# Best product I've seen yet!!!



## Navyman1 (Jan 31, 2010)

I'll start this thread here because I just did a search for Evacuated solar tubes and had no hits.

These tubes are amazing!!! One DIY show installed them in PA when it was 28 degrees out. It was producing a temperature high enough for a heating system or showering temps. Works great because of the vacumme between two tubes. There is a video on youtube showing a guy making his own. Though the video is not complete. This would be a great DIY project if only there was a easy way to manufacture this tube with the needed vacumme.
Any one familiar with these tubes?? Thoughts???


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## user1007 (Sep 23, 2009)

This something like what you saw? This was my google search string by the way "Solar Tubes for Hot Water"

http://solarhotwater.siliconsolar.com/evacuated-solar-tubes-20.php


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## Scuba_Dave (Jan 16, 2009)

I think I saw part of the DIY show
They were bending alum to go around copper pipes & then sliding them into the tubes
I forget what they said the tubes were from ?


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## user1007 (Sep 23, 2009)

Used same search string in You Tube. It kicked out several clips. Thought I would share the URL for this one. There was a DIY thing too. 

http://www.youtube.com/watch?v=RNQHjfftDVQ


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## Red Squirrel (Jun 29, 2009)

Good until you get 2 feet of snow over them.


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## Navyman1 (Jan 31, 2010)

Of course the snow will have to be broomed off, which is well worth the effort. There is another DIY video where it is made of PVC pipe. I'm not sure of how to post a link yet.

So far it seems like none are made in the US though. What a shame.


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## FLGarageDoors (Oct 24, 2009)

Hey, has anybody got any more information or experience with this yet? It seems like a really good way of solar heating, and I'd like to know if it's a good investment.


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## Daniel Holzman (Mar 10, 2009)

Hard core reality is you can't extract more energy than is available from sunlight, which is not as much as you would like, especially in the winter. See http://www.grc.nasa.gov/WWW/K-12/Numbers/Math/Mathematical_Thinking/sun12.htm

for a mathematical analysis of the maximum amount of extractable energy from sunlight at 42 degrees north latitude (about where I live) in the winter. The result is that over a given 12 housr period in the winter, the maximum amount of extractable energy from sunlight during a full sun day is about 720 Joules per square centimeter, or about 0.68 BTU per square centimeter. In terms of square feet, this yields about 630 BTU per square foot.

Assuming you want to heat your water from 60 degrees to 125 degrees, you need 65 BTU per lb, or about 500 BTU per gallon. So for every gallon you want to heat, you need a little less than 1 square foot of area over the course of a 12 hour day. If you use 50 gallons of hot water per day, you need at least 50 square feet of area, adjusted for efficiency. If the efficiency is about 1/3, you need 150 square feet of area. Of course, if the sun shines only 50 percent that day, you now need 300 square feet of area.

This is why everyone does not have a "free" source of hot water, by the time you get done building your evacuated tubes, installing the system with pumps etc to circulate the water, it doesn't look so good. Not to say you shouldn't try, just trying to point out the thermodynamics behind the promise.

By the way, I heat with wood, old fashioned, low cost technology. I love it.


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## Red Squirrel (Jun 29, 2009)

Yeah this is something I would see more useful or heating a pool, or maybe as a secondary heating source like if you want to take a bath and the sun happens to be out and the conditions right, then you use the water from that system instead, but for morning showers I'd stick to a HW heater. Can't afford to not have hot water when you have to get to work. 

This could maybe also be used for floor warming, now that I think of it. I doubt it could produce enough heat to make a huge difference, but maybe enough to remove the chill from the floor. Since it's almost free energy, may as well use it. Have some kind of thermostat that only turns the pump on if the water outside is hot enough.


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## Willie T (Jan 29, 2009)

I also did a Google search........
Solar Evacuated Tubes






Advanced search
About 55,900 results (0.33 seconds)


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## Scuba_Dave (Jan 16, 2009)

Solar used to heat a house in SW Montana
System was built on the side of a garden shed
http://www.builditsolar.com/Projects/SpaceHeating/SolarShed/Performance.htm

There are a lot of people using solar as a heat source


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