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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.

Two Entropy advisors, Dr. Mohammed Farid and Lucas B. Hyman, are pleased to take your questions about PCMs and thermal energy storage. Send your questions to We'll select the best and post the answers here each week.




Ice Energy to deploy up to 1,800 commercial-scale ice batteries in Orange County

Ben Welter - Wednesday, April 12, 2017

Ice Energy has partnered with NRG Energy to install up to 1,800 behind-the-meter ice batteries – the world's largest such deployment – in qualifying commercial and industrial buildings in Orange County, Calif.

Ice Bear 30The Ice Bear 30s will provide a total of up to 25.6 MW of peak storage capacity to Southern California Edison under 20-year power purchase agreements.

"Our distributed ice batteries will solve local grid issues in Orange County while reducing CO2 emissions by up to 200,000 tons over the life of the project," said Mike Hopkins, CEO of Ice Energy. "Orange County commercial and industrial customers that qualify for the program will get free use of Ice Bears, lowering electric bills and further extending the life of their HVAC systems."

The first dozen or so Ice Bears will be installed at commercial and industrial sites in Tustin, with completion expected in June.

During off-peak hours, the Ice Bear stores cooling energy by freezing water in an insulated tank. During peak hours, the company says, the stored ice delivers up to four hours of cooling, reducing the typical peak load by 95 percent.

More information on the Ice Bear and how to order through NRG Energy is available at or by calling 1-844-235-3182.

PCM briefing: A call for presentations on renewable heating and cooling; EnergyNest, Tata team up on demo project

Ben Welter - Friday, April 07, 2017

Frank Bruno, leader of the Thermal Energy Storage Group at the University of South Australia, talks about the advantages of thermal storage in an interview with the Guardian newspaper.

Robert Riebolge, chief network analyst of the Adelaide-based energy storage company 1414 Degrees, tells Ecogeneration magazine that storage is “quite clearly” the solution to the intermittency problem of wind and solar. But, he says, the way in which the Australian market is constructed and the regulatory system is set up doesn’t allow for its easy introduction.

• The Institute for Advanced Architecture of Catalonia has teamed with Basque technology company Tecnalia to develop On Site Robotics, a 3D printing construction project in which sustainable, low-cost buildings can be built on-site with a special clay-based material made of natural, biodegradable, recyclable and locally sourced materials.

• Get the latest information on the Toxic Substances Control Act in a free webinar April 19. The presentation by Mark N. Duvall of the environmental law firm Beveridge & Diamond will identify the principal amendments, discuss the impact on manufacturers and compare the amended TSCA to the European Union's REACH regulation.

• In a video posted on YouTube, Adam Tetz of Pelican BioThermal and other industry experts discuss the future of temperature controlled logistics at last month's Temperature Controlled Logistics Europe 2017.

• The Eu­ro­pean Tech­nol­ogy and In­no­va­tion Plat­form on Re­new­able Heat­ing & Cool­ing has issued a call for presentations to be made at the group's an­nual event in Brus­sels June 20. Topics include biomass; district heating and cooling; solar thermal heating and cooling; hybrid systems; and thermal energy storage. Applications are due by May 22. 

Tata Steel and EnergyNest have begun work on a thermal energy storage demo project at Tata's plant in IJmuiden, Netherland. EnergyNest's concrete-based TES system will store exhaust heat from steel production to cover some of the plant's energy demands. EnergyNest, meanwhile, won the top prize in the 2017 Nordic Cleantech Open last week. The contest, organized by Cleantech Scandinavia, consisted of several competitive rounds in which hundreds of companies applied.

Chris Pais has joined Axiom Exergy as director of field operations. Pais was previously director of system architecture at LightSail Energy. Axiom's "refrigeration battery" system, aimed at supermarkets and cold storage warehouses, stores water chilled at night, when electricity is cheapest, to take the load off condensers and compressors during the day.

Vaibhav Bahadur, assistant professor of mechanical engineering at the University of Texas at Austin, was one of eight faculty members at the university to receive National Science Foundation early career development awards totaling more than $2 million. Bahadur received funding for his project “Influence of electric fields on liquid-to-solid phase change associated with clathrate hydrate formation.”

• In a piece posted on LinkedIn, Liam Holmes, Europe and Asia engineering team lead at Sonoco ThermoSafe, writes about the role of industrial design in the temperature-assurance packaging industry's shift from single-use products to modular reusable green systems.

Patent application: Form-stabilized phase change compositions

Ben Welter - Thursday, April 06, 2017

U.S. patent application 20170096590 (applicant Smart PCM Patent Holdco LLC, Loveland, Colo.):

"Provided herein are form stabilized phase change materials and methods of their manufacture. Form stabilized phase change material compositions comprise porous particulate carriers impregnated with at least one phase change material. The particulate carriers are of a specific size range depending on the density and loading capacity of the particles. Exemplary carriers include expanded perlite with a particle size of greater than approximately 0.5 millimeters. In some examples, the products may have phase change material at 40% or more of the final composition by volume. Additionally, methods of manufacturing the form stabilized phase change materials are provided, and exemplary building materials and shipping containers are provided."

