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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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Novel PCM microspheres keep new therapy pack flexible when frozen

Ben Welter - Saturday, June 15, 2019

A novel phase change material developed by PureTemp LLC of Minneapolis is the key component of a new flexible therapy pack introduced at the American College of Sports Medicine conference in Orlando, Fla., last month.

Glacier Tek therapy packThe flexible PCM microspheres have a melt point of 18 degrees C and remain pliable when frozen. The flexible GlacierPacks, developed by Glacier Tek LLC of Minneapolis, are designed to provide targeted cooling relief for bruises, muscle strains, headaches and more. The patent-pending packs can be recharged in ice water in about an hour, hold their target temperature of 18 C for more than two hours and can be reused indefinitely.

The packs can be applied directly to skin without damaging tissue or causing discomfort. They can be used safely and effectively for longer periods than traditional ice packs or cold water immersion (CWI) treatments.

In research led by Dr. Malachy P. McHugh and Susan Y. Kwiecien of the Nicholas Institute of Sports Medicine and Athletic Trauma in New York, packs filled with PureTemp's biobased phase change material have been shown to provide a practical way to deliver prolonged post-exercise cooling and thereby accelerate muscle recovery.

A 2019 study, "Accelerated Recovery of Muscle Function in Baseball Pitchers Using Post-Game Phase Change Material Cooling," set out to examine the effectiveness of post-game PCM cooling on strength recovery in pitchers. Based on prior research (Kwiecien et al 2018 and Clifford et al 2018), it was hypothesized that PCM cooling would accelerate recovery. The flexible cooling packs were applied to the elbows and forearms of college pitchers after each had thrown 45 pitches. Pitchers in a control group received no PCM cooling treatment. The strength, soreness and creatine kinase levels of the athletes were then measured to gauge the effectiveness of the PCM cooling. CK is an enzyme released into the blood at elevated levels when there is muscle damage.

The researchers concluded that prolonged PCM cooling accelerated recovery of strength but did not affect soreness or CK levels. "The effect of PCM cooling of the medial elbow and forearm on grip strength recovery is very encouraging considering the role the wrist flexors play in dynamic stability of the elbow," the researchers wrote. 

"Can you believe it? A PCM that remains flexible when fully charged!" said RoxAnne Best, president of PureTemp and Glacier Tek. "I am really proud of our team for their commitment to bringing this technology to market. The consumer application possibilities are endless."

The therapy packs are available on Amazon and on the Glacier Tek website. A set of six packs retails for $229. Contact Glacier Tek to inquire about samples, volume discounts and custom configurations.

Croda adds 2 biobased phase change materials to its lineup

Ben Welter - Friday, May 17, 2019

Marco AuerbachCroda International Plc introduced two new biobased phase change materials, CrodaTherm 32 and CrodaTherm 37, in March. The British specialty chemicals maker developed the products at its PCM lab in Gouda, Netherlands. Marco Auerbach, technology development manager, said development work began about three years ago. He discussed the project in an email interview.

Q: What prompted Croda to create these PCMs -- customer requests, anticipated demand based on market analysis or a combination of factors?

A: "A combination of factors. Market demand was picked up by various means and also verified by customers, which prompted us at one point to start the development."

Q: What was your role in development of these PCMs?

A: "I am leading the technical development of PCMs within Croda. Therefore my task was to put a team together to find the right chemistry for the best possible technical product properties. Mainly meaning high latent heat, narrow melting and crystallization points and high cycle stability."

Q: Did the team surmount any unexpected challenges, technical or otherwise? 

A: "As with most developments, our project team also encountered challenges and set-backs. We had a few options to choose from, each with their own pros and cons. One challenge that is and will be taking more effort and time in future are chemicals registrations in various countries, but also raw material availability and pricing can have an impact."

Q: What specs can you share on each of the products, such as composition, peak melt point and latent heat storage capacity?

A: "For each launched PCM we have Product Data Sheets (PDS) available, so we also issued these for CrodaTherm 32 and CrodaTherm 37. They can be found on our website,  www.crodatherm.com. CrodaTherm 32 has a melting temperature of 32°C and crystallizes at 29.5°C. Latent heat is 190 kJ/kg. For CrodaTherm 37 melting takes place at 36.8°C, crystallization at 35°C and latent heat is 203 kJ/kg, measured by DSC."

Q: Do the new products have any properties, such as latent heat storage capacity or material compatibility, that set them apart from competing products?

