sealing air evacuated glass blocks

[Jay2TheRescue]

I replied to this a few hours ago. but I guess I didn't click send. I'll restate what I said earlier.

I think the energy used by the vacuum pump and control circuits will be greater than the energy lost if standard glass blocks were used. I don't think it would be economical.

-Jay

[GasSavers_Erik]

How about a cheap small quick connect valve that was epoxied into place (like a Schroeder valve used on car tires, but turn it around backwards). Then you could revacuum it every few years to bring out any air that has leaked in.

[GasSavers_maximilian]

It all depends on how much large panels wind up leaking (ruled out glass block now). I suspect they'll only need to be topped off on the order of several weeks or months, even if plain old silicone is used. Have to test it. This is for my next house, so it'll be a while before I have time to build a test piece. I already own a vacuum pump and pressure switches are cheap, so having it be automatic would be convenient. The R 70 per inch panels had plexiglass support structures, sealed in stainless steel foil. They were intended for high end refrigerators and were smaller than what I'm thinking, so I might even be able to beat their R values (fewer edge losses). I'm thinking the internal grid would just be made from 1/4" plywood with lap joints (like the partitions in wine boxes). Have to figure out a grid spacing that will work and that requires knowing the strength of the glasses available versus their price. Have to be pretty small at 14.7 psi. The edges would most likely be aluminum or steel. Sharing metal pieces between adjacent panels would cut costs and eliminate the need for piping each panel.

[Nrggeek]

Is this for the exterior walls of a house you are designing? Why not just use SIP panels? Or are you looking at ways to retrofit existing walls with additional insulation? Here's an example of an exterior wall from a PassivHaus design:
http://www.passivehouse.us/passiveHo...ametteWeek.pdf

[GasSavers_maximilian]

My current house has R50 walls and an R60 attic so I want to try and match that level. If you care about the view, the new window technologies are the way to go (although thermal shutters might be more cost effective still). I just want sunlight and thermal gain. Considering having an indoor garden. Just an idea I'm exploring, but I very well may not bother. My ultimate design would be to have a central courtyard with this overhead, so it'd stay warm all year round, but that'd be more effort than a simple wall installation. Require expensive safety glass as well. Cooler, though.



Garden not shown. Be in the center of the basement, along with the living areas (bedrooms upstairs so they have fire escape routes).

[bobc455]

Wish I'd seen this before! I work in the plastics industry and know quite a bit about material permeability...

Figure that metal and glass will provide a perfect seal (with sufficient thickness). But you are right, the adhesive will be quite permeable.

New windows will frequently have argon gas between the panes (which helps insulation) but it all bleeds out after a few months so insulation values drop dramatically over the first year. Some window companies take extra measures to prevent this, but they are really expensive.

Of course you're gonna have a hard time making a perfect vacuum inside your material anyhow...

-Bob C.

[GasSavers_maximilian]

At least the argon is at the same pressure as the atmosphere. Vacuum ought to leak much more, I'd think. My vacuum sealer for food seems to be able to keep a pretty good vacuum for a couple weeks at a time in the containers, and they're plastic and rubber, so I have high hopes for large glass panels on metal frames. Topping off on the order of weeks would be acceptable. We'll see. I may just go the route of making the house super tiny and use regular old windows, strategically placed and with thermal shutters. No garden, but it'd save a lot of time. I like to have things to think about while I'm working, since construction is sort of dull.

It would be really cool if a manufacturer started making such large panels. They could be all glass and hold vacuum for life. Use a clear support grid as well to increase light transmission. The supports could even form attractive patterns!

[Nrggeek]

It's always a challenge anytime you drastically change the window area of your house. You have to consider the added heat gain, not just in the winter but in the summer as well. Then you have the thermal heat losses as we've been discussing. Several designs for "thermal shutters" exist to help avoid night time heat losses in winter.

If you are designing a new house then you have all sorts of parameters to play with, especially floor plan and area, as you mention. Going smaller is a win-win-win for energy.

You can always add a greenhouse to the south-facing exterior wall, separated from the house by a good envelope, but with provisions to make use of the light and heat when appropriate.

~Bill

[GasSavers_maximilian]

I've been leaning that way as it's just so much easier to build. Not as sexy, but practical. I was looking at those hand carved Indonesian folding screens and thinking how pretty a support grid along those visual lines would be (not as dense a pattern and out of clear material). Not something you could easily do yourself.

[dkjones96]

Too bad you don't live in swamp cooler territory. Those make most issues like this a 'who cares' kinda thing since the air intake is outside anyways.

However, it won't work for the first few years, but plants are one of the best ways to keep your house insulated without a lot of money or hard work. Thick bushes or vines at the walls, those new green roofs that are basically grass. Tall trees covering your home.