Page 25 - Green Builder Sept-Oct 2020 Issue

BY MARC SCHAUS shading control.
F WE WANT OUR SOCIETIES TO APPROACH net-zero “Chromism” refers to chemical processes that induce a change in
carbon emission status, their many features must require color, often with the connotation that the change is reversible. The
less energy. They must integrate more sources of renewable term electrochromatic, then, refers to an electricity-induced chemical
energy systemically. These are largely the needs of developing change in color. Within the context of windows, scientists have found
I smarter homes for ourselves, as well: cut energy and resource that by putting materials with chromatic qualities inside panes of
expenditure needs signi cantly to become more sustainable. glass, they can alter a number of features with a very small electric
What kinds of new technologies can help reduce our home energy input. The result is that smart windows allow for reversible changes
needs? Generally, insulation to save on heating; air conditioning and in opacity and transparency.
shading developments to save on cooling; renewably produced hot Glass with opacity alteration means a new system of window
water; smart grid-capable appliances; and anything else that will blinds. The smart glass TruTint from Nodis reportedly allows for
reduce our draw on energy resources. instantaneous change while achieving up to •– times lower costs
Now, new insulating materials do not necessarily make for sexy in heat e—ciency. The product o˜ers an “in nite” number of tints
book content. And many are not all that futuristic: techniques like and infrared control to optimize indoor climate and energy savings,
advanced framing, high-performance
walls, closed-cell spray foam, rigid
foam boards, flooring insulation, and
minimizing thermal bridging have gotten
us pretty close to the insulation meeting
net-zero building standards. But newer
materials like nanostructured aerogels are
becoming more standard for new homes,
vastly reducing heat transfer beyond walls
and through the roof.
Newly developed Massachusetts
Institute of Technology (MIT) aerogels
are actually transparent and applicable for
smarter glass insulation, providing another
opportunity for advanced insulation (and
cost savings). Windows outfitted with
greater insulating material will be helpful
for colder climates, allowing more sunlight
to enter but not exit, like a greenhouse
effect. Scientists also envision passive
solar collectors with transparent insulation
heating hot water pipes or other areas Healthy harvest. Michigan State University has been working to finalize a transparent, glass-like solar
where heat is required all the time, rather harvesting system that when applied to windows is capable of producing as much electricity as bigger,
than merely lining speci c room windows. bulkier rooftop photovoltaic panels. CREDIT: MSU
according to suppliers. (Though I suspect the range of options is not
NOT YOUR EVERYDAY WINDOW GLASS literally in nite.)
Windows have already received a considerable upgrade with energy Newer developments allow for altered re™ectivity in response
harvesting tech. Transparent solar cell (TSC) panels have been used in to specific wavelengths of light, implying self-tinting windows
greenhouse roo ng and building windows, creating an opportunity for bright days. Project Drawdown has estimated that adopting a
for homeowners of the future to generate solar energy from window technology like smart glass into largescale commercial buildings and
space. But incredibly, that means new smart glass windows will also in residential applications can result in a greenhouse gas reduction
have the ability to block selective wavelengths of light from even of š.š gigatons. And the technology is particularly useful if it also
entering buildings. saves us money.
Transparent solar-harvesting systems will use molecular designs According to Drawdown, tests of electrochromatic glass in Japan
capable of absorbing only wavelengths of light that we cannot see— have reduced cooling loads by more than œ– percent on hot days. And
like ultraviolet and near-infrared—converting just those wavelengths while purchase and installation costs may be twice as expensive as
into energy while allowing us to see the rest of our visible spectrum. normal windows, energy savings make them more than competitive.
Aside from generating energy, this will allow windows of the future Some newer models of smart glass may have the ability to harness
to block out speci c wavelengths of light to also bypass some of the some energy from the sunlight hitting your windows through TSC
heat our homes would otherwise be absorbing, and to potentially tech, resulting in even more savings.
bypass the need for blinds on sunny days with electrochromatic For homeowners who don’t want to draw their shades via app,

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