more efficient solar panels (idea) - Page 1
Forum section: electronics / general

author: grifftech
author_rank: Frequent Contributor
timestamp: May 08, 2017, 03:14:43 pm
content: my idea is to add water pipes to the back of a regular solar panel, this will cool the panels and heat the water.the reason is that solar panels are more efficient when they are cool, and that the heat could be used

author: CatalinaWOW
author_rank: Super Contributor
timestamp: May 08, 2017, 03:18:33 pm
content: This is a case where numbers are your friend (or enemy). Your idea is sound. It works. The problem is that in every case examined so far it is cheaper to buy more panels than to install the plumbing. The efficiency gain is small, a few percent, and solar panels are cheap. Throw in the maintenance costs for plumbing over 25 years and the system cost efficiency is strongly negative.

author: CJay
author_rank: Super Contributor
timestamp: May 08, 2017, 03:46:10 pm
content: I'd mulled this over a couple of years ago, liked the idea of having hot water from solar panels but it seems as CatalinaWoW says, it's cheaper to add more panels as long as you have the space to add them, if not, I wonder if it might be worth trying (doubt it but)...

author: Seekonk
author_rank: Super Contributor
timestamp: May 08, 2017, 04:28:29 pm
content: this will cool the panels and heat the water.You can only choose one. Hot water gives you a lower output panel. Fluid systems are always a nightmare. This idea seems to have great appeal for those who have never actually worked with solar. You need to get the panels down to sub freezing to get any real gain in power. I heat water with PV as the panels are so cheap now.

author: james_s
author_rank: Super Contributor
timestamp: May 08, 2017, 06:23:39 pm
content: I suppose there might be some gain from using this as a first stage, cool the panels, preheat the cold water, then run the water through additional thermal solar heaters. I dunno if anyone does this anymore but when I was a kid one of the neighbors had water heating panels on his roof. They were little more than black pads with water run through them, I don't know how the rest of the system was set up. I also remember seeing swimming pools that had arrays of black tubing across the roof of the building to warm the pool.

author: mtdoc
author_rank: Super Contributor
timestamp: May 08, 2017, 06:33:20 pm
content: This has been done and it works but the gains are very small. I believe there was at one time at least one company selling a commercial product but it went no where for the reasons explained above.

author: CJay
author_rank: Super Contributor
timestamp: May 08, 2017, 06:42:55 pm
content: Quote from: james_s on May 08, 2017, 06:23:39 pmThere are evacuated tubes which seem rather popular here in the UK, dunno how efficient or cost effective they are.

author: james_s
author_rank: Super Contributor
timestamp: May 08, 2017, 06:55:30 pm
content: Quote from: CJay on May 08, 2017, 06:42:55 pmHeat pipes, they're totally neat, not sure how well they work in that application but small ones are common in laptop computers. IIRC they have acetone or water vapor inside at low pressure.

author: mariush
author_rank: Super Contributor
timestamp: May 08, 2017, 07:12:24 pm
content: Maybe they could be worth it if they can use some cheap energy during the night to pump water in some reservoirs on top of a hill or something like that, and then increase the efficiency of the panels when they're hot in the middle of the day when the power costs are also higher.Maybe letting gravity create the pressure require to flow water through all the systems could lower the costs enough to justify something like this?

author: badvoc
author_rank: Contributor
timestamp: May 08, 2017, 07:47:55 pm
content: I had a thought about this, not sure if i am barking up the wrong tree as i don't know much about solar panel tech. But would it be possible to filter out heat wave length IR i guess from the visible light wave length using some sort of filter. And would this keep the heat off the cells and still allow them to operate as they would receiving the visible light to produce electricity?!?Doing a Google search..."visible light" corresponds to a wavelength range of 400 - 700 nanometers (nm)Infrared radiation extends from the nominal red edge of the visible spectrum at 700 nanometers (nm) to 1 mm.Seems there is a slight difference / overlap with the wave lengths, so technically possible?!? - or just me 'beer' thinking againlol

author: james_s
author_rank: Super Contributor
timestamp: May 08, 2017, 08:05:34 pm
content: IR reflective coatings are common and fairly effective, oven door windows, low pressure sodium lamps and other applications use them, but I suspect in this case the cost outweighs the advantage. They also will reflect some percentage of the precious visible light away from the panels, I don't know how that compares to the potential gains but it's something to consider.

