BETEC Attendees Learn Windows Don't Have to
be "Energy Losers"
December 10, 2009
objective is to take windows from energy losers to neutral and then
net-energy suppliers," commented Joseph Deringer, AIA, LEED
AP, with the Institute for the Sustainable Performance of Buildings,
during today's Building Enclosure Technology and Environment Council
BETEC, which took place at the Washington Convention Center in Washington,
D.C., in conjunction with Ecobuild America, taking place this week,
focused on the topic of "Retrofitting Building Enclosures for
Energy Efficiency and Sustainability."
filled in for the Department of Energy's (DOE) Marc LaFrance today
on a presentation on window and building enclosure research at the
DOE. Deringer began by stating that the DOE's (conservative) goal
for energy efficiency is reaching net-zero-energy homes by 2025.
Toward that end, he listed several core areas of DOE's goals for
window research and development:
- Commercializing cost-effective R-5 windows;
- Development of affordable dynamic windows;
- After developing R5 windows, working toward the next generation
of R10 windows;
- Promoting efficient products with enabling research;
- Developing integrated daylighting strategies; and
- Developing fenestration test and rating standards internationally.
Dudley McFarquhar of McFarquhar Group looked at some of the challenges
of executing an energy retrofit for existing buildings in his presentation
titled "Designing Commercial Energy Retrofits for Curtainwalls."
Although McFarquhar early on defined a curtainwall as being able
to be composed of various substrates, he also put the responsibility
of energy efficiency on a building envelope's glazing materials.
"If we talk about energy and the building envelope we're actually
looking at the need to control light transmittance in the vision
areas," he said.
of the things to keep in mind in planning an energy retrofit, he
noted, include maintaining insulation at spandrel areas, focusing
on air and water infiltration and reviewing the status of building
materials such as gaskets, glazing, framing, sealants and, importantly,
framing anchors. He also advised his audience of building engineers
to determine what type of system is in place--whether stick-built
curtainwall, unitized, etc.--as that will, to some degree, determine
the retrofit design approach. He noted the age of a building can
offer some information on the type of materials and systems you're
likely to find yourself dealing with. For example, he noted, "The
sequence of [unitized] framing is difficult for retrofit because
you're stacking from the bottom up, etc."
Brandon Tinianov, chief technology officer of Serious Materials,
focused specifically on "Advanced Glazing and Window Technologies."
"In my simple view of the world there's three generations of
windows: high thermal insulation, dynamic glazings and building
integrated photovoltaics (BIPV)."
He offered a timeline for when these technologies might be expected
to become "mainstream" within the marketplace. "We're
seeing high thermal insulation; dynamic glazings might come out
in the next five years or so (not counting some of the commercial
offerings available today) and I think in the next ten years or
so we'll see BIPV."
The wait for BIPV is a result of high price tags and inefficient
designs, Tinianov said. "It's interesting, it's novel, it's
exciting, but it's just not compelling right now. These costs have
to come way, way down."
Dynamic glazing, too, largely suffers from high costs that are keeping
it from becoming commonplace in the market. He pointed to one problem
of some systems. "The last problem with dynamic glazing is
what it does is it [the opaque portion] creeps across the
window and becomes somewhat of an inkblot test
elements may be unappealing to the users."
Tinianov largely focused on more efficient developments for insulating
glass units (IGUs). He began by noting that dual-glazed systems
were invented as early as 1865. "What's really shocking is
that if you dig into this patent you can actually see a triple-glazed
unit," he said before providing his audience with background
information on what's only now growing as an energy-efficient option
"One of the reasons I'm very fond of multiple lite systems,"
Tinianov said, "is because you have so many possibilities."
For example, he said, "In a system that just has three total
lites I've got six available surfaces to work with
got the benefit of a deeper thermal pocket, now I can start to tune
that low-E coating."
Tinianov also noted, "Multiple lites are finding their ways
into all kinds of iconic retrofits and I think that's very important."
He pointed to the Sears Tower (CLICK
HERE for related article) and Empire State Building (CLICK
HERE for related article) as two notable examples taking up
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