Tag Archives: cooling

Chernobyl Cooling System Power Loss: Low Meltdown Risk Explained

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Chernobyl Nuclear Power Plant

The Chernobyl nuclear power plant has endured multiple attacks following Russia’s invasion of Ukraine.

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A recent power outage at the Chernobyl nuclear power plant in Ukraine has disrupted the spent fuel cooling system, increasing the risk of overheating and the potential release of harmful radiation. Fortunately, the stored fuel is aged and expected to remain safe until power is restored.

The International Atomic Energy Agency (IAEA) has confirmed that Russian military actions have targeted multiple electrical substations in Ukraine, leading to the current power outage at Chernobyl. “The IAEA is closely monitoring these developments to ensure nuclear safety,” stated IAEA Director-General Rafael Grossi in a recent update on X.

Spent nuclear fuel continues to emit radiation and generate heat for years after being removed from a reactor. Without proper cooling, the fuel can melt, resulting in dangerous radiation levels. Currently, Chernobyl’s old fuel is stored in large cooling ponds that are regularly replenished with cold water to maintain safe temperatures.

However, the IAEA reported that the site lacks a power supply, which halts cooling efforts, leading to increased water temperatures and evaporation rates.

“Once the fuel is out of the reactor, it remains hot due to the production of fission products and radiative materials. It’s essential to manage this heat effectively, or it may eventually lead to a meltdown,” explained Paul Cosgrove from Cambridge University. More information can be found on his profile here.


Fortunately, the risk associated with the stored fuel at Chernobyl is lower today compared to 2022 when similar power outages occurred, as the fuel has already cooled significantly over the years. New Scientist reported this decrease in risk.

“Power loss at nuclear facilities is concerning, but the perceived nuclear risks often far exceed the actual risks associated with comparable incidents,” noted Ian Farnan from Cambridge University. More details about his work can be found here.

The Chernobyl disaster involved a reactor explosion in 1986, with reactors 2, 1, and 3 being shut down in 1991, 1996, and 2000, respectively.

While details of the storage pool containing Chernobyl’s remaining fuel are classified, Cosgrove indicated that evaluations conducted in 2022 found minimal risk of overheating during power outages. “This fuel has been stored safely for over 20 years, leading to significant energy dissipation,” he emphasized.

Electricity delivery to Chernobyl, as well as much of Ukraine, has fluctuated since the commencement of the full-scale Russian invasion. Recently, heightened attacks on Ukraine’s infrastructure by Russian forces have exacerbated the situation.

This power outage at Chernobyl represents yet another instance of Russian actions undermining nuclear safety, including the temporary occupation of Chernobyl, preventing necessary maintenance, the seizure of the Zaporizhzhia nuclear power plant, and last February’s drone attack on the containment structures above the ruins of Chernobyl’s reactor 4.

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Source: www.newscientist.com

Emergency Measures for Artificial Cooling of the Great Barrier Reef Amidst Warming Surge

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Coral bleaching in the Great Barrier Reef off the coast of Queensland, Australia

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Researchers stress the urgent need for strategies to artificially provide shade from rising temperatures affecting Australia. This alerts us following recent findings that link changes in transport fuels to an increased risk of coral bleaching.

In recent years, significant sections of barrier reefs have experienced severe bleaching due to rising sea temperatures attributed to climate change.

Adjustments made in 2020 to regulations governing fuel composition have led to additional detriment, according to Robert Ryan from the University of Melbourne. These changes have decreased sulfur dioxide emissions, which are protective pollutants for health, but have also eliminated aerosols that contribute to the cooling of marine clouds over the reefs.

In February 2022, Ryan and his team leveraged computer models to analyze the impacts of cloud cover and solar radiation in relation to fuel emissions over a span of 10 days.