A: "It is important to define which competing products or technologies one compares our products with, but in general our PCMs are produced from renewable resources and are also biodegradable. They are non-corrosive to metals and have long-term stability. Another big advantage is the very much lower evaporation and higher flash points compared to the current paraffin industry standards."

Q: What applications are suited to each of the two PCMs?

A: "We do not define the applications our products can be used for, but we have seen most interest in personal cooling and heating applications, as well as temperature-controlled shipments. We are still regularly surprised where and how customers sometimes want to use our CrodaTherm PCMs."

Q: In what formats are the two PCMs available -- bulk, macroencapsulated, microencapsulated?

A: "Both CrodaTherms are available in IBCs and drums. We go down in size to about 16 kg pails as the lowest pack size, but on request other options are possible. Croda does not offer macro encapsulation as we see ourselves as PCM suppliers, not wanting to compete with our customers at the user level. We feel that our customers and partners are better equipped to do this from a technical and customer support point of view. Croda does give advice on materials compatibility and connect our customers with our partners for macro encapsulation though. We do offer micro encapsulated CrodaTherm and also plan to offer CrodaTherm 32 in micro encapsulated form. If there is interest, we will also consider to micro encapsulate CrodaTherm 37."

Q: In a LinkedIn post this month, Croda announced: "All our CrodaTherm materials are USDA certified bio based products." Croda lists 14 CrodaTherm materials on its site; I see only 13 CrodaTherm products listed on biopreferred.gov. Missing from the USDA list is CrodaTherm 9.5. Has that product been certified yet?

A: "CrodaTherm 9.5 is also a product that only has been launched quite recently. We target to have all our products on the USDA bio-preferred list and I am confident CrodaTherm 9.5 will be added to it as well, but all things take time. We expect this registration can be added to the list shortly."

Q: What do you enjoy most about your job?

A: "The development of new products and the joy when customers actually like the product and are buying it. At that point all the puzzle pieces come together and you know that the hard work is paying off. I am particularly pleased with our CrodaTherm PCMs because they do not only help to improve/protect the environment while in use (especially for building cooling/heating applications), but they are also made from renewable raw materials and are bio-degradable. The environment is important to me and as a developer I am really happy I can have a contribution in a sustainable future."

Research roundup: High-conductivity nanomaterials; paper board packaging; battery thermal management; more

Ben Welter - Thursday, May 16, 2019

From Heat and Mass Transfer:

Experimental and numerical analysis of composite latent heat storage in cooling systems for power electronics

From Journal of Sol-Gel Science and Technology:

A robust, flexible superhydrophobic sheet fabricated by in situ growth of micro-nano-SiO2 particles from cured silicone rubber

From Journal of Thermal Analysis and Calorimetry:

High-conductivity nanomaterials for enhancing thermal performance of latent heat thermal energy storage systems

From Building Simulation:

Optimization and sensitivity analysis of design parameters for a ventilation system using phase change materials

From Journal of Packaging Technology and Research:

Thermal Analysis of Paper Board Packaging with Phase Change Material: A Numerical Study

From Energy Storage:

Thermal performance of battery thermal management system using composite matrix coupled with mini‐channel

From Phase Transitions:

A study on preparation and properties of carbon materials/myristic acid composite phase change thermal energy storage materials

From ACS Applied Materials & Interfaces:

Melamine Foam Supported Form-stable Phase Change Materials with Simultaneous Thermal Energy Storage and Shape Memory Property for Thermal Management of Electronic Devices

From International Conference on Thermal Engineering:

Performance Enhancement of Unitary and Packaged Air Conditioners With Phase Change Material
Performance Comparison of Different Phase Change Materials For Solar Cooking During off Sun Sunshine Hours
A Review on Enhancement of Thermophysical Properties of Paraffin Wax PCM With Nanomaterials
Nano-Enhanced PCMs for Low Temperature Thermal Energy Storage Systems and Passive Conditioning Applications

From Chemistry Select:

Designing Coconut Oil Encapsulated Poly(stearyl methacrylate‐co‐hydroxylethyl metacrylate) Based Microcapsule for Phase Change Materials

From Evolution in Polymer Technology Journal:

Enhancement of Thermo-Regulating Textile Materials Using Phase Change Material

From Materials Research Express:

Improved thermal characteristics of Ag nanoparticles dispersed myristic acid as composite for low temperature thermal energy storage

From Applied Energy:

