Looking at a PV system - Some input would be amazing! Grid Tied - No Batts

[J.P.M.]

You can buy a Roll-Bond panel in aluminium and put it on the backside of the PV panel, you will reduce the temperature and you will increase the production of energy, in the meantime you can use Thermal energy for hot water, it's very easy and cheap

And just how would that be accomplished ? Sounds like more "you could just do this and 'POOF - a miracle happens' " .

After changing careers and returning to school because of an interest in R.E. and solar energy, and after a subsequent career as a mechanical engineer, a fair portion of which was spent designing heat transfer equipment and systems, my opinion about the ideas contained in your post is that they are, at this time, impractical for many reasons and probably not cost effective.
What you suggest is neither easy or cheap - at least not in the ways you seem to be suggesting, and at least not at this time.

Such ideas of energy scavenging have been around for a long time, and for many applications they make thermal and economic sense. For the residential or low temp. PV/solar thermal for example, the Univ. of Delaware did a lot of work. in the '50's on air cooled PV to supply heat for their experimental solar dwelling which was partially fitted w/early PV. Maybe SunEagle knows if it's still there. Others have done stuff, with the general conclusion that, while theoretically possible, it's not practical and/or cost effective at this time for all but specialized applications. Such schemes are great fodder for master's theses and journal articles, and activity in those areas continues. But, if it was cost effective and practical, it would be common place by now. Hope, progress and white collar welfare type research are always with us.

[SunEagle]

And just how would that be accomplished ? Sounds like more "you could just do this and 'POOF - a miracle happens' " .

After changing careers and returning to school because of an interest in R.E. and solar energy, and after a subsequent career as a mechanical engineer, a fair portion of which was spent designing heat transfer equipment and systems, my opinion about the ideas contained in your post is that they are, at this time, impractical for many reasons and probably not cost effective.
What you suggest is neither easy or cheap - at least not in the ways you seem to be suggesting, and at least not at this time.

Such ideas of energy scavenging have been around for a long time, and for many applications they make thermal and economic sense. For the residential or low temp. PV/solar thermal for example, the Univ. of Delaware did a lot of work. in the '50's on air cooled PV to supply heat for their experimental solar dwelling which was partially fitted w/early PV. Maybe SunEagle knows if it's still there. Others have done stuff, with the general conclusion that, while theoretically possible, it's not practical and/or cost effective at this time for all but specialized applications. Such schemes are great fodder for master's theses and journal articles, and activity in those areas continues. But, if it was cost effective and practical, it would be common place by now. Hope, progress and white collar welfare type research are always with us.

While I was there in the early 70's most of the solar thermal research performed at the U of D involved "salts" that helped gain solar energy to be used to heat a home. Some of the research I worked on included ways to remove the heat from the Thin Film solar panel but as always the cost to gain 1% of efficiency by cooling the panel used much more power then generated by the panel. It comes down to economics and the rules of thermodynamics.

[NYHeel]

I've been reading more on this and it seems it may only be for the initial install and nothing after that, however I haven't quite found a clear cut answer. The below is the most complete answer I have found:

"The solar PV system is new or being used for the first time. The ITC can only be claimed on the “original installation” of the solar equipment."

http://solaroutreach.org/wp-content/uploads/2015/03/ResidentialITC_Factsheet_Final.pdf

I'm not an accountant but I don't see anything there that would preclude you from taking the tax credit on an addition to your system. If you added more panels in year 2 then you'd be claiming the credit on the original installation of those panels. I think the term original is used to exclude someone who takes off the solar equipment and reinstalls it on a different roof and wants to claim the credit for the labor costs. That looks like it would not be allowed.

[J.P.M.]

While I was there in the early 70's most of the solar thermal research performed at the U of D involved "salts" that helped gain solar energy to be used to heat a home. Some of the research I worked on included ways to remove the heat from the Thin Film solar panel but as always the cost to gain 1% of efficiency by cooling the panel used much more power then generated by the panel. It comes down to economics and the rules of thermodynamics.

Understood. Thank you. I had several conversations w/ Dr. Telkes back in the day when I was looking/rooting around in the seasonal thermal storage side of things in the mid/late '70's.

[SunEagle]

Understood. Thank you. I had several conversations w/ Dr. Telkes back in the day when I was looking/rooting around in the seasonal thermal storage side of things in the mid/late '70's.

Small world. I actually never met Dr Telkes (undergrads did not get to rub shoulders with most of the solar scientists) but I would guess that her sodium sulfate salt was probably used and tested in the "Solar One" home at the U of D. I would also think that since Du Pont Co was right up the road they probably invested heavily in that research.

[J.P.M.]

