Commercial Solar Water Heaters ?

While in Spain and Isreal it seems that everyone uses solar-water heaters, here in California, there seems to be very little commercial activity, and painfully few solar water collectors on roofs.
With solar water heating being such an obvious way to save energy cost, I've been very surprized to find that solar water heating seems to be still in the almost build-it-from-scratch do-it-yourself projects phase.
Anyone knows where you can simply buy a 'package' for a typical direct pumped system, with solar collector, some insulated piping, pump, valves, control unit and optionally a standard (gas-powered) water-heater (if you cannot use the existing heater)....
This seems something that should be available at Home Depot....
Quick calculation of my own (average home) water-heating cost, solar water heating should save me $300/year easily. If I can buy the ready-to-install hardware for $1000 or less, I will get my investment back in just a few years. Or would commencial systems be more expensive than that ?
I have gas-powered water heater. Electric water-heater users should save much more. And for apartment buildings, with more water users in a single building, there would probably be much more potential for saving energy cost.
Where is the commercial activity ?
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Rob Dekker (in NttRe.1332$ snipped-for-privacy@newssvr22.news.prodigy.net) said:
| Quick calculation of my own (average home) water-heating cost, | solar water heating should save me $300/year easily. If I can | buy the ready-to-install hardware for $1000 or less, I will get | my investment back in just a few years. | Or would commencial systems be more expensive than that ?
| Where is the commercial activity ?
Rob...
I'm manufacturing passive solar heating panels and have designed, built, and tested /one/ prototype DHW system I considered good enough to take to market. That's not much of an experience base, but enough for me to develop some numbers.
A commercial high-quality (efficient, long-life, reliable) DHW system including the associated pumps and control subsystem suitable for installation in the upper midwest is likely to cost in excess of $2K - which I decided was more than most homeowners would be willing to fork over.
There's an additional "fly in the ointment" in that once such a system is sold and installed, it's (currently) extremely difficult to find anyone to provide after-sale maintenance/repair service.
-- Morris Dovey DeSoto Solar DeSoto, Iowa USA http://www.iedu.com/DeSoto/solar.html
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said:

One prototype is nice as a 'feasibility' experiment, so I have to assume that it will take you a while but sell 10 of the systems and you are a business. Then move to 100, to 1000 etc...

That's really cool ! Is that your production cost price ? Or you retail price ?
Considering that PV systems that people are installing today cost much more than that and probably create less $'s energy savings, there has to be a pretty good market for your system.
I would guess that in California (more sun-hours/day, virtually no risk of freezing) the collector could be smaller and the system simpler, and thus will be cheaper, so you might have a winner here !
Also note that the 'million solar roof initiative' is now on our Governator's desk : http://www.renewableenergyaccess.com/rea/news/story?id#711
If approved, there would be considerable rebates for buying solar systems. That would bring the price of your system down to less than $1000.- !
So the market might be ready for a good commercial system.

That probably depends on the system that you want to sell and the people you want to sell it to.
The first real market would probably be the 'self-installers'. People that know how to follow installation instructions, and know how to hold a crewdriver and would install their own stuff. People that buy water heaters at Home Depot, so to say.
It would require a fool-proof / safe-proof system though.... Easy to buy, easy to install, and self-correcting (no complicated tools, adjustements or test equipment needed).
Beyond that, a regular plumber should be able to learn how to service a simple solar heater system after in a day of training or so.... Where there is a market, service people will sprout up...