On the performance of ground coupled seasonal thermal energy storage for heating and cooling: A Canadian context

From Solar Energy Materials and Solar Cells:

Thermal stability enhancement of d-mannitol for latent heat storage applications

PCM briefing: Cold chain veteran joins Phase Change Energy Solutions; Outlast showcases new nylon filament yarn

Ben Welter - Friday, May 10, 2019

Bruce TruesdaleBruce Truesdale has joined Phase Change Energy Solutions of Asheboro, N.C., as director of business development - cold chain. He was formerly senior supply chain consultant at Verta Life Sciences and director of health care at Protek Pharma Worldwide. He declined an interview request, but his new job title suggests that PCES, whose product line now focuses on HVAC, building and thermal energy storage, has an interest in the temperature-controlled packaging market. Earlier this year, PCES announced an investment by Pegasus Capital Advisors, Emerald Technology Ventures and Third Prime, an early-stage venture fund and prior investor. The company said it would use the proceeds to fund the continued development of its thermal storage products and expand its operations globally.

Chalmers University of Technology of Sweden has an opening for a postdoctoral researcher in thermal energy storage for building applications. The research group Building Physics is working "to find out how novel TES with phase change materials (PCM) could complement the existing district heating and cooling networks and co-operate with other peak shaving techniques (water accumulator tanks, ground heat storage pumps, etc.) through smart thermal grids." The application deadline is June 9.

Outlast will showcase its new nylon filament yarn at the Techtextil trade show in Frankfurt, Germany, next week. "The PCMs optimized for this specific application," Outlast says, "are included directly inside the polyamide fibers." Potential applications include next-to-skin products such as undergarments, shapewear, sportswear and hosiery. The company says it now sources the majority of PCMs used in its products from renewable instead of synthetic raw materials.

PCM coolerA PCM coating designed to absorb heat from rockets is among the dozens of NASA spinoffs listed in the latest issue of Spinoff, an annual publication that has been documenting space agency spinoffs since 1976. In the early 2000s, Raj Kaul, a materials scientist at Marshall Space Flight Center, began researching a way to use PCM to keep the outside of spacecraft at a safe temperature. An entrepreneur eventually snapped up the patent for the coating Kaul developed and is working on a number of products based on the technology, including aircraft paint, pipe heat traps and an iceless cooler, shown at right. 

• The U.S. Department of Energy this week announced $89 million in funding for "innovative, advanced manufacturing research and development projects." "Innovations for the Manufacture of Advanced Materials," one of three areas to receive funding, includes phase change storage materials for heating and cooling applications. The department anticipates making up to 55 awards for up to three years. Concept papers are due on June 20.

Tennessee startup introduces PCM-equipped dog cooling collar

Ben Welter - Friday, April 26, 2019

In extreme heat, active dogs need more than water and shade to avoid heat stroke. Solutions such as canine cooling vests and evaporative collars have been on the market for years. A Tennessee company recently added a new product to that list: a PCM-equipped canine collar designed to suppress body temperature during rigorous physical activity.

T-CoolK9 cooling collarT-CoolK9 launched its website, t-coolk9.com, in mid-March and made its first sale a week later. For Blake Fohl, the company's chief operating officer, T-CoolK9 is both a passion project and a full-time job. He began working on the product about a year ago.

Q: What sparked your interest in developing a cooling product for dogs?

A: "I was approached by an individual who had an idea, but didn't know how to bring it to market in the right way. My wife has been breeding German shepherds for two decades. We have dogs all over the world and doing about anything a dog can do, so we understood the dangers of canine heat stroke. I felt if there was a significant market, if the product could be proven to work as intended, it would be worth the time to create a new company from scratch."

Q: How did you arrive at the design of the cooling collar? It's different from competing products.

A: "We enlisted the help of a research scientist with an competency in biology and physiology. Our objective was to obtain a real grasp of how canines cool themselves, and to conduct trials which demonstrated the ability to reduce the dog's blood temperature. During our research of other products, we found they either had no scientific research behind them, or they just don't work. Dogs cool themselves through respiration primarily and to a very small degree through vascular temperature transfer in the feet and around the anus. That knowledge, in itself, led to the design of the collar. Looking at the arterial and vascular pathways really explains the design. Heat deflection sheets actually have the opposite effect. Water evaporation vests simply add weight to the dog and as you now know, they don't cool themselves that way. Other products which use ice packs, or maybe even phase change material, place the packs in the wrong position."

