## 2 State-of-the-Art
Figure 1: Psychometric chart, dry bulb temperature (\({}^{\circ}\)C), and humidity rate (g/kg). For these new conditions, the thermal load of the equipment is 14.4 kW, with 4.69 kW of sensible heat and 9.79 of kW latent heat. The dehumidification rate is 15.5 kg/h of water. Again, this water must be replenished each hour to maintain, for example, a harvest condition. In this case of a specific AC system, it would require replenishing 17.11% less water compared to the adapted AC system, in addition to the reduced thermal load of the same proportion. In addition to the issue of thermal load and energy efficiency, there is also the issue of the refrigerant. Old equipment operates with HCFC 22 refrigerant (older equipment) or HFC 410 A (more modern equipment). Both have high GWPs; specifically, according to AR4, GWP\({}_{\text{HCFC 22}}\) = 1810 and GWP\({}_{\text{HFC 410 A}}\) = 2088. It is also important to remember that HCFC 22 also interferes with the ozone layer [40]. CO\({}_{2}\) emissions are classified as direct (from fossil fuel combustion, methane emissions, and process emissions of the other greenhouse gases) and indirect (primarily from electricity use). An example is a sewage treatment plant that emits GHG (greenhouse gas) in the direct process and indirectly in the form of energy [41; 42; 43]. On the same principle, in the case of refrigeration, there is the TEWI, which is a global warming impact metric, with total emissions related to the GWP (Global Warming Impact) of the equipment being used and all off-gassing in the system, at the end of the system's useful life. Direct and indirect emissions are considered in the TEWI [44]. 1. Direct Emissions--include losses that are not refrigerant gases released over the life of the equipment. 2. Indirect Emissions--fossil fuels are used in the generation of electricity, which have an environmental impact from the CO\({}_{2}\) emitted during the operation of equipment throughout its useful life. The method of calculating the TEWI is provided in Equations (1) and (2): \[\text{TEWI}=\text{GWP}(\text{direct, refrigerant leaks including EOL})+\text{GWP}(\text{indirect, operation})\] (1) \begin{table}
\begin{tabular}{c c c} \hline \hline
**Parameter** & **Air Return Data** & **Air Supply Data** \\ \hline Dry bulb Temperature (\({}^{\circ}\)C) & 25 & 13.8 \\ Wet bulb Temperature (\({}^{\circ}\)C) & 23.7 & 12.8 \\ Dew point temperature (\({}^{\circ}\)C) & 22.83 & 11.86 \\ Enthalpy (kJ/kg) & 76.47 & 38.83 \\ Specific volume (m\({}^{3}\)/kg) & 0.9726 & 0.9211 \\ Specific mass (kg/m\({}^{3}\)) & 1.0281 & 1.0857 \\ Relative humidity (\%) & 90 & 90 \\ Absolute humidity (g/kg) & 20.1581 & 9.8765 \\ Airflow (m\({}^{3}\)/h) & 1500 & 1500 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Climatic parameters of the adapted AC system for mushroom production located in Contenda (Brazil). \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter** & **Air Return Data** & **Air Supply Data** \\ \hline Dry bulb Temperature (\({}^{\circ}\)C) & 25 & 15 \\ Wet bulb temperature (\({}^{\circ}\)C) & 23.7 & 14.7 \\ Dew point temperature (\({}^{\circ}\)C) & 22.83 & 14.18 \\ Enthalpy (kJ/kg) & 76.47 & 44.21 \\ Specific volume (m\({}^{3}\)/kg) & 0.9726 & 0.9262 \\ Specific mass (kg/m\({}^{3}\)) & 1.0281 & 1.0796 \\ Relative humidity (\%) & 90 & 97 \\ Absolute humidity (g/kg) & 20.1581 & 11.52 \\ Airflow (m\({}^{3}\)/h) & 1500 & 1500 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Climatic parameters of the specific AC system in the mushroom greenhouse located in Contenda (Brazil). \[\text{TEWI}=(\text{GWP}\cdot L_{\text{annual}}\cdot n)+\text{GWP}\cdot m\cdot\left(1- \alpha_{\text{recovery}}\right)+(E_{\text{annual}}\cdot\beta\cdot n) \tag{2}\]  
where:  
EOL = End of Life;  
GWP = Global Warming Potential of refrigerant, relative to CO2 (GWP CO2 = 1);  
\(L_{\text{annual}}\) = Leakage rate p.a.