Phase Change Matters RSS


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.




Research roundup: PCM compatibility with metals, plastic; desiccant packet for cooling vest; paraffin viscosity; more

Ben Welter - Thursday, March 23, 2017

Investigation of the corrosive properties of phase change materials in contact with metals and plastic [Renewable Energy]

Preparation and thermal properties of SAT-CMC-DSP/EG composite as phase change material [Applied Thermal Engineering]

A numerical study on the usage of phase change material (PCM) to prolong compressor off period in a beverage cooler [Energy Conversion and Management]

Abilities and limitations of thermal mass activation for thermal comfort, peak shifting and shaving: A review [Building and Environment]

Corrosion effect of phase change materials in solar thermal energy storage application [Renewable and Sustainable Energy Reviews]

A review for phase change materials (PCMs) in solar absorption refrigeration systems [Renewable and Sustainable Energy Reviews]

Sodium nitrate – Diatomite composite materials for thermal energy storage [Solar Energy]

Innovative PCM-desiccant packet to provide dry microclimate and improve performance of cooling vest in hot environment [Energy Conversion and Management]

Heat transfer study of phase change materials with graphene nano particle for thermal energy storage [Solar Energy]

Energy performance evaluation of heat-storage gypsum board with hybrid SSPCM composite [Journal of Industrial and Engineering Chemistry]

Empirical equation to estimate viscosity of paraffin [Journal of Energy Storage]

Yearly energy performance of a photovoltaic-phase change material (PV-PCM) system in hot climate [Solar Energy]

Research roundup: Microcapsule-based composites; porous cellulose acetate films; underfloor heating; more

Ben Welter - Tuesday, March 07, 2017

Experimental study on effective thermal conductivity of microcapsules based phase change composites [International Journal of Heat and Mass Transfer]

Multi-objective RSM Optimization of Fin Assisted Latent Heat Thermal Energy Storage System Based on Solidification Process of Phase Change Material in Presence of Copper Nanoparticles [Applied Thermal Engineering]

Buildings cooling: An experimental study of phase change materials storage for low-energy buildings [2017 International Conference on Communication, Control, Computing and Electronics Engineering ]

Aluminum Mesh and Phase-Change Characteristics of n-Octadecane for Thermal Energy Storage [Journal of Thermophysics and Heat Transfer]

Analytical analysis of latent heat thermal energy storage model for solar thermal power plants [14th International Bhurban Conference on Applied Sciences and Technology]

Analysis of graphene-encapsulated polymer microcapsules with superior thermal and storage stability behavior [Polymer Degradation and Stability]

Experimental and numerical investigations on the thermal performance of building plane containing CaCl2·6H2O/expanded graphite composite phase change material [Applied Energy]

Fabrication and characterization of porous cellulose acetate films by breath figure incorporated with capric acid as form-stable phase change materials for storing/retrieving thermal energy [Fibers and Polymers]

In-situ preparation of a shape stable phase change material [Renewable Energy]

Proposal of a PCM Underfloor Heating System Using a Web Construction Method [pdf] [International Journal of Polymer Science]

PCM briefing: Sasol introduces Parafol 17; CIC Energigune seeks scientific director for energy storage group

Ben Welter - Tuesday, March 07, 2017

• In a LinkedIn post, the chemicals giant Sasol has announced the development of a new phase change material, Parafol 17. The product has a melting range of 20-22º Celsius. Potential applications include building/construction and the transportation of temperature-sensitive goods. The company says the new PCM is commercially available, but it is not yet listed on the company's websites.

CIC Energigune is seeking candidates for the position of scientific director in its energy storage group, which is focused on the research of systems that can store heat from medium to high temperatures. The research center, based in Spain's Basque Country, also has a leadership opening in the TES group's device, prototype and testing area. 

• Want to learn how your company can include sustainability in its business goals? Stanford University's Center for Professional Development is offering a free webinar, "The Pursuit of Sustainability," at 11 a.m Pacific time March 14. 

GreenCE is offering an online course titled "Inspiration Green: Biomimicry, Climate & Culture." The course, sponsored by T. Stern Sustainability of Seattle, will cover strategies used in high-performance buildings to reduce environmental impact and earn LEED credits. The cost: $35.

• New from Transparency Market Research: "1-Tetradecanol Market - Global Industry Analysis and Forecast 2024"

Sonoco ThermoSafe has posted the results of an industry survey on the "current and future state" of clinical trial supplies. Half of those surveyed said they planned to adopt new supply chain technology within the next two years.

Finland's Team HeatStock is developing a novel PCM designed to lock in solar, waste heat for later use

Ben Welter - Monday, March 06, 2017

Researchers in Finland are developing a novel phase change material that combines sugar alcohols and sodium polyacrylate, the superabsorbent polymer used in disposable diapers. The material is designed to store solar heat collected in summer and release it for use in winter. The material could also be used to store industrial waste heat.

