A sealed enclosure surrounding a rigid core from which the air has been evacuated, used in building envelopes.
A vacuum insulated panel (VIP) is a form of thermal insulation. It consists of a nearly gas-tight enclosure or membrane (such as aluminized mylar) that may be heat sealed, surrounding a semi-rigid core from which the air has been evacuated. The membrane prevents air from entering the vacuum panel. The panel is filled with a rigid, highly-porous or fibrous material such as aerogel to support the membrane walls against atmospheric pressure once the air is evacuated. Creating a vacuum reduces conduction and practically eliminates convection, since convection relies on the presence of gas molecules to transfer heat energy.
VIPs have better insulating properties than conventional materials. A one-inch thick vacuum insulated panel can provide an insulating value of R-25 to R-30. VIPs are compact and lightweight, making them useful in space-limited applications or on roofs where adding bulk is costly. While VIPs are used in niche applications, such as refrigerators, freezers, and insulated shipping containers, their use in buildings is constrained by cost. Currently available VIPs run $10 to $12 per square foot (Wilson, 2013).
Installation of VIPs must be done with care as even a pinprick can cause them to lose their high insulating value.
Status:
Probably OK in some restricted applications such as retrofit. But we already have fine, low-cost insulation that works for most applications.
Too expensive for res?
I have used these in two projects. They have the potential in both new and retrofit to provide assemblies with R values needed for net zero energy housing R 30 to R 80. Best used when sandwiched between two layers of rigid insulation, EPS, XPS or mineral wool board. Can be installed under floating floors. When used in walls may require separate support system for cladding. VIPs are vapor impermeable so when they are used as part of an exterior insulated sheathing system care must be taken to ensure that the inside face of the VIP does not fall below the indoor air dew point temperature in winter if the VIP fails. Costs are coming down and life is increasing. Some German VIPs are available with a rigid fiberglass case which should enhance their durability. If you wish to pursue you may find this useful ftp://ftp.cmhc-schl.gc.ca/chic-ccdh/Research_Reports-Rapports_de_recherche/eng_unilingual/Ca1_MH_12R22_w.pdf
Watch out for nails and screws.
Baseline Description:
It is unclear how VIPs would save energy over construction in accordance with existing building codes. The VIP is one of many ways of constructing a building to meet or exceed current code prescriptive or performance requirements.
Cost is $10 to $12 per square foot for a one-inch thick Dow Corning panel with an R-30 insulating value.
Simple payback, new construction (years): N/A
Simple payback, retrofit (years): N/A
Cost Effectiveness is calculated using baseline energy use, best estimate of typical energy savings, and first cost. It does not account for factors such as impacts on O&M costs (which could be significant if product life is greatly extended) or savings of non-electric fuels such as natural gas. Actual overall cost effectiveness could be significantly different based on these other factors.
Alex Wilson, 11/14/2013. Does Vacuum Insulation Make Sense? GreenBuildingAdvisor.com
Martin Solomon, 06/29/2012. Vacuum Insulation Panels Push the Envelope to R-30 Per Inch Building Green.com
Technical Advisory Group: 2014 Residential Building TAG (#10) TAG Ranking: Average TAG Rating: 2.4 out of 5 TAG Ranking Date: 04/10/2014 TAG Rating Commentary: Probably OK in some restricted applications such as retrofit. But we already have fine, low-cost insulation that works for most applications. Too expensive for res? I have used these in two projects. They have the potential in both new and retrofit to provide assemblies with R values needed for net zero energy housing R 30 to R 80. Best used when sandwiched between two layers of rigid insulation, EPS, XPS or mineral wool board. Can be installed under floating floors. When used in walls may require separate support system for cladding. VIPs are vapor impermeable so when they are used as part of an exterior insulated sheathing system care must be taken to ensure that the inside face of the VIP does not fall below the indoor air dew point temperature in winter if the VIP fails. Costs are coming down and life is increasing. Some German VIPs are available with a rigid fiberglass case which should enhance their durability. If you wish to pursue you may find this useful ftp://ftp.cmhc-schl.gc.ca/chic-ccdh/Research_Reports-Rapports_de_recherche/eng_unilingual/Ca1_MH_12R22_w.pdf Watch out for nails and screws.
Technical Advisory Group: 2014 Commercial Building TAG (#9) TAG Ranking: 22 out of 44 Technologies (2014 Commercial TAG strategies ranked separately) Average TAG Rating: 2.6 out of 5 TAG Ranking Date: 03/17/2014 TAG Rating Commentary: Good performance but very high costs; good thermal detailing needed to integrate with envelope I am not very familiar with this.