Microinverter confusion.. Doesn't make sense.

[robbyg]

At this time the extra output that a "cool" panel can provide is far outweighed by the cost of the cooling system. It just doesn't make financial sense.

Operative word being "At this time". After seeing the elaborate water cooling system that Tesla uses in their Powerwall's it's anybody's guess what may happen with PV in a few years.

I could imagine a very thin aluminum backing with a 5mm wide zig zag of water channels pressed into a thin plate and then bonded onto another thin flat plate. This could be bonded across the back of the panel with an inlet and outlet connection. Coolant is then pumping into a fan based radiator box that has multiple inlets and outlets for a panel array. I am thinking a unit the size of an condenser on a split AC unit. The idea is not to go above STC but to offset most of the heat losses you get in hot sunny climates.

Fossil fuel is on it's last legs even though it may not seem that way. Like all shifts in technology there has been a long slow hill to climb to eventually reach critical mass and then all of a sudden things move exponentially. At some point maybe 15 years from now its probably going to be a split between seeing Gas Pumps vs Charging Stations. A whole slue of things may start to come into play to make it very compelling to go fully electric and that means a lot more innovation and competition to grab the money that is being spent.

BTW I have been anti solar for decades, not because I don't like the idea of going green but because every time I did the math it made zero sense to invest in it. What swung me over was the recent changes in battery technology.

[J.P.M.]

Evidently those conditions do exists on certain days in certain places. I don't think all those videos are a lie.
As for cooling the Panels with water, I know it can be done economically in some situations. I have a cousin with ground mounted panels that are very close to a stream. The problem is that unless that water has been run through and RoDi system I suspect that the amount of deposits that are going to build up on the glass make it a bad idea.

Those systems are one off, don't work worth squat as a serious engineering analysis will show, and as anyone who knows something about fluid mechanics and heat transfer will quickly confirm.
And, agreeing with SunEagle writes, it's highly unlikely that any safe, practical and commercially viable panel cooling systems using water or other heat transfer liquids can be designed and brought to market using currently available technology and/or engineering.
Forced air cooling is less cost effective still so don't go mounting fans next to any solar arrays. The U-tubers will love that crap, but it'll be no more than an exhibition of ignorance.
Clincher: If force cooling of PV panels was viable, the big solar farms would be all over it.

[robbyg]

Those systems are one off, don't work worth squat as a serious engineering analysis will show, and as anyone who knows something about fluid mechanics and heat transfer will quickly confirm.
And, agreeing with SunEagle writes, it's highly unlikely that any safe, practical and commercially viable panel cooling systems using water or other heat transfer liquids can be designed and brought to market using currently available technology and/or engineering.

As you said, using "Current Technology" I am looking at what might be created 10-15 years from now!
If 15 years ago you honestly believed that a rocket booster would go into space and then land back down on the deck of a ship you must have had a crystal ball. I had never even considered that as a possibility back then and BTW as you know, it's done for a much cheaper price than anyone could have ever dreamed of.

I think your mistaking me for one of those free energy guys you find on YouTube. I have been a Electronic Engineer doing mostly design work for 35 years, I just recently retired. I am very aware of what is and what is not possible and the pace at which things change if there is a demand and money to be made.

Forced air cooling is less cost effective still so don't go mounting fans next to any solar arrays. The U-tubers will love that crap, but it'll be no more than an exhibition of ignorance.
Clincher: If force cooling of PV panels was viable, the big solar farms would be all over it.

A lot of things that are viable on the small scale cannot be scaled up and vice versa! It's pretty difficult to force air through 10,000 panels covering acres of land. In any case I am not proposing air cooling! Water cooling is about 10 times more efficient than air cooling. You just need to make the power gained far exceed what is used.

[scrambler]

Floating solar farms on lakes are the best way so far and are picking up

[J.P.M.]

As you said, using "Current Technology" I am looking at what might be created 10-15 years from now!
If 15 years ago you honestly believed that a rocket booster would go into space and then land back down on the deck of a ship you must have had a crystal ball. I had never even considered that as a possibility back then and BTW as you know, it's done for a much cheaper price than anyone could have ever dreamed of.

