Solar Water Heater

Cost is always a big parameter.

Cost of:

1) Consultation

2) Design

3) Equipment

4) Installation

5) Loss of business while installing

6) Periodic and annual maintenance

7) Loss of business while maintaining and/or repairing

8) Etc

With so many questions to answer, you would do best to consult face-to-face with an adequately qualified engineering firm rather than to obtain opinions based on a three or four sentence request.

BD touched on some of the major costs. A drawing of the existing HW system would be helpful, so we have an idea of what your wanting to do. My questions to you is, (1) Is this HW system used for Domestic or is it for HVAC? (2) How is your existing system plumbed, individual rooms, central or is it by groups of rooms? Plumbing into the existing HW system is going to be cheaper.

That would depend on how closely placed together the bathrooms/kitchenettes are.

If they are too widely separated the time for hot water to flow to the furthest units and the associated waste of water could be a downer both for the owner and his customers.

Distributed smaller thermo-siphon units may be a better alternative - perhaps one per two to four units. There are many factors to consider .....

Right - 110 units would indicate a hotel like complex.

Consider all the factors and then most likely the firm doing the engineering is going to specify a central system.

In a hotel people expect hot water when they turn on the faucet.

Central systems usually involve a loop with circulator to make sure the hot water is "right there" or at least fairly close.

We did both already. One system is avg too big for only one room. Both can work, the choice depends on many factors, earlier summarized by fellow members. You will need to hook in the existing plumbing. The collective system will probably be easier to install and also cheaper. We only work with Megasun (Greece) that comes with a closed system - the water you consume doesn't run through the panels. A heat exchanger is used.

Thanks for the help guys. Its a new project so there is no existing plumbing. I have to propose an appealing and cost effective quote for my client. Keep you posted.

I would go for a large solar collector and central tank, feeding out to the rooms just as from a regular hot water tank. Two temperature sensors, A in the tank and B near the outlet of the collector, could control a pump; running the pump whenever B > A.

That's just the basics; there might need to be some further control scheme if the water gets too hot. Also an electric or fuel-fired "instant heater" if the solar input is too low.

How about some information? Location, roof space, mainly. Solar hot water is almost always cheaper in the medium run, but be careful of liars. Ask questions and insist on hard figures. Copper is very expensive now. The Chinese are making some serious collectors. Mainly you'll need a much bigger tanks and some runs of insulated pipe. Do you use a circulating hot water system to give instant hot water? Payback for the typical large installation can be as low as three years.

I gave you a good answer.

I can give you solutions that work, and have been implemented in the Caribbean.

Somewhere else, different factors have to be taken into account.

I will slightly revise what I said earlier. You may consider some system zoning or a few smaller systems. It would come out in further detailed engineering, but it really depends how many collectors you can put on one loop, tank sizes for space allotment, thermal gradients with storage of large volumes, etc. You may want to look at some high efficiency boilers, i.e. Munchkin or similar along with possible on-demand heaters. On- demands in these systems can be a bit tricky and have some nuances which we have found installing some jobs with these, but may be a possible part of the solution. Paybacks are really dependent on state and if you have the opportunity for solar thermal renewable energy credits. One other consideration is the structural load on your roof if that is the ideal installation location. You may require additional structural beef-up. Just some more thoughts, I hope they help.

If you have a clean sheet of paper for the whole project, maybe your collectors can become exterior design features, saving money on cladding. Personally, I collect hot air, and then use an exchanger, so that any leaks are localized, or invisible, and freezing is not a problem. I can use the excess as hot air in my situation, though, most of the time, which also argues for air collectors.

Plan to be able to build in maybe 40% extra capacity, and advertise healthy, guilt-free bathing. Even people not usually sensitive to such things notice that solar-heated water just feels better. Spa-type features pay for themselves in many markets.

Hi there

My good buddy is an expert on Solar water system and hold the patent on a advance system . Please look into his web site . www.microsolar.com.my. His name is Teoh and his solar is evaluated by me on a field study of 7 branded system and is proven to be the most efficient and cost effective of the lot.

Good luck.

Steven Chew

No wonder he is your good friend, and/or vice versa. (The link didn't work.)

If you want to learn , then go and read up his web site. He was voted as one of those Hero of the

World by TIME magazine some time back for his system.

Oph.... the site is www.microsolarsystem.com.my

I already tried, but as I said before, the link didn't work. (Even when I took the .my off the end, the site I got didn't tell much, though the graphics were purty.)

You seem to be somewhat familiar with this system, so why not describe it informatively?

just check his site, its www.microsolarsystem.com

sorry about the .my

There are good details of History,development of Multivalves, comparitives system drawings and etc

email address.

Better get it from the horse itself.

Interesting; that was different from the other site that I got by dropping of the .my extension.

Similar layouts have been seen in the "Cricket" system, and other vacuum tube systems.

If you pick one of the Price List options, you don't get a price list. Instead, you get a "contact factory" message. Why not publish an actual price list, subject to the understanding that prices may change later?

