Electronic Cleaning Device

The key to effective cleaning of a solar cell or array, is adaptability to different kinds of contamination. Dry contaminants may include dust, sand, salt or twigs. Bird droppings may be particularly problematic.

Solar cell cleaning device implemented as a cover layer

The cleaning procedure applies voltage traveling waves (VTWs) at the surface, which electronically sweep the surface clean. The VTWs can effectively move dry particles of different sizes and also can move water in waves, to carry away large objects such as twigs. The key to moving the different contaminant types is programmability of the stimulus waveform. The patent describes algorithms and inexpensive circuits for varying wavelength, frequency, velocity, and direction.

The phase electrodes are preferably formed using a conductive ink that is translucent to the incident sunlight. One such ink is formed as a dispersion of carbon nanotubes (CNTs) in a liquid. Such inks are becoming available and are preferable to the traditional tin oxide coatings for cost reasons. The inks can be printed using ink-jet printers in a roll-to-roll manufacturing facility.

Control over the Internet

The electrodes that provide the cleaning stimulus can also be used to sense the cleanliness of the array, in order that cleaning cycles can be scheduled automatically. The sensing and stimulus circuits can be coupled to the Internet for cost-effective control and maintenance.

Cleaning Economics

Studies have shown that solar arrays should be cleaned at least quarterly, in order not to degrade performance. The cost of sending a maintenance crew to wash a solar array is approximately $200. Considering the cost of reduced energy production if the panels are allowed to become dirty, the cleaning subsystem may pay for itself in just a few months.