# Enhancing Monocrystalline Solar Module Efficiency through Front-Surface Cooling with 96% Alcohol
## 2 Materials and Methods  
### Theoretical Aspects  
The solar module's conversion of solar irradiation energy (\(G\)) into electrical energy is only a small fraction of the total solar irradiation energy that reaches the module's surface (\(A_{p}\)). Most of the solar irradiation energy is transformed into heat, which increases the module's temperature and internal energy \(\Delta U_{\rm module}\). Part of this energy is released to the environment through convection and radiation, resulting in \(Q_{loss}\). In the case of active cooling of the module by the working fluid from the front side, the process of heat release consists of loss due to convection (\(Q_{C}\)), radiation (\(\dot{Q_{R}}\)), and heat loss due to evaporation of the working fluid (\(\dot{Q_{E}}\)), as depicted in Figure 1.  
The solar irradiation energy that reaches the module's surface can be defined by the equation:  
\[\dot{Q_{Solar}}\ =aGA_{p}, \tag{1}\]  
where \(a\) represents the absorptivity coefficient. The total heat loss, \(\dot{Q_{loss}}\), can be calculated using the following equation:  
\[\dot{Q_{loss}}\ =\dot{Q_{C}}+\dot{Q_{R}}+\dot{Q_{E}}, \tag{2}\]  
Since the process of heat release by convection occurs on both sides of the module, \(\dot{Q_{C}}\) can be expressed as:  
\[\dot{Q_{C}}=\dot{Q_{C,F}}+\dot{Q_{C,B}}, \tag{3}\]  
where \(\dot{Q_{C,F}}\) and \(\dot{Q_{C,B}}\) are the heats given off by convection from the front and back side of the module, respectively. \(\dot{Q_{C,F}}\) and \(\dot{Q_{C,F}}\) are calculated as follows:  
\[\dot{Q_{C,F}}=h_{F}A_{p}(T_{p,F}-T_{a,F}), \tag{4}\]  
Figure 1: The process of heat release for active cooling of the module by the working fluid from the front side. \[\dot{Q_{C,B}}=h_{B}A_{P}(T_{P,B}-T_{a,B}), \tag{5}\]  
where \(h_{F}\) and \(h_{B}\) represent the convection coefficients of heat transfer from the front and back sides of the module, \(T_{P,F}\)  and \(T_{P,B}\)  are the temperatures of the front and back sides of the module, and \(T_{a,F}\)  in \(T_{a,B}\) represent the temperatures of the air around the front and back sides of the module, respectively. The total heat loss by radiation can be expressed using the following equation:  
\[\dot{Q_{R}}=\dot{Q_{R,F}}+\dot{Q_{R,B}}, \tag{6}\]  
where \(\dot{Q_{R,F}}\) and \(\dot{Q_{R,B}}\) represent the heat losses by radiation from the front and back side of the module, respectively. \(Q_{R}\)  is defined as:  
\[\dot{Q_{R}}=\sigma\cdot\varepsilon\cdot A_{p}\cdot F_{21}\Big{(}T_{2}^{4}-T_{ 1}^{4}\Big{)}, \tag{7}\]  
This equation should be formulated for both the front and back surfaces of the solar module, taking into account the relevant view factors \(F_{21}\) and temperatures \(T_{2}\) and \(T_{1}\). In Equation (7), \(\sigma\) is the Stefan-Boltzmann constant, \(\varepsilon\) represents emissivity, \(F_{21}\) is the view factor for the front and back side of the module and represents the fraction of irradiation leaving one surface which is intercepted by a second surface. The temperature \(T_{2}\) refers to the temperature of the front and back surfaces of the solar module, where \(T_{1}\) is the ambient temperature near the front and back. The heat loss due to evaporation can be obtained using the following equation:  
\[\dot{Q_{E}}=Q_{E,F}^{`}+\dot{Q_{E,B}}, \tag{8}\]  
A more general form of the heat loss due to evaporation is:  
\[\dot{Q_{Solar}}\ =aGA_{p}, \tag{1}\]0  
The variables \(P_{s}\) and \(P_{a}\) represent the vapor pressure on the module surface and ambient vapor pressure, respectively. The difference between \(P_{s}\) and \(P_{a}\) is the difference in vapor pressure of the fluid (alcohol) in the atmosphere and at the skin surface. The evaporation coefficient plays a significant role in determining the amount of heat released through evaporation and is dependent on various factors including the temperature of the surrounding air, the temperature of the fluid and the relative humidity of the surrounding air, which is related to the water vapor pressure in the environment.