They discovered that emissions at the pre-2020 levels would enhance the local cooling effect of clouds and noted that regulations aimed at reducing sulfate aerosol pollution diminished this cooling effect. Consequently, the new transport fuel regulations led to a rise in sea surface temperatures equivalent to 0.25°C, which created coral bleaching conditions that ranged from 21-40% during the studied period.

“There’s been an 80% reduction in sulfate aerosol transport, likely contributing to conditions that favor coral bleaching in the Great Barrier Reef,” states Ryan.

Bjørn Samset from the International Climate Research Centre in Oslo, Norway, asserts that this study will help address critical inquiries regarding the effects of reduced aerosol pollution on the surrounding environment. “The local aerosol influences may be more significant than previously considered, and we still have limited understanding of their impacts on ocean heat waves,” he remarks.

However, he cautions that the findings illustrate evident links between air quality and the conditions of clouds around notable reef systems, though they only represent a brief timeframe and are complex compared to other related research.

Ryan is also involved in efforts to devise methods to artificially cool coral reefs using Marine Cloud Brightening (MCB), a climate intervention technology that involves dispersing ocean salt particles into the atmosphere to amplify the cooling effects of marine clouds.

Researchers suggest that given their recent findings, such artificial cooling measures for large barrier reefs may be more crucial than ever. “If changes in sulfate emissions have diminished the brightening effects of ocean clouds, it could be worth reconsidering their reimplementation in targeted programs,” Ryan explains.

Daniel Harrison from Southern Cross University in Australia emphasizes that their findings indicate that MCBs can effectively cool the reef, mirroring the cooling effects seen with past shipping emissions. “This study highlights the real-world implications of ongoing changes,” he adds. “It confirms that it was indeed effective.”

Harrison has secured funding from the UK’s Advanced Research and Innovation Agency for a five-year initiative to test the MCB in the Great Barrier Reef, asserting that MCB “aims to harmonize our efforts to lower emissions.”

On the other hand, some experts remain skeptical, arguing that there is insufficient evidence to confirm the safety and efficacy of intentional MCBs. Terry Hughes from James Cook University in Queensland, Australia, has stated that previous trials of MCB were “not successful” and produced no compelling evidence that it can reduce the local sea temperatures of the reef.

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Source: www.newscientist.com

Penguin Droppings Contribute to Antarctica’s Cooling Effects

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Adelie penguins on the sea ice off the Antarctic Peninsula

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Ammonia emitted from droppings in a bustling Antarctic penguin colony contributes to cloud formation.

“This highlights the profound relationship between ecosystems and atmospheric phenomena,” remarks Matthew Boyer from the University of Helsinki, Finland.

The connection lies in how ammonia influences atmospheric particle counts. Cloud formation requires water vapor to condense around significant particles, which are scarce in the frigid, pristine air of Antarctica.

Typically, available cloud formation particles arise from dust, vegetation, or air pollution, primarily sulfate clusters generated by natural emissions from nearby phytoplankton. It has been established that high ammonia levels can enhance the creation of these clusters by up to a thousand times. But where does this ammonia originate in Antarctica? The droppings of penguins appear to be a significant source.

To verify this, Boyer and his team analyzed the concentrations of ammonia, sulfuric acid, and larger particles in the air around Pygoscelis adeliae on the Antarctic Peninsula. “They have a strong odor,” Boyer comments. “They are quite messy birds.”

When the wind blew from the direction of the colony, the ammonia concentrations were significantly higher compared to air from other directions. This uptick in ammonia prompted the formation of sulfuric acid particles large enough to attract condensation, potentially resulting in cloud formation. This phenomenon persisted for several weeks even after the penguins vacated the colony.

Increased cloud cover, particularly at sea, reflects sunlight away from the Earth’s surface, producing a cooling effect. Boyer also notes that declines in penguin populations could lead to warming trends in Antarctica by diminishing cloud cover, particularly due to climate change-driven ocean ice loss. However, current measurements do not adequately estimate the magnitude of this effect.

