# Solar water heaters



## Prscptn Plmbng (Feb 15, 2011)

I've worked on a few types of solar systems and lead towards passive, but have no idea about good brands to provide, or if passive is the best setup to use. Looking for thoughts and suggestions.

Prescription Plumbing Inc 
P.O.Box 6378 
Oceanside, CA 92502


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## vinpadalino (Aug 27, 2010)

Prscptn Plmbng said:


> I've worked on a few types of solar systems and lead towards passive, but have no idea about good brands to provide, or if passive is the best setup to use. Looking for thoughts and suggestions.
> 
> Prescription Plumbing Inc
> P.O.Box 6378
> Oceanside, CA 92502


Anti freeze systems & Drain back systems.

I might get my first install this summer from a friend. If I get it, I'll use Anti freeze set up. With a 50 Gal electric water heater back up. Flat plate panels.


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## Prscptn Plmbng (Feb 15, 2011)

What makes that better than a passive system? 

My thoughts bout the antifreeze type systems are it's just more parts to go bad...


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## vinpadalino (Aug 27, 2010)

Prscptn Plmbng said:


> What makes that better than a passive system?
> 
> My thoughts bout the antifreeze type systems are it's just more parts to go bad...


I never heard of Passive system?


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## Protech (Sep 22, 2008)

The up side to passive systems is that they are mechanically more reliable. The down side is that they don't produce as much free heat and in some cases cannot regulate the heat.

Solar systems should always fit the structure and the occupants. There is no "my system is better than yours". Initial cost, solar fraction, maintenance, space usage all need to be evaluated for the particular application. 

For central and south Florida, flat plate active-direct systems work well and provide the shortest pay back periods for domestic water heating.

I have never worked in cali, But I would take a hard look at flat plate active-indirect systems. Propylene glycol systems would be my preference. The downsides are that you have to chance the heat transfer fluid every so often and the system must not leak a drop.

If you have a specific application in mind, just post it.


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## Tommy plumber (Feb 19, 2010)

vinpadalino said:


> I never heard of Passive system?


 



'Passive' means there is no re-cirulating pump(s). 

As opposed to 'active' where there is a re-circulating pump.


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## Prscptn Plmbng (Feb 15, 2011)

Protech said:


> The up side to passive systems is that they are mechanically more reliable. The down side is that they don't produce as much free heat and in some cases cannot regulate the heat.
> 
> Solar systems should always fit the structure and the occupants. There is no "my system is better than yours". Initial cost, solar fraction, maintenance, space usage all need to be evaluated for the particular application.
> 
> ...


thanks for the input, 
No specific app in mind, just looking into systems and the pros and cons of each, also what my peers are using...

I would think a tempering valve would be regulating the output temp. 

Not sure but aren't all solar setups just a pre-heater for a standard heater and to cut the workload down? Or can they work on a stand alone basis? 

I have yet to price or install one complete... I understand it's all an as per installation to determine pricing but to service a small house sized for a 40 gal tank, in a single story house with flat asphalt shingles on the roof, which setup is the most cost effective route?


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## Protech (Sep 22, 2008)

See bold



Prscptn Plmbng said:


> thanks for the input,
> No specific app in mind, just looking into systems and the pros and cons of each, also what my peers are using...
> 
> I would think a tempering valve would be regulating the output temp. *Yes, that is a good idea as solar systems can easily go out of wack and over heat.*
> ...


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## Prscptn Plmbng (Feb 15, 2011)

Protech said:


> See bold


What manufactures are choice in the solar Game?


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## Protech (Sep 22, 2008)

One that is close by and that has been in the game for a while.

try http://www.heliodyne.com/



Prscptn Plmbng said:


> What manufactures are choice in the solar Game?


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## gusty60 (Oct 21, 2008)

Prscptn Plmbng said:


> What manufactures are choice in the solar Game?


We use SunEarth. I have one and like it.


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## Protech (Sep 22, 2008)

I currently service a few sunearth systems here in central Florida. I have seen no major defects in their systems. I would not hesitate to recommend them to anyone near cali.

I like to source my stuff locally though. I like being able to walk into the factory and physically see them being made and the American workers making them.



gusty60 said:


> We use SunEarth. I have one and like it.