Q: How did you arrive at the melt point of the PCM (8°C)? Other products use 15-18°C.

A: "We identified pretty quickly that the PureTemp 15 we initially tested just wasn't cool enough, especially with double-coated dogs, such as German shepherds. So the scientist, a really smart guy, did some calculations and, working with PureTemp, we landed on PureTemp 8."

Q: How much PCM, by weight, is used in each collar?

A: "There are three PCM packs in the collar, two in the neck and one in the chest. We are averaging around 200 grams per collar."

Q: What kind of feedback are you getting from dog owners?

A: "It has been a little overwhelming. From search-and-rescue teams, police dogs, sport dogs, from people who do serious hiking with their dogs to owners who are just active with their pets, people are falling in love with the product. I think it is due to two reasons. First, the owners have a sense of confidence that they are doing the right thing to keep their dogs safe and comfortable, and secondly, they tell us the dogs actually get excited when they put the collar on."

Q: The collars are designed to fit all dogs with neck circumference of 10 inches or more. Do you plan on offering additional sizes?

A: "If the demand is there, we will make it. Our collar can fit any dog with a neck of 10 inches up to about 34 inches. That's a big dog. Seventy-five percent of the registered dogs in America fall into that range."

Q: Your site mentions that a portion of the profits from the sales of our product will be reinvested in additional scientific research. What's the focus of the research?

A: "We will be working with our original scientist and he is exploring creating a group of scientists and technologists to help understand the problem of canine heat stroke better and create new products and technologies to prevent the deaths of dogs. I could write for hours about how complicated this issue is, and how difficult it is to identify all the variables that go into creating a solution. We have a good first solution to help prevent the problem, but it is not the ultimate fail-safe product that we hope to have one day."

Research roundup: PCM use in mortars; compatibility with selected plastics; myo-inositol sugar alcohol; more

Ben Welter - Tuesday, April 23, 2019

From Materials:

Phase Change Materials for Energy Efficiency in Buildings and Their Use in Mortars

From Polymer Testing:
From Renewable Energy:


From Molecules:

From Applied Energy:

Natural convection during melting in vertical finned tube latent thermal energy storage systems
Year-round performance analysis of a photovoltaic panel coupled with phase change material

From Energy Procedia:

A Review of the Performance of Buildings Integrated with Phase Change Material: Opportunities for Application in Cold Climate

From Journal of Applied Polymer Science:

Encapsulation of polar phase change materials via multiemulsification and crosslinking method and its application in building

From Journal of Energy Storage:

Thermal performance of shell and tube latent heat storage unit: Comparative assessment of horizontal and vertical orientation
Experimental investigation of phase change in a multitube heat exchanger

From Chemistry Select:

Preparation and Thermal Properties of Stearic Acid/n‐Octadecane Binary Eutectic Mixture as Phase Change Materials for Energy Storage

From Journal of Materials Research:

Synthesis of novel shape-stabilized phase change materials with high latent heat and low supercooling degree for thermal energy storage

From Science of Advanced Materials:

Fabrication and Performance of Polyurethane/Polyurea Microencapsulated Phase Change Materials with Isophorone Diisocyanate via Interfacial Polymerization
Design and Analysis of Battery Box Based on Graphite-Phase Change Material and Air Cooling

From Experimental Techniques:

Design, Build, and Test a Hybrid Cooling System for Crash Helmet

From Journal of Thermal Analysis and Calorimetry:

Capric acid/intercalated diatomite as form-stable composite phase change material for thermal energy storage
Preparation and thermal performances of microencapsulated phase change materials with a nano-Al2O3-doped shell

Research roundup: Hollow aluminum bricks; animal-fat-based PCM for building applications; floor heating system design; more

Ben Welter - Wednesday, March 27, 2019

From Applied Thermal Engineering:

Thermal characteristics of aluminium hollowed bricks filled with phase change materials: Experimental and numerical analyses

From Energies:

Assessing the Potentiality of Animal Fat Based-Bio Phase Change Materials (PCM) for Building Applications: An Innovative Multipurpose Thermal Investigation

From Sustainable Energy and Fuels:

Innovative design of microencapsulated phase change materials for thermal energy storage and versatile applications: A review

From Environmental Research:

Design and analysis of phase change material based floor heating system for thermal energy storage

From Solar Energy Materials and Solar Cells:

