New Technologies Reduce Home Energy Needs
These new and emerging technologies may make electrification the greenest way to power up the household.
If we want our societies to achieve net-zero carbon emission status, their many features must require less energy. They must integrate more sources of renewable energy systemically. These are largely the needs of developing smarter homes for ourselves, as well: Cut energy and resource expenditure needs significantly to become more sustainable.
Solar Hydropanels act like solar panels, providing renewable energy off the grid. But they also pull moisture out of the air and produce up to five liters of drinking water per panel each day. Photo courtesy SOURCE
What kinds of new technologies can help reduce our home energy needs? Generally, insulation to save on heating; air conditioning and shading developments to save on cooling; renewably produced hot water; smart grid-capable appliances; and anything else that will reduce our draw on energy resources.
Now, new insulating materials do not necessarily make for sexy book content. And many are not all that futuristic: Techniques like 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.
Michigan State University has been working to finalize a transparent, glass-like solar harvesting system that when applied to windows is capable of producing as much electricity as bigger, bulkier rooftop photovoltaic panels. Photo courtesy MSU
Scientists also envision passive solar collectors with transparent insulation heating hot water pipes or other areas where heat is required all the time, rather than merely lining specific room windows.
New Smart Glass Windows
Windows have already received a considerable upgrade with energy harvesting tech. Transparent solar cell (TSC) panels have been used in greenhouse roofing and building windows, creating an opportunity for homeowners of the future to generate solar energy from window space. But incredibly, that means new smart glass windows will also have the ability to block selective wavelengths of light from even entering buildings.
Transparent solar-harvesting systems will use molecular designs capable of absorbing only wavelengths of light that we cannot see—like ultraviolet and near-infrared—converting just those wavelengths into energy while allowing us to see the rest of our visible spectrum.
Aside from generating energy, this will allow windows of the future to block out specific wavelengths of light to also bypass some of the heat our homes would otherwise be absorbing, and to potentially bypass the need for blinds on sunny days with electrochromatic shading control.
Scientists from Chalmers University of Technology in Sweden have developed a molecular solar thermal (MOST) window film that can absorb energy from the sun’s rays and later emit it as heat for up to eight hours after sunset. Illustration courtesy Yen Strandqvist/Chalmers
“Chromism” refers to chemical processes that induce a change in color, often with the connotation that the change is reversible. The term electrochromatic, then, refers to an electricity-induced chemical change in color.
Within the context of windows, scientists have found that by putting materials with chromatic qualities inside panes of glass, they can alter a number of features with a very small electric input. The result is that smart windows allow for reversible changes in opacity and transparency.
Glass with opacity alteration means a new system of window blinds. The smart glass TruTint from Nodis reportedly allows for instantaneous change while achieving up to 10 times lower costs in heat efficiency. The product offers an “infinite” number of tints and infrared control to optimize indoor climate and energy savings, according to suppliers (though I suspect the range of options is not literally infinite.)
Newer developments allow for altered reflectivity in response to specific wavelengths of light, implying self-tinting windows for bright days. Project Drawdown has estimated that adopting a technology like smart glass into largescale commercial buildings and in residential applications can result in a greenhouse gas reduction of 2.2 gigatons. And the technology is particularly useful if it also saves us money.
According to Drawdown, tests of electrochromatic glass in Japan have reduced cooling loads by more than 30 percent on hot days. And while purchase and installation costs may be twice as expensive as normal windows, energy savings make them more than competitive. Some newer models of smart glass may have the ability to harness some energy from the sunlight hitting your windows through TSC tech, resulting in even more savings.
For homeowners who don’t want to draw their shades via app, some new smart window models simply use coatings that offer similar—but offline—features like auto-shading. Smart window coatings are essentially filled with very small, water-filled balls that shrink or expand with temperature.
One academic team published in the science journal Joule revealed that their film of microscopic particles alone could reduce temperature (without a loss of visibility) by as much as nearly 10 degrees F. The coat reportedly reflects up to 70 percent of the sun’s heat while letting in visible light, freeing up more of our energy from use on air conditioning.
Some researchers have been hard at work producing a do-it-yourself (DIY) paint-on coating version of the aerogel tech, offering homeowners an energy-efficient window coating at one-tenth the cost of professionally installed retrofits.
Bridge to Solar Plus Storage Technology
We may even be able to capture the thermal energy of incoming sunlight streaming through our windows, and—rather than harnessing the electricity through TSC—use materials similar to the thermal energy “hybrid” panels to retain it. To recap, thermal hybrid panels will soon be capable of placement on rooftops as traditional solar panels are, but they would capture thermal energy for immediate or (through storage) later use.
The device may bridge our much-needed gap in “solar+storage” technology. In terms of window tech, one new film with a uniquely designed molecular chemistry now offers the ability to capture thermal energy from solar rays and distribute it evenly throughout the glass. Materials have a yellowish tint at the start of the day, isomerize and turn transparent in response to solar heat, then reverse over time at night to restart the cycle.
As long as the sun is shining on the window’s film, less heat can penetrate into rooms. But the added bonus is that heat can be stored for much longer periods than just hours, or even days. Researchers envisioned that by using a molecular solar thermal (MOST) storage system, homeowners may be able to store thermal energy for weeks or even months.
