Our FIRST residential radiant window project (ME)

Unknown

most glass today is 2.85 (getting down to 15-20 BTUs/sq ft at your 60 degree differential) but regardless, even if you replace R2 with this, someone is going to have to explain how ADDING heat energy to a window REDUCES its heat loss... I'm sure you understand that just doesn't make any sense to me.

Mars_3

Mark call me when you get the chance

Mars_3

Mark thank you for our talk.

Mark it was very informative to speak to you concerning this product. I think I have an application that might fight this product. On top of that I would like to talk to you concerning up coming projects that we might be able to work with. thanks mars.

[Deleted User]

You're welcome Matt...

And I look forward to working with you on this and any other projects you see appropriate.

Thanks

ME

Cliff Brady

Similar performance without the watts

I have followed this stock for a while but never bought, nor do I have a recommendation. I didn't know they were working on this but it may have similar performance to the wired glass or they may work well together.

http://biz.yahoo.com/bw/071207/20071207005042.html?.v=1

Southwall's Heat Mirror Insulating Glass Achieves Insulation
Value of R-20/U-0.05 . . . Equal to the Insulation of a Solid Wall

Friday December 7, 8:00 am ET
Available for Residential & Commercial Applications in Windows, Doors & Fixed Glass

PALO ALTO, Calif.--(BUSINESS WIRE)--Southwall Technologies, Inc., the worldwide innovator of high performance, energy-saving films and glass products, announced today the ability of Heat Mirror® insulating glass to insulate against heat loss at a record breaking R-20/U-0.05 insulation value.

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R-20 Heat Mirror insulating glass consists of three heat reflective coated films mounted inside an insulating glass unit between two pieces of low-e coated glass. This super insulating glass construction creates four heat-impeding gas-filled cavities and achieves R-20 performance when used in conjunction with a thermally insulated fiberglass frame. Heat Mirror R-20 is a product of Alpen Energy Systems, a leading Southwall customer licensed to fabricate Heat Mirror insulating glass.

“This astounding achievement in energy efficiency is a tribute to the collaborative team effort of Southwall and its window and insulating glass customers who jointly push the envelope in enhancing the performance and value of Heat Mirror technology,” said John Meade, Southwall’s Director of Business Development

Superior to any low-e glass currently available, Heat Mirror is a technologically advanced low emissivity and solar reflective film that can be mounted inside an insulating glass unit in a variety of configurations (one, two or three coated films, uncoated or low-e coated glass) to provide energy conservation performance ranging from R-6 to R-20 to meet the unique requirements of commercial and residential new construction and renovation projects.

Heat Mirror is the technological alternative to coated glass that extends performance well beyond that of generic low-e glass available today. Heat Mirror insulating glass, as well as other innovative glass technologies currently under development, is driving the US Department of Energy to revise the glass performance standards of its Energy Star program that rates the energy efficiency of appliances and building components.

Scheduled to debut as early as 2009, revised Energy Star glass performance standards will make clear that generic low-e glass, with a maximum insulating performance level of R-4, no longer represents a level of energy efficiency required to “transform the market”, a key charter of the agency’s ratings and standards program. Among Energy Star’s objectives is increased market penetration of windows achieving insulating performance of R-10 by 2010, an objective readily achieved by Heat Mirror technology today.

Why is increasing the energy efficiency of glass important? According to Chris Mathis, a founding member of the National Fenestration Rating Council (NFRC), which sets standards for window energy efficiency, 64 percent of the 110 million existing homes in the US have single-pane windows. This contributes 25%-35% of the total energy wasted in buildings and 10% of the total carbon emissions in the US annually.

Southwall Technologies, Inc., (OTCBB:SWTX - News) introduced the world’s first low-e coated glass product in 1981, a pioneering technology recognized in 2000 by Popular Science magazine as one of the "Top 100 Inventions of the Millennium.” Southwall’s Heat Mirror insulating glass units are available from over 50 window and insulating glass manufacturers worldwide.

Mike T., Swampeast MO

Unusually Low Outside Glass Temp

I have a suspicion why the outside of the unheated windows is only slightly cooler than the heated. Before I go on one of my kooky radiation rants, can you repeat the measurements on one of your clear nights?

[Deleted User]

Yes but...

It might take some time Mike.

Let me get back to you.

