Effect of the Fins Length for the Passive Cooling of the Photovoltaic Panels

Abstract

A two-dimensional (2D) Keywords PCM, Natural convection, Cooling PV panel IntroductionThe photovoltaic (PV) panel absorbs only about 16 % of the incident solar energy that is converted into electricity; the remaining insolation absorbed is transformed into heat [1]. The photovoltaic cell efficiency decreases with increasing temperature [2]. This can typically result in an efficiency drop off of 0.5 % per °C increase in the cell operating temperature. Since, for example, silicon solar cells are characterized at 1000W/m 2 and 25 °C as ideal temperature for the cell, maintaining the cell temperature at 25 °C can retain the rated efficiency of the cell. Cells will also exhibit long-term degradation if the temperature exceeds a certain limit [3].This problem can be avoided by keeping a uniform temperature across the panel. The use of the extracted thermal energy from cooling can lead to a significant increase in the total conversion efficiency of the receiver. Natural or forced air circulation is a simple and low cost method to remove heat from PV modules, but it is less effective if ambient air temperature is over 20 °C, as it is usual for many months in low latitude countries.Another, more efficient way is to use a liquid as the coolant of the panel, in order to absorb more heat and to cool the panel more effectively [4]. This is the general philosophy of hybrid photovoltaic-thermal collectors. In such kind of cooling, various investigations have been made producing interesting results.In the desert, the PV temperature can exceed 40 °C inducing a power drop in crystalline silicon PV. Increased operating temperature also results in accelerated PV degradation due to cell delamination allowing moisture ingress. The air or water cooling systems are limited by very low heat transfer and large capital as well as maintenance costs [5].However, a novel method to regulate the rise in PV temperature, phase change materials (PCM), which absorb energy as latent heat at a constant phase transition temperature has been developed and employed recently. The phase change materials undergoing solid-liquid phase transition at or close to 25 °C can absorb the excess thermal energy during phase change, which otherwise would raise PV operating temperature, and can maintain the PV operating temperature at or close to 25 °C.

Experimental Investigations Conducted for the Characteristic Study of OM29 Phase Change Material and Its Incorporation in Photovoltaic Panel

“…Thin aluminium is difficult to weld because of its melting temperature, which is lower than other metals. During sunny days, PCM changes its phase and, considering this phase change, PCM container is fabricated in the thickness of 4-8 mm metal [32][33][34][35][36]. In T PV reduction, low operating PCM temperature is used, which is sensitive in thermal conduction whenever the thickness of PCM container material increases.…”

A parametric study of a photovoltaic panel with cylindrical fins under still and moving air conditions in Iraq

“…The inner fin on the back of the panel, however, greatly reduced the efficiency of the PV/PCM system with regard to panel cooling. 11 The energy consumption of the solar absorption cooling system, the solar cooling system, and the conventional steam compression cooling system have been evaluated. Also, economic efficiencies were compared using the annual cost method.…”

“…Length configurations of L = 25, 30, and 35 mm achieved better cooling of the PV panel. The inner fin on the back of the panel, however, greatly reduced the efficiency of the PV/PCM system with regard to panel cooling 11 . The energy consumption of the solar absorption cooling system, the solar cooling system, and the conventional steam compression cooling system have been evaluated.…”

The Potential of Solar Air Heating in the Turkish Industrial Sector

“…Photovoltaic panels can be combined with transpired solar collectors creating PV-T systems. A PV panel converts only 16 % of the incident solar radiation into electricity and the rest is transferred into heat, which further decreases the efficiency of the PV cell [11]. The utilization of this heat with a TSC increases both the PV efficiency and the solar fraction of the heating system.…”