How to Double Solar Panel Output for a few Pounds…

Shadowalker Although solar panels can only convert about 18% of total light into electricity, that doesn’t mean doubling the available light doesn’t double the output –whilst technically efficiency remains the same. I know most panels absorb UV, which means using a glass mirror (rather than say aluminium foil) isn’t such a bright idea after all, since “transparent” glass tends to absorb UV (at least I understand this is why you don’t get sunburnt whenever working in e.g. a greenhouse).

However ChungTsuU is right about (standard PV solar panels) having lower efficiencies at higher temperatures (for one thing electrical resistance increases). To me this means two things…
1. In England a bit of reflective foil would do far, far, more good than harm, as temperature (for all but three months of the year, i.e. mainly May-August) isn’t that much of a problem, and even during those months most of the time it won’t be.
2. Why, Why!!! Can’t solar panels be cooled from behind, by plate containing water (the front-hot side of this plate made from metal, the back being plastic)? The hot-warm water could obviously be transferred to a water tank, which could either warm the house directly, or warm it to an even higher temperatures through an electric Heat Pump. However: During the summer this heat would be a complete nuisance, therefore it could also be piped round either: To shady sides of the roof-road, or the soil-water pond of your garden, or your house foundations (beneath floor insulation) (more likely foundations, if it’s a new build property, of course).
I know the cooling water could freeze during winter, but thankfully somebody invented anti-freeze!!

Either way: Circulating coolant water (inside a loop) isn’t such a major energy expense, especially when the electricity required comes from the solar panels, and cooling this panel increases (net) electrical output, since this (relatively expensive) panel can now absorb several times more sunlight, from (a relatively extremely cheap) piece(s) of glued down, aluminium foil.

Thanks everybody for the comments, I’m installing solar panels sometime soon.

12volts

Using less power is a much better alternative.Do you really need 2000watts to burn a piece a bread or nuke a can of spaghetti.

Not in a world with about 5 billion people aspiring for Western living standards (or even about one quarter as much). Besides I always believe the way of the past is less consumption, and the way of the future is more. The only challenge is cost effective, sustainable consumption, and that’s not a challenge (talented) engineers are afraid of (even if certain companies & the politicians they finance, are petrified!!!)

reply to post by Liberal1984


Active coolant-based circulating systems, and passive "heat sink" systems are both used in solar systems that concentrate the equivalent of multiple suns of light onto solar cells.

This is true for magnifier systems using Fresnel Lens (or other techniques), and for reflective array systems where heliostat-mounted multiple mirrors reflect light onto a centralized CPV receiver.

The approach you are suggesting is in fact used by at least a couple of commercially available CPV systems where the heat energy collected is then cycled through, and put to alternative uses (heating and air conditioning, for example)...thus dramatically increasing the overall efficiency of the solar energy collection system.

It comes down to dollars and cents, as to what approach to use, and whether the costs of dissipating and/or cycling the heat energy results in an overall net gain to the user.

Certainly many people do believe that this is one of the ways to go to increase the overall efficiency (and therefore cost-effectiveness of solar energy systems).

That’s great. But solar cells are so expensive, I’d have thought that (particularly on a large scale) using foil to increase output, and e.g. pond water to cooling the cell would be the only wise approach.
Why in Germany (for example) did they build massive solar cells, and that’s it. No sun tracking system, no foil to amplify returns?
Did no one think of it? It’s just hard to imagine how cooling the things (in exchange for e.g. 300-400% more electricity) would be that prohibitive.

reply to post by Liberal1984


being an old dog at designing and installing small scale pv systems, your posts got me thinking a bit more. i wonder if anyone here has felt the underside of a panel on a v.hot day? that heat generated could possibly be exchanged into a piping system and complement a hot water system. just seems a waste imo.
f

reply to post by Liberal1984

2. Why, Why!!! Can’t solar panels be cooled from behind, by plate containing water (the front-hot side of this plate made from metal, the back being plastic)?

Many concentration-based designs do this. Water is circulated behind the panel to draw heat off of the cell.

Some of the better cells out there are up to 30 and 40% efficiencies - with an Israeli design setting the new par at 72% : inhabitat.com...

a reply to: sonofliberty1776
Take heart Solarworld is working on the problem. Currently they are at 17.2%

a reply to: Liberal1984

Do not paint or glue your roof. Have an expert do this.

Any change to one house system affects every other house system.

Your roof is meant to breathe. Asphalt shingles are not waterproof. Nor are slate or any other roofing material. Saving a few bucks on electric is well and good,except when you need to spend 40k on a new roof after all your trussez have rotted out and your fancy solar system is sitting on your dining room table.

Homeowners are so bad at things like this. They go up and insulate their whole attic and then wonder why their house is rotting away from the top down. Some of the ways houses are meant to work are counter intuitive to many homeownes. Especially wh3n it comes to roofs attics and crawlspac3s.