I think your mistaking me for one of those free energy guys you find on YouTube. I have been a Electronic Engineer doing mostly design work for 35 years, I just recently retired. I am very aware of what is and what is not possible and the pace at which things change if there is a demand and money to be made.




A lot of things that are viable on the small scale cannot be scaled up and vice versa! It's pretty difficult to force air through 10,000 panels covering acres of land. In any case I am not proposing air cooling! Water cooling is about 10 times more efficient than air cooling. You just need to make the power gained far exceed what is used.

I don't believe I'm mistaking you for anyone, or referring to you at all for that matter.
I'm stating what I believe to be an informed opinion about the current and future practical and economic viability of an applied heat transfer application.

What I am is knowledgeable in solar engineering and, unrelated to my solar energy interests, more knowledgeable about mechanical engineering and systems as they relate to power generation, distribution and control, particularly as it relates to boilers, condensers and other types of heat transfer equipment with respect to thermal and mechanical design. I also try to stick to what I think I know something about.

There isn't much, if anything, new under the sun with respect to heat transfer, fluid mechanics and Thermodynamics, or materials science. Things will change, but heat still flows from where it's hotter to where it's colder and entropy will always extract a price both in efficiency and cost when that happens.

I spent an engineering career squeezing heat out of processes. There is not currently any money to be made by PV panel cooling. And, given what I think I know about how the finer points of some of the design challenges to be dealt with are, the technology will need to be pretty exotic (read costly) if possible at all, and as yet uninvented. The Second Law of Thermodynamics will extract payment in ways that the solar process cannot repay.

What you are talking about is the cooling of PV panels using sensible cooling via forced convection of fluids, either a liquid or a gas. Using gasses such as air is less efficient from a heat transfer standpoint but for reasons inherent to their nature, using liquids is, to a rough first approximation, about inversely proportional in cost to the gain in film heat transfer coefficient, even before any considerations for liquid containment, handling and treatment.

Your last sentence says it all with respect to why PV panels aren't cooled by forcing fluids to be in contact with them. Entropy won't let that happen in any viable way at least not until someone figures out how to violate the 2d Law of Thermodynamics. Then, there's the question of making it cost effective.

The problem is not new. It's been around at least as long as an ancient Greek by the name of Hero invented an ancient form of radial steam turbine that could actually produce shaft power. The types of problems he faced (but wasn't aware of) are are still with us. I'm not as optimistic as you about solving them any time soon.

How about this : You stick with electronics and I'll stick to solar energy and mechanical engineering. That way neither of us will be putting out and spreading B.S. around. Fair enough ?

[robbyg]

Then, there's the question of making it cost effective.

Your whole argument is really based on this one statement. Reducing the temperature of a Panel from 50C to 30C is a power gain of anywhere from around 6-10%. It's hard to imagine going forward towards a global green society that this kind of energy loss is not going to be considered as something to be seriously reduced and who knows how it will be done. That is why I bought up the SpaceX rocket, because it was one of those things that engineers kept saying could be done but nay sayers in rocket science insisted that it would never be worth it or reliable.
Since the only argument here is the question of making the solution cost effective, which is an issue that engineers have been solving for thousands of years I would not place my bet on it not happening.

[SunEagle]

Your whole argument is really based on this one statement. Reducing the temperature of a Panel from 50C to 30C is a power gain of anywhere from around 6-10%. It's hard to imagine going forward towards a global green society that this kind of energy loss is not going to be considered as something to be seriously reduced and who knows how it will be done. That is why I bought up the SpaceX rocket, because it was one of those things that engineers kept saying could be done but nay sayers in rocket science insisted that it would never be worth it or reliable.
Since the only argument here is the question of making the solution cost effective, which is an issue that engineers have been solving for thousands of years I would not place my bet on it not happening.

IMO in 15 years solar panels will have increased in efficiency without the need for cooling. But for now a water or air cooling system or even a dual axis tracker for a home user does not make financial sense to install due to the cost of maintaining the system just to get a few extra % output of those panels.