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Somehow strange that in the US this seems to be so rare...
Here in Germany it's easy to buy one, either for do-it-yourself installation, or a finished, installed system. Buy collectors, pump systems, exlectronic control, ... anything. It's more difficult to get a good heat tank, but manageable. A lot of plumbers also (at least announce that they do) know how to install and manage them. Which is fairly trivial. I had no experience at plumbing whatsoever, and I was able to install the solar circuit part myself. Experience in some details of planning and design would be an advantage (where to optimally install the heat tank, how large the system should be, etc).
Costs are higher here though, but oil also is more expensive, so it is getting cost-neutral in about 10-15 years here (faster maybe due to the rise in oil price in the last months!)... but it's always a good feeling not to need any oil (well, nearly) during summer.
I installed a relatively large system, but it can supply us with warm water for up to 4 bad weather days, which is needed here where I live :) I always compare economical systems with ecological ones, and I chose ecological (more expensive than needed, but it also saves a few percents more of oil than the other due to the layout of the system).
Christian
said:

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Having lived both in Northern Europe and in the US for 20 years each, I have some ideas about that. There are many, many factors that play a role, but the most important ones I think are the low cost of fossil fuel (low taxation of energy) in the US, and a business attitude towards solving recognized problems, rather than the more longer-term visions and of Europeans.
One thing that is important for this subject is that in the US, if there is a business opportunity, someone will jump on it. Usually big-time.

So, where do you buy this ? At the local do-it-yourself home centers, or at specialty stores ? And how much does a typical collector cost (per m^2) ? How many choices do you have (are there many companies building these panels ?)
Does the German covernment issue rebates for solar systems to end-users ? Or do they subsidize the manufacturers directly ? How much (as a %) does the government subsidize solar heating systems ?

Isn't this just a good standard water heater ? (I think they are called 'boiler' in Europe). What does the tank use as backup ? Gas-burner ? oil burner ? or electric heater element ?

Do you need a building permit before you can install your system on the roof ? Does an inspector need to sign-off on the installation ?

10-15 years for return on investment is probably too long for US customers.
Most Americans don't live in the same house for more than 7 years, and real-estate assessors do not yet recognize any value for a solar system on the roof. There is much more value in adding a bathroom (that's why US homes have so many bathrooms..:o) or an updated kitchen, or nice landscaping.
How many homes in Germany use solar water-heating ? In the face of this long investment period, it should not be that many... This might the difference in consumer attitude that I described above.

[...]
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Special stores and/or internet, usually around 140 EUR/m^2 or more. We get subventioned by about EUR105/m^2, though, so collector area is very cheap here. There are many companies building collectors, but I don't know how often they are just rebranded ones. Austria is very experienced in collectors, they offer several companies that exist longer than 10 years, which is a good thing to know. ;-) They guarantee a life-time of 10 years, some more.
I bought Austrian ones, at 360EUR for 2.6 m^2, they are "landscape" oriented, a little bit more expensive than the "portrait" ones.

Yes, by gross collector area. By the above amount (changed recently from 110 to 105 EUR). As I have 11 m^2, it was (at 110 EUR/m^2) about 1210 EUR! That is, if you have collectors of a certain quality (which they of course all fulfill), that need to be able to get a minimum of 525 W by each m^2.

Well it is a tank that has two heat exchangers. In the tank there's water from the oil heating, so not exchanged (thus no problem with lime.
The lower heat exchange is used for heating by the solar system, the upper one to heat the water for the household.
For smaller systems, the tank is filled with the water you use, and the upper heat exchange is used for the backup heating.
The heating itself (oil in my case, but could be anything that gets more than 40 C into the tank) heats up the upper 30% or so of the tank, if needed.
There are a lot of different tank systems, with "heat level" separation and such, different forms of heat exchangers, ... you choose :) - they all try to minimize convection.

Depends. Usually not, but might be for historic city centers that it is not allowed to install one as it would destroy the nice roofs.
Actually I installed it at the front of the house, just on the wall. Best to check with the local authorities whether the area the house resides has some limitations. Usually not.

No. To get the money from the government, you have to sign that it works, that's all, and to agree to let them check if needed.

Unfortunately, yes. Well look at the oil price, it becomes less time to ROI point.

