I've just been sent a link to 'Serious Windows', who oddly enough with a name that, are an American window company. But they have some very interesting technology that I've not come across before, that looks like it could give the 'decent European windows' companies some competition.

http://index.seriouswindows.com/suspended-coated-film.html

Shows the use of 'suspended coated films' instead of a 3rd (or 4th!) pane of glass. So this gives you the extra coatings and convection-transmission reductions but with much less weight and less thickness and presumably less expense. Seems like a really good idea (so long as the film materials have sufficient durability).

They also have foam-filled fiberglass frames which seems like an excellent way of getting Uw down really low (I've seen a few passivehouse windows done this way) whilst avoiding the maintenance cost of wood.

Unfortunately all their numbers are in 'English' units so I haven't quite worked out how good their U-values are, but I expect them to be good if not excellent. What does a US 0.25 Uw translate to in metric? (they vary from 0.09 (2pane, 3film, Xenon, fixed light) to 0.3 (Dual pane, Argon, Door)

The specs are here: http://www.seriouswindows.com/performance-specs/seriouswindows.html

Is anyone doing this suspended film thing in Europe. Do we think it's any good?

They're serious kit, AFAIK. Amory Lovins uses them - he started in 1984 apparently http://www.solaripedia.com/13/220/amory_lovins_uber_solar_home_(colorado).html

I believe the film is made by these people http://www.southwall.com/southwall/Home.html

I don't know anything about availability except as Tom posted. I guess there's a patent that keeps the cost high.

Posted By: wookeyJust that one building will have a peak power load of 6Megawatts

According to wikipedia it has a floor area of 257,211 m2, which would make the specific power 6,000,000 / 257,211 = 23 W/m2

I don't believe that; it seems way too low. Where did the 6 MW come from? There are huge assumptions of course:
-1- 'peak' power rather than average power, which implies the true figure would be even lower
-2- the gross floor area is probably significantly larger than PH 'treated' floor area, which would make it larger
-3- the peak power load presumably includes all incidentals (office machines etc), which again probably makes the true figure lower

This page has some more background:
http://knowledge.allianz.com/en/globalissues/energy_co2/energy_efficiency/empire_state_building_retrofit.html

Posted By: Paul in MontrealLarge buildings have a relatively small surface area compared to their internal volume and floor area. Plus there's lots of incidental heat gains from the occupants and all their associated computers etc. so I can easily believe the 23W/m²figure. Probably the bigger saving is in cooling load, rather than heating.

Paul in Montreal.

Indeed, there's very little floor slab or roof area considering the volume.