author: m98
author_rank: Frequent Contributor
timestamp: May 08, 2017, 08:29:28 pm
content: Had the same idea a few years ago, turned out that I too wasn't the first one to come up with the idea of hybrid solar collectors...http://res-energie.de/res-produkte/pv-kombimodule-hybridkollektor-pv-t/http://www.wagner-solar.com/waerme/produkte/solarwaermesysteme/solarheizsysteme/2-powersystem.html

author: badvoc
author_rank: Contributor
timestamp: May 09, 2017, 06:27:46 pm
content: Quote from: m98 on May 08, 2017, 08:29:28 pmDamn all my best ideas have been done, ah well best stick with the day job then

author: edavid
author_rank: Super Contributor
timestamp: May 09, 2017, 06:37:10 pm
content: Quote from: badvoc on May 08, 2017, 07:47:55 pmThere's no need, silicon does not absorb IR. As long as there is metal under the silicon, the IR is reflected back out.

author: james_s
author_rank: Super Contributor
timestamp: May 09, 2017, 06:40:49 pm
content: Quote from: badvoc on May 09, 2017, 06:27:46 pmPretty much all the simple stuff has already been invented. I've just come to accept the fact that if I come up with something cool, somebody out there somewhere has already come up with something even cooler and done so a year before me.

author: Seekonk
author_rank: Super Contributor
timestamp: May 09, 2017, 10:06:55 pm
content: Efficiency is becoming secondary in importance in home solar applications. The utilities hate the homeowner dumping power into the grid at peak solar times. Feeding onto the grid, the homeowner gets paid almost nothing and the utilities often have to pay to dump the power. You may not even get that soon enough with smart meters. Smart home controls to schedule home loads like cloths and dish washing machines water heating, heating and AC, and even your refrigerator will be the next technology wave to get better payback.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: May 10, 2017, 12:30:30 am
content: Quote from: james_s on May 09, 2017, 06:40:49 pmThat is probably not true. But all of the obvious stuff has.

author: james_s
author_rank: Super Contributor
timestamp: May 10, 2017, 12:47:22 am
content: Well that's more or less what I meant. The days of one or two guys coming up with something really revolutionary in their garage are long past.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: May 10, 2017, 03:58:43 am
content: I was actually trying to say that I believe there is a chance that two guys in a garage can come up with something really new. If so it will come out of left field, totally unsuspected. It may or may not be simple. But it probably won't be a simple application of principles taught in schools.

author: Red Squirrel
author_rank: Super Contributor
timestamp: May 10, 2017, 03:17:38 pm
content: This has crossed my mind, but the opposite. Use glycol to heat the panels in winter to melt the snow off. To stick to renewable sources the heat could be done with a wood boiler. Not sure what is the best way to heat glycol with fire though, it sounds kinda unsafe lol.In summer the system could very well be used to cool the panels too. Just not sure if the power to run pump etc would be worthwhile vs the extra power you get.

author: bazza
author_rank: Contributor
timestamp: May 13, 2017, 02:22:18 pm
content: Here's something really revolutionary:* good insulation in homes* Energy Use literacyThe only problem is mass ignorance, which means the gov-endorsed Solar Scams are allowed to exist, and not only exist, but flourish while everyone gets told to bend over whenever they see their bill & their hidden taxes being used to subsidise the thieving Energy Cartels.Solar panels should be cheap enough for at least 50% of the earth's population to have some sort of self-sufficiency. But too many are ignorant of energy use and the regulations make it hard for them to break free - by design. Which brings me to the political parasites: it's not a tech problem we have, really. And today it's not really a prohibitively expensive cost problem. It's making small changes to the way we live by being conscious of our energy usage and then making changes to severely reduce it using tech we have now.This is 99.9% of the 'real' problem now, in my estimation.