Green Building Bible, Fourth Edition |
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These two books are the perfect starting place to help you get to grips with one of the most vitally important aspects of our society - our homes and living environment. PLEASE NOTE: A download link for Volume 1 will be sent to you by email and Volume 2 will be sent to you by post as a book. |
Vanilla 1.0.3 is a product of Lussumo. More Information: Documentation, Community Support.
Posted By: Ian1961It's quite possible that better than expected air-tightness compensated for any under-performance in the Triso insulation.
Posted By: Ian1961we would have been the first to find out if the heating system hadn't performed as designed or if the house had been draughty.
Posted By: Ian1961It had stitching at intervals to hold the layers together.In that case
Posted By: Ian1961 A lot of attention was paid to airtightness - taping etc.was a waste of time, if that means taping the Triso joints. I once calc'd that those stitch holes are equiv to a 70mm diam hole per m2 of Triso. So let no one say that Triso's 'performance' is in any way due to the airtightness is provides (not) as a bonus.
Posted By: ringiIt's quite possible that better than expected air-tightness was BECAUSE of using the Triso insulation.How come, when there's equiv of a 70mm hole per m2 in it?
Posted By: Mike Georgemake a valid comparison is how big a diameter hole all of the air paths in flexible insulation are equal to.... (ie compared to your calculated 70mm hole)No need - the point is that either is a hole quite big enough to fall into. You know, Mike, that 'airtight' isn't airtight until the very last crack sealed up - it's very steeply 'geared' - 'quite good' isn't any good at all.
Posted By: fostertomI once calc'd that those stitch holes are equiv to a 70mm diam hole per m2 of Triso.
Posted By: mike7the possibility - in my mind at least , not ever having seen a stitched multifoil - that the various layers are not pulled tightly together, but with a bit of distance remaining between each layerYes, stitching was soon abandoned by the industry, in favour of spot-welding, giving both unbroken membranes and a lot less local compression of the layers - with that then yes it's worth bringing airtightness into the picture. But the Trisos, incl the ones in the notorious 'twin shacks' test, were far from airtight, so that can't justify any of the measured performance.
Posted By: BeauIs it still worth counting the holes. Hoping you're going to say no
Posted By: Ed DaviesWhy is radiant heat transfer considered “instant action� OK, photons move pretty quickly but still it takes time for heat to move from one object to another with a similar order of magnitude rate as conduction.This was in answer to
Posted By: fostertomThat way, there would be great resistance to the instant-action radiant heat transfer across the void spaces,Consider an ideal extreme: a slab of 'solid' with lots of tiny irregular granular voids, a high void to solid ratio, so convoluted long-perimeter walls of solid between the voids. All is at static, equilibrium temp.
leaving nearly all the heat transfer to be done by conduction via the circituous solid path between the bubbles,
and by convection across the voids.
As the latter two modes are subject to lag due to the thermal capacity of the solid, and the thermal capacity and the inertia of the air, their delivery of transfered heat is much delayed compared to the instant-action radiant heat transfer.
Posted By: fostertomThe point is, that the whole of the re-equilibriation (equalisation) may have been done and completed by radiant means, direct from near to far wall, by the time heat transfer finishes. The conductive and convective need not have bothered.I would think this needs calculations - intuition could be very misleading so I wouldn't want to even guess if this is right or not. Have you done, or seen, any?
Posted By: Mike Georgea certified Vapour Resistance of 6000MNs/gLike poythene then - not rocket science. Like polythene, all depends on the joint-taping.