coating

Lampshades And Indoor Air Pollution | Earth Wise

September 26, 2023 By EarthWise Leave a Comment

We mostly think of air pollution as an outdoor problem. Common sources of air pollution include emissions from vehicles, byproducts of manufacturing and power generation, and smoke from wildfires. What we don’t often spend a lot of time thinking about is indoor air quality.

Indoor air pollution refers to harmful pollutants within buildings and structures, which can lead to a myriad of health issues. Sources of indoor air pollution include smoke from tobacco products, as well as volatile organic compounds (VOCs), including acetaldehyde and formaldehyde, emitted from things such as paints, cleaning products, plastics, and cooking.

A team of scientists from South Korea’s Yonsei University has developed a special coating that when applied to lampshades can convert pollutants into harmless compounds. Composed of titanium dioxide and a small amount of platinum, this thermocatalyst can be applied to the inside surface of a lampshade and is triggered to break down VOCs when warmed by the lamp’s existing incandescent or halogen bulb.

In lab tests, the coating was applied to the inside of an aluminum lampshade, warmed by a halogen bulb, and then placed into a sealed chamber containing air and acetaldehyde gas. The researchers found that the material quickly converted the gas into acetic acid, then into formic acid, and finally into carbon dioxide and water. The scientists are now looking for ways to extend the pollutant-destroying-lampshade concept to LED lightbulbs.

The findings offer a promising and eco-friendly solution to improve indoor air quality and reduce the health risks associated with prolonged exposure to VOCs.

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Clever coating turns lampshades into indoor air purifiers

Photo, posted March 21, 2009, courtesy of Levent Ali via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Windows To Cool Buildings | Earth Wise

December 15, 2022 By EarthWise Leave a Comment

About 15% of global energy consumption is for cooling buildings. Because of this, there is an ever- growing need for technologies that can more efficiently cool buildings. Researchers at Notre Dame University have used advanced computing technology and artificial intelligence to design a transparent window coating that is able to lower the temperature inside buildings without using any energy.

The idea is to create a coating that blocks the sun’s ultraviolet and near-infrared light, which are parts of the solar spectrum that otherwise pass through glass and help to heat an enclosed room. Cooling needs can be reduced further if the coating can radiate heat from the surface of the window so it can pass through the atmosphere into space. Designing a coating that does both of those things simultaneously while transmitting visible light is difficult. Coatings should not interfere with the view out the window.

The Notre Dame researchers used advanced computer modeling to create a so-called transparent radiative cooler that meets these goals. The coating consists of alternating layers of common materials like silicon dioxide, silicon nitride, and aluminum oxide or titanium dioxide on top of a glass base and topped with a film of polydimethylsiloxane. The computing method was able to optimize this structure far faster and better than conventional design techniques.

The researchers say that in hot, dry cities, the coating could potentially reduce cooling energy consumption by 31% compared with conventional windows. The same materials could be used in other applications, such as car and truck windows. In addition, the quantum computing-enabled optimization method used for this work could be used to design other composite materials.

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Clear window coating could cool buildings without using energy

Photo, posted September 6, 2015, courtesy of Robert Otmn via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A Smart Window | Earth Wise

March 31, 2022 By EarthWise Leave a Comment

Researchers at Oxford University have developed a new adaptable smart window technology that has the potential of reducing the energy usage of the average home by a third.

The technology uses a spectrally tunable low-emissivity coating that can control the amount of heat that comes into a room without affecting the quality of the light that enters.

The thermal energy from the sun’s infrared rays is absorbed by the glass and then is re-emitted as heat. That heat can either be used to warm the room using transparent electrical heaters embedded in the glass or can be reflected away to cool the room. The windows can change according to seasonal needs.

The researchers built a prototype using a material called an active chalcogenide-based phase change material. When it is cold, the infrared rays from the sunlight are harvested and used to heat the building. When it is warm, the new glass can switch state to reflect the heat and reduce the need for air conditioning. The active phase change material is adjustable so that the amount of heat absorbed or reflected can be tuned for precise temperature control. There is essentially no effect on visible light passing through the window. Current low-emissivity glass for windows can reduce heat transfer, but its properties cannot be altered according to seasonal needs.

The researchers estimate that using windows fitted with the new prototype glass – including the energy required to control the film – would save 20 to 34% in energy usage annually compared to double-glazed windows found in many modern homes.

A spinout company from Oxford called Bodle Technologies is collaborating with two existing industrial partners to develop the technology further.

