Solar panels

Ron Huber

A non profit(?) outfit up here in NH uses these tubes, I question the durability. They are given a few extra tubes with every system because out of 30 tubes there may be a few that have lost the vaccum. I never heard of getting extra equipment in case some of the materials may be defective. How well will they be working 5 years from now? Again, you get what you pay for.

Ted_9

Have you heard?

I saw this today at an ICP/SIPs house. They had Evacuated tube type solar panels. It was just a demo. Looks slightly different than the ones Viessmann uses.



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Unknown

A solar company up here uses these and likes them just fine... more affordable than the viessmann ones.

We did have a client use them and some corroded after the first year of use. However, he had a strange mounting detail... no idea if that contributed or not.

[Deleted User]

Chinese sorar correctors...

Those little beuaties are Chinese. They have a sputtered black chromium onyx absoerber on the inside of the second tube (double walled tube) and they claim a higer perentage of solar collection due to the absortive surface being at a right angle to the hourly incidence angle. They use a heat pipe technology similar to Viessmann, and a heat transfer headerb on the top of the colector that can be set upas a drainbacktype of system. They were on display at the Foothills Conference in Edmonton Canada.

Significantly less expensive than the alternatives...

ME

[Deleted User]

seem to be good

I just lost a job that i speced Viessmann on to this product. The price for them was half as much. I am going to look into these as an altenative to Viessmann. I really couldn't beleive the price difference.

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Ted_9

well,,,

as far as construction, these seem durable. Thats all I know.



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joel_19

another point

The panels from china are much cheaper.
The question is do you want to support an Opressive Comunist regime?? how about the fact that China makes HUGE amounts of polution from air to water and ground. So the question becomes will buying the panels reduce or increase polution?

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Paul Pollets

Quality Tubes

..should hold vaccuum for 40-50 years.. I've heard the Chinese tubes will do 10-20. I'd be concerned.

Wish there was a protocol for tube testing!!

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Ted_9

well..

Joel I agree but take a close look at all of the products that you or people you know purchase. Made in China?? If Americans want cheap then it's from China, usually.

I don't like that North America and Europe support the Chinese economy, but it's true.

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Tim Doran_4

tubes

I have put in a few of these in the past 6 months. No problems so far and no extra tubes were sent.

Thanks, Lund

Metro Man

Haven't drank the cool aid yet

After looking and re-looking at ewackualted tubes I STILL don't see the justification to use instead of a good old flat plate. For residential use you just can't beat the reliability, servicabiity, parts availability (glass, frame, absorber plate--- that' it) and many other bilities. Plus the fact that they can withstand hail and poorly thrown rocks.

I've watched E.V.'s take until 10-11 in morn. on a sunny cold winter day (frost on tube issues) to heat enough to create a delt T. A flat plate would have been chuggin along for a couple of hrs. already.

I guess if you wanted to push storage temps above 180 deg F, then maybe these systems would be better.......... but why????

Flat is PHatt!!!!

jp_2

interesting comment

I have never seen frosted south facing glass by 10am on a sunny morning?

hot_rod

solar cooling is

not that far off and it will need those higher temperatures, provided by evac tubes, to operate.

So the "insiders" tell me.

I've been a flat panel solar guy up until now. I may re-think my system with the new cooling info I hear floating around.

hot rod

jp_2

hot rod

hey, a solar frig, I like that idea way more than propane, even more than the solid state frig I'm getting for my PV panels.

Metro Man

frosty the tube man

Will try to dig out article (on other lap top) from 3rd party german test group. Early morning on winter days because the nature of the beast evac's glass tube stay cold hence not insolation going on through tube, system does not turn on.

I have also heard some muttering of solar cooling through high temps..... would love to see something in action. We don' do much on the refridge side but.....

hot_rod

I too would like to see one

in operation. Solar thermal driven cooling that is. A person in the know at a panel discussion I attended claims they are under operation and testing. Although we may have to travel over seas to see them

In my area I gladly trade some "ice up" days for thermal cooling all summer. If the load was mainly thermal heat, and at temperatures that panels could provide, then the potential tube icing would sway my choice.

hot rod

Jerry Scharf_4

I have these installed

When I was looking for solar collectors, I did some research and found these guys. Apricus is based out of NZ, and the folks seem quite knowledgable. I asked them about why they made them in China. They said is was partly about money, and partly because the Chinese have a manufacturing base for large glass tubes (from their television industry.) So finding manufacturing for tubes to their specs was easier in China than anywhere else, certainly easier than NZ.

