This past June was a significant month in climate history. Marked by extreme temperatures in the Pacific Northwest, it was the hottest recorded June in North America. Not surprisingly, according to NOAA’s National Centers for Environmental Information (NCEI), 2021 will almost certainly be counted as one of the 10 warmest years on record. Given the extreme heat, it’s hard to imagine life without air conditioning. And yet, as a significant contributor of CO2 emissions, A.C. is actually helping to accelerate climate change. Gabrielle Dreyfus, a program manager at the Institute for Governance and Sustainable Development, puts it this way: “If we deal with cooling wrong, we essentially cook ourselves.”
Thankfully, a collection of recent innovations could help reduce A.C.’s global warming problem. For example, the engineers at Gradient, a San Francisco-based startup, want to revolutionize the window unit. Gradient’s founders aim to marry the high performance of heat pump technology with the installation convenience of a conventional window unit. The Gradient unit resembles a bench with two thick supports that you hang over a window sill. The clever design means the unit doesn't obstruct the view out the window and places the noisier components on the outside. The company claims a 75% reduction in carbon footprint compared to conventional A.C. systems when used year-round for cooling and heating. Furthermore, the device relies on a reduced-footprint refrigerant to generate more energy-efficient variable conditioning.
Dublin, Ireland-based Exergyn, on the other hand, aims to eliminate refrigerants altogether. Instead of relying on hydrofluorocarbons (HFCs) or other gases that contribute to global warming and ozone depletion, the company uses nitinol, a shape memory alloy (SMA) made of nickel and titanium. The design features perforated nitinol plates assembled into stacks. Alternately compressed and released by actuators, the SMA absorbs and removes excess heat. Exergyn anticipates its gas-free air conditioner will deliver a reduced environmental footprint as well as a 30% to 40% cost savings versus conventional systems. The technology will also have a smaller physical footprint and will not require gas refills.
Los Angeles-based SkyCool Systems, meanwhile, has developed a cooling method for buildings that does not involve air conditioning. The company’s approach employs radiative materials that reflect sunlight and heat away from building roofs, saving 10% to 40% in energy use. SkyCool Radiative Cooling Panels are similar to solar PV panels in size, configuration, and aesthetic, but they help conserve energy instead of generating it. And they work at night. Another advantage: The radiative panels weigh about half as much as the solar PV ones, and they reportedly save two to three times as much energy as solar panels can generate within the same roof area. (SkyCool conserves 500-600 kWh/m2 of electricity annually; solar PV produces 250 to 300 kWh/m2 per year.) Because the panels do not need to be oriented toward the sun, they can be easily combined with a solar array to maximize the benefits of both technologies.
And finally, the renewable energy sector may get a boost from a new battery. Form Energy, based in Somerville, Mass., has found a way to deliver ultra-long-lasting electricity storage using iron. While today’s conventional lithium-ion-powered batteries have seen measurable advances in performance, they still have storage limitations. The critical elements used to make these batteries—cobalt, nickel, and manganese—cost $50 to $80 per kilowatt-hour of storage. Form Energy’s battery will reportedly discharge power over several days, and the raw materials will cost under $6 per kilowatt-hour of storage.
If Form Energy manages to take this technology mainstream, it will yield “the kind of battery you need to fully retire thermal assets like coal and natural gas,” the company’s CEO, Mateo Jaramillo, told The Wall Street Journal. The iron-air battery won’t be ready for the marketplace for at least a few more years. But Form Energy’s invention—and the other innovations described here—may one day help prevent us from “cooking ourselves.”
The views and conclusions from this author are not necessarily those of ARCHITECT magazine or of The American Institute of Architects.
