Methods of Cleaning Solar PVs
Research has shown that solar PV panels are not durable and often suffer from failure. They deteriorate regarding efficiency and thus need regular cleaning (Hanaei et.al, 2016).Solar panel cleaning does not require a lot of skills. Anyone can do it. The solar panel contains solar cells that are covered by glass coating, and when it gets dirty, there is a need of cleaning it. Pollution and traffic dust prevents sunlight from reaching the solar cells hence the need for cleaning them so as to function properly. When they are dirty, they affect the amount of electricity that is produced. Research has shown that dirty solar panels do not produce much electricity as compared to the clean ones (Jain et.al, 2013).
Two ways can be employed to check whether the panels need to be cleaned. The first way is through physical inspection (Heo et.al, 2014). The panels should be inspected on a regular basis so as to remove debris and dirt. This ensures that all the connections are tight. If solar panels are located in dirty areas, they should frequently be inspected. The second way to check them is through the use of a monitoring service. PV system is supposed to produce a particular amount power at the end of each month (Jain et.al, 2013). Thus, one can use a monitoring system to determine the amount of energy that is produced. The control system can tell a person whether it is performing according to the required expectations. If they are not performing as expected, then they need cleaning.
The solar systems and large scale solar PV systems are designed by precise engineering methods. They are built in such a way that there will be minimum loss. However, most solar systems are vulnerable and reduce efficiency over time due to dust, bird droppings, sand, tree leaves and salty water-stains. Soiling also which accounts for dust, snow and other foreign matter can prevent solar radiation from reaching the cells.
The increase in soiling during the operating life of the solar panels caused loss in electric power production. Despite the PV system owners having a fundamental interest to appreciate properly the negative effects of soiling and the use of the most appropriate cleaning system. Studies show that the size of the particle affected to the losses (Adinoyi& Said, 2013).The smaller the particle the more the loss of energy. The rain can act as a cleanser, but it just washes the dirt to the bottom edges where it continues to accumulate. Removing this dirt needs a lot of work and time. The cleaning effects of the rains is considered when calculating annual loss due to the pollution. The effect of rain depends on the amount of falling rain, and the frequency of it. If a solar panel, for instance, has a loss rate of 8- 9% the significant cleaning process starts from 5-7 mm of rain falling. For the rainfall to reduce the loss by 1-1.5%, then the amount of rain falling needs to be at least 7-8% (Mondal & Bansal, 2015).
However, rain does not guarantee 100% cleaning effect since the lower corners of the panel are not cleansed completely.
The cost of cleaning depends on the locality of the solar panels. The actual cost needs the full knowledge of the local conditions (Kjaer, et.al, 2015). When cleaning a solar panel, the cost of cleaning would depend on the gross outcome and the economic benefits of the solar PV panel. A number of conditions have to be met in productive cleaning technology. Therefore, the amount paid by the electric company to the owner of the solar system considering the amount of electricity generated. During the winter, it would be advisable to clean the panels three times per week although snow can slide away by itself. In desert areas the cost of cleaning would be higher due to the amount of water and manpower needed to clean every day. This is because the dust levels are very high and this would mean that cleaning is done almost every day to avoid inefficiency. (Kjaer, et.al, 2015).
Ways of Cleaning the PVs
Various ways can be used to clean solar panels. To begin with, an individual can clean the surface of the solar panel with warm water and soap so as to remove the accumulation of dirt. Solar panel cleaning service can be used to clean the solar panels.
Robotic Device for Cleaning PV
Automatic cleaning robots can be used to clean solar panels. This is obtained by the use of sensors and microcontroller circuit. The microcontroller circuit controls the cleaning system and implements an interface circuit that is used in converting the output signs of microcontroller through the actuators for the motors and the water pumps to do the cleaning process. This automated system senses the dust that is on the solar panel and cleans it automatically. The goal of the robotic device for cleaning PV arrays is to increase the power efficiency of the PV system and to improve the effectiveness and the cleaning speed. This device cleans the panel while conserving cleaning water and power. This robotized device mostly used in cleaning PV panels at large-scale parks. An example of cleaning robotics that cleans the solar panels is the PV Cleaner Robot V1.0. It is consists of two trolleys that provide horizontal motion and cleaning head for the vertical motion and is driven by pulley and belt system.
The cleaning head cleans the panel while moving both upwards and downwards. The head is also made up of two sprayers that are applied in the cleaning solution. It also contains two cylindrical brushes that are used to brush dust and dirt on the PV panels and move it away from the panels that have been cleaned (Mazumder, 2013). Another example is GEKKO, a cleaning robot was developed specially for large free-field solar parks. GEKKO has cleaning capacity can reach up to 2000m2 per hour, and can be used up to an incline of 30. This robot is attached to a vehicle that supplies it with electricity, water, and compressed air. GEKKO can be controlled by using a joystick (GEKKO Solar Farm).
Robotic device are very economical in cleaning the PV panels because it reduces the number of workers that are needed to clean the solar panel arrays and taking a little time. Robotic device cleans the solar panel at a faster rate as compared to how a human being would clean it (Schneider, 2015).
Automated brushes need no water to clean and have a medium efficiency. The initial cost for setting up the automated brushes is very high and hence have a very expensive maintenance program. Another disadvantages are the implementation difficulties, adhesive soiling and scratches on the solar glass (Dornier, 2001).