Small world. I actually never met Dr Telkes (undergrads did not get to rub shoulders with most of the solar scientists) but I would guess that her sodium sulfate salt was probably used and tested in the "Solar One" home at the U of D. I would also think that since Du Pont Co was right up the road they probably invested heavily in that research.

I met her at a couple of solar conferences and spoke via phone 1X. The Glauber's salt was used in Solar One. Also, in one iteration, and somewhat relating to the current thread about cooling PV arrays, some of the early PV on the building was air cooled. Proof of concept stuff. I believe she was responsible for that as well as other non HVAC solar applications.

[SunEagle]

I met her at a couple of solar conferences and spoke via phone 1X. The Glauber's salt was used in Solar One. Also, in one iteration, and somewhat relating to the current thread about cooling PV arrays, some of the early PV on the building was air cooled. Proof of concept stuff. I believe she was responsible for that as well as other non HVAC solar applications.

You are correct. They had some type of air flow system that was supposed to remove the heat that the solar panels absorbed and transfer it to the salt storage tanks. The heat was then supposed to be used to heat the house at night. It was an interesting process but as far as I remember the heat transfer was not that much and really didn't improve the CdS panels efficiency.

[live4soccer7]

It seems I can get the panels at about .50 a watt. Then installation, inverters, etc.... If I went with 72 cell mono it is still about .50/watt on the panels. I can get them around 310watts in this configuration.

If I went with a 20kW system, that would come out to be about 65 panels. Speaking with the manufacturers, the higher cap panels aren't anymore expensive. That seems to be a marketing thing over here to get more $$$. There is a small price difference between the mono and poly/multi and that seems to be about a .02. I think I'd rather go with the larger panels if using a Solar Edge inverter system with the optimizers since the less optimizers needed then the less $$ in the inverter system.

The panels for that would be approximately $10k
Solar Edge Inverters (2 x 10kW): $3800 (haven't shopped around for prices on these)
Solar Edge Optimizers P400 (65 @ 79 each): $5135 (haven't shopped around for prices on these)
Install Materials, home made mounting system for ground, trenches, meters, inspection (just throwing a number out there, might not be realistic): $3000

It looks like the total would be around $22k, a little more than a dollar a watt. I'm sure it would end up being closer to $25k as there are always more expenses than one would think. That would come out to be about $1.25/watt

PV watts says the system would generate about 25,000 kWh annually with a savings on utilities of almost 1800 a year.

As a rough estimate, if I took $25,000/$1800 then the payback would be a little less than 14yrs. This assumes that the price of electricity stayed the same and everything performed well.

With the incentive program (Fed): $25,000 x .30 = $7500 (no other incentives available to me)
25,000-7500=17,500
New payback time would be: $17,500/1800 = 9.72yrs.

I can build up to a 25kW system before I need additional approval and probably a different grid tie in setup.


I see a lot of the solar panels have a 25yr warranty, what is the typical lifetime of a panel? 30yrs, 50yrs, etc...?

One of my questions that I can't find a clear cut answer to is whether I can build 10kW system one year, get the incentive, add more the next year and then take more incentive on the addition.


Thoughts? Not worth it still?

[J.P.M.]

Thoughts? Not worth it still?

Since you ask, One, and, it depends.

In a comparison of alternatives type analysis, various ways to invest the assets according to your lifestyle and needs in order to estimate which of those alternatives is the best fit in balancing your lifestyle and guessing (really) which of those alternate investments will have the greatest return. For example, instead of solar, I could put the money in a long term bond ETF or a bond fund, get about a 3% return at this time, maybe more (or less) in the future. Regardless of the return, I'd have some reasonable (according to my risk profile only) assurance of preserving capital and relatively quick access to the asset if needed. To offset that, there's any future electric rate changes to consider - those may go up or down, just like bond returns - and the long, but still limited array life, as well as some maint. costs to consider and as many other things as deemed important.

That's just one possible alternative investment of many possible alternatives. There are lots of others, and as many ways to assign value to the non financial considerations as there are people to look at the situation. It's all part of life cycle costing and process economics.

Solar's great stuff, but it may or may not be the best use of assets. Do your homework. Pay your money and take your choice.

[live4soccer7]

Well thank you very much for you input! Perhaps I'll end up doing something like that. I've already got my hands in investments of different sorts. I kind of liked the idea of solar and being able to produce most/all of my own power. Kind of a self sufficient type of feeling, not to mention it uses clean energy, and is now cost effective.

[live4soccer7]

I might just end up waiting until 2018 and do an install over the last two years of the federal incentive program. The benefits will be the same still and I'm sure solar prices will be down that much further and the tech will be even better.