Team HeatStock, whose members include chemists, energy engineers and physicists from three universities, is one of 20 semifinalists in the 2017 Helsinki Challenge. Finalists, to be selected in June, will compete for a share of 375,000 euros in research funds. The winners will be announced in December.

Team HeatStock PCMTeam HeatStock presented its technology at the Helsinki Challenge pitch night last month.

“The charging of our storage happens by melting the active material of our solution,” said Aalto University research scientist Salla Puupponen. “However, when the melt material starts to cool, it doesn’t release the heat on crystallization as conventional phase change materials, but instead we can keep our material as low temperatures as we want, as long time as we want without losing the stored energy.”

In an interview with Phase Change Matters, team leader Ari Seppälä, a senior scientist at Aalto, describes the technology in further detail.

Q: On the Helsinki Challenge website, you mention that the material will be used to store heat from "solar collectors.” That’s solar thermal, not photovoltaic, correct?

A: Yes, that meant solar thermal collectors. But that is just a one possibility. Other options include such as storing waste heat from industrial processes and storing the surplus heat produced by CHPs (combined heat and power plants) during summertime. As CHPs are often linked with district heating systems (at least in Nordic countries) delivering hot water to residents, the surplus heat could also be exploited for charging the storages of residential buildings during summer for wintertime use.

Q: How is the project being funded now?

A: We have Aalto University strategic funding (Aalto Energy Efficiency Program) and also funding from Fortum Foundation. However, our funding ends during this year. Currently we are looking for new funding possibilities. We are also looking for more collaborators and community members for the research and the competition. So, experts, scientists, companies and organizations who are interested in our research are most welcome to join us!

Q: Your PCM sounds like a composite. What are its components and how are they combined?

A: Our PCM can be classified more likely as a mixture than as a composite. It is composed of a polyol in a cross-linked polyelectrolyte matrix.

Q: What is the PCM's melting point?

A: The melting point is about 100º C.

Q: What is the PCM’s thermal energy capacity in joules per gram?

A: The heat of melting is 180-280 J/g depending on the composition. The heat of crystallization of the material is currently approximately 140-170 J/g. We aim at developing the latent heat of our material further.

Q. You have describe the material as having “phase-change properties that had never been seen before with any material.” What are those properties?

A: Operation of our novel material is based on so-called cold-crystallization, in which the conventional melt-crystallization on cooling is prevented and the material crystallizes only on heating. Supercooled PCM does not seem to crystallize even with a seed crystal below the cold-crystallization temperature. Anomalously, the PCM seems to be stable also above the glass-transition temperature. The novel operation principle enables long-term storing of thermal energy, and discharge of the storage by a small heat pulse.

Cold-crystallization is previously observed also for hydrated polymers, in which water is absorbed by hydrophilic polymers. However, in these cases the amount of cold-crystallizing water is small and the crystallization properties are not conserved in the repeated melting-crystallization cycles. Our material instead can consist up to 90 percent of actual PCM and can be cycled without notable changes in phase change properties.

In addition, the cold-crystallization temperature can be adjusted by the changing the material composition.

Q: What are the key steps in your scale-up plans?

In the beginning, we aim at scaling-up our sample size from tens of milligrams to a kilogram scale. In the scale-up, it is crucial that the material properties, especially the stability of supercooled state, remain unaltered. That is of course an open question, as it is well known that the stability of metastable states decreases with increasing volume of the sample. However, our small, deeply supercooled samples did not crystallize even with seeds and thus the operation of our material differs substantially from conventional materials. After the scale-up process, we will study the triggering of the crystallization by the heat pulse. We also aim at building a practical demo linked with a heat loading and releasing system.

We will later also look for creating similarly behaving materials based on different PCMs.

Q: Have you published research papers on the material?

A: There are no published papers concerning this new material so far. The manuscript on this material, (Puupponen and Seppälä, Cold-crystallization of polyelectrolyte absorbed polyol for long-term storing of thermal energy) has just been submitted for review and a patent application is pending.

Here are links to recent journal papers related to our other PCM studies:

PCM for long-term storage:

Puupponen S, Mikkola V, Ala-Nissilä T, Seppälä A, (2016) Novel microstructured polyol–polystyrene composites for seasonal heat storage, Applied Energy 172 96–106.

Thermodynamics of solidification and melting:

Seppälä A., Irreversibility of solidification and of a cyclic solidification-melting process, (2012), International Journal of Heat and Mass Transfer, 55 1582-1595.