Transparent nanostructured aerogels can reduce heat transfer beyond walls and through the roof. When applied to windows, these aerogels allow more sunlight to enter but not exit, making it ideal for heating homes. Photo courtest Stuart Darsch/MIT
One of the most fascinating new developments in refrigerant technology involves the concept of radiative cooling…yet another interesting take on generating energy from the world around us. But given that the concept implies a sky-facing surface should be cooler than the air around it, does that not also imply a plausible connection for our cooling needs?
Indeed it does. Because heat escapes along a thermal gradient leading out into the cold of space from the surface(s) of our planet, this has led some scientists to conclude that we might build materials to recycle the slight dip in surface-level temperature.
And by setting up a specially structured reflective material, scientists were recently able to direct a wavelength of light back out into space that escapes our atmospheric cover more easily—leading to a radiative cooling effect even during the day. As a result, a material able to direct unique wavelengths more readily can become about 5 degrees Celsius cooler than ambient air temperatures.
A similar device was also developed by scientists at the University of Buffalo. It requires no added electricity to function. The system is essentially a low-cost polymer/aluminum film installed inside a box located at the bottom of a solar “shelter.”
The film performs radiative cooling and keeps ambient air within the shelter cool by re-directing more of the surrounding heat—with a sky-facing design that actively channels thermal radiation more directly from the film into the atmosphere.
The device helps to corral and focus directed heat away from ambient surroundings without any use of electricity. According to the team’s research, temperature reductions around the enclosed space dropped by about 6°C (11°F) during the day and 11°C (about 20°F) at night.
One geoengineering initiative falling under a category of solar radiation management (SRM) includes painting our rooftops colors that reflect away more sunlight to reduce the amount of heat absorbed.
So-called “cool roof” coatings can not only reduce the amount of heat warming up a home, but can also slightly reduce the surrounding air temperature—particularly if many homes in an area use them. New research from the Department of Energy’s Lawrence Berkeley National Laboratory has shown that widespread adoption of cool roofs can also lower overnight temperatures during hotter evenings as well.
Cool roof materials will definitely benefit from new applications in nano-scale surface material developments. For example, a growing number of nanophotonic materials have been developed, allowing scientists to manipulate the way light encounters materials at the nano scale.
One new development in materials sciences from Berkeley, California-based Cypris Materials involves self-assembling reflective coatings offering tailored optical properties for even more selective wavelength reflection. The company’s coatings enable more heat mitigation by reflecting ultraviolet and near-infrared radiation like the models above—but rather than merely applying to windows, Cypris’ coatings could be also placed on walls and rooftops to reflect more of the sun’s rays with a transparent, colorless coating.
In terms of saving on resources in homes (simultaneously saving the city at large from shuttling them in), nothing may be more upending than the ability to procure one’s own water. And now, tech similar to the devices used by scientists to draw in moisture from ambient air and harness the molecular portions of water can also be used by homeowners—in the form of solar panels able to draw in and sequester water for domestic use.
Tempe, Ariz.-based SOURCE Global produces a line of solar Hydropanels that not only provide renewable energy off the grid, but also reportedly produce between 2 to 5 liters of drinking water per panel, per day (relative to sunlight and the surrounding humidity, of course—about a half-gallon to 1.3 gallons in conversion).
Essentially, Hydropanels use solar power to pull in large amounts of air, then collect moisture from that air onto an absorbing material, with solar heat converting it into water [and then] into a 30-liter (7.9 gallon) reservoir, where it is mineralized and kept clean using ozonation. Incredibly, reservoirs can also be run directly to internal faucets.
Engineers with SOURCE have more recently unveiled an additional series of system sensors to fine-tune owners’ monitoring of the water reservoir itself. Sensors will allow customers to keep tabs on the water quality in real-time and monitor daily reports via the SOURCE app.
Monitoring Emissions in Building Materials
Standardized assessment protocols also now exist for gauging the emissions standards for various materials throughout construction. This is especially encouraging because of how complicated it must be.
Any one construction project may contain literally thousands of different materials, all with varying carbon emission impacts. Immense tracking applications for materials worldwide have been entered into an Environmental Product Declaration (EPD) increasingly utilized by more construction companies to chart carbon cost for different materials. Anything from insulation and ceiling tiles to metal framing and insulation materials is included.
New tools like EC3 (Embodied Carbon in Construction Calculator) use Microsoft-driven analysis of thousands of EDP items to calculate carbon impacts more quickly. We will explore the concept of “regenerative architecture” as one strategy among many others to sequester more CO2 over the coming years, but for now, yet another avenue exists primarily for cutting emissions while still producing first-class buildings.
This story was excerpted from Our Livable World: Creating the Clean Earth of Tomorrow by Marc Schaus. Content has been edited for length and is being reprinted by permission of the author and the publisher, Diversion Books.
Marc Schaus is a professional research specialist across the sciences for research ventures, craft product manuals, and policymakers. He is the author of Post Secular: Science, Humanism and the Future of Faith, and has written articles that have appeared in Areo Magazine, Free Inquiry Magazine, The Huffington Post, Patheos, and the academic journal Antennae. He currently resides in Ontario, Canada.