diy solar

diy solar

Solar Water Heating in Cold (Colorado) winters?

I think 50 X more efficient is said for effect. I was just trying to find out how efficient these evacuated tubes are. I’m sure that aside from the 20% efficiency of the solar panels, there’s a pretty huge loss of taking this electricity and converting it to heat, but now enough to make the 50 X efficiency that’s claimned. Anyway, that google research will come later.

I’m also wondering if these Tubes are used for the Canadian winters, I understand the vacuum tube not freezing, but how about the copper pipes between the tubes? Some pretty cold nights up there. The problem was overcome somehow because people are using these, I just don’t know how. FOr me, that’s google research for later.
The products I've seen have evacuated tubes clamped in a manifold. They will work in freezing, and stagnate above boiling.
You either need to run an antifreeze mixture (e.g. non-toxic propylene glycol) and heat exchanger, or push warm water through the pipes when weather gets down to freezing.

Alternatives could include an air relief/vacuum breaker for a drain-back system. I've also thought about putting an air-filled silicone tube through the pipe to allow water to expand as it freezes.

You'll find systems on eBay and elsewhere, around $1000. Some have a storage tank at the top end, so no pipes between collector and storage.
They do have some finite lifespan. Not entirely clear that exceeds a decade.

Because I'm on-grid with net metering, I've just over-paneled PV and used resistance heating.

For OP, water tank above evacuated tubes and PV/battery circulator pump sending water through tubes under yurt floor might work pretty well.
Blowing air over a radiator attached as thermo siphon to water tank could do it too; then all plumbing is in insulated volume.
But the warm floor is nice. Probably want warm air to go under it if not water. I want something like that in my house.
 
Why? is something wearing?
OK, the reflectors need cleaning from time to time to keep efficiency up.
I was trying to see in an owners manual if there’s a way to “recharge” the vacuum, which would be taking out any gasses that leaked in over the years. I’ve seen gas shocks recovered by doing the opposite, installing an inflation valve to recharge.

Once the vacuum is gone, There’s no insulation.
 
I was trying to see in an owners manual if there’s a way to “recharge” the vacuum, which would be taking out any gasses that leaked in over the years. I’ve seen gas shocks recovered by doing the opposite, installing an inflation valve to recharge.
Once the vacuum is gone, There’s no insulation.
Isn't glass able to keep vacuum quasi forever?
I think the only gas able to diffuse through dense materials is elementar hydrogen, that exists only to 0.000055% in earth's atmosphere.
 
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Some references are indicating 15-25 years




But warranties of 10 years, which is probably where I got the idea


Tubes are made with a "getter", which captures outgassed oxygen. May continue to do so for a while. Wouldn't do anything with nitrogen but at least that isn't reactive. Things do leak, but a truly hermetic glass/metal seal is pretty much leakproof except to hydrogen and helium; not much of that floating around.

PV panels have a longer history and larger industry. They are surprisingly reliable, except for some (usually) off-brands which isn't surprising.
 
PV panels typically convert 20% of the solar radiation to electricity. How does a vacuum tube solar collector collect 50 * 20% = 1000% of the available solar?
OK, 50 times is exaggerated. But they are really out-beating ANY other technology by far when it comes to harvest heat under diffuse solar irradiation and cold environment.
And 20% is not realistic under real life conditions either, most panels don't get that much and rapidly lose efficiency if the incidence to sun is not 90°, that means quasi all the time of the day, without tracking.
Don't be fooled from data sheets...
 
Re: $1500 on 50 gal water tank; I would pivot to "When there is a Will, there's a WAY (and it will be more cost effective) !!!

Re: Radiant Floor Heating, I would consider a "Heat Pump" style water heater that gets allot more heat per watt of electricity than any heating coil (maybe 6 times as much heat). I have studied heat pump options on Amazon, as in ones made for pool and/or spa heating. Seems like kind of a new arena of products (that make so much sense to me), while looking like quality, and customer support are possibly still lagging. I also notice the REEM water tank heaters at Home Depot with heat pump technology, that looks like dialed in dependability for home water heating, with attractive rebates, and raised efficiencies, ... but not for volume of heat one might need for a radiant floor system ... I want to someday do a radiant floor over "Aircrete" as in homemade high density foam injected in cement mixing/ got a little dragon foam maker for such a project, here). I might add more expensive foam along outside edges of a radiant floor if I lived in a colder climate (I am in Northern California where ground does not freeze) ... Been thinking of combo heat pump and water heating panels on roof, and maybe a drain down to non pressurize water tanks to protect my solar direct to water heat paneling on roof for when it get below freeze temps ... Food for Thoughts, while looking for greener ways. Anybody powering up heat pumps for water heating? How's it working ??? How would you gauge its' tech support from customer service?

I have two Pioneer brand 12000 BTU mini split heat pumps (about $750 each) online now for my big room heating or cooling needs that functions on 9 amps 120ac (x 2) for my cool weather heating, and also functions on about about 6 amps 120ac for my summer AC cooling needs. (... with my lower watt evaporative cooler option, still online). Those mini split just draw current part time via their built in thermostat adjustment; and the efficiency of have been going upwards with their newer versions of variable speed dc powered compressors. I see some kind of heat pump(s) for my water heating task(s) in my future. :+)
 
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The real problem to heating with a solar system is getting the heat loss down to something the solar can keep up with.

If your yurt had an R50 rated insulated floor, roof, and ceiling, you would have chance of providing enough heat from solar.

You would need a large array of panels and adequate heat storage, due to the short, cold, winter days in Colorado.

Hydronic (liquid) panels offer more efficiency than PV panels, but the cost to install may be higher.

If you would watch the UTube video of electrodacus when he builds his off grid house, it would help you see the scope of a solar dependency.

He used PV panels due to the cost off a hydronic system.

A Heat Loss report of your yurt will be the first step, then you will have an energy value to work with.

Knowledge is the quest, dave
 
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