By the way I am also a retired electrical engineer and have worked on solar panel technology since the mid 70's. They have come a long way and have yet to fulfill their true output potential.

[azdave]

IMO in 15 years solar panels will have increased in efficiency without the need for cooling.

The technology already exists to increase the output of your system more than the few percent gained through forced cooling. That technology is called "BMP" (buy more panels). It is far cheaper and has virtually no maintenance. You'll find it in stock wherever PV panels are sold.

[J.P.M.]

Your whole argument is really based on this one statement. Reducing the temperature of a Panel from 50C to 30C is a power gain of anywhere from around 6-10%. It's hard to imagine going forward towards a global green society that this kind of energy loss is not going to be considered as something to be seriously reduced and who knows how it will be done. That is why I bought up the SpaceX rocket, because it was one of those things that engineers kept saying could be done but nay sayers in rocket science insisted that it would never be worth it or reliable.
Since the only argument here is the question of making the solution cost effective, which is an issue that engineers have been solving for thousands of years I would not place my bet on it not happening.

My stated opinions on this thread - not argument - are based on what I think I know, not just one statement.
I can engineer stuff all day long and improve it, but if it's not cost effective no one will buy it. Sensible cooling of PV panels via fluids is not cost effective because it's too complicated in ways most folks are clueless about. Those who do know something about the subject don't waste their time.

As far as such a loss being considered because of some potential efficiency gains, it's been considered. A Lot. There is a well developed technology in heat recovery, and there's not a lot that's new and at the same time cost effective. That there isn't much seen in the way of such devices and schemes on PV panels isn't because it hasn't been explored. It's precisely because it has been explored and found to be not economically viable.
Also, since something like 80% of a panel's input is rejected as waste heat or reflection losses, there's a better chance that other avenues and methods to pick up/recover/utilize the same or greater amount of otherwise lost energy in other ways before running off on what amounts to some waste heat recovery scheme that will wind up as some Rube Goldberg type system cobbled together by a bunch of snowflake 20 somethings who know precisely squat about what's required.

Saving 10% of a 20 % efficient panel - that is, a 2 % production improvement can be had in ways that are a lot less expensive and less complicated.

One possible out of the thought box example: Selective surface treatments for glazings that reflect all the irradiance above the cutoff frequency for formation of electron-hole pairs (~ 1.15 micrometers wavelength). Doing so would theoretically remove ~ 30 % of the solar heating potential to a panel while not reducing the power output. Doing so might reduce cell temps. by maybe 5-10 C. depending on irradiance levels with no parasitic pumping and a lot less or maybe zero added maint. costs. for what might be a 2-5 % improvement in production.
Better/cheaper/faster and a whole lot less complicated than a piping and service nightmare. Better to avoid the non useful energy input potential in the first place by not letting the non PV useful energy in rather than get all the hassle of removing it via sensible and forced heat transfer systems.

[solardreamer]

Evidently those conditions do exists on certain days in certain places. I don't think all those videos are a lie.
As for cooling the Panels with water, I know it can be done economically in some situations. I have a cousin with ground mounted panels that are very close to a stream. The problem is that unless that water has been run through and RoDi system I suspect that the amount of deposits that are going to build up on the glass make it a bad idea.

I haven't seen the videos you are talking about but I have seen videos that show effects that are not meaningful (e.g. cloud edge effect) in real world systems or not financially worthwhile so they are not lies just not practical and/or not financially worthwhile. As others have explained, PV cooling solutions in general are not financially worthwhile at this time despite many years of various attempts. If you believe it's practical and financially worthwhile then try it for yourself and share the results. Otherwise, you are just arguing against lots of evidence to the contrary without substantiation. I would certainly be interested in a cooling solution for rooftop solar that is practical and financially worthwhile if it's available.

[SunEagle]

The technology already exists to increase the output of your system more than the few percent gained through forced cooling. That technology is called "BMP" (buy more panels). It is far cheaper and has virtually no maintenance. You'll find it in stock wherever PV panels are sold.

I totally agree with that approach.