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The award-winning Phase Change Matters blog tracks the latest news and research on phase change materials and thermal energy storage. E-mail tips and comments to Ben Welter, communications director at Entropy Solutions. Follow the blog on Twitter at @PureTemp. Subscribe to the weekly PCM newsletter. Or join the discussion on LinkedIn.

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Patent application: Enclosure cooling for thermal management of unmanned aerial vehicles

Ben Welter - Friday, January 11, 2019

Qualcomm drone patent drawing

U.S. patent application 20190009878 (applicant Qualcomm Inc., San Diego, Calif.):

"Arrangements described herein relate to apparatuses, systems, and methods for a housing of an unmanned aerial vehicle (UAV), the housing includes but is not limited to a metallic porous material having a shape of an enclosure of the UAV, and a phase change material (PCM) provided in at least a portion of the metallic porous material. The metallic porous material and the PCM are configured to passively cool the UAV."

http://www.freepatentsonline.com/20190009878.pdf

PCM briefing: Isomer can store energy for up to 18 years; concept combines pumped storage and heat storage using water as a medium

Ben Welter - Friday, November 02, 2018

• Researchers at Chalmers University of Technology and Universidad de La Rioja have created a system capable of storing solar energy for extended periods. The Molecular Solar Thermal Energy Storage system uses a molecular photo switch made from carbon, hydrogen and nitrogen. Sunlight turns the molecule into an energy-rich isomer. The isomer can be stored in a liquid form to be used for heating at night or in winter. “The energy in this isomer can now be stored for up to 18 years. And when we come to extract the energy and use it, we get a warmth increase which is greater than we dared hope for,” said Kasper Moth-Poulsen, professor at Chalmers.

• New research at California's Lawrence Livermore National Laboratory reveals how an unusual type of ice known as Ice VII can form at speeds over 1,000 miles per hour. "This ice type was only discovered occurring naturally in March, trapped inside diamonds deep underground," reports Science Alert, "and this latest study looks in detail at how exactly it takes shape – apparently in a way that's completely different to how water usually freezes into ice."

• A research team at the Graz University of Technology, Austria, has combined the advantages of pumped storage technology and heat storage using water as a medium in a hybrid storage concept called "hot-water pumped storage hydropower." The new system stores and supplies electricity, heat and cooling energy. 

• The U.S. Department of Energy's Advanced Research Projects Agency-Energy (ARPA-E) has openings for program directors, tech-to-market advisors and two-year fellowships.  

Registration is open for the 2019 ARPA-E Energy Innovation Summit, to be held in Denver, Colo., July 8-10. Now in its 10th year, the annual conference and technology showcase "brings together experts from different technical disciplines and professional communities to think about America’s energy challenges in new and innovative ways."

A full agenda is available for the World Bio Markets conference, to be held in Amsterdam, Netherlands, April 1-3. Speakers include Rolf Hogan, executive director, Roundtable on Sustainable Biomaterials; Chris Sayner, vice president customer alliances, corporate sustainability, Croda; and Davide Bragholi, project manager, environmental innovations, Tetra Pak. 

• Registration is open for the inaugural Thermal Materials Summit to be held in Los Angeles on May 2. This technical forum will explore the latest advancements in thermal interface materials for professionals working in aerospace, automotive, telecom, batteries and other fields. Presentation proposals are due by Dec. 7.

Ecozen Solutions of India is one of five finalists in Rabobank’s inaugural Food Loss Challenge Asia. The competition aims to identify innovative ag-tech start-ups working to solve farm-to-market food loss problems. The finalists will present their solutions to a panel of judges at Rabobank’s annual Asia Food & Agribusiness advisory board meeting in Singapore later this month. Ecozen makes portable solar cold rooms for small farms, using a thermal storage unit that can store power for more than 36 hours in case of cloudy or rainy weather.

Aerospace manufacturer seeks PCM for use in heat exchanger

Ben Welter - Monday, August 20, 2018

An aerospace/defense contractor in Bengaluru, India, is looking for a noncorrosive phase change material with high thermal conductivity and a heat storage capacity of 280 joules per gram. Rangsons Defence Solutions Pvt. Ltd. says the PCM will be used in a heat exchanger the company is developing for an aerospace application.

This document describes the heat exchanger and lists the properties of the required PCM:

Specifications for PCM heat exchanger

Contact Sivaram Subramanian, an associate mechanical engineer at Rangsons Defence Solutions, for additional information on the heat exchanger. His e-mail address is sivarams@rangsons-ds.com.

Patent application: Use of PCMs to delay icing or to cause de-icing in wind-driven generators

Ben Welter - Sunday, August 19, 2018

U.S. patent application 20180230972 (applicant Gamesa Innovation & Technology, S.L., Sarriguren, Spain):

"The invention relates to the use of phase change materials (PCMs) to delay icing or to cause de-icing in different wind-driven power generator elements. The invention also relates to the method for delaying icing or causing de-icing in different wind-driven power generator elements based on the use of phase change materials (PCMs), said method comprising: a) obtaining the PCMs, and b) incorporating the PCMs obtained into different wind-driven power generator elements."

http://www.freepatentsonline.com/20180230972.pdf

Patent application: Method and system for phase change material component cooling

Ben Welter - Monday, August 06, 2018

U.S. patent application 20180216894 (applicant General Electric Co., Schenectady, N.Y.)

