Solar Panels and Drinking Water Collection

[Mr. Mik]

Can anyone tell me what substances (if any) are likely to be released into the water that is running off solar roof panels?

Are there any likely differences between types/brands of panels? How about in 25 or 35 years time? How about really cheap panels, the worst you can think of?

How about the bracket systems, the cables and possibly multiple micro-inverters?

It all runs straight into my drinking water tanks, hence the question.

[Sunking]

Glycol and sewage come to mind.

[Mike90250]

I'll assume solar PV panels, 98% of their surface is glass, the rest is sealant and aluminum.

I'd toss the first rain of the season, likely to have a lot of collected dust and bird droppings. After that, it's pretty clean, much cleaner than water off an aged asphalt shingle roof.

[peakbagger]

Your question was a tad bit generic. If you have sealed direct system with no intermediate fluid and it is plumbed properly, you really should only be concerned about potential contaminants in the piping and collectors.

My first assumption is that you have a standard solar collector that has a upper and lower header with tubes running between the headers. If its one of the trickle type that ran water from an upper supply tank down over an absorber plate that was then collected by an open trough dont even consider it for potable water as exposing the water to air in hot conditions could lead to bacteria issues..

Most panels are now built with copper piping, some older units were made using aluminum piping but I expect few will still hold pressure. If the system has copper piping, the biggest long term issue may be the use of lead solder in the joints. Lead was banned for potable water piping years ago, but I ma not sure if collectors would need to meet this standard. If the system has been out of service, there could be biological activity that has collected. If the panels previously were used with a heat transfer fluid, there could be contamination left over in the pipes. In general if they are used, its wise to "boil" out the collectors with a product that is designed for potable water systems. Essentally you would use heated water and an additive which would be circulated through the system with a temporary pump. I know that TSP is used by heating contractors but not sure if its got toxicity issues.

[russ]

Last I knew he was posting about solar PV.

Like his other worries - they aren't worries unless you go to some fuzzy headed green site.

[Mr. Mik]

Indeed, the question is about solar PV systems.

I have solar hot water systems since over 10 years, I'd hope they have thought about making them drinking water quality....although they might well have forgotten about the outside of the solar hot water system. The exterior paint will of course end up in the gutters and tanks over the years.

[peakbagger]

Sorry, my screw up. I would expect far more junk coming from the environment than from the panels. If you have "roof washers" on the collection system that discard the first few minutes flow, I wouldnt expect any significant issues from panels