balance boundary (final energy),  
\(\mathrm{\eta_{s}}\)--average seasonal efficiency of heat accumulation in storage components of the greenhouse's heating system,  
\(\mathrm{\eta_{d}}\)--average seasonal efficiency of heat carrier transport (distribution) within the greenhouse (within balancing boundaries or outside),  
\(\mathrm{\eta_{e}}\)--average seasonal efficiency of heat control and utilisation in the greenhouse (within the balancing boundaries). The values of the efficiencies listed above are adopted from [31].