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## okcplum (Jul 16, 2011)

*solar water heaters*

i use a closed loop system with a flat plate collector, it provides 95% of my yearly needs and has not given me one issue in two years of running.
there seems to be a lot of companies branding systems that they do not make them selfs and charging a fortune for it.
i paid $1600 for a complete kit including the water heater with a single coil for transfer of the heat. 
i have installed glow worm, veissman, verridian and vailent systems for years and there kits are more than $3000 and the system i used is the same core of parts and wilo pump.
i have back up heat but never really use it.
closed loop is the way to go i think.
the only thing i see go down on systems is the electronics and they all come from japan.


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## Protech (Sep 22, 2008)

I guess you would have to specify which passive system you were talking about. "passive" is about the broadest term one could find in the solar lexicon.



Prscptn Plmbng said:


> What makes that better than a passive system?
> 
> My thoughts bout the antifreeze type systems are it's just more parts to go bad...


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## Protech (Sep 22, 2008)

In America, $1600 for a complete system is very low even at a contractors price from a wholesaler. Do you mind telling what system you purchased and what it included? Seems at that price you would have to be talking about a small unit sized for one person.



mark kiernan said:


> i use a closed loop system with a flat plate collector, it provides 95% of my yearly needs and has not given me one issue in two years of running.
> there seems to be a lot of companies branding systems that they do not make them selfs and charging a fortune for it.
> i paid $1600 for a complete kit including the water heater with a single coil for transfer of the heat.
> i have installed glow worm, veissman, verridian and vailent systems for years and there kits are more than $3000 and the system i used is the same core of parts and wilo pump.
> ...


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## okcplum (Jul 16, 2011)

the unit i got had the following,
1 40 gallon water heater with electric back up heat and thermostat, t&p valve and check valve.
electronic control module and lcd display.
pump housing with pump, check valve, flow meter, filling valve, expansion vessel, mounting hardwear, pressure gauge, sensors
flat plate collector with brackets (blutec coating) made in germany.
the only things that didnt come with the kit was pipe work and minor fittings to connect to existing plumbing.


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## smoldrn (Oct 4, 2010)

I've installed a couple of 'hybrid' systems here for another contractor. He used 2 evacuated tube panels on a drain back system with no antifreeze. The storage tank was 80 gal with 1 element back up which we didn't need to hook up. The reason was, we also tied in a geo thermal system into the heat exchangers in the tank, & were producing 165 degree water in the summer, & 120 in the winter. The drainback tank was just a 20 gal electric water heater.


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## Protech (Sep 22, 2008)

Must have been a small collector as you only have a 40 gallon tank.

Sounds like a very low output system (1 person system)

What kind of system are we talking here? What method of freeze protection?




mark kiernan said:


> the unit i got had the following,
> 1 40 gallon water heater with electric back up heat and thermostat, t&p valve and check valve.
> electronic control module and lcd display.
> pump housing with pump, check valve, flow meter, filling valve, expansion vessel, mounting hardwear, pressure gauge, sensors
> ...


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## Protech (Sep 22, 2008)

120 seems a bit low. How many tubes total? I would think

Are you saying you had the geo and the solar on the same loop and not on parallel loops?



smoldrn said:


> I've installed a couple of 'hybrid' systems here for another contractor. He used 2 evacuated tube panels on a drain back system with no antifreeze. The storage tank was 80 gal with 1 element back up which we didn't need to hook up. The reason was, we also tied in a geo thermal system into the heat exchangers in the tank, & were producing 165 degree water in the summer, & 120 in the winter. The drainback tank was just a 20 gal electric water heater.


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## okcplum (Jul 16, 2011)

its a 40 gallon water heater (closed loop) glycol based. freeze protected.
collector is blu tec, not like the black chrome ones on the market.
collector size is 80 inches x 36 inches, rated at 36000 btu, its hard to rate panels for btu but this is the guideline they give upon testing.
flow rate of the closed loop is 2 ltr min.
as for 1 person... mmmmmmm. serves all our needs, 2 adults and 2 children.
recovers great for me. 
i most definatley would not put another panel with the kit and run the risk of the system heating the water to fast and then going stagnent.
i would have put a larger unit in if i needed to but based on solar gain here in oklahoma it would have been to much for us..
i have just about managed to also get my hot tub totaly of grid.
also i have just installed a solar assisted heat and air unit that has a dc heat pump.


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## Protech (Sep 22, 2008)

Sorry, those numbers don't jive.

try turning the breaker off to the backup element and see how many days out of the year you have too run over to turn it on for someone to take a shower.