Other studies indicate significant implications; for instance, Jeffrey Pierce from Colorado State University and his peers have found ammonia in puffin droppings in the Arctic, leading to increased cloud cover during summer, estimating that this cooling effect could offset about one-third of warming caused by carbon dioxide in the region. “I’m confident it has some effect,” states Pierce.

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  • Antarctica/
  • Animal behavior

Source: www.newscientist.com

Canada’s Major Wildfires Contributed to Global Cooling in 2023

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A wildfire in British Columbia, Canada, blazes in June 2023

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2023 set new records as one of the hottest years, but it could have been even warmer. Climate models indicate that without the cooling effect of smoke from large wildfires in Canada, the average summer temperature in the Northern Hemisphere would have been approximately 1°C higher. Smoke may also be present in August, India’s driest month.

“It’s difficult to grasp the scale of such a massive fire. It was extraordinary,” remarks Iurian Allyn Roz from the Crete Institute of Technology in Greece.

According to Rosu, emissions from wildfires this year were estimated to be five to six times higher than those recorded during previous wildfire seasons in Canada. Although carbon dioxide from these fires contributes to warming, in 2023, this warming was offset by the cooling effects of the smoke blocking sunlight.

To quantify the smoke’s cooling impact, Ross and colleagues conducted a series of climate model simulations, comparing scenarios with and without emissions from Canadian wildfires. The findings suggest that between May and September, smoke caused local cooling up to 5.4°C (9.7°F) in certain areas of Canada, leading to an overall cooling of 0.9°C (1.6°F) for the Northern Hemisphere.

This might be unexpected given that record temperatures were reported in parts of Canada that summer. However, while the heat was mostly concentrated in the west, Ross explains that the smoke drifted eastward, where it had the most significant cooling effect.

The effects extended beyond Canada as well. In this model, emissions from wildfires altered wind patterns in Asia, diminishing the monsoon and reducing rainfall in India. This aligns with actual observed phenomena.

“The precipitation discrepancies observed in the data closely resemble those predicted in the model,” notes Rosu, affirming the model’s accuracy.

Nonetheless, the cooling effect proved to be short-lived. “Data analysis for November and December showed minimal impact,” says Rosu.

The record for the hottest year of 2023 may not last long, as 2024 is shaping up to be even hotter.

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Source: www.newscientist.com

Making Refrigerators More Sustainable with Crystal-based Cooling Technology

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Refrigerators and freezers typically derive their cooling power from environmentally harmful liquids.

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A new type of crystal could help refrigerators and air conditioners keep us cool without warming the planet.

Refrigerators and air conditioners obtain their cooling power by circulating liquid within the device. The liquid absorbs heat and causes cooling through cycles of evaporation and condensation. However, many such liquids contribute to the greenhouse effect and cause further warming if they leak. now, jenny pringle Researchers at Australia's Deakin University have created a climate-friendly alternative to these liquids using “plastic crystals” – crystals containing molecules that can move enough to make them flexible. Developed.

If enough pressure is applied, these plastic crystals can deform. Their molecules go from a random orientation to an ordered grid. Then, when the pressure is removed, they disturb again. As part of this disordering process, the crystals absorb heat, effectively cooling their surroundings.

Although pressure-based cooling like this has been studied before, most materials capable of making this transition can only do so at mild temperatures, limiting their cooling power, Pringle said. In contrast, her team's crystals exhibit their heat-absorbing ability at temperatures between -37°C (-34.6°F) and 10°C (50°F), a temperature suitable for home refrigerators and freezers. .

However, the new crystals are not yet ready to leave the lab. That's because the pressure required to make them work is so high, Pringle says, that it's hundreds of times greater than atmospheric pressure and equivalent to thousands of meters underwater.

david boldrin Researchers at the University of Glasgow in the UK said materials like the new study “have the potential to almost completely decarbonize this giant carbon”. [cooling] However, he shares concerns about the high pressure required.

