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The Other Solar: Solar Water Heating

By Eric Paul
April 7, 2011   |   34 Comments

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34 Reader Comments
Comment
1 of 34
April 7, 2011
Eric, you're right on everything except one thing. Solar water heating has been around since the first drop of water existed on earth. Making people realize that even our vast oceans are heated mostly through solar radiation would probably help to push the SHW revolution further and faster.
Comment
2 of 34
April 7, 2011
Solar water heating continuing to get accepted in the SREC marketplace will help the technology's further adoption as well.

http://heattab.blogspot.com/2011/04/why-srecs-work-for-solar-water-heaters.html
Comment
3 of 34
April 7, 2011
Eric,

This is interesting, but because the commercial solar water heating market has lacked a consistent presence in the industry news, I think it is challenging for people to understand the dollar value of the opportunity here. For instance, what are the average costs of systems installed per MWth offset? What is the average LCOE of solar thermal technologies in different market segments?

People involved in solar PV have seen years worth of press releases about project costs and there is a lot of data available to quantify the market opportunity from several different research and consulting firms.

It is not clear to me from the toplevel analysis of your report whether your firm has put a dollar value on the market opportunity for industry growth in the next 1-5 years.
Comment
4 of 34
April 7, 2011
Hi Pamela,

It is true that for many customers grasping the value of a SWH may be difficult especially since water heating costs aren't always as obvious as electricity costs. Typically, we have seen LCOE figures ranging from 4 to 8 cents/kwh, but it is very dependent on the type of system and location.

In our report, we focused on the overall market opportunity and also defined the trends driving the market without putting a large emphasis on forecasts or projections. We are saving that for a future report.
Comment
5 of 34
April 7, 2011
I agree with all of the comments made by Clee. I arrived at the same conclusion. To be viable solar thermal for the home must heat not only the water, but the home as well and it must have thermal storage. Who wants to wait for the sun to be up for several hours before you can have a hot shower! The other major obstacle is the price/payback period. Solve those problems and solar thermal will sell based on it's own merits. PV works even with it's lower efficiency because the grid serves as the storage medium.
Comment
6 of 34
April 7, 2011
Very good post.


Solar Thermal systems are the simplest way of utilising abundant solar energy available.

There are records of solar collectors in the United States dating back to before 1900comprising a black-painted tank mounted on a roof. In 1896 Clarence Kemp of Baltimore, USA enclosed a tank in a wooden box, thus creating the first 'batch water heater' as they are known today. Although flat-plate collectors for solar water heating were used in Florida and Southern California in the 1920s there was a surge of interest in solar heating in North America after 1960, but specially after the 1973 oil crisis.

Hot water heated by the sun is used in many ways. While perhaps best known in a residential setting to provide hot domestic water, solar hot water also has industrial applications, e.g. to generate electricity. Designs suitable for hot climates can be much simpler and cheaper, and can be considered an appropriate technology for these places. The global solar thermal market is dominated by China, Europe, Japan and India.

When Solar water heating is so simple how is it that many sunbelt countries are not using it widely. The reasons are social and cultural besides technical. In Japan there are about 6 million solar water heaters even though Japan has moderate sunshine. Yhe reason is that Japanese have the habit of taking bath in the evening and as such the solar water heaters does not require overnight storage.

The innovative way of using PV for heating water is in parallel of using wind pumps through electrical routing.

I designed a mobile,vertical and cylindrical solar water heater with omni directional concentrator which costs around US$150(100 litres in South India).

Dr.A.Jagadeesh Nellore(AP),India
E-mail: anumakonda.jagadeesh@gmail.com
Comment
7 of 34
April 8, 2011
Clee, using data maps to design a system is just that, a tool to design and give some sort of assignment of numbers to work with. It does not truly give you real results. So basing an opiniion of using SHW using these numbers is not a real reality.
Every SHW system I have worked on or installed has created payback in around 5 years. Sometines less when rebates are considered. Maybe your situation is not suitable for SHW. Is there only one person in the household of whom likes to take their showers early in the morning and does all their laundry on cloudy, rainy days. Of course a SHW sytem used in this manner will take many more years to get a paybck. Same thing applies to PV. If I only use one lamp in my house with a 20 Watt bulb, it's going to take much longer for a payback.
Knowing how to properly use any system is the key. Do you run your furnace in the middle of July? Do you turn on all the lights at midday? Do you let your car idle overnight while your asleep?
Now think of a family of 4 or more with teenagers taking showers and doing laundry every day and do the math.
Comment
8 of 34
April 8, 2011
Hi:

Wow, so many misconceptions about SDHW in one post....
This should not be the case in 2011....
I will not go point by point, but, using ROI as a do or do not is a fools path. If you can afford it, you should do it, assuming you have the orientation and access to the sun. Looking 10 or 15 years out at the price of any conventional fuel..??.. Give me a break... But dollars aside, it is the right way to generate energy. Period. The system over its life will create hundreds of times the energy it took to mfg it, without any pollution or environmental harm, and that is the "real deal" in a nut shell.