Generally speaking, you figure 30 gallons of hot water per day for the first person and 20 gpd for each additional person. Your system is adequate for only 1 person maybe 2 (unless you all take "navy showers") if you are to achieve more than a .9 solar fraction.

For active direct systems (more efficient that yours), you use a ratio of .5 sqft of collector surface area to gallons of tank capacity. You must increase that to .6-.7 depending on your heat exchange efficiency.

If their is something you know that I don't, I am always eager to learn.

Not trying to bust your balls or anything, just stating some facts.



mark kiernan said:


> its a 40 gallon water heater (closed loop) glycol based. freeze protected.
> collector is blu tec, not like the black chrome ones on the market.
> collector size is 80 inches x 36 inches, rated at 36000 btu, its hard to rate panels for btu but this is the guideline they give upon testing.
> flow rate of the closed loop is 2 ltr min.
> ...


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## okcplum (Jul 16, 2011)

your not missing anything, i see you are not busting my balls.
my electric back up heat is not even connected :whistling2:
in other words at the minute and for the last 3 months it has been solar only.
we just use our water right, well to some degree.
i store my water just above 140 f
code is 140 f for water heaters.
my wife showers in the morning, around 11.00 a.m ish.
i shower in the evening when i finish work and thats after the kids have had a bath. not run out of hot water yet.:thumbup:
and i have customers her in the usa that have the same systems and they always have great things to say on how the system performs.
i know they say 2 meter square for collector size for the first two people and then 12 feet per person after that, rule of thumb and all.
the systems i use are,
upto 40 gallon units = 1 solar collector.
upto 80 gallon units = 2 solar collectors.
i did however start the system of with the black type absorber coating first and the results were not as impressive as they are with the auro therm blu tec coating used on the collector im now using and its been on the roof for two years.
i have got the sources to get all types of collectors direct from the factory's and am registered with the federal government as a solar importer/exporter.
i usually get a 40 foot container stuffed with kits and products that i install for customers around oklahoma and they all love the kits. 
the reason i have not mentioned i do this is because i am not on this site to try and sell products, just here to sit back and learn.
and help if i can.
i do see a lot of over sized systems on my travels here were the only thing companies wanted was a massive sale.
i just make a living and am happy at that.
most installs here in oklahoma are around $8000, then they call me and i give my price of around $4000 installed and wonder how i do it, remember i buy direct in bulk from factory's. yes i have around 40k at anytime just sat there in products but i do sell a lot of systems. around 6 to 10 a month.
i have seen solar bloom and die several times in 20 years and the systems have got so good now it would be silly not to install one.
but like you say my figures dont add up, well my solar water heater is doing great and giving me all i need for my family of four people. the dishwasher gets the last of the hot water at night when we are all done with our needs. 
one method of install i use is no restrictions in the closed loop, i,e less solder joints, no solder 90 elbows as these create loss as does the pre insulated flexi pipe we see a lot of now, yes its easy to install but the pump works harder, just my opinion, i learned this when we did a trial site in germany and compared the difference on systems installed. they were the vaillant 200 ltr systems (53 gallons usa).
solar is a little bit of a obsession with us here as far as i have 1kw monocrystal photo voltaic off grid with xantrex inverter and controller mppt, solar assisted heat and air, solar water heater, solar attic cooler. 
hot tub almost of grid and a work in progress but not hard to do.
if any of you have any personal install stories i would love to hear them and your views on the kits you install.
:thumbsup:


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## okcplum (Jul 16, 2011)

here is a system i set up for a training center and is layed out as requested by range (they make the kit)


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## SlickRick (Sep 3, 2009)

That was strange. When I viewed it there was a double post of #22. When I moved it to the trash, it turned into the new post. Moved it back.


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## Redwood (Sep 8, 2008)

SlickRick said:


> That was strange. When I viewed it there was a double post of #22. When I moved it to the trash, it turned into the new post. Moved it back.


Your clutch is slipping as a moderator Rick... :laughing:

First you ban me, now you are deleting this guys posts... :whistling2:

No it was a double post but I suspect he edited it... :laughing::laughing::laughing:


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## okcplum (Jul 16, 2011)

my computer tried to give me crap and posted twice,, not my fault :whistling2:
honest, but i did edit it,,, sorry.