He says there may be other practical problems with this approach. Bing Li At the Chinese Academy of Sciences. With each repeated use, the grid formed by the molecules becomes more distorted and each crystal absorbs less heat. Still, Lee said he was optimistic and believed the technology could be applied in the “near future.”

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Source: www.newscientist.com

Cooling fabric reduces heat transfer from pavements and buildings in urban areas with high temperatures

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A scorching hot day in Bucharest, Romania, June 2019

lcv / Alamy

In the future, city dwellers could beat the heat with clothes made from new fabrics that keep them cool.

Made from plastic material and silver nanowires, the fabric is designed to keep you cool in urban environments by using the principle of radiative cooling, a natural process in which objects radiate heat back into space.

The material selectively emits a narrow band of infrared light that allows it to escape the Earth’s atmosphere, while at the same time blocking radiation from the sun and from surrounding structures.

Jo Bo-jun, a researcher from the University of Chicago, Illinois, and his team say the material “is more than half [the radiation]” from buildings and the ground,” he says.

Some cooling fabrics and building materials already use this radiative cooling principle, but most of their designs don’t take into account radiation from the sun or infrared radiation from structures like buildings and pavements, and they assume the materials are oriented horizontally against the sky, like roof panels, rather than vertically like clothing worn by a person.

Such designs “work well when they face something cooler, like the sky or a field,” Su says, “but not when they face an urban heat island.”

Xu and his colleagues designed a three-layered fabric: the inner layer is made from common clothing fabrics like wool or cotton, and the middle layer is made up of silver nanowires that reflect most of the radiation.

The top layer is made of a plastic material called polymethylpentene, which does not absorb or reflect most wavelengths and emits a narrow band of infrared light.

In outdoor tests, the fabric remained 8.9°C (16°F) cooler than regular silk fabric and 2.3°C (4.1°F) cooler than a broad-spectrum radiation-emitting material. When tested against the skin, the fabric was 1.8°C (3.2°F) cooler than cotton fabric.

Su said this slight difference in temperature could theoretically increase the amount of time a person can comfortably be exposed to heat by up to a third, but that this has yet to be tested.

“It’s always been difficult to make this material practical as a fiber.” Aswath Raman, the UCLA researcher added that the study is a good example of applying the physical principles of radiative cooling to a practical material. Other materials with similar properties could also be used on vertical surfaces in buildings, he said.

Science
DOI: 10.1126/science.adl0653

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Source: www.newscientist.com

Astronomers discover floating crystals preventing cooling in high-mass white dwarf stars

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Astronomers have proposed a new theory to explain why a mysterious population of white dwarfs has stopped cooling for at least 8 billion years.

This diagram shows a white dwarf and the moon. Image credit: Giuseppe Parisi.

White dwarfs are the remains of stars without a nuclear energy source that gradually cool over billions of years, eventually freezing from the inside out to a solid state.

Recently, it was discovered that a population of frozen white dwarfs maintains a constant brightness for a period comparable to the age of the universe, indicating the existence of an unknown, powerful energy source that inhibits cooling.

“We find that the classical picture that all white dwarfs are dead stars is incomplete,” said astronomer Dr Simon Bruin from the University of Victoria.

“To stop these white dwarfs from cooling, we need some way to generate additional energy.”

“We didn’t know how this happened, but now we have an explanation for this phenomenon.”

The researchers say that in some white dwarfs, the dense plasma inside them doesn’t just freeze from the inside out.

Instead, the solid crystals that form when frozen tend to float because they are less dense than the liquid.

As the crystals float upwards, the heavier liquid moves downwards.

As heavy material is transported toward the star’s center, gravitational energy is released, and this energy is enough to interrupt the star’s cooling process for billions of years.

Dr Antoine Bedard, an astronomer at the University of Warwick, said: “This is the first time this transport mechanism has been observed in any type of star, and it’s very interesting because it’s not every day that a completely new astrophysical phenomenon is discovered.”