.....Bill
Comment
9 of 34
April 8, 2011
To all commenters: Please note that this post is about commercial water heating and not residential. The value proposition for solar water heating or process heat is orders of magnitude better than on a residential scale. The usage is much higher and price tiers for energy to offset are very different.

Clee points out something very important about residential SDHW- if you are a natural gas user, the value proposition is not there yet. I've run numbers on many SDHW systems I designed- the natural gas users just didn't pen up to a wise investment. Those who will reap the most reward from SDHW at their home at current costs of energy are those who heat their water with electricity or heating oil.
Comment
10 of 34
April 8, 2011
Commercial or residential, the calculations are the same. Does the sun shine hotter because it is shinning on a commercial roof? Do the properties of water change between residential and commercial plumbing? Do the rules of thermodynamics and heat transfer apply differently for each?
Maybe it's the economics, or the money that has the real problem and that's what should be investigated, and to say that SHW is better for one and not the other is just.......and just running numbers doesn't mean squat, unless you can magically tell how many btu's are going to shine each day from your crystal ball.....
Comment
11 of 34
April 8, 2011
Commercial thermal is a great value proposition because there is huge demand for hot water at institutions like hospitals, nursing homes, food-related industries. That's an opportunity for huge savings and investment return, which is what these facilities managers care about.

Yes, Thomas, it's the economics. Follow the money.
Comment
12 of 34
April 8, 2011
So Pam, are you suggesting that homeowners do not want to save money and that commercial systems are the only value? Maybe if money is all you're concerned with, you should get out of the solar business and try banking or politics where money makes sooooo much more sense.
Comment
13 of 34
April 8, 2011
Hi Thomas, let's be civil now. For residential, it pens out much more favorably when offsetting electricity or heating oil, like I said. Clee already pointed out the problem of it penning out for much cheaper natural gas use. I don't think I need to explain my viewpoint any further.
Comment
14 of 34
April 9, 2011
Hi Thomas:

You too are wasting your breath. Allot of these people want to follow the money bus, period. That determines their course of action. Whats worse, is they use ROI as the rule of measure. They have bought into the conventional's game as many people out there have. Their lack of vision will not be exposed to them from some blog site. It will have to come from mother nature unfortunately, and maybe not even then.
But I know how you feel, the urge to try and open their eyes is very compelling....

.....Bill
Comment
15 of 34
April 9, 2011
The technology involved in solar waters whether it be for your commercial business or home use. Solar water heaters works in conjunction with your existing water heater. It works on the premises of; the hotter the incoming water, the less power needed to bring the water temperature up to the desired level. Using this type of system can offset the emission of carbon dioxide; that would have been used, to provide the commercial electricity to heat the water.
Comment
16 of 34
April 9, 2011
Hi:

"If you think that ROI is unimportant, and that it is worth $4000 to reduce global CO2 emissions by 150 therms of natural gas per year, then send me $4000 of your hard-earned money, and I will have a solar hot water system installed on my roof. "

Why would I send you money for anything??? I take my hard earned money and put it towards my goal of being a net electrical energy producer. That goal will be reached in the next 5 years. I will produce enough energy through wind and PV to not only power my house and business but power one EV as well. And I AM NOT DOING IT BECAUSE OF ANY ROI!!! I am doing it because it is the right thing to do and for the energy independence.
If NG was 3 times as expensive as it is now, you would be the first one to jump on the SDHW wagon even though it would still displace only (by your number) 150 therms worth of created CO2. You choose by money and yet try to negatively dismiss by emissions, but would flip flop given a high enough NG price. Logically, you can not have it both ways!!

"If every SHW system that Thomas Mayrand has worked on or installed has created payback in around 5 years, that suggests to me that the typical customer will decline to have a SHW system worked on or installed if it will require a payback of more than 5 years and that perhaps I'm more the exception in that I'd accept a longer 10 year payback."

You are probably correct, and there EXACTLY is the problem. Everyone is playing their game, including you....

