The key element of the cleaning system is a steel rod attached to the upper side of the solar module. The rod is equipped with several nozzles for spraying liquid, through which water enters the front side of the panel, from where it trickles down into a special storage container. The accumulated water is then fed back to the rod via a 36 watt (W) water pump powered by the solar module. This results in a closed loop that makes it possible to reuse up to 85% of the sprayed water, which is especially important in countries with arid climates.
The authors of the study tested the solar module by placing it at an angle of 23, 33 and 43 degrees. They discovered that in all three cases the power output of the cleaned panel was 13.7% higher than that of the module that had not been cleaned (reference panel). This was achieved thanks to, among other things, the fact that water spraying, which took place for five minutes every 24 hours, made it possible to reduce the temperature of the solar battery’s working surface by 0.8 degrees Celsius compared to the reference panel. The scientists estimate that the resulting capacity increase can save the owner of the panel about $0.03 per day, which means that the cost of the cleaning system can be recovered in two and a half years.
The solution developed by the Pakistani scientists is yet another in a series of innovations designed to solve the problem of soiling-caused power losses in solar panels. Previously, researchers from the University of Johannesburg came up with a solution by developing an automated cleaning system that detects dirt via colour and moisture sensors. The device is activated if humidity exceeds the threshold of 80% or if the sensor detects that the color of the solar panel surface deviates from the specified norm. The device can remove up to 95% of dust and dirt from the surface of the solar battery within one minute.
