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: djhwhere are you reading the 0.62?Converted it from Murican.
Posted By: passivhausfanThey can do a higher SHGC
You really need the edge to be lost in insulation so that the path for heat transfer is lengthened.
Posted By: passivhausfanThat is an inherent property of vacuum glazing: no convection.
Posted By: WillInAberdeenIn conventional DG filled with noble gas, the partial pressure of air between the glass is ~zero. For vacuum glazing, the same. So no good reason why a vacuum would be lost any earlier than an argon fill might be lost.
Posted By: Peter_in_HungaryThe usual problem with DG units failing is a failure of the sealing around the edgesthe two panes in the spacia glass unit are actually welded together (IE not sealed with a sealant or bead) at the edges, across the 0.2mm cavity. Welds are generally much more reliable than seals.
Posted By: Peter_in_HungaryThe argon gas in a DG unit is at 1 bar (absolute not gauge pressure)- the same as the air - so the pressure to exchange gas is just the daily variation in atmospheric pressure. With a vacuum unit the internal pressure will be close to zero absolute pressure so there is a suction into the unit driven by the 1 bar pressure on the outside thus a very small failure in the seal between the panes of glass will result in a (quick) failure of the unit.Perhaps I wasn't clear what a ’partial pressure' means? The partial pressure of argon etc inside a conventional DG unit is 1bar, and in the outside air the partial pressure of argon is nearly zero, so there is 1 bar of partial pressure trying to make the argon escape. Likewise the partial pressure of nitrogen+oxygen+watervapour outside the unit is 1bar, and inside it is zero, so there is another separate 1bar of pressure, trying to force air into the unit. The N2/O2 molecules 'think' that the inside of a DG unit is a very high vacuum, which they really ought to rush in and fill, and the argon 'thinks' the same about the outside air.
Posted By: WillInAberdeenThe seal of a conventional DG unit has to resist two completely separate pressures, each of 1bar, in opposite directions but not cancelling each other out. If there were a tiny hole, the pressures would not cancel each other out, instead there would be 1bar worth of partial pressure forcing air in through the hole, and another 1bar worth of partial pressure forcing argon outward.
By comparison, vacuum panels only have to deal with a single 1-bar pressure difference, not two at once. There is a net (mechanical) pressure difference, which squashes the panes together, so the spacia ones have tiny spacers every 20mm.