.....Bill
Comment
17 of 34
April 9, 2011
Thanks Bill, the worst part is the fact that people who do not have a system, or have had a bad experience trying to install a system, make arguements against it. All my customers love their systems. A lot of them are installs from back in the 70's that they want to keep going because it works.
Comment
18 of 34
April 11, 2011
Bill, did you read the article I wrote back in March outlining the topline results of SolarTech's study of consumer attitudes about solar? Here it is: http://www.renewableenergyworld.com/rea/blog/post/2011/03/hot-showers-and-cold-beer-solartech-study-findings-on-consumer-attitudes-about-solar

These results reflect the concerns of the demographic that is involved in the purchase of PV: price, reliability, warranty, customer service, incentives. Bill, Clee represents the predominant attitude amongst solar consumers. If we as an industry are going to limit ourselves to only selling solar to people who want to do the right thing, who are doing it for carbon offset/being green or other unquantifiable reasons, we are going to have trouble growing into mass market adoption.

There is nothing wrong with selling solar to people who are concerned with energy independence- they are out there. But if we try to shoehorn all buyers into that message, we will find people turning themselves away because they don't fit that ideological profile. That's just a shame.

Natural gas prices are extremely volatile and micro-regional in terms of costs. However, they have consistently been below the cost of oil and electricity.

The Prius took off because gasoline costs were high, but it became popular because it offered a new and better driving paradigm that outlasted the last gasoline price spike. Solar needs to take a page from that book.
Comment
19 of 34
April 11, 2011
Right now, it is difficult to make a short term ROI case for SWH in many residential systems, with the exception of perhaps Hawaii, where it's not only the law for new construction, but there IS a fast ROI, since imported fuel costs there are so high.

But as Eric points out, commercial is another matter and sees a faster return, especially with all of the extra subsidies and tax incentives. California's CSI Thermal program is already increasing commercial sales and projects for my client, Free Hot Water, and commercial systems OUTSIDE of California -- with little or NO subsidies except 30% ITC -- are also seeing an uptick. Residential, on the other hand... much less so.

For those who'd like to make some quick comparisons, check out this solar thermal calculator and you can compare retail costs and ROI for either commercial or residential: http://www.freehotwater.com/SolarThermalCalculator.html

As usual, Europe and China are well ahead of the curve with SWH due to their lack of domestic fossil fuels. Unless gas prices shoot up --very doubtful given the politics-- I think commercial and perhaps solar pool heating will see the most growth over the next few years.

One solution, as suggested above, are residential solar thermal systems for space heating/cooling/and hot water. These systems are of course expensive, but will be offsetting the most expensive types of energy during summer and winter, thus having a faster ROI.

Great info and discussion, as always!
Comment
20 of 34
April 11, 2011
The ROI discussion regarding PV vs SWH seems to be missing a key element. For the amount of usable energy delivered to a building (residential or commercial), SWH is a fraction the cost of PV and takes up a fraction of the space for the same amount of energy. While SWH only handles a particular energy load, it's an energy load that is consistent and significant for every home and mostly definitely not best met with PV.

The most common way for PV systems to outperform SWH systems with respect to ROI is because SRECs play a role. That was the point of my previous comment (#2)--SWH should be credited as an SREC generation technology across the country. This would level the playing field in the solar world and give the more efficient technology a fair shake at the applications it is best suited for. PV will continue to grow in this environment and our buildings will move even closer to net zero energy.

In football, you can't call a team the better one if it starts with a 30 point lead and 6 more players on the field at the opening kick-off.
Comment
21 of 34
April 11, 2011
Hi Pam:

Yes I read it before.... you seem to misunderstand my point of reference...

"If we as an industry are going to limit ourselves to only selling solar to people who want to do the right thing, who are doing it for carbon offset/being green or other unquantifiable reasons, we are going to have trouble growing into mass market adoption."

Why should we limit????? By always talking and promoting only ROI, it is you who are limiting the market. If all you ever spend any time with is ROI, then the market will only care about ROI.... That is how you move a market into wanting only what you feed them... and ROI is in the interests of the conventionals, hell, they have to hammer on that because what else do they have going for them??? Nothing!! The use of their product destroys everything!!! Can't go around promoting that can you...

"unquantifiable reasons"

UNQUANTIFIABLE!!! Air pollution, aquifers polluted (fracking etc.), planetary fresh water decreasing, massive warming of the planet, planetary storm systems intensifying greatly, the whole Nuclear problem in its entirety, destroying of habitable land, etc.., etc.. the list is endless... these situations are not fantasy. They are impacting real people, real flesh and blood... this destruction is no longer limited to third world poor people.. it is happening to us... and soon to you...

Why are you so eager to use the weapons supplied by the enemy???