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New adaptable smart window coating could help heat or cool a home and save energy

Photo, posted April 26, 2008, courtesy of Lima Andruska via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Smart Roof | Earth Wise

January 21, 2022 By EarthWise Leave a Comment

Scientists at the Lawrence Berkeley Laboratory have developed an all-season smart roof coating that can keep homes warm during the winter and cool during the summer, and the coating does not consume any gas or electricity.

Existing cool roof systems consist of reflective coatings, membranes, shingles, or tile that lower house temperatures by reflecting sunlight as well as emitting some of the absorbed solar heat away from the roof as infrared radiation. The problem with such systems is that they continue to radiate heat during the winter, which actually drives up heating costs.

The new material is called a temperature-adaptive radiative coating or TARC. It enables energy savings by automatically turning off the radiative cooling in the winter. TARC reflects about 75% of sunlight year-round, but its thermal emittance is high when the temperature is warm – promoting heat loss to the sky – but decreases in cooler weather, helping to retain the heat in a building.

The researchers produced thin-film TARC material that looks like Scotch tape that could be affixed to a surface like a rooftop. They applied the material to a balcony alongside a sample of commercial dark roof material and a sample of commercial white roof material.

In experiments simulating 15 different climate zones across the US, they found that the TARC material outperforms existing roof coatings for energy savings in 12 out of the 15 zones, particularly in regions with wide temperature variations between day and night, such as in the San Francisco Bay Area, or between winter and summer, such as New York City.

The researchers believe that installing TARC coatings on roofs would save the average U.S. household about 10% in utility costs.

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New Smart-Roof Coating Enables Year-Round Energy Savings

Photo, posted May 18, 2017, courtesy of Damian Gadal via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Seeds And Climate Change | Earth Wise

August 19, 2021 By EarthWise Leave a Comment

Farmers and agricultural communities around the world are on the frontlines of climate change. They are among the first to feel the impacts of hotter temperatures as well as more frequent and intense droughts and precipitation. These challenges pose a massive threat to both farmer livelihoods and global food security.

As the planet continues to heat up, many arid regions that already have marginal conditions for agriculture will be increasingly under stress. As a result, researchers from the Massachusetts Institute of Technology and the King Mohammed VI Polytechnic University in Morocco are working on a promising new way to protect seeds from this stress during their crucial germination phase. Their simple and inexpensive process, which was recently described in a paper published in the journal Nature Food, also provides plants with extra nutrition at the same.

The research team has developed a two layer coating for seeds designed for tackling issues related to drought. Drawing inspiration from natural coatings that occur on some seeds like chia seeds, the first layer is designed to protect the seeds from drying out. It provides a gel-like coating that grips any moisture that comes along and surrounds the seed with it. The second (inner) layer of the coating contains preserved microorganisms called rhizobacteria, as well as some nutrients to help the seeds grow.

The materials for the coatings are biodegradable, readily-available, and often used in the food industry already. According to researchers, early tests using common beans have demonstrated encouraging results in Morocco, and more field tests of the seeds are currently underway.

As the climate continues to change, more innovations like this will be necessary for global food security.

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Engineering seeds to resist drought

Photo, posted September 17, 2010, courtesy of Stacy via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Preserving Produce With Eggs | Earth Wise

July 17, 2020 By EarthWise Leave a Comment

Researchers at Brown University have developed an inexpensive coating to protect fruits and vegetables that is made from eggs that would otherwise be wasted. The micron-thick coating solves problems for the produce and its consumers as well as for the environment.

The coating relies on eggs that never reach the market. The U.S. produces more than 7 billion eggs a year. The supply chain rejects about 3% of them, typically because of shell damage, which means that more than 200 million eggs end up in landfills.

The coating is mostly made from egg, the rest consisting of nanoscale cellulose extracted from wood, a tiny amount of curcumin (the main active ingredient in turmeric that has antimicrobial properties), and a bit of glycerol for added elasticity. The coating is applied to produce by spraying or dipping. It shows a remarkable ability to resist rotting for an extended period comparable to standard coatings like wax, but without their shortcomings.

Along with being edible, the coating retards dehydration, provides antimicrobial protection, and is largely impermeable to both water vapor to prevent dehydration and to gas to prevent premature ripening. The coating is entirely natural, and it washes off with water. So, anyone sensitive to the coating, such as someone with an egg allergy, can easily eliminate it.

Lab tests of the coating studied its effects on strawberries, avocados, bananas and other fruits. All were seen to maintain their freshness far longer than uncoated produce.

The researchers are continuing to refine the coating. They are also considering other source materials. They chose egg proteins because there are so many wasted eggs, but it may be possible to make use of plant proteins instead to address the needs of vegan consumers.

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Egg-based coating preserves fresh produce

Photo, posted July 13, 2012, courtesy of Liz West via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.