Heat transfer nanofluids with PCM particles:

Puupponen, S., Seppälä, A., Vartia, O., Saari, K., Ala-Nissilä, T., Preparation of paraffin and fatty acidphase changing nanoemulsions for heat transfer (2015), Thermochimica Acta, 601, 33-38

Mikkola V, Puupponen S, Saari K, Ala-Nissila T, Seppälä A., Thermal properties and convective heat transfer of phase changing paraffin nanofluids, (2017), accepted for publication in International Journal of Thermal Sciences.

Research roundup: 2 promising PCM candidates; calcium carbonate shell; thermocapillary effects; more

Ben Welter - Tuesday, February 21, 2017

Thermal properties characterization of two promising phase change material candidates [Journal of Thermal Analysis and Calorimetry]

Self-assembly synthesis and properties of microencapsulated n-tetradecane phase change materials with calcium carbonate shell for cold energy storage [ACS Sustainable Chemistry and Engineering]

Thermal Analysis of a Thermal Energy Storage Unit to Enhance a Workshop Heating System Driven by Industrial Residual Water [Energies]

Effect of a low-cost parabolic reflector on the charging efficiency of an evacuated tube collector/storage system with a PCM [Solar Energy]

Numerical study on free-surface jet impingement cooling with nanoencapsulated phase-change material slurry and nanofluid [International Journal of Heat and Mass Transfer]

Heat transfer performance and melting dynamic of a phase change material subjected to thermocapillary effects [International Journal of Heat and Mass Transfer]

Evaluation and optimization of melting performance for a latent heat thermal energy storage unit partially filled with porous media [Applied Energy]

Carbon nanotube/paraffin/montmorillonite composite phase change material for thermal energy storage [Solar Energy]

Synthesis and thermal properties of novel solid-solid phase change materials with comb-polyurethane block copolymer structure for thermal energy storage [Thermochimica Acta]

Synthesis and Properties of Polyurethane/Coal-Derived Carbon Foam Phase Change Composites for Thermal Energy Storage [Acta Physico-Chimica Sinica]

Patent application: PCMs comprising alkanolamides and diesters and methods of making and using them

Ben Welter - Monday, February 20, 2017

U.S. patent application 20170044414 (applicant Entropy Solutions LLC, Plymouth, Minn.):

"This invention generally relates to thermoregulation and temperature stabilization, thermal protection and insulation, and nucleating agents. In particular, in alternative embodiments, provided are organic phase change materials comprising diesters and alkanolamides. In alternative embodiments, provided are Phase Change Material (PCMs) compositions comprising diesters and alkanolamides, and methods for making and using them. In alternative embodiments, the Phase Change Material (PCMs) compositions are used for thermal energy management, including energy storage and/or temperature stabilization, in various applications such as building, automotive, packaging, garment and footwear, textiles, fabrics, synthetic fibers, foods, microcapsules and other energy storage systems."

Research roundup: Encapsulation techniques for inorganic PCM; effects of flake graphite nanoparticles; more

Ben Welter - Monday, February 13, 2017

From Renewable and Sustainable Energy Reviews:

A review on encapsulation techniques for inorganic phase change materials and the influence on their thermophysical properties
Phase equilibrium in the design of phase change materials for thermal energy storage: State-of-the-art

From Applied Thermal Engineering:

Investigating the impact of Cp-T values determined by DSC on the PCM-CFD Model
Performance of a Finned, Latent-Heat Storage System for Solar Thermal Power Application

From Applied Energy:

Impact of periodic flow reversal of heat transfer fluid on the melting and solidification processes in a latent heat shell and tube storage system
The effects of flake graphite nanoparticles, phase change material, and film cooling on the solar still performance
A quick-fix design of phase change material by particle blending and spherical agglomeration

From Journal of the Taiwan Institute of Chemical Engineers:

Phase-change heat transfer in a cavity heated from below: The effect of utilizing single or hybrid nanoparticles as additives

From Energy:

Field evaluation of microencapsulated phase change material slurry in ground source heat pump systems

From Renewable Energy:

Numerical studies on thermal and electrical performance of a fully wetted absorber PVT collector with PCM as a storage medium
Glass encapsulated phase change materials for high temperature thermal energy storage

From SAE World Congress Experience:

Integration and Validation of Thermal Energy Storage System for Electric Vehicle Cabin Heating

From Engineering Technology International Conference 2016:

Preparation and characterization of form-stable paraffin/polycaprolactone composites as phase change materials for thermal energy storage

PCM briefing: California utility will buy up to 100 Ice Bears for residential use; Malouf unveils new graphite-PCM pillow

Ben Welter - Thursday, February 09, 2017

Ice Energy will join forces with the Southern California Public Power Authority to provide up to 100 Ice Bear 20 cooling units for residential use within utility's 12 member territories in 2017. Installations will begin in June. The Ice Bear 20 stores cooling energy during off-peak hours 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. The new deployment is designed to demonstrate the Ice Bear 20's grid value to utilities. The units will be installed in single-family homes chosen by Ice Energy based on site visits. Homes that need 4-, 5- or 6-ton air-conditioning systems replaced are the likely targets. The utilities pay for the Ice Bears; it's unclear at this point who will pay installation costs. If all 100 Ice Bear 20s are purchased, the total cost to the utilities will be $1.33 million (not including installation).

