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Salt Provides Electricity-Free Cooling
Demand for cooling is increasing amid a rise in global temperatures. Thirteen percent of the world’s population lacks access to electricity; methods that can provide cooling in its absence are essential not only to address this disparity, but also to make existing air conditioning more environmentally friendly. Researchers at Lawrence Livermore have developed a fabrication process to turn sodium chloride (NaCl) and potassium chloride (KCl) salts into foams, which can be packed into panels that generate 24-hour, electricity-free cooling called passive daytime radiative cooling (PDRC). Their results are published in the December 1, 2023, issue of Materials Horizons.
PDRC supplements air conditioning, reducing the energy a building needs to keep cool. PDRC can also increase power plant efficiency, collect water from the air, and potentially desalinate water. Since NaCl and KCl are abundant and infrared-transparent, they insulate cooling surfaces effectively while allowing infrared heat to escape. By flash freezing and freeze drying the salts, the researchers fabricated them into aerogel-like foams capable of thermal insulation, scattering visible light, and transmitting infrared radiation.
The team hopes these salt foam panels will serve as one solution to the global issue of increasing temperatures, especially for those who lack access to electricity and traditional air conditioning. “I am thrilled that our research has the potential to impact the global community, particularly those in hot climates without access to electricity,” says research scientist Mariana Reale Batista. “I am hopeful that this affordable cooling technology will save many lives.”
Contact: John Roehling (925) 422-2605 (roehling1 [at] llnl.gov (roehling1[at]llnl[dot]gov)).
Assessing Nuclear Devices for Asteroid Deflection
Nuclear devices are a potential defense mechanism against future catastrophic asteroid impacts but cannot be tested beforehand. Computational modeling is necessary to assess nuclear devices’ impacts on an asteroid’s surface and ensure the strategy would succeed. Livermore researchers developed a modeling tool to simulate the x-ray energy deposition emitted from a nuclear device onto an asteroid’s surface. The research is published in the December 2023 issue of The Planetary Science Journal.
Nuclear devices’ unparalleled ratio of energy density per unit of mass makes them an invaluable tool in asteroid threat mitigation. The new model improves understanding of the nuclear deflection’s radiation interactions on an asteroid’s surface while enabling new research on shockwave dynamics affecting the inner asteroid. The model’s development involved computationally demanding simulations tracking photon penetration of several asteroid-like materials, such as ice, rock, and iron. The model takes a comprehensive approach that considers a diverse set of initial conditions, making it applicable to a variety of potential asteroid scenarios.
In a potential planetary defense emergency such as an asteroid impact, modeling will be critical to inform decision-makers. Mary Burkey, the Livermore physicist who led this research, states that the model will simplify and hasten the calculations needed to determine what viable mitigation strategies are available. “The device could either deflect the asteroid, keeping it intact but providing a controlled push away from Earth, or it could disrupt the asteroid, breaking it up into small, fast-moving fragments that would also miss the planet,” says Burkey.
Contact: Mary Burkey (burkey1 [at] llnl.gov (burkey1[at]llnl[dot]gov)).
Agricultural Byproducts as Feedstocks for Fuel
Reducing production of traditionally petroleum-based products offers one means of approaching carbon neutrality. To replace petroleum, plant residues such as grasses, weeds, and wood could serve as an ingredient for fuels and other sustainable materials. A research team featuring Livermore physical chemist Sankar Raju Narayanasamy and colleagues from Lawrence Berkeley National Laboratory and University of California, Davis, has shed light on accessing the sugars in plant materials to support their use in fuels. Their work is published in the January 7, 2024, issue of the Royal Society of Chemistry’s Green Chemistry journal.
Cellulose, a structural component of plants, contains sugars that are crucial to certain biochemical reactions. Biocatalysts need sugars for some carbon conversions, such as fermentation. The team used a first-of-its-kind autonomous open-channel microfluidics system, and Lawrence Berkeley’s Synchrotron Fourier Transform Infrared instrument, a spectromicroscopy tool, to measure real-time enzymatic hydrolysis of cellulose, allowing the analysis of infrared wavelengths and characterization of biochemical processes. Their analysis furthers understanding of spatial and temporally resolved changes of cellulose’s structural processes during these reactions, potentially enabling control of bulk reaction kinetics and use of cellulose for different renewable energy purposes.
The research paves the way for future studies that involve characterization of biomolecules, as well as the effective use of otherwise discarded biomaterials for valuable products. “The inherent value of biowaste plays a crucial role in promoting a circular bioeconomy by efficiently utilizing organic waste to create valuable products or energy, minimizing environmental impact,” says Narayanasamy.
Contact: Sankar Raju Narayanasamy (925) 758-3679 (narayanasamy1 [at] llnl.gov (narayanasamy1[at]llnl[dot]gov)).
