Image credit: Chad Malone/ORNL, U.S. Dept. of Energy

New Eco-Friendly Home Insulation Cuts Heating & Cooling Costs

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Ever since the first homes were built, people have been trying to find insulation materials that would keep them warm in winter and cool in summer. Just about everything has been tried — seaweed, sod, asbestos, tar paper, rolled up newspapers, urea foam, and pink fiberglass batting from Owens Corning. A March 23 press release from Oak Ridge National Laboratory says rigid polystyrene panels are a popular choice, but come with environmental drawbacks. It says the blowing agents used in foam production, such as hydrocarbons and hydrofluoro-olefins, wind up in the atmosphere and contribute to global warming.

Scientists at ORNL say they have developed a competitive, eco-friendly alternative insulation made without harmful blowing agents. The nontoxic thermoplastic foam is made using hollow glass spheres and expandable polymer microspheres. “The combination of these two sources allows us to tailor formulations to maintain the material’s thermal performance across a limited range of densities,” says ORNL’s Meghan Lamm. “We are also working with thermoset materials, which offer high temperature stability for improved flame resistance.”

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“The technology is readily adoptable by industry and opens avenues to develop safer composite foams for a variety of insulation systems,” said ORNL’s Tolga Aytug, one of the lead researchers on the insulation project. The technical side of all this is explained in a research paper published February 13, 2023 in the journal Polymers.  Here is the abstract of the research paper. The details are behind a paywall.

“We report a simple and commercially viable strategy to produce thermoplastic composite foams using synergistic foaming approaches — incorporating porous shell hollow interior glass spheres (PHGS) as a filler and utilizing expandable thermoplastic microspheres (EMS) as a physical blowing agent — for thermal insulation applications. The EMS in these composites ensure formation of highly porous, low density foam while the PHGSs provide low thermal conductivity and lightweight mechanical reinforcement.

“Through systematic optimization of the PHGS and EMS loadings, a lightweight and robust insulation with thermal resistivity greater than 27.7 m·K/W (R/in. > 4) is achieved. Notably, the fabricated foams also demonstrated comparable compressive strength to some commercial thermoplastic insulating materials. Through optimization of PHGS and EMS concentrations, results indicated similar thermal performance characteristics at varying foam densities, while higher loadings of both components lead to reduced insulation performance and weak mechanical stability of the foams.

“The results obtained, when coupled with the potential scalability and tailor ability of the overall process towards targeted insulation performance, not only endows competitiveness with current commercial thermoplastic insulating materials but also offers great promise for the development of unique thermoplastic composite foams for a variety of insulation systems.”

Air Is The Best Insulation

Just about every kind of building insulation there is depends on trapped air to provide the actual insulation power. All those glass fibers in regular fiberglass insulation are there just to create a barrier of still air that does the actual work of controlling heating or cooling losses. It is the trapped air between sheets of glass in so-called thermopane windows that makes them effective.

Oak Ridge National Laboratory does a lot of research into building insulation products because it says the investment in research and development within the industry is about 1% — far lower than in most other industries. “The buildings construction industry is notable for its slow acceptance of new technologies. The industry is highly fragmented, which contributes to the market’s resistance to adopting new technology. DOE funded research plays a critical role in developing technological advancements that reduce energy consumption and increase building longevity,” ORNL says.

Oak Ridge National Laboratory provides state of the art building envelope research through internationally recognized experts using modern test facilities at the Buildings Technology Center (BTC), a DOE National User Facility. The need for ongoing research into insulation materials is ongoing, since space heating, cooling, and ventilation account for 35% of energy consumption for buildings — 29% commercial and 41% residential.

In a recent study of deployment of energy efficient technologies in commercial buildings, more than $1.5 billion annually was saved from use of three such technologies alone. In addition, energy efficiency innovations in home building have resulted in substantial efficiency improvements over the last 20 years. Nevertheless, homes built in the last 10 years consume more energy than those built in the previous three decades, likely as a result of having more cooling requirements, which has resulted in the ongoing need to pursue energy efficient solutions for buildings.

Making Buildings More Energy Efficient

Rewiring America is intent on addressing building efficiency all across the United States. While it focuses on converting homes and businesses to heat pumps for heating, cooling, and making hot water, and upgrading electrical panels as required, it knows those improvements amount to little if the warmth or coolness inside just leaks through the walls and windows into the world outside. That’s why it also conducts energy audits to determine how buildings can be made more energy efficient. Upgrading insulation in walls and ceilings is a big part of what Rewiring America does.

My colleague Tina Casey recently reported on new energy efficient windows that use an aerogel made from the beer brewing process to dramatically increase their insulation properties. (Windows are responsible for about a quarter of all heating and cooling losses from buildings in America.) According to Ivan Smalyukh at CU Boulder, the aerogel can be made from cellulose derived from the waste wort left over at the end of the beer brewing process and can also be derived from wood waste.

The Takeaway

Here’s an analogy. When contemplating the energy grid of the future, we can either build more generating plants or lower the demand for electricity.  There are a number of strategies that include demand response mechanisms to smooth out the peak demand for electricity at certain parts of the day and if utility companies take advantage of them, they can avoid building new generating capacity that can cost billions of dollars to construct.

The same applies to energy efficiency in our built environment. If our buildings are more energy efficient, we need less of whatever we are using to heat and cool them. Even if they are equipped with heat pumps and state of the art water heaters, it’s silly to waste any energy even if it originates from renewable resources.

Industry seems to have little interest in researching new insulation techniques, which is why the work being conducted by Oak Ridge National Laboratory is so important.

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Steve Hanley

Steve writes about the interface between technology and sustainability from his home in Florida or anywhere else The Force may lead him. He is proud to be "woke" and doesn't really give a damn why the glass broke. He believes passionately in what Socrates said 3000 years ago: "The secret to change is to focus all of your energy not on fighting the old but on building the new." You can follow him on Substack and LinkedIn but not on Fakebook or any social media platforms controlled by narcissistic yahoos.

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