[Greenbuilding] Vacuum insulation panels...

[John Straube]

On Robs interesting comment on windows. 

As part of our Decathalon project 2 yrs ago, we designed an all glass wall (cause the architects wanted this) and tried to get it to use less than a super insulated wall.
After much hourly modeling for the Toronto climate we found that
1. Solar gain through high percentage of high performance windows will cook the interior of homes, dangerously so. Thus exterior shading is critical. If someone is not home all the time, a sunny day in March can melt plastic without so automatic shading or venting. 
2. With automatic shading on the exterior, a window area of 100 percent requires an R10 window to equal the performance of an insulated wall. If the window area is less, the window R-value required is less. 
We built the best we could: wood frame, fiberglass clips, quad glazed Krypton filled units 10' tall and 4' wide. This got us to a bit over R8 with edge losses and frame losses! My MASc student could not figure out how to get to R10. 

Sent wirelessly from my BlackBerry device on the Bell network.

-----Original Message-----
From: RT <archilogic at yahoo.ca>
Sender: greenbuilding-bounces at lists.bioenergylists.org
Date: Thu, 03 Nov 2011 12:29:09 
To: Green Building<greenbuilding at lists.bioenergylists.org>
Reply-To: archilogic at chaffyahoo.ca,
	Green Building <greenbuilding at lists.bioenergylists.org>
Subject: Re: [Greenbuilding] Vacuum insulation panels...

On Wed, 02 Nov 2011 10:40:37 -0400, Gordon Howell -- Howell Mayhew  
Engineering <ghowell at hme.ca> wrote:

> a Korean company that is now offering
> vacuum insulation panels (VIPs)

> a VIP encapsulated in a thin layer of EPS

Notwithstanding the issues of longevity and ability to accommodate people  
with sharp and pointy objects, I did wonder how much of an improvement the  
vaccuum (ie not including the EPS skins) provided over a simple reflective  
still air space (or couple of), also sandwiched between layers of  
insulation ?

My *guess* is "Not enough to justify the incremental 3x cost and  
questionable longevity of the vaccuum seal."

I would also venture that if a VIP is an absolute "must-have" on a  
shopping list of nifty building envelope items, then superwindows might be  
a better way to go since some would have the capacity to be net energy  
gainers, even when placed on a non-equator-facing orientation.

Unlike the Korean VIPs, Super-IGUs would provide the homeowners with the  
ability to visually assess the integrity of the vaccuum seal and allow for  
reasonably easy replacement of the failed units and subsequent re-use of  
the "panel" materials.

Seeing Stephen Thwaites here amongst us again reminded me of the novelty  
superwindow his company made sometime in the last millennium just for fun,  
claimed to outperform a conventional 2x6 stud wall.

Although I know nothing about that window, my guess is that it was well  
under 150 mm thick (through the glazing), probably thinner than an  
equivalent R-value Korean VIP.

As my brother's high school pool room buddies used to say after pulling  
off a pretty good shot "Not tea bag ! Eh ?"

-- 
=== * ===
Rob Tom
Kanata, Ontario, Canada

< A r c h i L o g i c  at  Y a h o o  dot  c a  >
(manually winnow the chaff from my edress if you hit "reply")

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