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## SlickRick (Sep 3, 2009)

Redwood said:


> Your clutch is slipping as a moderator Rick... :laughing:
> 
> First you ban me, now you are deleting this guys posts... :whistling2:
> 
> No it was a double post but I suspect he edited it... :laughing::laughing::laughing:



Must be the heat.


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## Protech (Sep 22, 2008)

mark kiernan said:


> your not missing anything, i see you are not busting my balls.
> my electric back up heat is not even connected :whistling2:
> in other words at the minute and for the last 3 months it has been solar only.
> we just use our water right, well to some degree.
> ...


Sounds like your family uses water VERY frugally. That's a good thing. However, the majority of American households of the same size would completely overrun that size system. The average system here is florida is an 80 gallon open loop tank with a 40 sqft collector tilted to latitude with a azimuth with 45 degrees of true south. That system is just enough for 2-4 people depending on usage habits. I have that system at my house for 2 people and run at a 95% solar fraction even with guests using showers here and there.

My point is this: It does not make sense that you have 2 more people, 1/2 the system size, live in an area with less solar insolation, and have a less efficient system (indirect vs direct) and claim the same results. The only explanation that makes any sense is that your family is VERY frugal with it's hot water consumption. Even then, I have a real tough time believing you don't run out of hot water with such a low output system.


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## okcplum (Jul 16, 2011)

we do use our water very wise and work with the system, like i said, we have never run out of hot water in the three months that the back up heat has been totally disconnected from the breaker.
why is it disconnected you ask, because it has a bad breaker and i have not got round to changing it. 
almost every solar water heater demands are different and are sized on a maximum use basis.
i find working with it and being wise with the hot water helps, i dont need a 1 hour shower, 10 -15 mins maximum, with a water saver head.
now when some one asks me what size of water they need i use the rule of thumb and tell them what i would have for maximum use and there needs.
most people step up from a 40 gallon unit to a 60 gallon unit, i also never suggest the rheem solar assist water heaters as the heat exchanger is wrapped around the in tank for heat transfer, i always suggest a heat exchanger that is inside the unit, double lined of course. gotta meet code.
the only time i use my back up heater is in the dead of winter and that is also powered from solar p.v.


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## Prscptn Plmbng (Feb 15, 2011)

Protech said:


> I guess you would have to specify which passive system you were talking about. "passive" is about the broadest term one could find in the solar lexicon.


Ya when I posted this I was very green on this topic... since I have taken a few classes on different types of solar and figure the best out here in so. Cali is the drain back type... still researching brands, currently taking the classes from green plumbers usa, which will touch more on the subject. Thanks for your input you seem to know your solar


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## TraTech (Jan 22, 2012)

I use viessmann


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## pilot light (Apr 21, 2012)

Tommy plumber said:


> 'Passive' means there is no re-cirulating pump(s).
> 
> As opposed to 'active' where there is a re-circulating pump.


 Me neither!


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## pilot light (Apr 21, 2012)

Okay got it figured.


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## Tommy plumber (Feb 19, 2010)

xiaoneitie said:


> i also bought one from somewhere last month


 






http://www.plumbingzone.com/f3/why-post-intro-11368/


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## Protech (Sep 22, 2008)

xiaoneitie said:


> i also bought one from somewhere last month


Spammer


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## deerslayer (Mar 29, 2012)

mark kiernan said:


> your not missing anything, i see you are not busting my balls.
> my electric back up heat is not even connected :whistling2:
> in other words at the minute and for the last 3 months it has been solar only.
> we just use our water right, well to some degree.
> ...


I have only dealt with solar one time and that was taking out a system put in in the 70's. So I am curious how much a solar heater will work in the winter months?


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## okcplum (Jul 16, 2011)

They work real well.
I'm not saying it will provide all your needs in winter but they will provide for most of your needs depending on where you live and it also depends on how you use your water.
I have just started my install at my new home.
I'm making my own heat exchanger that I will use on a regular dwh.


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## Paddy (Sep 2, 2011)

A contractor I know in NM installs solar thermal for radiant floor heating and hot water. A federal lab (Sandia) is monitoring energy use in one of the homes, and the preliminary data show about reduction in electrical use of around 50 percent. The homes also treat the waste water from sinks and showers to flush the toilets and water outdoor plants. The data show a 50 percent reduction in water usage, and the homes have greenery around them instead of xeriscaping.


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