It looks as though there are two "multivalves" per tube, but I didn't find any details of what they do or how they work.

This sounded like hype/blather to me, and was unimpressive; but I suppose that's what one gets directly from a horse.

i think its business sense.

But drop him a mail for details and catalogs which I do have one and its very very detail in researchs findings.

Like I say, speak to the horse. Not his Pic.

Not if he wants my business.

Are you just stringing me along, or what?

If you want to learn about Solar Heating and its progress to hybrid system and improvement till now , then email him. He dont charge to give his life researches and infact he will welcome your contributions for his quest for better improvement to the world. By the way he dont need your business. We talk Science here. Bye

Oh, really. You haven't talked any science yet--no numbers, no data, no principles, no operational descriptions, no answers to questions. You call that "Science"?

After going through the www.microsolarsystem.com ,you don't get science there, you don't get numbers,data ,principles,no operational descriptions????

and you want answers when you haven't even pose any question!!!!. When asked to email to the Horse who can enlightened you ; you talk of stringing ....Good Luck

I am hoping that the originator who seek guidance on solar panel for his project refer to the www and get his knowledge and FREE advice.

Done.

Now you have so many good questions, so sent him all this you have just written and he will englightened you . His email address is there for you . You will be blessed with his research and knowledge and he hold the Patent , not me.

As the subject matter is so academic , it will be too long for this page. Email him.

Sure ,you could tell Mr Teoh that i state that he does not need your business.i offered him Millions for his Patent rights years ago but he prefer to developed further and not sell.

That's all.

In our multi block residential enclave, Microsolar heaters are installed two sets in each block. I think this is more suitable system then installing a huge one for whole complex or a small system for individual flat. Selecting size suitable for 8 to 10 rooms should be good enough. Two systems can be further interconnected to have supply in case of maintenance of other system.

Like any system, generally it is better to have a central unit and just transport the water to each room, but depending where you are located, insulation and a recirculation line maybe needed, to maintain the efficiency of the installation.

Your usage is going to be very variable depending on occupancy , the size of your tank or tanks is going to depend on this usage. Efficiency wise one large tank will retain the heat better than a lot of smaller tanks.Also cheaper than a lot of smaller tanks.

The other problem is if you have a spell of cloudy weather bringing the heat up electrically in a large tank consumes a lot of power and consider only a small part of that water would be used with low occupancy so it is wasted power.

the best way although with some increase in cost would be to arrange an instantaneous gas heater in line for say each 4 or 6 units the heater only has to bring the solar water up to a set temperature say 45 Deg C. this is efficient as it only heats the amount of water required. if the water coming from the solar tank is higher than this the gas heater does not cut in. also being close to the units the hot water is quickly available saving waste of water

Your decisions how large a tank and lots of massive insulation.

When first viewing this topic, I would not have anticipated so many responses and to the depth that is being provided. CR4 is really responding.

However, I've not seen any replies yet from the originator TIShot and what he thinks of all this feedback.

BDThompson, i have been reading everything, and I appreciate the responses ive been getting . I have been able to get in touch with some manufacturers and suppliers and have begun to gather the information i need.

thumbs up to CR4.

for those who wanna know, climate is savanna. the project is to be in northern nigeria. conserving the heat generated is not so important as the amount of sunlight and heat available all year round is massive.

like i said earlier, thanks to all

i would use the btu rating of the solar panels vs. the the btus needed. climate in the area will be a major concern. consult different manufactures on specifics.

Instead of capturing the heat directly from the sun, how about indirectly capturing the heat after the sun warms the building?

Your air conditioning system is dumping cudzillions of BTU's into the air. If you install a heat exchanger, the AC system heats the water, and the water system makes the AC operate much more efficient. Additionally the AC works during the night so will continue to heat water after the sun goes down.

Not a bad idea to pre-warm water returning from your heat exchanger, if it is exiting cool enough to take heat from the AC system.

Drew K

You are talking about very low differential temperatures here.

That in turn means large exchangers - outside of being good for getting invites to green parties the idea won't fly.

My last post was incorrect - I was thinking about the air temperature not the refrigerant temperature.

That would work - actually it is done in some ASHP and GSHP units.

Friends,

The idea of drawing the energy for the hot water from the hot side of the AC loop is very good. This reminds me that the entire structure and its various systems should be looked at from a perspective of energy flows and energy needs. Solar collectors for DHW are a good item, but they are not the only source of energy, as the previous post has reminded us. Also, a 30+ year-old dictum is still valid today--spend as much on conservation as you spend on solar.

--John M.

One technology that has been proven out, that may be a viable alternative and very cost effective, is using the engineered "Solar Wall" by Conserval engineering or equal. They have Solar duct etc as well. Basically, this system uses dark perforated metal, that heats the air behind it, which is then used to economize, the AHU units. There is a bypass for summer. It is an engineered system. It can integrate with the Facade, or be put on the roof. It's worth looking up. Good luck.