Effects of Dust accumulation on PV Panel of any Type

Effects of Dust accumulation

A number of PV panel pair operating under the same environmental condition but with different level of dust deposition their surface was compared More specifically the performance of five pair PV- panel was examined each one composed of two panel connected in series the pair is depicted for various solar irradiance densities “Gt” a cell temperature of 25 degree Celsius and with a spectral distribution corresponding to air mass 1.5. According to the experimental procedure adopted, the pairs of PV-panels were firstly well cleaned and were accordingly kept exposed to natural air pollution over a certain time period (i.e. from 2 to 8 weeks), adjusted at 30 degree inclination. After the first 2 weeks, pair panel 1 was carefully cleaned and its performance was compared with the polluted pair panel 2. The procedure was repeated every two weeks so that the performance of the rest of polluted pair panels (3, 4 and 5) would be evaluated (always compared with the clean pair panel 1) after a specific time interval of their outdoor exposure, i.e. 4, 6 and 8 weeks respectively. Note that special attention was paid on the weather forecast so that cases of rainfall could be avoided.

Specifically, the experimental procedure comprised the following steps:

1. The previous day of the experiment the PV-panels were switched off in order for the batteries to be drained up to a point via the consumption loads

2. The day after, during the hours of increased solar radiation (usually around noon), under cloudless sky, a number of measurements was conducted. The high solar radiation (700e900W/𝑚2) hours were selec

ted in order to ensure the calculation of the maximum energy difference (loss) between the clean and the polluted PV-panels. Firstly, pair panel 1 was well cleaned so that the total mass of the accumulated dust on its surface would be removed. During The recording procedure (approximately 1 h) the values of the current and the voltage of the two pairs of PV-panels under investigation were recorded along with the intensity of solar radiation on the PVs’ surfaces. Besides that, the ambient temperature was also specified and compared with that of the panels.

When the recording procedure was completed, the surface of the polluted panel was carefully cleaned with the use of known weight wetted (with filtered water) cotton pieces which had been

previously put in a dehumidifier (for 24 h) so that any trace of humidity could be removed. Later on, after repeating the dehumidification of the polluted cotton pieces, weighing with the use of a precision weighing balance of 0.1 mg accuracy was performed, in order for the total mass of the pollutant 𝑀𝑗 𝑎𝑓𝑡𝑒𝑟−𝑀𝑗 𝑏𝑒𝑓𝑜𝑟𝑒 accumulated on the panel’s surface “Ac” (area of each panel equal to 0.442624 𝑚2) during the time period of study to be estimated. In this context, the specific mass deposition is expressed as:
𝛿 𝑀𝑗=(𝑀𝑗 𝑎𝑓𝑡𝑒𝑟−𝑀𝑗 𝑏𝑒𝑓𝑜𝑟𝑒) /𝐴𝑐 j=, 2, 3, 4, and 5 (1)

4.Presence of dust considerably affects the PVs’ performance since the reduction of the generated power reached almost 6.5% of the respective mean pair panel output in the examined case of the highest dust deposition density (i.e. 1 g/𝑚2e 8 weeks pollution). Although this value may not seem considerable, it is comparable with the one imposed by the temperature increase of the PV panels’ surface.