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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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Have you ever seen a DSC quite like this?

Ben Welter - Friday, June 07, 2019

More than 120 years ago, German chemist Emil Fischer said his lab had developed a crystal that seemed to defy the laws of physics. The solid form of acetaldehyde phenylhydrazone kept melting at two different temperatures. One batch might melt at 65° C; another at 100° C. Physics Today explains how the mystery was eventually solved: 

DSC of mysterious crystal APH"Colleagues and rivals at the time told him he must have made a mistake. Fischer didn’t think so. As far as he could tell, the crystals that melted at such different points were identical. A few groups in Britain and France repeated his work and got the same baffling results. But as those scientists died off, the mystery was forgotten, stranded in obscure academic journals published in German and French more than a century ago.

"There it would probably have remained but for Terry Threlfall, an 84-year-old chemist at the University of Southampton, UK. Stumbling across Fischer’s 1896 paper in a library about a decade ago, Threlfall was intrigued enough to kick-start an international investigation of the mysterious crystal. Earlier this year in the journal Crystal Growth and Design, Threlfall and his colleagues published the solution: APH is the first recorded example of a solid that, when it melts, forms two structurally distinct liquids. Which liquid emerges comes down to contamination so subtle that it’s virtually undetectable."

https://physicstoday.scitation.org/do/10.1063/PT.6.1.20190606a/full/

Sunamp signs its first major UK contract

Ben Welter - Friday, June 07, 2019

Sunamp Ltd. has signed a memo of understanding to supply its PCM-based heat batteries to Fischer Future Heat under an original equipment manufacturer contract. Sunamp, based in Edinburgh, Scotland, says the deal involves "many thousands" of units and will be worth seven figures as sales ramp up. Leicester-based Fischer began selling the product, dubbed the Aquafficient, in February.

Andrew BissellIn an email interview, Sunamp CEO Andrew Bissell filled in a few details on the deal.

Q: Can you tell me about the PCM aspects of this product?

A: "Sunamp’s success in making a super-stable (40,000+ cycles tested) salt hydrate PCM (very energy dense) at 58C and combining it (in a highly insulated, cuboid enclosure) with a very high power heat exchanger (high power, high flow rate hot water) made a whole class of heat battery devices possible. Not least electric water heaters, with about 4x the energy density of a classic electric hot water tank and 5+ gallon per minute performance. A key innovation (patent pending around the details) was to use electric elements immersed inside the PCM to melt the PCM and charge the heat battery."

Q: What can you tell me about the manufacturing process?

A: "Because Aquafficient by Fischer Future Heat is based on Sunamp UniQ, it’s effectively been in production at Sunamp Factory for nearly a year. 

"By going down this OEM white label route, Fischer Future Heat could hit the ground running with Aquafficient - which they did! Sunamp’s manufacturing has had to scale already this year from 75 units a month to 75 units a week, with 75 a day on the near horizon. This to keep up with exponentially rising combined demand from Fischer, other OEMs, and large housing and regeneration projects.

“We keep scaling production and the demand keeps outpacing us! We're working really hard on scaling up production and appreciate our partners’ and their customers patience when they sometimes have to wait quite a number of weeks for the product they want.”

https://www.insider.co.uk/news/heat-storage-battery-pioneer-sunamp-16252849

Patent application: Composite construction panels and applications thereof

Ben Welter - Thursday, June 06, 2019

U.S. patent application 20190161967 (applicant Phase Change Energy Solutions, Asheboro, N.C.):

"In one aspect, composite construction materials are described herein. In some embodiments, a composite construction panel comprises a substrate layer, a cover layer separated from the substrate layer by one or more spacers, and at least one mat disposed between the substrate layer and the cover layer, wherein the mat comprises at least one phase change material disposed in at least one phase change region."

http://www.freepatentsonline.com/20190161967.pdf

Patent application: Method and device for heating a mold

Ben Welter - Thursday, June 06, 2019

U.S. patent application 20190168432 (assignee Roctool, Le Bourget-du-Lac, France):

"A mold, particularly for injection molding, includes a shell defining a cavity delimiting a molding surface, a heat accumulator and inductor heater, configured to heat the heat accumulator. A receiving surface, which is a part of a surface of the shell other than the molding surface, is either exposed to or shielded from the heat of heat accumulator, to bring the entire molding surface to a predetermined temperature to inject the material into the cavity. ... [The] heat accumulator comprises a phase change material. This embodiment makes it possible to store thermal energy in the latent phase change heat of said material."

