# Enhancing Monocrystalline Solar Module Efficiency through Front-Surface Cooling with 96% Alcohol
## 2 Materials and Methods
### Experimental Setup  
The city of Ni\(\bar{\text{s}}\) is in the south-eastern region of the Republic of Serbia, in the Nisava valley, with a moderate-continental climate and pronounced local characteristics. The experiment was conducted at the Solar Energy Laboratory located in the Faculty of Science and Mathematics in N\(\bar{\text{s}}\), Serbia. The setup shown in Figure 2 was used to investigate the changes in output power of actively cooled solar module using 96% ethyl alcohol. Two monocrystalline silicon solar modules LX-100M/125-36 (manufactured by Luxor Solar GmbH, Stuttgart, Germany), each with output power of 100 W, were used and their technical specifications are given in Table 1.  
The solar modules were positioned one above the other at an optimal annual angle of 32\({}^{\circ}\) for Nis. The lower solar module (B) was equipped with an active cooling system, while the upper module (A) was used as a referent (uncooled). The front surface of the module was cooled with 96% ethyl alcohol (96% alcohol and 4% water), and its physical properties are presented in Table 2.  
A pipe, 1200 mm in length, was placed on the upper edge of module B, which contained 23 holes spaced 5 cm apart, to allow the flow of alcohol over the front surface, forming a thin layer of fluid. The cooling system was equipped with a submersible pump (power of 3 W) to facilitate alcohol circulation at a flow rate of 1.5 L/min. A pipe was placed on the lower edge of the module to collect and return the fluid back into the tank. \begin{table}
\begin{tabular}{c c} Dimensions (size) & \(1.194\times 542\times 35\) mm \\ Weight & 7.8 kg \\ Cell type & Si monocrystalline \\ Power of solar module & 100 Wp \\ Module efficiency & 15.6\% \\ Maximum power current & 5.39 A \\ Maximum power voltage & 18.7 V \\ Short circuit current & 5.87 A \\ Open circuit voltage & 21.6 V \\ Nominal Operating Cell Temperature (NOCT & 47 \({}^{\circ}\)C \\
800 W/m\({}^{2}\), 20 \({}^{\circ}\)C, AM 1.5, 1 m/s) & \\ \end{tabular}
\end{table} 
Table 1: Technical characteristics of LX-100M/125-36 solar module. Figure 2: Experimental setup. The plastic tank with a volume of 8 L was insulated during the experiment to prevent heating of the working fluid. Continuous measurements of the modules' output power were recorded every 5 s using the PV CHECK device (manufactured by HT ITALIA S.R.L., Faenza, Italy), (Figure 3). The solar irradiation intensity that reached the modules' surface was measured using a pyranometer CMP22 (manufactured by Kipp & Zonen, Delft, The Netherlands) placed in the plane of the modules (at an angle of 32\({}^{\circ}\)). Wind speed and ambient temperature were measured using the DAVIS Vantage PRO meteorological station (manufactured by Davis Instruments Corporation, Hayward, CA, USA). FLIR C5 (manufactured by Teledyne FLIR LLC, Wilsonville, OR, USA) infrared camera was used to measure the temperature of the solar modules before, during and after cooling and to obtain images of thermal distribution of the front and back sides of the modules. The flow rate of the working fluid was measured by a Kamstrup MULTICAL 401 device (manufactured by Kamstrup A/S, Skanderborg, Denmark), while the temperature of the working fluid in the tank was measured by a high-speed and accuracy digital thermometer NIGOS DTM-921(manufactured by Nigos elektronik, Nis, Serbia). If ethanol is released to the atmosphere, it quickly disperses in the vapor phase and settles in low-lying areas. Since evaporated alcohol can have negative impacts on air quality and lead to safety hazards, it is important to carefully consider the use of ethanol as a cooling fluid and take appropriate safety and environmental precautions, assess in the appropriate context and in accordance with relevant regulations and guidelines [30]. Before experimental measurements, reference values of the solar modules' electrical parameters were determined. On 1 November 2022, the experimental measurements were conducted from 10:30 to 11:30, which corresponds to solar noon and the maximum solar