# Enhancing Monocrystalline Solar Module Efficiency through Front-Surface Cooling with 96% Alcohol
## 4 Conclusions  
Increase in the solar modules temperature is the main limiting factor for electrical energy generation, thus heat removal process plays an important role. The measurements presented in this paper were taken on a clear, sunny day on 1 November 2022 in Nis, Serbia (which has a moderate-continental climate). During the experiment the ambient temperature ranged from 18.2 \({}^{\circ}\)C to 20.7 \({}^{\circ}\)C, and the average wind speed was 0.5 m/s. The solar irradiation intensity was around 700 W/m\({}^{2}\). Based on the measurement results, it can be concluded that the temperature of the cooled module did not exceed 42.1 \({}^{\circ}\)C, which means that it was maintained below the NOCT value of 47 \({}^{\circ}\)C. The lowest temperature of the cooled module was achieved at the end of cycle II and was 35.5 \({}^{\circ}\)C. After five cycles of active cooling, the maximum temperature of the back side of the cooled solar module was 36.8 \({}^{\circ}\)C, while the temperature of the uncooled module was 59.4 \({}^{\circ}\)C, resulting in a temperature difference of 22.6 degrees. The highest cooling rate was achieved in cycle I and was 3 \({}^{\circ}\)C/min, while the lowest was in cycle V at 0.7 \({}^{\circ}\)C/min. Alcohol loss due to evaporation, after five cooling cycles, was measured and the rate of evaporation was 0.0285 L/min. All cycles are characterized by approximately the same form of change in power, with rapid increase in power for the first 45 s of cooling, after which the power increases slowly. When the each cooling cycle ends, a further increase in power due to rapid alcohol evaporation, which lasts about 70 s, was recorded. For the first 45 s in cycle I, power increased by 3.2%, in cycle II by 2.7%, in cycle III by 2.7%, in cycle IV by 2.6%, and in cycle V by 2.7%. The time interval of 70 s after the pump was turned-off, an additional increase in power was recorded: 1.1% for cycle I, 0.9% for cycle II, 0.3% for cycle III, 0.4% for cycle IV, and 0.6% for cycle V. The highest increase in power occurred at the end of cycle III, when \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Number of Cycle**} & \multirow{2}{*}{**Time**} & \multicolumn{2}{c}{**Efficiency before Cooling**} & \multicolumn{2}{c}{**Efficiency at the End of**} & \multirow{2}{*}{\(\Delta\eta=\frac{\pi A_{-}-\pi R_{A}}{\pi R_{A}}\)**100\%**} \\  & & **Cycle [W]** & & **Cooling Cycle [W]** & & \\ \cline{3-8}  & & **A-Solar** & **B-Solar** & **A-Solar** & **B-Solar** & **Before Cycle** & **After Cycle** \\  & & **Module** & **Module** & **Module** & **Module** & **Before Cycle** & **After Cycle** \\ \hline I cycle & 10:45:55–10:48:55 & 12.23 & 12.27 & 12.56 & 12.82 & 0.3 & 2 \\ II cycle & 10:52:55–10:57:10 & 12.52 & 12.58 & 12.73 & 13.09 & 0.4 & 2.8 \\ III cycle & 11:01:15–11:05:15 & 12.82 & 12.89 & 12.91 & 13.55 & 0.5 & 4.9 \\ IV cycle & 11:10:25–11:16:30 & 12.93 & 13.06 & 12.97 & 13.38 & 0.9 & 3.1 \\ V cycle & 11:21:20–11:26:20 & 12.97 & 13.11 & 13.02 & 13.42 & 1.1 & 3 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Calculated efficiency before and after the cooling cycles, as well as the percentage difference in efficiency before the start of the cycle and at the end of the cycle. the power of the cooled module was 4.9% higher than the power of the uncooled module. On average, solar module efficiency for all five cooling cycles increased by 3.2%. Based on the obtained results, a recommendation of additional alcohol cooling system for the already existing active and passive cooling systems in solar modules can be given, since alcohol cooling can be applied for further increase the solar module's power output and delay the start of a new cooling cycle. The following authors contributed to conceptualization, S.D., L.P., M.K., I.R., A.P. and M.M. ; methodology, S.D. and L.P.; formal analysis, S.D. and A.P. ; investigation, S.D. and L.P.; writing--original draft preparation, S.D., A.P. and L.P.; writing--review and editing, S.D., L.P., M.K., M.M. and I.R., visualization, S.D. and M.K.