http://www.freepatentsonline.com/20190168432.pdf

Patent application: Heating a sports device

Ben Welter - Thursday, June 06, 2019

Drawing of lacrosse stick with PCM

U.S. patent application 20190168091 (applicant Robert Marc Goldberg, Fayetteville, N.Y.):

"A sports device configured to generate thermal energy to warm surfaces. In one implementation, the sports device embodies a lacrosse stick with a shaft and head. The shaft includes a thermal core with a phase change material that can retain and dissipate heat over an extended period of time. ... Suitable materials may maximize energy storage per unit volume/mass so as to add little weight to the lacrosse stick but still maintain surfaces at temperatures for extended periods. This feature can make the lacrosse stick comfortable for the player to grasp and to handle during game play and practice."

http://www.freepatentsonline.com/20190168091.pdf

Patent application: Polyurethane gel particles, methods and use in flexible foams

Ben Welter - Thursday, June 06, 2019

U.S. patent application 20190169390 (applicant Peterson Chemical Technology LLC, Austin, Texas):

"Combinations of open cell flexible foams with polyurethane gel particles, and methods of making the combinations are described using a variety of procedures. The open cell flexible foam may partially or wholly comprise polyurethane foam and latex foam. ... The composition of claim 1 where the polyurethane gel particles contain at least one phase change material with a solid/liquid phase transition temperature range of from about −10° F. to about 220° F. (about −23° C. to about 104° C.)."

http://www.freepatentsonline.com/20190169390.pdf

Research roundup: Energy management of household refrigerator; borehole heat exchangers; more

Ben Welter - Thursday, June 06, 2019

From Energy:

Energy management of a household refrigerator using eutectic environmental friendly PCMs in a cascaded condition
Use of encapsulated phase change materials in lightweight building walls for annual thermal regulation
Screening of sugar alcohols and their binary eutectic mixtures as phase change materials for low-to-medium temperature thermal energy storage.

From Industrial and Engineering Chemistry Research:

Biodegradable Polymeric Solid Framework-based Organic Phase Change Materials for Thermal Energy Storage

From Renewable Energy:

Thermal Management and Uniform Temperature Regulation of Photovoltaic Modules Using Hybrid Phase Change Materials-Nanofluids System
Polyethylene glycol/silica (PEG@SiO2) composite inspired by the synthesis of mesoporous materials as shape-stabilized phase change material for energy storage

From International Journal of Energy Research:

Thermal buffering effect of a packaging design with microencapsulated phase change material
Laboratory investigation on the use of thermally enhanced phase change material to improve the performance of borehole heat exchangers for ground source heat pumps

From IOP Conference Series: Materials Science and Engineering:

Thermal properties of cool asphalt concrete containing phase change material

From International Journal of Advance Research and Innovation:

Experimental Investigation of Thermal energy storage with phase changing material [pdf]

From Thermal Science and Engineering Progress:

Experimental study on thermal storage and heat transfer performance of microencapsulated phase-change material slurry

From Journal of Molecular Liquids:

Thermal conductivity modification of n-octanoic acid-myristic acid composite phase change material

From International Journal of Refrigeration:

Experimental study of enhanced PCM exchangers applied in a thermal energy storage system for personal cooling

From Applied Thermal Engineering:

Development of paraffinic phase change material nanoemulsions for thermal energy storage and transport in low-temperature applications
Effect of micro encapsulated phase change material on the anti-dry-out ability of pulsating heat pipes

From Construction and Building Materials:

Integrating phase change materials in construction materials: Critical review

From Solar Energy Materials and Solar Cells:

Compatibility of vegetable oils with solid filler materials for thermocline thermal energy storage systems
Novel paraffin/ethylene propylene diene monomer phase change latex with excellent stability and low viscosity

From Applied Materials and Interfaces:

Natural Microtubule-Encapsulated Phase-Change Material with Simultaneously High Latent Heat Capacity and Enhanced Thermal Conductivity

From Applied Energy:

System performance and economic assessment of a thermal energy storage based air-conditioning unit for transport applications
Experimental investigation of a cementitious heat storage medium incorporating a solar salt/diatomite composite phase change material

PCM in stadium seating: For fans on the hot seat, it's a pretty cool idea

Ben Welter - Saturday, May 25, 2019

Dustin Schafer of Henderson EngineersDustin Schafer, senior vice president and director of engineering at Henderson Engineers of Lenexa, Kansas, first became familiar with phase change material when he read an ASHRAE article about conference room air conditioning.

