Economical Reflector for Solar boosting/heliostats

medicdude · 11-17-17, 04:17 PM

What are the cheapest/most durable outdoor reflector options for use in boosting thermal solar and photovoltaics? This could be used for a tracking heliostat or for passive reflection during winter conditions onto existing fixed panels, or other solar collector applications.

I have spent about 10 hours so far looking for stuff, and it seems like there is no reasonable product on the market for this, anything I've been able to find is just astronomically expensive and/or not suitable for outdoor use.

The biggest problem is simply outdoor longevity from UV breakdown, a lot of the common tapes or films I could find simply have no protection from UV and get destroyed after less than a year (often only a single month).

I was thinking some kind of acrylic or UV protected plastic might be the best protector just placed over conventional aluminum foil, with the cheapest backing you can come up with to seal against water and corrosion.

Than again, maybe just buying conventional mirrors off the market is the best bet.

I'm looking for something in the 2-10 dollar per square foot range, to be competitive with existing DIY designs, otherwise why have a mirror at all?

NiHaoMike · 11-17-17, 04:37 PM

For PV, I'd imagine keeping the panels cool might be a problem on a hot day. For solar thermal, it would probably be more economical to just make a bigger collector as opposed to deal with the complexity of keeping the mirrors aligned.

medicdude · 11-17-17, 04:56 PM

Quote:

Originally Posted by NiHaoMike

For PV, I'd imagine keeping the panels cool might be a problem on a hot day. For solar thermal, it would probably be more economical to just make a bigger collector as opposed to deal with the complexity of keeping the mirrors aligned.

Yeah cooling could be an issue for PV. Using reflected light to boost an existing thermal collector would not (significantly) increase losses to ambient, and could be a big advantage in northern latitudes where the lower light combined with the lower temperature is a huge killer for losses to ambient in a collector-only setup. This all depends on cost of course. Snow coverage could also be an issue, but if you could make portable panels that could just be dropped on the ground in the morning in favorable conditions, and removed at sunset, it could be a very attractive option. Or even just un-buried and replaced again atop the flat snowbank, with a portable design this would be very easy and take a couple minutes tops even after heavy snowfall.

My original interest in this area was for the purposes of solar cooking and other high temperature solar applications; the existing products I've found are pitiful in their longevity, and a semi-permanent heliostat DIY installation should perform much better. I also have some interesting ideas for mechanical linkage to maintain alignment of a linear array parallel to the meridian (longitude line), so you only need one set of XY tracking motors. Although I think I could make individual trackers for each mirror even cheaper than the cost of such a linkage.

11-17-17, 04:17 PM	#1
medicdude Lurking Renovator Join Date: Nov 2017 Location: CT USA Posts: 18 Thanks: 0 Thanked 3 Times in 2 Posts	Economical Reflector for Solar boosting/heliostats What are the cheapest/most durable outdoor reflector options for use in boosting thermal solar and photovoltaics? This could be used for a tracking heliostat or for passive reflection during winter conditions onto existing fixed panels, or other solar collector applications. I have spent about 10 hours so far looking for stuff, and it seems like there is no reasonable product on the market for this, anything I've been able to find is just astronomically expensive and/or not suitable for outdoor use. The biggest problem is simply outdoor longevity from UV breakdown, a lot of the common tapes or films I could find simply have no protection from UV and get destroyed after less than a year (often only a single month). I was thinking some kind of acrylic or UV protected plastic might be the best protector just placed over conventional aluminum foil, with the cheapest backing you can come up with to seal against water and corrosion. Than again, maybe just buying conventional mirrors off the market is the best bet. I'm looking for something in the 2-10 dollar per square foot range, to be competitive with existing DIY designs, otherwise why have a mirror at all?

11-17-17, 04:37 PM	#2
NiHaoMike Supreme EcoRenovator Join Date: Oct 2008 Location: Austin, TX Posts: 1,154 Thanks: 14 Thanked 257 Times in 241 Posts	For PV, I'd imagine keeping the panels cool might be a problem on a hot day. For solar thermal, it would probably be more economical to just make a bigger collector as opposed to deal with the complexity of keeping the mirrors aligned. __________________ To my surprise, shortly after Naomi Wu gave me a bit of fame for making good use of solar power, Allie Moore got really jealous of her...