## 3 Results
### Optimization of the Suction Temperature  
As can be deduced from Equations (4) and (33), the suction temperatures of the compressors are the most direct parameters that determine \(ESR\) at a given compression ratio, and further determine the overall cooling load of the compressed air. Thus, we first analyzed the optimization of the suction temperatures under different working conditions. Firstly, to avoid water condensation in the compressors, which is harmful to the compressor operation, a minimum suction temperature (\(ST_{min}\)) must be established, defined as the air temperature with 90% relative humidity. As shown in Figure 5a, the minimum suction temperature of each compressor increases with the air humidity and pressure. It can be deduced that the \(ST_{min}\) in humid areas is higher than the suction temperatures in dried areas. The highest \(ST_{min}\) over a year usually occurs in July or August, the most humid months (Figure 5b). As long as the \(ST_{min}\) is higher than the cooling water temperature, water condensation of the compressed air occurs, which is inevitable even when 40 \({}^{\circ}\)C intercoolers are adopted; thus, adequate drainage must be ensured to minimize the damage to the compressors. Operation parameters, such as the evaporation temperature (\(T_{eva}\)), the solution-to-air flow ratio in the generator (\(FR_{s-a}\)), suction temperature of each compressor (\(ST_{com}\)), and approach temperatures of SAHEXs (\(AT_{sabtex}\)) can be optimized to adjust the cooling load allocation. Thus, we varied \(AT_{sabtex}\) from 10 to 24 \({}^{\circ}\)C, \(T_{eva}\) from 10-14 \({}^{\circ}\)C, and \(FR_{s-a}\) from 2 to 5, and calculated the corresponding \(ST_{com}\), as show in Figure 6a-d. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & **This Work** & **Literature [14]** & **Error** & & **This Work** & **Literature [32]** & **Error** \\ \hline Temperature at the outlet of compressor I (\({}^{\circ}\)C) Pressure at the outlet of compressor I (\({}^{\circ}\)A) Temperature at the outlet of compressor II (\({}^{\circ}\)C) Pressure at the outlet of compressor II (\({}^{\circ}\)C) Pressure at the outlet of compressor III (\({}^{\circ}\)C) Pressure at the outlet of compressor III (\({}^{\circ}\)C) Pressure at the outlet of compressor III (\({}^{\circ}\)A) Power consumption of compressors (kW/kg) & 106.3 & 0.025 & Generation heat (kW) & 13,214 & 12,732 & 0.036 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Model verification of simulation results with reported results. Figure 5: **(a)** Minimum suction temperature of each compressor under different feed air humidity; **(b)** Minimum suction temperature for each compressor in different months in Hangzhou.However, without external heat or electricity sources, the \(ST_{min}\) cannot always be achieved. It is constrained by the cooling load allocation between SAHEXs (\(Q_{subacs}\)) and CWAHEXs (\(Q_{cachus}\)). \(Q_{subacs}\), which provides the generation heat of the OAR, and \(Q_{cachus}\), which is provided by the evaporation heat of the OAR, have to be distributed carefully to obtain enough generation heat while ensuring adequate cooling capacity for air cooling. In Figure 6, suction temperatures of compressor II (\(ST_{com2}\)) and III (\(ST_{com3}\)) vary from 14.01 to 40 \({}^{\circ}\)C and 23.66 to 40 \({}^{\circ}\)C, respectively, at a given suction temperature (13.8 \({}^{\circ}\)C) of compressor I, which is equal to the feed air temperature. Figure 7 indicates an inverse relationship between the \(ST_{com2}\) and \(ST_{com3}\). This can be explained as follows: The decrease in \(ST_{com2}\) leads to the increase in the cooling load of CWAHEX1 and a decrease in the cooling load of SAHEX2, while CWAHEX3 and SAHEX1 remain unchanged. In addition, \(ST_{com3}\) has to be raised to increase the cooling load of SAHEX3 and decrease the cooling load of CWAHEX2, to establish a new cooling load balance between the SAHEXs and CWAHEXs, which is also an energy balance between the generation heat and evaporation heat of the OAR.