.....Bill
Comment
22 of 34
April 11, 2011
Unfortunately Bill, when given the choice most people choose the less costly path over the better for the environment path. That is how we got in the mess in the first place. So if we choose to limit the market, and I do mean limited to a small number of peopel, to only those people willing to pay more for a product because it is good for the planet then we will have a very small market of folks who will buy solar. We are not talking about spending a dollar more for an organic peach here, we are talking about tens of thousands of up front dollars.

I agree with you that people should be doing things because they are right and because they protect the future, but I am realistic enough to know that most people will not do these things if they cost more than the alternative. So I say go after the conventional people with the tools of the conventional market. Let's beat the conventional energy marketers at their own game with their own tools.
Comment
23 of 34
April 12, 2011
Solar water heating as many others have said has a far better return on investment for commercial systems than domestic systems.

1. Commercial systems require substantially less labor and related costs to plan,deliver and install per square meter installed than domestic systems.

2. When an organisation is installing many collectors - possibly hundreds at each of many sites, they will get a substantial discount on the collectors, and the installers will accept a smaller margin for the large amount of work such a contract represents.

3. In a commercial system, it is very likely that nearly all the solar heat collected will be useful whereas with a domestic system, in summer more heat will be available to collect that gets used, and when the family go away for holidays, no heat gets used.

4. If you want to incorporate storage, the larger the system the better as large tanks hold heat better than small ones due to area to volume ratio, and greater cost effectiveness in increasing the insulation. Large tanks are also less expensive per volume stored.

5. For very large systems such as those supplying district heating to whole cities the system can be combined with ground source heat pumps with multiple boreholes to provide inter-seasonal heat storage.
Comment
24 of 34
April 12, 2011
Hi MP:

"Unfortunately Bill, when given the choice most people choose the less costly path over the better for the environment path. That is how we got in the mess in the first place."

I agree with YOU 100% here!!!

The point you seem to miss, or are ignoring for whatever reason, is that this did not happen by accident!! Specifically, caring about the money, first and foremost regardless.
That was promoted by the conventional industries as what you should only care about, coupled with most importantly, a mis- information and lying campaign on the real impacts of their products. This is TODAY, STILL, where they spend a huge amount of their money. Why??, because they know if they can get the people to believe lies about what is truly happening, or at the very least remain confused, they win... if they fail and people by the numbers start to see the truth about the real consequences, the people flee those choices faster than a jack rabbit!!
This fact is most observed when a disaster occurs. Whether its an oil spill, melt down, oil fire, water polluted, etc.. its really not fear by itself that drives the opinion change. It is an awaking to the truth, of that energy choice's ramifications. Then the conventionals re-double their efforts to say they have "fixed" the situation and it won't happen again, blah, blah, blah.... Not to eliminate the fear so much, but to try and transform the "MARKETING IMAGE" back to "we are safe and clean for the planet", plus we make jobs, etc...
The whole thing plays like a bad worn out broken record.

Maybe as sales and marketing people, you feel it is not your job to transform a market, only to play to it?? My response to that is, the conventionals do not think so....

.....Bill
Comment
25 of 34
April 12, 2011
There are some really good comments here along with some that truly "suck" due to lack of knowledge.(More polite than ignorance)

I could not help but notice, out of all these fine comments not once was there any mention of "independence." Should a terrorist do away with you power provider, and your kid says,"Dad, why don't we have hot water?" Will your answer be:" Well son the ROI on a solar water heater wasn't to my satisfaction, plus the system took 8 years to "pay for itself" and not 6 years like I wanted."

My personal goal is to have a home with 100% "Point Of Use" power. The first most logical step to reach such a goal is to install a solar water heater,especially if you now have an electric water heater. Having installed over 300 such systems in the early eighties, I know first hand how good it feels for a consumer to have paid for a device that provides him free energy.

I love PV but where is your independence at night, unless you have spent thousands of dollars for storage. Don't forget that lots of thermal energy can be stored in a home with a 120 gallon water heater.

Along with independence, we need extreme promotion of solar water heaters to avoid building nuclear plants.China has installed enough solar water heaters, that they can do without FORTY nuclear plants.( Can you possibly imagine how much dangerous, radioactive waste they have avoided by such an action?)On the other hand, We can just "pass along" the cost to securly guard the radioactive waste that produced our electricity. The huge monopolistic power brokers, who control our lifestyle (and budgets) very seldom recommend solar water heaters. Thermal solar is more of an immediate threat to their income than photovoltaics.

You live with your ROI,IRR, Cap Rate, etc, I'll take independence and how good it will feel having those damn unsightly, unreliable, wires removed from my home.

Jim Lindsey, Solar Pioneer,--solarplexusco.com
Comment
26 of 34
April 12, 2011
Is not CSP a form of water heating?
Comment
27 of 34
April 12, 2011
Hi:

#30... please note my comment #20..

