## 3 Methodology
### Simulation of Half-Effect Absorption Cooling System  
#### 4.2.1 Analysis of COP of the Half-Effect Cycle  
The simulation of the half-effect cycle was performed considering the temperatures of both geothermal wells described previously. Table 2 shows the operating ranges of the main variables involved in the thermodynamic analysis. Figure 8: Temperature profile from static formation temperatures of well W-LV5 from Las Tres Virgenes geothermal field (reported by [PERSON] et al. [30]). Figure 9: Temperature simulated along the U-tube heat exchanger in well W-LV5. T\({}_{\rm out}\) corresponds to the temperature of water to the heat exchanger outlet, \(\upsilon\) to fluid velocity, and \(m\) to mass flow. The present section shows a sensitivity analysis of the operation of the half-effect cycle for the different operating conditions. In Figures 10-13, the COP of the system is shown as a function of the evaporation temperature (\(T_{E}\)) and the pressure factor (\(PF\)) for different condensing temperatures (\(T_{C}\)), keeping fixed the thermal source or generation temperature (\(T_{C}\)). \begin{table}
\begin{tabular}{c c} \hline \hline
**Variable** & **Range** \\ \hline Condensation temperature, (\(T_{C}\)) & 25 to 40 \({}^{\circ}\)C \\ Evaporation temperature, (\(T_{E}\)) & \(-\)16 to 10 \({}^{\circ}\)C \\ Generation temperature, (\(T_{G}\)) & 56 to 70 \({}^{\circ}\)C \\ Pressure factor, (\(PF\)) & 0.4 to 0.8 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Operation range of selected variables for the half-effect cycle. Figure 10: Coefficient of performance (COP) of the half-effect cycle against \(PF\) and \(T_{E}\) for different \(T_{C}\). Analyzed case: \(T_{G}\) = 70 \({}^{\circ}\)C.  
Figures 10-13 show the variation of the COP as a function of the condensation temperature (\(T_{C}\)), the pressure factor (\(PF\)), and the evaporation temperature (\(T_{E}\)) of the half-effect cycle for different values of the generation temperature (\(T_{G}\)). In all the figures, it can be seen that the COP was directly proportional to the evaporation temperature and inversely proportional to the condensation temperature. Besides, for a fixed condensing temperature, better COPs were obtained for high pressure factors (\(PF\)): However, at high \(PF\) values, low evaporation temperatures could not be achieved. Therefore, depending on the particular application of the system (cooling or air conditioning) the \(PF\) value was set. The \(PF\) defined the mean pressure of the cycle, and this factor was fixed through the concentration of the working mixture. From Figure 10, it can be seen that the coefficients of performance varied from 0.10 to 0.36 at \(T_{G}\) = 70 \({}^{\circ}\)C. It can be observed that for condenser temperatures of 25, 30, and 35 \({}^{\circ}\)C, the half-effect cycle could work for refrigeration and freezing since it could achieve evaporation temperatures as low as \(-\)16 \({}^{\circ}\)C with coefficients of performance between 0.25 and 0.36. However, at \(T_{C}\) = 40 \({}^{\circ}\)C (only at PF values of 0.5 and 0.6), the system was still capable of being used for refrigeration, but at higher PF values the system could only be used for food conservation or air conditioning. Figure 11 shows COP variations from 0.10 to 0.36 at a generation temperature of 65 \({}^{\circ}\)C. Evaporation temperatures of \(-\)16, \(-\)16, \(-\)12, and \(-\)4 \({}^{\circ}\)C could be reached at condensation temperatures of 25, 30,  
Figure 12: COP of the half-effect cycle against \(PF\) and \(T_{E}\) for different \(T_{C}\). Analyzed case: \(T_{G}\) = 60 \({}^{\circ}\)C.  
Figure 13: COP of the half-effect cycle against \(PF\) and \(T_{E}\) for different \(T_{C}\). Analyzed case: \(T_{G}\) = 56 \({}^{\circ}\)C.  
35, and 40 \({}^{\circ}\)C, respectively, for low values of \(PF\). As the condenser temperature increased, the cycle significantly reduced its ability to operate as a cooling system.