Patent application: Temperature-control pallet cover

Ben Welter - Thursday, April 06, 2017

CCT pallet cover patent drawingU.S. patent application 20170096283 (applicant Cold Chain Technologies Inc., Holliston, Mass.):

"A pallet cover suitable for use in covering at least a portion of a payload on a pallet and a kit for use in making the pallet cover. In one embodiment, the pallet cover includes a top wall, a front wall, a rear wall, a left side wall, and a right side wall, wherein the walls are detachably joined to one another. Each of the top wall, the front wall, the rear wall, the left side wall, and the right side wall includes a first fabric sheet and a second fabric sheet, the first and second fabric sheets being joined together to form a plurality of pockets. Each pocket [37] may removably receive a temperature-control member containing a phase-change material. At least one of the top wall, the front wall, the rear wall, the left side wall and the right side wall includes a plurality of detachably joined portions."

Research roundup: SiO2 nanoparticles; multilayer wall thermal performance; spherical shells

Ben Welter - Wednesday, April 05, 2017

Effects of SiO2 nanoparticles on structure and property of form-stable phase change materials made of cellulose acetate phase inversion membrane absorbed with capric-myristic-stearic acid ternary eutectic mixture [Thermochimica Acta]

Influence of the PCM Layer Location on the Multilayer Wall Thermal Performance [Open Journal of Energy Efficiency]

Numerical Model for Solidification and Melting of PCM Encapsulated in Spherical Shells [Energy Procedia]

Forum on Germany's VDI 2164 guidelines set for June 20 in Düsseldorf

Ben Welter - Monday, April 03, 2017

Several members of the RAL Quality Association PCM will present lectures at the Expert Forum for VDI Guideline 2164, set for June 20 in Düsseldorf. 

The Association of German Engineers' building and building technology group (Verein Deutscher Ingenieure, or VDI) will host the meeting. VDI Guideline 2164 defines the fundamentals for latent-heat storage systems in buildings. 

Dr. Bernd Boiting, chairman of the VDI 2164 committee, will present a brief overview of the guidelines. Other speakers include Esther Kieseritzky of Rubitherm; Marco Schmidt of BASF and Stefan Thomann, managing director of the quality association. The complete agenda will be available in a few weeks.

Inspired by nature: PCM capsules shaped like red blood cells show promise in study

Ben Welter - Monday, April 03, 2017

Capsules fabricated for use in Chinese study

Phase change material used in latent thermal energy storage systems must, of course, be encapsulated. The stiff containers, often made of high-density polyethylene, come in a variety of familiar shapes. The two most common are cylinders and spheres. Fins and dimples can be added to improve melting and solidification rates.

Researchers at Shanghai Jiao Tong University in China say they have identified a better shape. They found it in the circulatory systems of mammals.

Red blood cells, or RBCs, are filled with hemoglobin, not PCMs, and their purpose is to deliver oxygen, not thermal energy. Still, the researchers wondered, is the distinctive biconcave shape conducive to more effective heat transfer?

In a paper recently accepted for publication in Applied Thermal Engineering, “Thermal performance analysis of a novel PCM capsule in red blood cell shape,” Xiwen Cheng and Xiaoqiang Zhai described their investigation, in which they compared the RBCs with four other shapes by experimental and simulation methods. 

All five tested shapes – RBCs, spheres, cylinders, drums and ring-shaped capsules – were sized to contain 25.5 grams of PCM (capric acid, lauric acid, palmitic acid). The sphere’s interior diameter was 40 mm. The shell material was nylon 12 with a thickness of 1.5 mm.

The researchers found that the RBC-shaped capsule performed significantly better than the other shapes. The average charging rate of the RBC capsule, for example, was twice as fast as that of the sphere. 

Dr. William R. Sutterlin, Entropy Solutions’ chief science officer, who was not involved in this research, said he was intrigued by the results. "Until good alternatives are established to increase the thermal conductivity of the PCMs themselves,” he said, “novel designs such as these, which increase surface area, are welcome developments."

Patent application: Thermoregulating shawl and method of making same

Ben Welter - Thursday, March 30, 2017

U.S. patent application 20170086522 (Welspun India Ltd., Mumbai, India):

"A shawl article configured for thermoregulation, the shawl article comprising: an elongate panel having a first end, a second end spaced from the first end along a first direction, and opposed side edges spaced apart with respect to each other along a second direction that is perpendicular to the first direction, the elongate panel including a plurality of warp yarns that extend along the first direction. ... The plurality of weft yarns include phase change yarns, wherein the phase change yarns comprise at least about 50% by weight of the shawl."

Patent application: Adhesive thermal gasket with PCM

Ben Welter - Thursday, March 30, 2017

Thermal gasket patent drawingU.S. patent application 20170089648 (applicant Jones Tech, Cupertino, Calif.):

"An adhesive-thermal gasket, including: a body of thermally conductive material having a set of openings formed through the body; and an adhesive disposed into each opening for holding together a heat-generating component and a heat-dissipating structure as the body thermally couples the heat-generating component to the heat-dissipating structure. ... The body [16] can be formed from a thermal pad, a thermal phase-change material, a graphite thermal interface material, etc."

Patent application: Flexible PCM sheet materials

Ben Welter - Thursday, March 30, 2017

U.S. patent application 20170087799 (applicant Smartpolymer GmbH, Rudolstadt, Germany):

"The invention relates to flexible PCM sheet materials having a high latent thermal energy storage density for the purpose of heat management. The flexible PCM sheet material includes a flexible supporting structure and phase-change-material elements arranged thereon separately in a specific geometry. The phase-change-material elements are geometrically defined structures composed of polymer-bound phase-change material. The flexible PCM sheet materials are characterized by a high latent heat storage capacity and optimized thermal conductivity, are dimensionally stable even in the event of temperature changes and after phase transitions, can be rolled, folded, wound, or cut to size without problems, and can be transported, stored processed, or used in a single layer or in multiple layers."