I don't know numbers, but they are not very rarely to be seen.
For Austria, a study claims that there had been 1.7 million m^2 in 1997 (thus this country is leader!), which is about 4% of the homes. They expect 4 million m^2 in 2010.
Planned number for the whole European Union is 100 million m^2 up to 2010 (but I don't know if they succeed)! See http://www.aee.at/projekte/projektunterlagen/Endbericht_Thermische_Solaranlagen_fuer_Mehrfamilienhaeuser.pdf (in German).
Christian
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Thank you Christian, for all this good info.
After some more (web) checking, it seems that commercial collectors are not more expensive here in the US than they are in Germany. $300 - $400 / m^2.
There are a couple of things changing here too :
- rebates for solar energy systems starting to be a bit more common (and hopefully will hold) - increasing natural gas prices (not to mention increasing electric prices for those dumb enough to buy electric water heaters) - long-term financing for consumer products is very popular here, and could work well for solar equipment
Now all we need is more businesses that jump onto this opportunity..
But to show you what we are up against (info from my own gas/electric bill) : The base rate for (small) residential natural gas, here in California is about $1 / therm.
$1 / therm : 1 therm == 100,000 BTU == 100 ft^3 == 2830 liter == 2.83 m^3 So nat gas cost $0.35 / m^3 (28 EURct / m^3).
Electric : $0.11/kWh.
And California is one of the most expensive states. Most other people probably pay only $0.09/kWh or so. Many 'bigger' users are paying (much) lower rates.
Rob

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Sorry, the price here is 300-400 EUR for my collector, which has 2.6 m^2. I wrote "around 140 EUR/m^2", so the US is still very expensive.
I know that all these systems are not saving very much - but ecology is also an aim! If one has economy in mind, it might not be worth it, especially in the US.
Petrol is up to 1.30 EUR/liter here, which is about 5 EUR/gallon. Oil for the heating is about 70 Cts/liter. I don't know about gas - but as 1 m^3 has about the same energy as 1 liter of oil, I would expect the same, more than 2 times than the US.
One good thing to say about the New Orleans oil shock: it seems that more and more people think twice before using the car, and alternative energies become more popular...
Christian
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wrote "around 140 EUR/m^2", so the US is still very

Sorry. Isn't one Euro worth like $700 now ? Just kidding.
Any way, 140 EUR / m^2 is nice.... $150 / m^2 would be better.. Do you have a link to some providers with lower cost, good quality panels ? Here is an American provider ($259 / m^2), in full 'flashy' style folder : http://www.solarroofs.com/pdf/10-01Customer.pdf

Well, I think the time has come. Around $1000 for a 4m^2 (4 persons in a home) system, there is a real market. And we are almost there....

the same, more than 2 times than the US.
1 m^3 natural gas in Holland is now almost 50 Cts EURO retail price.

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Rob,

I don't think it will be useful for you, concerning the costs of transport or - as the internet shop I bought it from do - you might have to fetch it yourself ;-)
Very interesting that here in Germany (www.ebay.de), a lot of the offers are thermal collectors or systems (or other parts thereof), I did not find and in the US eBay (www.ebay.com), which very much reflects what we read here!
http://cgi.ebay.de/Aufdach-Solar-Kollektoren-fuer-Solaranlage-0-EUR_W0QQitemZ5997851809QQcategoryZ83800QQrdZ1QQcmdZViewItem
http://cgi.ebay.de/Marken-Solarkollektor-ECOSTAR-III-mit-315-EUR-Foerderung_W0QQitemZ5996933596QQcategoryZ83800QQrdZ1QQcmdZViewItem
http://cgi.ebay.de/Solaranlage-4-6m-300L-Wolf-Heiztechnik-TopSon-F3-Neu_W0QQitemZ5997264368QQcategoryZ30567QQrdZ1QQcmdZViewItem
and others. Maybe you find a way to translate the info (babelfish or such)?
There MUST be a market in the US...

