New vanadium “tape” for energy efficient roofs

After all, it may not be too late to stop catastrophic climate change. Researchers at Lawrence Berkeley National Laboratory in California explored the unglamorous world of energy-efficient roofing for solutions, and last week they came up with a simple vanadium-based roof coating that can both cool and heat a building as needed. Since there’s no free lunch, there must be a catch, and there’s: where will all the vanadium come from?

Electric cars are good, energy efficient buildings are good too

Despite all the attention to the latest zero-emission electric cars (raise your hand) as a thrifty replacement for the planet of gasoline motorcycles, fuel-efficient buildings should also receive a little love. As in the transport sector, buildings make a significant greenhouse gas emissions, at least here in the United States. Let our friends at the US Department of Energy explain:

“The buildings sector accounts for about 76% of electricity use and 40% of the entire United States. primary energy use and associated greenhouse gas (GHG) emissions, making it essential for reducing energy consumption in buildings to meet national energy needs and environmental and reduce costs for building owners and tenants.

If you separate electricity production out of the mix and focus only on end use in buildings, which the US Environmental Protection Agency is doing, the numbers drop dramatically. However, this is just a different perspective on the same problem, which is that buildings use a lot of energy.

The good news is that energy efficient technology isn’t rocket science.

“The possibilities for improving efficiency are enormous. By 2030, the energy consumption of buildings could be reduced by more than 20% using technologies known to be profitable today, ”observes the Ministry of Energy, adding that new technologies could be added. at 15% additional savings, or even more.

Saving the planet, one energy efficient roof at a time

This brings us to the new research at the Berkeley Lab. The team was looking for a way to make “cold roof” coatings work over a wider temperature range when they used a vanadium-based solution.

The cold roof movement focuses on painting roofs white or using other materials that divert heat in hot weather, lowering the interior temperature and avoiding higher energy consumption for air conditioning or fans. The problem is that the same cool roof deflects sunlight in cold weather, depriving the household of the natural heat of the sun and increasing energy consumption for home heating.

Berkeley Lab found the solution: a new energy-efficient vanadium-based material called TARC for temperature-adaptive radiative cooling.

“Our all-weather roof covering automatically switches from keeping cool to keeping warm, depending on the outside air temperature. It is air conditioning and heating without energy and without emissionsall in one device, ”enthuses Junqiao Wu, principal investigator at the Berkeley Lab, faculty member in the laboratory’s materials science division, and professor of materials science and engineering at UC-Berkeley. .

How it works?

Vanadium is a silvery transition metal, not to be confused with vibranium. It regularly appears on the CleanTechnica radar primarily due to its use in flux battery technology. In addition to the safety and durability benefits, vanadium has multiple states of charge, which means you can create a flux battery with just vanadium instead of having to deploy two different materials.

Most metals heat up when they conduct electricity, but vanadium doesn’t heat up much at all, and that’s the key to it all.

“Vanadium dioxide below about 67 degrees Celsius (153 degrees Fahrenheit) is also transparent to (and therefore not absorbing) thermal infrared light. But once the vanadium dioxide reaches 67 degrees Celsius, it turns metallic, absorbing thermal infrared light, ”adds Berkeley Lab.

“This ability to switch from one phase to another – in this case, from an insulator to a metal – is characteristic of what is called a phase change material,” they explain.

The team made samples that looked like scotch tape, tested them, and combined their data with other data sets to model the results for buildings representing 15 climate zones in the continental United States.

The results were impressive. Although TARC still reflects about 75% of the sunlight for the year in total, it deflects more heat in hot weather and retains more heat in cold weather.

“With the installation of TARC, the average household in the United States could save up to 10% electricity,” said Kechao Tang, co-lead author of the study (former postdoctoral researcher at Wu Lab, Tang is currently assistant professor in Beijing. University in China).

The fight for the vanadium roof of the future

Don’t hold your breath for TARC to appear in the toolbox of your friendly neighborhood roofer anytime soon. The team has yet to evolve the prototype and determine if it really is a practical solution.

In practice, they can think of who is going to collect all the vanadium. Vanadium is an abundant material on earth, but just a few years ago the domestic supply of vanadium in the United States was lagging behind.

Regardless, the field of vanadium flux batteries started to gain momentum around 2014 with support from the US Department of Energy and it shows no signs of slowing down. If this energy-efficient vanadium roofing business really takes off, roofers will have to fight battery manufacturers for a cut in the supply chain, and both will have to beat the metal industry, which accounted for over 90%. of the use of vanadium in the United States from 2019.

During this time, vanadium production picks up here in the US. Part of the business is refining raw materials shipped from overseas (hello, American Vanadium business). In 2019, the US Geological Survey noted that “small quantities” were also produced from various sources, including uraniferous sandstones on the Colorado as well as waste such as petroleum residues, spent catalysts, utility ash and pork the iron slag.

If all goes according to plan, you can add used vanadium flux batteries to the supply chain. US Vanadium claims a 97% recovery rate for recycling of the vanadium-based electrolyte of its flux batteries.

The next steps for Berkeley Lab’s energy-efficient roof covering also involve raising the funds to continue research, and things have gotten a bit more difficult now that U.S. Senator and coal player Joe Manchin (D-Virginia of the West) has almost on its own blew up the purse and blew up President Biden’s signature Build Back Better climate bill.

The Department of Energy relied on Build Back Better funds to increase its R&D funding by focusing, among other things, on energy efficient buildings. clean technologies, but that seems to have evaporated after Manchin said he would not vote for the bill in an appearance on Sunday on a Fox news program.

However, all is not lost. Help may come from an unlikely source. The United Mine Workers of America have gone into energy transition mode, and earlier this year the union sided with the creation new green jobs for unionized workers.

To be clear, UMWA continues to advocate for maintaining jobs in coal. Yet the point is, coal workers are – or should be – a constituency for a U.S. senator representing the iconic coal-producing state of West Virginia.

Senator Manchin has just given a boost to his own constituents by removing the extension of the child tax credit, among other aid to families of coal workers and retirees in the Build Back Better bill, in addition to choke this thing on new green jobs for unemployed coal workers.

Apparently UMWA doesn’t take this while lying down. On Monday, the union issued a polite but direct statement detailing all the reasons why Build Back Better should pass.

“We urge Senator Manchin to reconsider his opposition to this legislation and to work with his colleagues to adopt something that will help keep coal miners working and will have a significant impact on our members, their families and their communities,” said they concluded.

Of course, none of this would matter if a single senator from the Republican side of the aisle stepped in to replace Manchin’s vote. Looking at you, Republican U.S. Senator Shelley Moore Capito from West Virginia. After all, why should Manchin take all the blame when the 50 Republican senators also dug their heels, including one representing his own home state.

Looks like UMWA has a message for both.

“I also want to reiterate our support for the passage of voting rights legislation as soon as possible, and I strongly encourage Senator Manchin and all other senators to stand ready to do whatever it takes to get there, “the UMWA statement concludes, adding that” Undemocratic lawmakers and their allies are working every day to roll back the franchise in America. The Senate’s failure to oppose it is unacceptable and constitutes a breach of its duty to the Constitution. ”

Follow me on twitter @TinaMCasey.

Photo: Kaichen Dong (left) and Jiachen Li adjust a pulsed laser deposition (PLD) device used to develop the TARC smart roof coating for energy efficient buildings (credit: Thor Swift / Berkeley Lab).

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