"A transient cooling system includes a first phase change material (PCM) element and a second PCM element. The first PCM element includes a first PCM, a first surface, and a second surface, the first surface complementary to a surface to be cooled. The second PCM element includes a second PCM and a third surface in thermal contact with the second surface. The first PCM and the second PCM may have different thermal characteristics."

http://www.freepatentsonline.com/20180216894.pdf

Patent application: Thermal management device using phase change material

Ben Welter - Monday, June 04, 2018

U.S. patent application 20180149437 (applicant Boeing Co., Chicago, Ill.):

"A device manages thermal energy applied to a composite patch on a structure having a heat sink. The device includes an enclosure configured to be placed on the structure overlying the composite patch, and a phase change material within the enclosure for absorbing the thermal energy."

http://www.freepatentsonline.com/20180149437.pdf

Patent application: Passive thermal system comprising heat pipe and PCM for use in space

Ben Welter - Thursday, May 24, 2018

WorldVu Satellites patent drawing
U.S. patent application 20180134416, (applicant WorldVu Satellites Ltd., Arlington, Va.):

"A passive thermal system for use in a satellite and other aerospace applications includes a container having a heat-pipe working fluid disposed in a first chamber and a Phase Change Material (PCM) disposed in a second chamber that substantially surrounds the first chamber. The first chamber contains a wick for transporting the heat-pipe working fluid. The exterior of the first chamber has fins, etc., that extend into the PCM for heat spreading and increased interface area."

http://www.freepatentsonline.com/20180134416.pdf

Patent application: Electronic device with protective shield containing PCM

Ben Welter - Monday, May 07, 2018

U.S. patent application 20180124945 (applicants French Alternative Energies and Atomic Energy Commission and Airbus Operations SAS, France):

"An electronic device includes an electronic component and a protective shield including a phase change material having a phase change temperature of between 20 degrees C. and 90 degrees C., an antivibration gel having hyperelastic and/or viscoelastic behavior at 20 degrees C., and a separation barrier positioned so as to separate the phase change material and the antivibration gel. The antivibration gel is positioned, at least partly, in contact with the electronic component, and has a thermal conductivity of greater than 1 W/mK at 20 degrees C."

http://www.freepatentsonline.com/20180124945.pdf

Patent application: Support tool for composite parts

Ben Welter - Monday, October 23, 2017

U.S. patent application 20170291404 (applicant Boeing Co., Chicago, Ill.):

"Systems and methods are provided for forming composite parts. One embodiment is an apparatus that includes a forming tool. The forming tool includes a body, which includes an exterior that defines a shape for forming a laminate that will be cured into a composite part. The body also includes elements of phase change material that provide rigidity to the body below a threshold temperature, and that exhibit a phase change above the threshold temperature causing the body to become pliable. Further, the body includes flexible material that encloses the elements of phase change material."

http://www.freepatentsonline.com/20170291404.pdf

Paraffin-enhanced concrete shows promise in melting ice, snow

Ben Welter - Monday, September 25, 2017

PCM LWA video

Dr. Yaghoob Farnam has spent four years combining concrete and phase change material in various ways in a quest to develop a durable paving material that can melt ice and snow. 

Farnam, an assistant professor in Drexel University’s College of Engineering, has previously measured the effectiveness of paraffin oil and methyl laurate, materials that have relatively high heat storage capacity (about 130 to 170 joules per gram) and a suitable phase transformation temperature (about 2 to 3 degrees Celsius). Both showed promise when contained in plastic tubes embedded in concrete. But the paraffin oil proved to be far more effective than methyl laurate in concrete made of lightweight aggregate infused with the PCMs. Chemical reactions between the methyl laurate and materials in the cement rendered that PCM ineffective and also appeared to cause cracks in the concrete.

In his latest paper, published in Cement and Concrete Composites, Farnam's research team focused on paraffin oil. The team used concrete slabs to compare two methods of deploying the PCM. Steel pipes filled with paraffin and sealed with PVC caps were embedded in one slab. A second slab was made of porous lightweight aggregate infused with paraffin. A third slab, containing no paraffin, served as a reference point. Each slab was sealed in an insulated container and then covered with about 5 inches of shaved ice.

DrexelNow describes what happened in two tests:

"With temperatures inside the boxes held between 35-44 degrees Fahrenheit, both of the paraffin-treated slabs were able to completely melt the snow within the first 25 hours of testing, while the snow on the reference sample remained frozen. The slab with the paraffin-filled tubes melted the snow slightly faster than the one composed of paraffin-treated aggregate. Farnam suggests that this is because the paraffin inside the tubes is able to solidify more quickly — thus releasing its energy — because of the regular diameter of the pipes. While the diameter of the pores of the aggregate vary in size.

"But in the group’s second experiment, in which the ambient air temperature in the box was lowered to freezing before the snow was added, the paraffin-treated aggregate was more effective than the embedded pipes. This is because the capillary pore pressure delayed the freezing of the paraffin, thus allowing it to release its heat energy over a longer period of time." 

The research is of particular importance to the airline industry, which has a keen interest in finding cost-effective and environmentally friendly ways to clear runways of ice and snow. The Federal Aviation Administration has supported Farnam's work with nearly $500,000 in grants through its PEGASAS program.

Farnam says additional research is needed to better understand how the addition of PCM affects pavement durability, skid resistance and long-term stability.  

http://drexel.edu/now/archive/2017/September/self-melting-concrete-roads/