# Chinese hot water



## wg_bent (Jun 4, 2006)

Linky


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## elkimmeg (Jun 5, 2006)

I went to there web site  the cost  and descriptions make this a very appealing


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## begreen (Jun 5, 2006)

Thanks for the post Warren. I have thought that China and India will lead the world in alternative energy production very soon. They are quite pragmatic and this just makes sense. Too bad we are trapped in a petroleum dominated congress and economy. The opportunities for development and industry right now are huge.


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## Eric Johnson (Jun 5, 2006)

Neat. I did a web search about a month ago and was surprised to see that many of the evacuated tube collectors are made in China.


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## Sandor (Jun 5, 2006)

I would really like to implement a solar water heater within a year.

Has anyone taken the plunge? Eric, I know you were interested.


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## Eric Johnson (Jun 5, 2006)

I haven't plunged yet, Sandor, but I'm saving up my nickles. There's a two-year window of opportunity to take advantage of the state and federal tax incentives, so I'm thinking about a two-part strategy: Buy one collector this summer and cobble up the piping, pumping, storage and heat exchange myself. If it needs tweaking or expansion, I can do that in '07 and still get it for half price.

Another option I'm considering (reluctantly) would be to buy a used set-up. They're around. But I think it makes more sense to buy evacuated tube collectors. That's the state-of-the-art and seems to make the most sense for those of us who live up north.


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## babalu87 (Jun 5, 2006)

elkimmeg said:
			
		

> I went to there web site  the cost  and descriptions make this a very appealing



Link to the website?????

We bought a Solar shower for camping and I have used it three times...... now I just need to build a shower stall before the neighbors wife sees me


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## Rhone (Jun 6, 2006)

Eric Johnson said:
			
		

> I think it makes more sense to buy evacuated tube collectors. That's the state-of-the-art and seems to make the most sense for those of us who live up north.



Just a warning about evacuated tubes.  They're state of the art but I've found some problems with their advertising and statements.  If you notice they always say "they're more efficient" but you have to watch that.  A flat plate is more efficient than an evacuated tube until the outside temperature gets to 10-15F or below.  I live further north I think than most, and only a couple weeks of the year does it get to 15F or below in sunlight otherwise over 96% of the time a flat plate collector is more efficient.  They may twist it and say more efficient per square foot.  I have a big problem with that.  What's better, a single 92% efficient 4x4 panel, or two 85% efficient 4x4 panels.  I think it's a no brainer you're better off with two slightly less efficient panels and have twice the collecting area than 1 slightly higher.  Evacuated tubes are 4x4,  and flat plate collectors are 4x8.  Evacuated tubes on average last 15-20 years but a flat panel lasts 25-30 years.  Evacuated tubes are also around twice the cost.  They also advertise that when it gets cloudy the evacuated tubes can still heat unlike flat plate collectors.  Notice they don't say how much energy they contribute on cloudy days.  I saw someone say when it's cloudy out their evacuated tubes make barely warm water and they have to turn on the backup hot water heater so that point is sort of pointless.  They then advertise because of their round shape they're always in perfect alignment with the sun and "extend" your heating in the morning and evenings.  Then show you a picture of the sun shining on the evacuated tubes in the morning and looky thar all the sun is being collected by the evacuated tubes but the flat panel is reflecting some.  Well, that's great and all but there isn't a lot of energy in the morning and evening sunlight.  Show us the picture when it matters most, around noon where we'll be able to see the sunlight passing between the evacuated glass tubes not being collected because there's spaces between them, but collected by the flat panel because there is no space when it matters most and you can collect the most energy.  They do have their place, but just make sure you know what you're getting into.  Generally, if you can do flat plate collectors and they work in your situation you're going to be much better off with them.  Otherwise, if doing flat plate collectors will mean you have to rip out your current heating system, you need hotter than 140F - 160F, or you find them repulsive, or can't fit a flat plate then evacuated tubes are probably the better bet.


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## Eric Johnson (Jun 8, 2006)

Thanks for the analysis, Rhon. To be honest, I didn't realize that the evac. tube collectors are smaller.

Do you think it's worth the premium to go with black chrome vs. paint on flat plate collectors?

Also, you mentioned the life-span of the tubes vs. the plate collectors. I've seen used flat plate collector panels for sale that are at least 25 years old. Aside from the obvious problems like freeze burst and glycol-induced pitting and corrosion, what kills flat plate collectors? If buying used, in other words, what should you be looking for?


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## Sandor (Jun 9, 2006)

Eric Johnson said:
			
		

> Thanks for the analysis, Rhon. To be honest, I didn't realize that the evac. tube collectors are smaller.
> 
> Do you think it's worth the premium to go with black chrome vs. paint on flat plate collectors?
> 
> Also, you mentioned the life-span of the tubes vs. the plate collectors. I've seen used flat plate collector panels for sale that are at least 25 years old. Aside from the obvious problems like freeze burst and glycol-induced pitting and corrosion, what kills flat plate collectors? If buying used, in other words, what should you be looking for?