"...OF ANY ROI!!! I am doing it because it is the right thing to do and for the energy independence."

Just an FYI for you...

.....Bill
Comment
28 of 34
April 12, 2011
Bill:
Your comments were a joy to read, as were some others.
Are you on linkedin?
Jim Lindsey
Comment
29 of 34
April 12, 2011
Hi:

I don't know... maybe.. LOL..
I don't go much for those types of sites..
I think in fact there should be a $100 federal fine for using the "T" or "FB" word!! LOL... All proceeds to benefit RE!!.
I have my own website, which to me, renders the other types of comm pointless..
I think I was just in I.T. too long, and I don't see the appeal the same way newbies do... using an, at most 3" x 4" I.O. interface to manage your daily life seems really skimpy to say the least...

.....Bill
Comment
30 of 34
April 12, 2011
Good thread. Solar thermal needs more understanding. It returns more watts power per dollar invested than PV. That high use services haven't moved more on this is confusing. There seems to be little trust and allot of politics. I also feel the intervention of SRCC is a redundant and expensive test recorder that benefits large companies. It makes SHW more expensive! Not better. Almost all collectors are already tested and quality assured in many ways, internationally.

Also about industrial NG users. They get preferential pricing for using larger quantities. This is hardly beneficial for resource use and fuel efficiency.

I also encourage self installing of systems. I help people to do it themselves. Current collectors and pump/control kits are simple to install.
An entire home can be heated with solar heated water too. Yes, it costs more, but the load it offsets merits the investment. Imagine; a fuel-less heating system without a costly heat pump. Unfortunately a backup source is still needed, but many conventional means can be employed for that.
Botom line is that the "Solar Sweetlife" is practical and attainable.
Comment
31 of 34
April 13, 2011
Hey Everyone,

This is a great article and I really love reading through everyones comments. I agree with the majority of folks in the comments section about how this shouldn't be about ROI and it should be more about the sustainability factor and the overall carbon footprint.

I also agree with the article itself that commercial sites are really missing out on an opportunity to reduce their carbon footprint, save some money and a big selling point for commercial customers is the marketing factor. Everyone wants to "shop" with companies that are thinking about our future.

I am also writing here to mention something that is very close to this article. I work for a company in Seattle that does installations of solar hot water systems on commercial locations. We just got done installing an 8 collector evacuated tube system on our 3rd school here in Seattle. Along with the installation of the solar, they also installed new, high efficient boilers, approximately 20% more efficient than the ones they were using. With the solar and new boilers combined the school is looking to save close to $15,000 per year!

Along with the savings, we are also providing them with a curriculum that the school can use to teach the kids about what the solar energy is providing them.

I guess what I am trying to get to is that it is possible to cater to both the "ROI only" person and the "Green, Green, Green" person as well. Solar hot water alone takes time to payoff, but if you mix it with high efficient new technology you save money and you are drastically reducing your carbon footprint.

You can see a press release about it here if you would like:

http://www.renewableenergyworld.com/rea/partner/net-zero-impact/news/article/2011/04/two-more-parishes-go-green-with-net-zero-impact-technology

Thanks,

NZI
Comment
32 of 34
April 15, 2011
37 I have been licensed in insurance for several decades. When I educated myself enough to know that ALL insurance is some type of term insurance.

Anyway: My presentation was like this: "There are 3 things we must have food,clothing,shelter and should you die you need to leave your family funds to buy the "basic three."
I should have said, "the basic 4, due to energy."

Your comment seems like you do not have a family, for once you have little ones to care for, your life does change.
It also seems you don't need any independence and you have your little solar shower, so it is likely you are already one happy camper.
Others, like most here, are wanting to make the world a better place for ourselves or at least our decendants.

One thing that should help you rest easy: I've never seen independence pushed on anyone but quite the opposite.
Comment
33 of 34
April 18, 2011
The economics of solar water heating, without incentives, particularly when offsetting natural gas, are no worse than the economics of grid-connected PV without even larger incentives (federal, state, net metering, FITs, etc). The unfortunate reality is that without incentives or government mandates, no major markets for either technology are likely to develop in the presence of subsidized non-renewables. And unfortunately for small-scale SWH in particular, tax-based incentives tend to favor larger systems and more expensive technologies, for a number of reasons.
Comment
34 of 34
October 19, 2011
C Lee,

I have read a few of your comments. Agree with some, not so much with others. I have been working past 2 years to create a new line for SWH for both residential and commercial that are affordable. I think you do your math pretty dead on, so I want your opinion on quality v. affordability.
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Eric Paul

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