As for tube relaibility, it's great how different people can see the same thing differently (meant honestly.) I looked at the fact that there was no glass to metal seal as a real plus, it's just a big glass vacuum tube. Since there was no dissimilar expansion interface, I figured the chance of failure was less. The extra tube is for possible hail/FOD rather than for a seal failure. Becuase the collector/heat pipe is not inside the vacuum tube, the glass can be replaced over the collector. With the V design, you lose the collector when you lose the glass.

It's been up for about 18 months and is working fine. Since I have no other collectors next to it, I can't tell you the relative ability to collect heat. On a sunny winter day with 45F outside air, I get 150+F out of the collectors. We will only know about reliability long after the purchaces of all current generation devices is done. I put my bet in and we'll see how it turns out.

jerry

Kevin_in_Denver_2

solar thermal cooling

There are a couple ways to cool homes with solar heated water or air.

The best way with water uses an ammonia absorption cycle. ARKLA used to make a commercially available unit, but I don't think they make anything for residential applications any more.

The bottom line is this technology will never make more sense than putting up grid-tied PV panels, and selling your excess electricity back to the utility at retail. This option will eventually be available nationwide.

jp_2

kevin please tell more, PV panels

grid tied PV panels?

what is your sell back rates out there? around here I think its 10 cents.

mich requires a special meter, i here wisconsin doesn't.

from Real Goods catalog, around $10,000.00 gets you 1,000 watt grid tie system, if you sell back all that you generate, thats about a dollar a day for $10,000.00 investment. somehow I do not see the sense in this? seem to me the cost associated with grid tie is a pure waste an Alore Gore-ism.

Ron Huber_2

frost

This is from the German study on flat plates vs. the tubes,
I think you just have to weigh out the cost/benifit results for each job. The flat plates on average are going to be pretty close in performance, but sometimes the tubes are either going to look better or fit easier into the area that the array is going in. But a tube is a lot easier to get up on the roof than a 110 lb panel.

Ted_9

Thanks

Thanks for the thoughtful responses.



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Uni R_2

Ontario would pay you 42¢/kWh

Under the "Standard Offer Program", residents in Ontario can install smaller PV systems as you've described and the province will buy your production directly from you for $0.42/kWh. Not only that, but because you are supplying the grid with the PV power, you don't have the hassles and issues of maintaining battery farms. Consumption would all be charged at the normal rate of just over 10¢/kWh. If you can guarantee 80% coverage of peak loads then you will be eligible for another 3.52¢.

Doesn't that sound sweet?

Now to sour the whole situation. Suppose your panels produce a 1000 kilowatts per year. That would work out to $420/yr or $35 per month. In order to get set up you have to buy a special meter that costs a few thousand. The meter needs to communicate with the power company through a dedicated phone line. A dedicated residential phone line is around $30/mo so there is $5 left for to cover the capital costs for the meter and that doesn't even include the amortization on the PVs.

Obviously, bumping up the scale by about 10x (which I think is the maximum before local capacity assessments and other impediments arise) would reduce the metering and monitoring charges by 90% as a percent of revenue, but you'd probably also have to treat the whole generation system as a business or you'd be stuck paying the full generation revenue at your top marginal tax rate (taxation here is progressive and everyone pays very little tax on the first 30K, more on the next 25K and then through the nose thereafter - somewhat oversimplified). Anyway, nobody is going to get rich doing this (unless you're selling PVs and loose with the truth).

If, North American utilities could bring the meter costs down and use IP connections for monitoring, it would be far attractive solution for all parties. The true value of PV for this market is that peak loads tend to happen in the sunny summer. That's most likely why only PV is eligable for the higher rate. All other forms of generation can also participate in the SOP, but they are only paid 11¢/kWh.

Netmetering is also an option in Ontario, and given the economics of monitoring and metering, it's probably the best way to go for anyone wanting to add PV capacity. Still, we should pressure utilities to look into similar strategies.

Kevin_in_Denver_2

PV payback

$.10/kwh is about right. Colorado has mandated that Xcel pay for half of your system up front, and there are additional tax breaks.

