Mobile water treatment

Task

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A small proportion of solar modules lose their insulating properties after a few years and therefore need to be replaced.

 

Our customer collects large quantities of defective modules and recycles them using various processes. The defective insulation is often a plastic film or plastic coating used on the back of the solar cells that develops cracks. Water and dirt penetrate the cracks, reducing the insulation resistance.

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The back of the solar modules is cleaned with water, which improves the insulation values, but these are not always satisfactory.

 

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Solution

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We carried out a test setup for cleaning in the laboratory. After mechanical cleaning, the modules were rinsed with completely demineralized water, then recoated, and the increase in conductivity was measured periodically. Conductivity is a measure of the substances removed.

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When there was no further increase, the modules were rinsed again with demineralized water. The modules were then dried and resealed.

 

The following data was derived from this experiment:

• Required exposure time for deionized water (DI water)

• Required DI water quality and quantity for cleaning

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This data was used to determine the effort required for water treatment and purification and the proportionate costs for purification. In addition, a reclaim system was designed to recover most of the deionized water.