The method struck him as a small-scale version of a stadium or arena. "From there," he says, "I began I began devising a plan for us to implement this into our large-scale venues we design." 

Schafer developed the idea of using PCM inside the hollow portions of seats and seating structures to keep open-air stadiums cooler on hot days. The concept underwent testing at Kansas State University and was awarded a U.S. patent, "Stadium Ambient Temperature Control System," in 2017. He is giving a presentation on the concept June 12 at an event sponsored by AIA Kansas City at the Center for Architecture & Design in Kansas City, Mo. In an email interview, he discussed the development process. 

Q: How long have you worked at your company?

A: "I joined Henderson in 2008 and have nearly 20 years of industry experience."

Q: Can you briefly describe the process of testing the concept?

A: "In looking to develop an innovative, cost effective, and energy efficient option, we began conducting research on the potential implementation of PCM on venue seats to increase the thermal mass in the space and extend the length of time occupants are comfortable. Essentially, the material could be frozen (the material we used has a freezing point of 70° F) prior to the event, then as the PCM reaches its melting point, it would absorb some of the heat brought on by the human and/or solar load, prolonging the time the space is comfortable for attendees.

Henderson patent application drawing"I led a team in conducting a variety of tests to determine the efficacy of this idea. We worked with Kansas State University and utilized their Institute for Environmental Research to complete our testing. We set up a lab that included actual stadium seats arranged in a layout consistent with typical venues. Each seat in the testing area had 10 pounds of PCM attached to the back and a dummy in the seat equipped with electric resistance heaters that produced an amount of heat equivalent to that of a human being. The layout also included suspended wires with thermocouples to create the temperature sensor array around the dummy occupant.

"We conducted two tests to evaluate the impact this technology could have, each with two test value temperatures, 90° F and 100° F. In both tests we took measurements in an environmental chamber that simulated different ambient conditions during an event and compared both a control chamber and a chamber with PCM attached to the chairs. The tests ran until the effect of PCM was no longer noticeable."

Q: Can you provide a summary of the test results?

A: "In our research, we determined that PCM could be an impactful option for open stadiums situated in mild climates where the night temperatures drop low enough to freeze the material. To have an even greater impact, application of PCM should be seriously considered in enclosed arenas. Because the HVAC system could be used to pre-charge the bowl and freeze the material, this application could be even more significant. Additionally, the cooling result could materially affect the peak load needs for the HVAC systems in these spaces, saving the owner on energy costs.

"We also identified areas where PCM would not make sense a part of the temperature control solution, such as in climates with high winds that would simply blow away the cooled air, areas where the temperature does not drop below 70° F and thus doesn’t allow the PCM to freeze, or areas where the temperature rises too far above the melting point prior to the event meaning the cooling effect is lost before it is needed. Finally, we’ve found it necessary to note that this process only impacts spaces that need to be cooled – it cannot be used in heating conditions.

"We determined that phase change material does have a significant and sustained impact on occupant comfort. While it is not the whole solution, it can be a meaningful portion of the overall answer."

Q: Can you provide information on the PCM used in testing?

A: "We used InsolCorp’s Infinite-R phase change material." 

Q: Is Henderson now working on any projects that include the use of PCMs in this manner?

A: "We are not working on any projects that include the use of PCM."

Q: What interests you most about the use of PCM in building and construction?

A: "It’s a sustainable solution that is relatively low cost. It’s not the end all, be all, but it’s a small step that can have a nice impact. Professional sports teams focus heavily on the fan experience and this is a difference maker when it comes to their in-venue comfort."