Every time a PV array goes up on a homeowner's garage, it means that part of a new coal fired power plant doesn't need to be built. Xcel likes this program, because if enough people install PV, they don't need to build any more new plants.

They are selling great here, even if the ROI is only 4%. People feel good doing it, and if you can actually prevent a new coal-fired power plant, it's doing good too.

In CA, electricity is up to $.25 and going higher.

There are still a few research projects with solar absorption cooling, but that was true in 1975, and there's no progress.

Dawn Solar makes a hydronic heat collection system that can be used underneath PV Roof integrated metal roofs. On a year round basis, that will maximize the dollars collected from the sun.

Roof integrated solar panels are currently the best way to guarantee that the snow slides off the collection surface.

jp_2

good points uni & kevin

like to see how many people go for it in colorado, of course if not enough, they still need another power plant.

would be a lot easier if you could sell back at what they sell to you for. then you only need one meter. in a way, you sell them power during the day and they sell that same power back to you at night, for a profit. but i still agree its a good idea, as long as people really know what they are getting into.

Batteries:

thing about batteries, they are cheaper than PV panles, allows you to use more of your own power than the panels themselves can generate. as in my 30 watt PV system, without batteries I could only use a 30watt device, with the battery I can use a 400 watt device for short periods of time. as most applicances go, we only use them for short periods, power tools, blenders, wash machines.

in reality, wouldn't a home owner be better off improving the house itself? max out the insulation & weather proofing? heating and cooling seems to be the biggests loads and users of carbon, thus improvement produce the largest savings of energy.

Uni R_2

if you could sell back at what they sell to you for

That's called "net metering" for grid customers. What you generate is subtracted from what you consume using the standard meter. It can even put backspin on the meter, but the utilities won't pay a credit, but they will let you keep one on the books for up to a year. Still, it would be nice to only pay the $20 monthly fee if you could get generation and consumption to match. With you being off the grid, it wouldn't be an option and of course batteries are pretty well a requirement.

I'm a self-confessed gridslut - but not just for the convenience - it can be used to save money and reduce pollution. Corded mower for example... It cost 2½¢ to mow the front and back (not a large yard but big enough - 45 minutes to mow it). The gasoline alone would cost over 40¢ in comparison. The corded mower's still a step down from a pushreel mower or no lawn, but neither are workable options for me.

I think PV will take off once the manufacturers improve the conversion rates. I think right now they're around 14% - if all costs stayed more or less the same and that ratio went to 40 or 50%, I'd be measuring the roof! ;-)

Metro Man

the load down

THE best use of solar currently IMO is; heating cooling.... solar thermal, electrical loads..... PV. These systems working hand in hand are a great way to off-set whatever your paying in utilities.

Good insulation and power reducing equip. are a must.

Calc what your loads are month to month and figure what you need. Colorado has very high annual heating loads and 300 days of sunshine which is why solar thermal heating systems work so well here. Couple this with the radiant low temp systems and you now have a system that will heat with a couple hundred watts / hr. Install a stainless steel storage tank and this system should last forever (or so).

Adding batteries to a PV system that is grid tied ads cost and higher maintenance issues. Batteries may only last 5 - 12 years and can be 30% the cost of the system. PV panels on the other hand should last 20 yr or more. Weak link on a grid ties will be the inverter.

jp_2

grid tie no battery

thats true metro, thing is, most people are gone during peak sun production(going to work/school). so who then are the panels working for? the utility company, which is fine as long as they pay you what you have to pay them!

but then you've spent a ton of money for little pay back, but i still like the idea of it.

for me I like the idea of charging the batteries all day and use that power all night, people I have talked to up here are all off grid. one guy has a 3,000watt wind gen, but sees no economic in grid tie.

Metro Man

storage is storage

J-p, that's the whole idea of the stainless steel storage tanks that we fab up for our jobs. The solar thermal system collects energy during good insolation periods and is used when there is a demand. In fact I see no reason to install a solar thermal heating system without storage unless it is a commercial day only situation. If you think about it when the sun is shinning the building is (usually) at it's lowest heat loss for the day. It's 5 am when the temps are low and heat loss is high is when you need to be in hot water.

A grid tie PV system is still an expensive proposition. With rebates you could still be looking @ 10 - 16 year payback. But........ the reason for going solar or renewable should not only be a monitary one.