“We don’t know why this happens in some stars and not others, but it’s probably due to the star’s composition.”

“Some white dwarfs are formed by the merger of two different stars,” Dr Bruin said.

“When these stars collide to form white dwarfs, the star’s composition changes, allowing the formation of floating crystals.”

White dwarfs are routinely used as an indicator of age, and the cooler a white dwarf is, the older it is considered to be.

However, the extra delay in cooling seen in some white dwarfs means that some stars at certain temperatures may be billions of years older than previously thought.

“This new discovery will not only require a revision of astronomy textbooks, but will also require a reexamination of the processes astronomers use to determine the age of stellar populations,” Dr. Blouin said.

of the team paper Published in today’s diary Nature.

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A. Bedard other. Buoyant crystals stop the white dwarf from cooling. Nature, published online March 6, 2024. doi: 10.1038/s41586-024-07102-y

Source: www.sci.news

Scientists Develop New “Cooling Glass” to Combat Climate Change by Channeling Heat from Buildings into Space

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Innovative “cooling glass” developed by researchers at the University of Maryland provides a groundbreaking, non-electrical solution for reducing indoor heat and carbon emissions, and significantly advances sustainable building technology. It shows great progress.

Applying new coatings to exterior surfaces can reduce air conditioning usage and help fight climate change.

Researchers at the University of Maryland have developed an innovative “cooling glass” designed to reduce indoor temperatures without using electricity. This revolutionary material works by harnessing the cold air of outer space.

New technology, microporous glass coating, described in paper published in the journal sciencecan lower the temperature of the material beneath it by 3.5 degrees. Celsius According to a research team led by distinguished professor Liangbing Hu of the university’s School of Materials Science and Engineering, it has the potential to reduce the annual carbon dioxide emissions of mid-rise apartments by 10%.

Cooling mechanism with two functions

This coating works in two ways. For one, it reflects up to 99% of solar radiation, preventing buildings from absorbing heat. Even more interestingly, this universe emits heat in the form of long-wave infrared radiation into the icy universe, whose temperature is typically -270 degrees Celsius, or just a few degrees warmer. absolute temperature.

In a phenomenon known as “radiative cooling,” spaces effectively act as heat sinks for buildings. They use new cooling glass designs and so-called atmospheric transparency windows (the part of the electromagnetic spectrum that passes through the atmosphere without increasing its temperature) to dump large amounts of heat into the infinitely colder sky beyond. Masu. (Although the emissions are much stronger than those from the new glass developed at UMD, the same phenomenon causes the Earth to cool itself, especially on clear nights.)

State-of-the-art durable materials

“This is an innovative technology that simplifies the way we keep buildings cool and energy efficient,” said research assistant Xinpeng Zhao, lead author of the study. “This could help us change the way we live and take better care of our homes and the planet.”

Unlike previous attempts at cooling coatings, the new glass developed by UMD is environmentally stable, withstanding exposure to water, UV light, dirt, and even flame, and withstands temperatures up to 1,000 degrees Celsius. can withstand. Because glass can be applied to a variety of surfaces such as tile, brick, and metal, the technology is highly scalable and can be adopted for a wide range of applications.

The research team could use finely ground glass particles as a binder, bypassing polymers and increasing long-term durability outdoors, Zhao said. We then selected a particle size that maximizes the release of infrared heat while reflecting sunlight.

Climate change solutions and global impacts

The development of cooling glass is in line with global efforts to reduce energy consumption and combat climate change, Hu said, adding that this year’s Independence Day could have been the world’s hottest day in 125,000 years. He pointed out recent reports that it was a day of sex.

“This ‘cooling glass’ is not just a new material, it’s an important part of the solution to climate change,” he said. “By reducing the use of air conditioners, we have taken a big step towards reducing energy usage and reducing our carbon footprint. This is because new technology is helping us build a cooler, greener world. It shows how it can help.”