Direct impregnation and characterization of Colemanite/Ulexite-Mg (OH) 2 paraffin based form-stable phase change composites
Experimental analysis of solar air collector with PCM-honeycomb combination under the natural convection

From Journal of Molecular Liquids:

Fabrication and characterization of phase change nanofluid with high thermophysical properties for thermal energy storage

From Renewable Energy:

Investigation of thermal properties and enhanced energy storage/release performance of silica fume/myristic acid composite doped with carbon nanotubes

From International Journal of Thermal Physics:

Thermal Property Characterization of a Low Supercooling Degree Binary Mixed Molten Salt for Thermal Energy Storage System

From Journal of Energy Storage:

From Energy Procedia:

Development of Corn-Oil Ester and Water Mixture Phase Change Materials for Food Refrigeration Applications
Experimental study on the performance of a new encapsulation panel for PCM's to be used in the PCM-Air heat exchanger

From Case Studies in Thermal Engineering:

Thermal characteristics on melting/solidification of low temperature PCM balls packed bed with air charging/discharging

Research roundup: Micro/nano PCM for solar thermal applications; photovoltaic cooling; beeswax emulsions; more

Ben Welter - Thursday, March 21, 2019

From Renewable Energy:

Review on micro/nano phase change materials for solar thermal applications

From Jordan Journal of Mechanical and Industrial Engineering :

Photovoltaic Cooling Using Phase Change Material

From Advanced Materials Interfaces:

Phase Change Materials: Superhydrophobic Coatings from Beeswax‐in‐Water Emulsions with Latent Heat Storage Capability

From Energy Storage:

Experimental Observations on the Interface Front of Phase Change Material inside Cylindrical Cavity

From Applied Energy:

Effect of different dimensional carbon materials on the properties and application of phase change materials: A review

Research roundup: Personal cooling system; optimization of active wall system; cement mortar; asphalt pavement; more

Ben Welter - Friday, March 15, 2019

From International Journal of Refrigeration:

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

JMR illustration of microencapsulated n-octadecane with silk From Journal of Materials Research:

Fabrication and characterization of microencapsulated n-octadecane with silk fibroin–silver nanoparticles shell for thermal regulation

From IOP Conference Series: Earth and Environmental Sciences:

Simple Thermal Energy Storage Tank for Improving the Energy Efficiency of an Existing Air-conditioning System
An optimization study into thermally activated wall system with latent heat thermal energy storage
Simulation of operation performance of a solar assisted ground heat pump system with phase change thermal storage for heating in a rural building in Xi'an
Experimental Study on the Demand Shifting Effects of PCM Integrated Air-Conditioning Duct

From International Journal of Energy Research:

Efficiency optimisation of the thermal energy storage unit in the form of the ceiling panel for summer conditions

From Materials Research Express:

Experimental study on thermal conductivity of composite phase change material of fatty acid and paraffin

From Energies:

Design Optimization of a Hybrid Steam-PCM Thermal Energy Storage for Industrial Applications

From Construction and Building Materials:

Analysis of thermoregulation indices on microencapsulated phase change materials for asphalt pavement

From Applied Thermal Engineering:

Experimental and numerical characterization of an impure phase change material using a thermal lattice Boltzmann method

From Energy Conversion and Management:

Experimental and numerical study of a vertical earth-to-air heat exchanger system integrated with annular phase change material

From Materials:

Thermal and Structural Characterization of Geopolymer-Coated Polyurethane Foam—Phase Change Material Capsules/Geopolymer Concrete Composites

From Applied Sciences:

Microstructure and Mechanical Properties of Cement Mortar Containing Phase Change Materials

Patent application: Dimensionally stable phase change material

Ben Welter - Friday, March 15, 2019

U.S. patent application 20190078006 (applicant Microtek Laboratories Inc., Dayton, Ohio):

"Methods for producing a dimensionally stable phase change material (PCM), and dimensionally stable PCMs are disclosed. The methods include providing a porous base material, mixing a phase change material having a polar functional group with a substance that increases the polar attraction of the phase change material for the porous base material to form a mixture thereof; and, thereafter, mixing the mixture with the porous base material until a selected saturation of phase change material in the porous base material is reached. The methods may include filtering the porous base material after the selected saturation is reached to form a cake of dimensionally stable PCM and, thereafter, reducing the size of the dimensionally stable PCM to an average mean particle size of about 10 to about 50 μm, or more preferably 20 to 30 μm."

http://www.freepatentsonline.com/20190078006.pdf