# Selection of a Photovoltaic Panel Cooling Technique Using Multi-Criteria Decision Analysis
## 1 Introduction
In the case of concentrated solar PV, cooling is essential due to intense heat generation, and the power gained due to cooling is proportionately higher compared to non-concentrating PV panels. Experiments were conducted using four PV panels of polycrystalline silicon type which had a rated power production capacity of 55 W each, and the back side of the panels with an area of 0.78 m\({}^{2}\) was cooled with forced air circulation [6]. Air was circulated through specially designed air channels and a 1% enhancement of power output was obtained. The optimum air mass flow rate was 0.055 kg/s for a single panel. A study provided forced air cooling by using specially constructed ducts on the back of the panel using a 3.6 W fan and an improvement in the overall efficiency of 0.6% was obtained. Water cooling experimented with aluminum pipes attached to the panel backside and an efficiency gain of 0.8% was reported [18]. Figure 2a-f illustrates the arrangement of some of the different cooling systems considered in this study. Fin cooling (Figure 2a) uses a natural convective heat transfer mechanism in which heat from the PV cell is conducted to the fins and further travels by convection by natural wind movement [15]. Forced convection (Figure 2b) uses air movement with fans, and the heat is removed from below the panel with fins or without fins [15]. The availability of multiple methods for panel cooling necessitates a scientific procedure to select an appropriate method. Local metrological conditions such as ambient temperature and wind speed play a key role in the performance of the cooling mechanism [19]. Two different climatic conditions have been considered in this study, namely, hot and dry arid desert conditions (BWh) and continental dry winter (Dwa). This study pertains to flat plate non-concentrating photovoltaic panels. Figure 2: _Cont._  
The various alternatives for cooling PV panels in PV installations that have been reviewed above demonstrate that choosing the optimum method for cooling PV panels involves the use of a scientific instrument to evaluate the options. Different cooling techniques have been used successfully in a number of cases, thus making choosing difficult. Hence, five attributes were used to select the appropriate method. These attributes are technology feasibility in terms of efficiency increase, economic performance, environmental aspects, reliability and ergonomics. The attribute values were obtained with calculations and from published sources in order to select the best method. Multi-criteria decision analysis is the best instrument and has been utilized well in these circumstances. One should weigh the trade-offs between the advantages, possibilities, costs and dangers of alternatives in order to have an effective, sustainable, environmentally friendly and economically sound strategy. In order to compare, evaluate and rank the various PV panel cooling techniques, it is necessary to include numerous qualitative and quantitative criteria. Therein, expert evaluation is used with qualitative evaluation methods such as the safety check list method, the fault hypothesis analysis method, etc. Techniques for quantitative evaluation include artificial neural networks, fuzzy synthetic evaluation, probability, exponential and probability [20]. Aside from their unique qualities and viability, they also have significant drawbacks. Researchers and practitioners paid close attention to multi-criteria decision-making (MCDM) while evaluating, assessing and rating alternatives across many industrial and non-industrial sectors. Examples include assessing urban sustainable development in China [21], assessing sustainable energy planning techniques [22] and optimizing renewable energy systems [23;24]. Comparing and evaluating various choices for PV panel cooling techniques in large PV systems is one of the main goals of this multi-criteria decision analysis.