ME

Mike T., Swampeast MO

Time's no problem.

jp_2

only valid IF

he also measures glass on cloudy night at same temp. and then as stated before better measure temp at the same location on the window. statements before, suggest varying temp diff across window.

jp_2

why 80F window temp????????????

mark, I can see where this has potential for cold weather big window people, like myself. my ideal winter house would be a glass dome.

but why such high glass temp? you wouldn't suggest this temp for ceiling or floors so why the windows? I can see maybe 60-65F but not higher?

Al Roethlisberger

Might be an excellent application for interior storm retrofits


This is indeed very interesting technology.

As discussed, I can see where this would be best suited for large glass and/or new construction applications.

Obviously for multi-pane or retrofit applications, it could be more challenging. The perhaps biggest trick would be on operable windows or historic windows that are to be preserved.

But, if you think about it, this is something of a non-issue. After all, in the winter, no one is really going to be opening a lot of windows regularly.

So, this might be an excellent fit for interior storm windows. One could build contact points into the sill/frame and each season just "snap" some of these radiant windows in(or leave them in for summer too, just don't run the heat).

Al

Gordy

JP Measured window temps.

I have done some extensive temp. measurements on my old 50's, but in good condition multi lite double hungs with gasketed storm.

On a 32* day Room temp. 72* 4" between glass

Cloudy day drapes open

outside the glass storm = 36.1*
Between the doublehung and storm favoring the double hung glass = 55.8*
inside of doublehung window = 63.5


Delta t room temp to room side of glass on doublehung =8.8*



Delta t room side of glass to between the storm and doublehung = 7.7*



Delta t between double hung and storm to outside surface of storm = 19.7*



Delta t room side of glass to outside of storm surface = 27.4*



Delta t Room temp to outside surface of storm = 35.9*


I have a pella combination window that is from the 80's thermopane fixed unit with casements on either side no low e not close to out performing my older window units.

Point is you need to keep that radiant window temp. close or a little higher than the room setpoint to negate the losses of the window to realise some comfort (window sucking your body heat away).


Thats IF you are just using this sort of window as a supplement to a main heating plant.



If the window were to be used as a sole source to heat a dwelling then higher temps. would be needed. example a low loss SIP home.



As you can see by my window temp measurements keeping the window at 65* won't do much better than an older window like mine, so why bother with the radiant glass.



My experiment is on going, and await a design day(-10*) at night to see what kind of delta t's I get.

Gordy

jp_2

surround ing wall temp

let us know what the outside walls temps are too.

just can't see the use of electrical surface heating. big windows to reduce losses but not heating, a btu is a watt too, or is it a watt is a btu? and for the most part NG btu's are 1/4 the cost of electric btu's around here.

why not use a thin perimeter window radiator? like a panel radiator going all the way around instead of window trim?

Gordy

Will do JP

I know my walls have a higher delta t from inside face to outside face. Especially the lower the outside temp gets.

Heating the window area to negate its losses has always been in the history of hot water heat. Why do you always see Rads in front of the windows in the old victorian homes with hot water heating.

Yes you are right in reference to the cost to operate electric verses gas. But it depends on where ya live to the cost of those kilowatts, and whether or not this is an alternative heat sorce.

I believe Marks thinking goes way deeper then just off setting the heat losses of a window. He is more excited about the fact that there is a solution out there to a problem in heating these super insulated homes.

The straight forward RFH tends to be a little over powering in these homes. Couple that with the fact that to keep conventional RFH tamned enough for such homes they lose their cozy warm feet luster.

The only solution is to cut down on the area of radiant,and raise the temps to get that cozy feeling back which means the RFH has to be strategically placed to benifit the warm feeling floor to the occupant. That can create another issue... who knows where furniture will be for the next century in the home.

Since windows are the greatest heat loss in any structure why not heat them its still radiant, a heated window on a 10* day would probably give the same cozy effect to an occupant as RFH, maybe even better. This glass goes farther than off setting losses they will heat to a higher temperature than needed to off set the windows losses.

Who would think that one day it may be said, we need to add another window to meet the load of this room.

I for one think the applications are endless. The one hurdle is operating, and product costs. But as the dino juice supply dwindles there are not many alternatives to electric yet on the horizon besides hot water solar, and when you get alot of sun you ususlly don't need much heat.

PV panels are cost prohibitive for something of this high of wattage.

Think outside the box on this one I think it will be big.


JMHO Gordy