In addition to Hu and Zhao, Jelena Srebric and Zongfu Yu, professors of mechanical engineering in the University of Wisconsin-Madison’s Department of Electrical and Computer Engineering, are co-authors of the study, each contributing expertise in CO2 reduction and structural design. There is. .

The team is now focused on further testing and practical application of the cooled glass. They are optimistic about its commercialization prospects and have formed a startup company, CeraCool, to scale and commercialize it.

Reference: “Solution-processed radiatively cooled glass” Xinpeng Zhao, Tangyuan Li, Hua Xie, He Liu, Lingzhe Wang, Yurui Qu, Stephanie C. Li, Shufeng Liu, Alexandra H. Brozena, Zongfu Yu, Jelena Srebric, Liangbing Written by Hu, November 9, 2023, science.
DOI: 10.1126/science.adi2224

Source: scitechdaily.com

Revealing an Innovative Approach to Cooling

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Schematic diagram showing cooling of nanopores by charge-selective ion transport. Credit: 2023 Tsutsui et al., Peltier Cooling for Thermal Management of Nanofluidic Devices, Devices, ed.

Groundbreaking work by Japanese researchers demonstrates nanopore-mediated cooling, revolutionizing temperature control in microfluidic systems and deepening our understanding of cellular ion channels.

Have you ever wondered how water boils in an electric kettle? Most people may think that electricity just heats a metal coil inside the kettle and transfers that heat to the water. . But electricity can do so much more. When electricity causes ions in a solution to flow, heat is generated. If all ions and surrounding molecules are free to move, this heating effect will be uniform throughout the solution. Now, Japanese researchers have investigated what happens if this flow is blocked in one direction.

Cooling with nanopore technology

In a recently published study, deviceA team led by researchers at Osaka University’s SANKEN (National Institute of Scientific and Industrial Research) has shown that cooling can be achieved by using nanopores (very small holes in membranes) as gateways that allow only certain ions to pass through. Through.

In general, when electricity is used to drive ions in a solution, positively charged ions and negatively charged ions are attracted in opposite directions. Therefore, the thermal energy carried by the ions travels in both directions.

Understanding ion flow and temperature control

If the path of the ions is blocked by a membrane that can only pass through the nanopores, it becomes possible to control the flow. For example, if the pore surface is negatively charged, negative ions can interact without passing through, and only positive ions will flow with energy.

“At high ion concentrations, we measured an increase in temperature as the power increased,” explains study lead author Mayu Tsutsui. “However, at low concentrations, the available negative ions interact with the negatively charged nanopore walls. Therefore, only positively charged ions passed through the nanopore and a decrease in temperature was observed. ”

Applications in microfluidics and cell biology

The demonstrated ionic cooling could potentially be used to cool microfluidic systems, setups used to move, mix, or interrogate very small volumes of liquids. Such systems are important across many fields, from microelectronics to nanomedicine.

Additionally, this discovery could help further our understanding of ion channels, which play a key role in the delicate balance mechanisms of cells. Such insights could be key to understanding function and disease and designing treatments.

Broader implications and future prospects

“We are excited about the breadth of the potential impact of our findings,” says Yuji Kawai, lead author of the study. “There is considerable scope to tune nanopore materials to tune cooling. Additionally, arrays of nanopores can be created to amplify the effect.”

The list of areas that could be enhanced by this discovery is indeed considerable, extending to the use of temperature gradients to generate electrical potentials. This has potential applications in temperature sensing and blue power generation.

References: “Peltier Cooling for Thermal Management in Nanofluidic Devices” by Mayu Tsutsui, Kazumichi Yokota, Wei Lung Su, Dennis Garoli, Hirofumi Oguji, and Yuji Kawai, December 5, 2023. device.
DOI: 10.1016/j.device.2023.100188

Source: scitechdaily.com