... with only 0.866 m^2 for $259! ... with very little information about the insulation on the back (which is 6 cm rock wool or such usually), or did I overlook it? I guess there's none, so usable only in the southern part of the US or during summer time. ... no glass, but polyacrylic surface (I myself prefer glass, but I have no experience for a real comparison)
The ones I have are (I have the "Q" version for horizontal placement, but the technical data is the same):
http://www.sunfiction.de/pdf/Kollektoren/Kollektor_SFK270A.pdf (from: http://www.sunfiction.de/Datenblaetter.htm )
(see the maximum temp of 220 deg C "Stillstandstemperatur"="stagnation temperature" compared to 120 deg C of the one mentioned by the US firm- I guess that's due to the missing isolation? But at least the "absorbtivity" is the same (95%))
The manufacturer of my panels has English information: http://www.sun-master.at /
Christian
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Thanks again Christian, The "stagnation temperature" indeed says something about the quality. At least about the heat losses. You have good quality collectors there.
I found one California supplier that is in the ballpark of these prices (or actually a bit below), and also has a much more 'down-to-earth' website : Sun Ray http://www.sunraysolar.com has collectors which look to be pretty decent quality : Aluminum frame, all-copper absorbers/tubing and tempered glass covers. A 4'x10' (3.5 m^2) collector goes for $526, which is about $150/m^2. We are getting close (for my target $1000 system)...
I wonder if anyone made a web-site with all (US) commercial solar heating system providers.

http://cgi.ebay.de/Aufdach-Solar-Kollektoren-fuer-Solaranlage-0-EUR_W0QQitemZ5997851809QQcategoryZ83800QQrdZ1QQcmdZViewItem
http://cgi.ebay.de/Marken-Solarkollektor-ECOSTAR-III-mit-315-EUR-Foerderung_W0QQitemZ5996933596QQcategoryZ83800QQrdZ1QQcmdZViewItem
http://cgi.ebay.de/Solaranlage-4-6m-300L-Wolf-Heiztechnik-TopSon-F3-Neu_W0QQitemZ5997264368QQcategoryZ30567QQrdZ1QQcmdZViewItem
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Rob,

Better, but still only 1" insulation. ;-) And: does a Poly-Isocyanurate persist two decades of the temperatures that the collectors have? The max temperature of that insulation material is about 300 deg F (150 deg C) - pretty near to the stagnation temperature, or even below it for good collectors.
Christian
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[...]

I know. But I wonder how important the insulation material is. Common sense tells that the (single-pane) 3mm glass glazing should loose a lot more heat by radiation and transmission/convection than even 1/2" of good insulation material on the backside of the collector..

Mmm. Yeah, that is kind of tightly designed isn't it...

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When Gary sent me the nice solar pond water heater model he tested in Montana, I put it together in partial sun with the pump unpowered and had a meltdown :-) The 2" Styrofoam cover (under a layer of EPDM under 2 layers of polycarbonate) developed multiple 1" hills and 2" valleys.
A 2" double-foil polyiso replacement with foil-taped edges has worked fine so far. One polyiso ap engineer says it's good to at least 350 F, when the surface starts to develop cosmetic wrinkles. But I think we should replace both polycarbonate layers with greenhouse polyethylene to lower the cost and assembly complexity and stagnation temperature.
I put some polyiso on top of a toaster oven, and it deformed badly...
Nick
Don't miss this opportunity to have every solar question you ever asked answered in three different ways...
Join PE Drew Gillett and PhD Rich Komp and me for a workshop on Solar House Heating and Natural Cooling Strategies at the first Pennsylvania Renewable Energy Festival at 9 AM on Saturday September 24, 2005 near Allentown. See
http://www.paenergyfest.com/workshop-info.shtml
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snipped-for-privacy@ece.villanova.edu wrote:

Here are some additional (unintended) thermal sculptures. http://www.builditsolar.com/Experimental/pinkfoam.htm

I like polycarbonate on the outside layer for weathering, durability, impact resistance, AND the dog can't chew a hole through it to get to a warm spot (like she did on my poly film sunspace) :-)

--


Gary

www.BuildItSolar.com
  Click to see the full signature.
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That's OK too. Does your dog get to vote?
Nick
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