PCM briefing: Building Skins conference agenda; tough words for CALMAC and Axiom Exergy

Ben Welter - Saturday, May 25, 2019

• The agenda is set for the 14th International Conference on Advanced Building Skins, to be held Oct. 28-29 in Bern, Switzerland. The Japanese architect and Pritzker laureate Shigeru Ban will be the keynote speaker. Among the more than 150 speakers is Thomas Friedrich of Innogration GmbH, Germany, who will discuss "collection of thermal energy from the façade" and "decentralized PCM storage elements for saving thermal energy." The registration fee is 680 euros and includes the conference documentation as well as meals during both days. Participants who register by May 31 will receive a 20 percent discount.

Mike HopkinsIn a LinkedIn post, former Ice Energy CEO Mike Hopkins shared his take on two of the California company's competitors in distributed thermal energy storage. "Look at @CALMAC, a Portfolio of Trane - been in our industry forever, good product, but haven't been able to secure utility deals because their large bespoke systems make it too risky to commit to MWs in a location on a schedule," wrote Hopkins, who is now CEO at Bakken Midstream. "Relative newcomer [Axiom Exergy] came to market with their #refrigeration #battery. Good concept but not plug and play. Not surprising, they seem to have recast themselves as a #cloud based power management company."

• Speaking of CALMAC: CEO Mark McCracken will speak on "some of the myths surrounding ice-based TES" at an ASHRAE technical seminar on thermal energy storage in building design in Hong Kong June 13. 

FedEx Express has launched a temperature-controlled shipping solution in Japan, Korea and Singapore. The company says its Medpak VIºC packaging, first introduced in Europe, provides 96-hour temperature stability. The reusable thermal packaging features vacuum insulated panels and phase change material validated to International Safe Transit Association 7D standards.

CIC energiGUNE, a research center in Spain's Basque Country, has an opening for a researcher in its thermal energy storage area. The research will focus on the storage of heat through reversible chemical reactions "in a range of temperature few explored so far (120 - 250 °C)." The application deadline is Sept. 11, 2019.   

Barbara Pause of Textile Testing & Innovation will be among the speakers at this year's Advances in Thermal Management conference, to be held Aug. 7-8 in Denver, Colo. Her topic: "Measuring and Modeling the Thermal Performance of Products Equipped with Phase Change Materials." 

• Thermal energy storage startup NET Energy of Chicago is among 10 finalists for the University of Chicago’s 19th annual Edward L. Kaplan New Venture Challenge. Winners will be announced next week, with the top companies sharing $250,000 in cash, along with $250,000 worth of office space and professional services from program sponsors. 

Research roundup: Night ventilation study; residential ice storage; fly ash and slag cement slurry; more

Ben Welter - Friday, May 24, 2019

From Building and Environment:

A parametric study of phase change material behaviour when used with night ventilation in different climatic zones

From Energy and Buildings:

Development and Evaluation of a Generalized Rule-Based Control Strategy for Residential Ice Storage Systems
Characterization of potassium carbonate salt hydrate for thermochemical energy storage in buildings

From International Journal of Energy Research:

Fly ash and slag cement slurry containing microencapsulated phase change materials

From Applied Energy:

Thermal response of annuli filled with metal foam for thermal energy storage: An experimental study
A scalable environmental thermal energy harvester based on solid/liquid phase-change materials

From International Journal of Hydrogen Energy:

Thermal management of metal hydride hydrogen storage reservoir using phase change materials

From Macromolecular Research:

Multiple Energy Harvesting Based on Reversed Temperature Difference Between Graphene Aerogel Filled Phase Change Materials

From Solar Energy:

Experimental studies on the effect of using phase change material in a salinity-gradient solar pond under a solar simulator

From Chemical Engineering Journal:

Thermal enhancement and shape stabilization of a phase-change energy-storage material via copper nanowire aerogel

From U.S. Office of Scientific and Technical Information:

Prototype Testing of Encapsulated Phase Change Material Thermal Energy Storage (EPCM-TES) for Concentrated Solar Power

From E3S Web of Conferences:

A PCM based cooling system for office buildings: a state of the art review

From Solar Energy Materials and Solar Cells:

Design of MtNS/SA microencapsulated phase change materials for enhancement of thermal energy storage performances: Effect of shell thickness

From Journal of Molecular Liquids:

Investigating the effects of hybrid nanoparticles on solid-liquid phase change process in a Y-shaped fin-assisted LHTESS by means of FEM

From Renewable and Sustainable Energy Reviews:

A review of microencapsulated and composite phase change materials: Alteration of strength and thermal properties of cement-based materials