Rhone, whats your favorite system pick.

Right now, this is the one I'm really looking at:

http://solardirect.com/swh/active/closed/helio-pak.htm


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## Rhone (Jun 12, 2006)

Eric Johnson said:
			
		

> Do you think it's worth the premium to go with black chrome vs. paint on flat plate collectors?
> 
> Also, you mentioned the life-span of the tubes vs. the plate collectors. I've seen used flat plate collector panels for sale that are at least 25 years old. Aside from the obvious problems like freeze burst and glycol-induced pitting and corrosion, what kills flat plate collectors? If buying used, in other words, what should you be looking for?



You have to watch out for air leaks & moisture in old panels.  Moisture condenses on the glass and inhibits its ability to collect.  You want a tight and air proof panel and without moisture.  Glycol is thinner than water so you really need to watch the pipes that they don't leak.  If repairing, you want to be sure to repair them on a dry day, and be sure the glass isn't cloudy.  I wouldn't do it just because that was the 80's, when the government decided to offer incredible solar incentives before solar was ready and glazing wasn't common.  Many uneducated and unexperienced solar people all of a sudden started making panels in their basements/garage and installing them on people's houses sometimes putting them in full shade or using clear fiberglass that fogs in a year exposed to the sun.  So much of the 80's solar panels being home made or crap nearly killed the industry.  It caused a total revamp, laws, codes, research, and since the 90's they've been putting out panels of exceptional quality trying to sway the bad rap solar got.  I personally wouldn't go for a 25 year old panel, maybe one from the 90's+.   There were a few good ones made in the 80's, I can't bash them all my in-laws have solar panels 28 years old and they've got another 10-15 years but most aren't the quality of the ones made in the 90's or later.  I personally would pick black chrome.  The difference between the two is pretty much how hot.  Black paint heats up faster than black chrome but 95% of the heat collected is allowed to re-radiate.  Whereas, if you get black chrome it only allows around 5% of the collected heat to reradiate through the glazing whereas 95% gets trapped.  In short a black chrome panel can heat water to higher temps than black paint.  This site explains the emissivity difference in easy terminology and examples, emissivity is definetely not my specialty.  

The systems I've been looking at Sandor are from Radiantec (either Domestic Hot Water, or Solar Option 2) for the simple reason they were the ones that sold and installed the solar to my in-laws 28 years ago, and their panels have another 10-15 years left, and their heating system still has another 40 years left.  Simply fantastic quality and work.  Being still in business and still maintain the same standards, and owned by the same person as back then I feel very confident in Radiantec.  The company you mention is rather similar, and seems to have the same goals as Radiantec.  I'm slightly cautious of having the controller and works on top of the storage tank in one package like that, I'm not certain how it will handle upgrading or expanding the system in the future but really glad to see the system you mention certified to SRCC OG-300.


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## Eric Johnson (Jun 12, 2006)

I like the fact that Radiantec is in Lyndonville, VT, not somewhere in California. I could drive up there and pick the stuff up and save the shipping.

What I'd really like to do is buy the collectors and put everything else together myself (pumps, aquastats, heat exchanger, tank, piping, etc.). Does that sound like a realistic approach to you, Rhone, or are you way ahead buying an already-engineered system?


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## Rhone (Jun 12, 2006)

I prefer to buy "kits" from people who know what they're doing and you know everything's going to go smooth, and generally they make them very simple, and with simplicity comes reliability so for me I prefer to buy the kit, and install it myself and not buy individual components seperately.  You'll have to check your codes to see if you can install.  Those 80's caused some cities/states to outlaw the installation of solar by unlicensed individuals to protect homeowners from all the idiots back then making and installing them.  Now, those laws aren't applicable much anymore but may still be active and prohibit one from installing their own.   

Next year is the year I plan to spring for it, I tried to make it work this year but spent my money on a new roof and just couldn't make ends meet financially to do it.  I'm getting Solar Option II, already have $500 saved for it.  I want it to heat my hot water and supplement my heat.  My goal in the end is to have almost all the hot water that we need saving us probably $800/year, and heat with solar only in spring & fall and hopefully drop our wood use by 2 cords saving us $400/year there since we buy it.  I'm also springing for 6 panels, not the 5 in that kit.  In the dead of winter I'm hoping it to just heat our hot water.  A solar analyses told me there's a couple months my house loses too much heat for the amount of solar I receive, along with the sun going so low it becomes partially blocked by my neighbors trees during that time as well.  Besides, only houses built around solar have any chance heating at that time anyway.  All I hope during those 2 months, is that there's still enough to heat my hot water, at 6 panels I know there's going to be.  My oil boiler will be my backup, insurance companies require a form of heating that doesn't require intervention (like a wood stove) nor depends on the weather (like solar).


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