Malouf CarbonCool pillow• Bedding maker Malouf's new CarbonCool Plus OmniPhase pillow combines the temperature-regulation properties of graphite and microencapsulated phase change material. "At the molecular level," Furniture Today reports, "the material inside the capsules changes from a solid to a liquid when the temperature is high and vice versa when the temperature is low. This continuous cycle is designed keep the pillow surface between 87 and 91 degrees, which research shows is the ideal skin temperature range for deep sleep." The queen size shown here retails for $299.99.

• New from Absolute Reports: "United States Advanced Phase Change Materials (PCM) Market By Manufacturers, States, Type And Application, Forecast To 2022"

SPX Flow's new FLEX Series refrigerated air dryer uses phase change material to tightly regulate temperatures and reduce compressor cycling.

Prongo insulin bagPluss Technologies' PronGo bag, introduced last year for consumers to transport frozen and chilled food and beverages, is  now being promoted as a way to keep insulin at the right temperature for up to 10 hours. The 3-liter bag comes with two sets of PCM cooling packs. It's available on for about $52. In an interview with Express Pharma, company director Samit Jain talked about the Prongo and another new product, Celsure, a passive shipper designed to keep pharma products "at the right temperature for 96 hours and beyond at the tropical temperatures that countries like India, South East Asia and Africa have."

1414 Degrees, the Australian company that has developed a way to store electricity as thermal energy by heating and melting containers full of silicon, is now scaling up the technology and plans to launch the first commercial systems this year. Executive Chairman Kevin Moriarty said the company is waiting for AusIndustry, a division of Australia's Department of Industry, Innovation and Science, to sign off on the 10MWh project in February so manufacture can begin.

PCM briefing: New denim features phase change material; Sasol 'back on the expansion trail'

Ben Welter - Monday, February 06, 2017

• Thinking about attending BiobasedWorld 2017 in Cologne, Germany, this month? Sorry, the trade show was canceled a few months ago due to the industry's "challenging economic environment." A related show is on the horizon: Bio-Based Live Europe in Amsterdam, May 31-June 1. The focus will be on "Process Innovation and Technology" and "Sustainable Products." Speakers include Freek Snieders, managing director, Croda International; and Jean Luc Dubois, scientific director, Arkema.

Oak Ridge National Laboratory takes a look at how University of Michigan researchers used a Cray XK7 Titan supercomputer to study melting in two-dimensional systems. Deeper understanding of the process, Oak Ridge says, "could yield insights into surface interactions in materials important to technologies like solar panels, as well as into the mechanism behind three-dimensional melting." 

• The cold chain packaging class developed by Sonoco ThermoSafe’s ISC Labs will be offered at the Cold Chain GDP & Temperature Management Logistics Global Forum in San Diego in May. The all-day session on May 25 will cover the design, development and qualification of temperature-controlled packaging. The conference agenda is available for download. reports that chemicals giant Sasol is "back on the expansion trail, seeking out suitable acquisitions."

• Among the new fabrics on display at the Munich Fabric Start trade show this week: Cordura denim combined with Schoeller phase change material. 

• The University of the West of England has installed two Monodraught Cool-Phase hybrid units in the university's Estates Management Office in Bristol. Monodraught says its PCM-equipped systems have been shown to "use up to 90% less energy than traditional a/c systems."  

• The 12th Conference on Advanced Building Skins, scheduled for Oct. 2-3 in Bern, Switzerland, has issued a call for papers. Possible topics include financial models, new products, advanced design and building performance. The deadline is Feb. 10. 

Pelican BioThermal has announced that its new passive pallet shipper system, CrÄ“do Cargo, is now available to rent or buy. The reusable bulk shipper uses phase change material cooling panels to maintain temperature ranges +2C to +8C and +15C to +25C. 

PCM briefing: Long-haul cyclists reach Myanmar; papers sought for symposium on waste heat

Ben Welter - Friday, January 27, 2017

Riccardo Rocchi and Chiara RicciardiRiccardo Rocchi and Chiara Ricciardi,  the Italian couple who began an 18,000-kilometer bike ride in June to raise awareness about diabetes, have reached Myanmar. Ricciardi has type 1 diabetes and needs a daily dose of insulin. She is using Pelican BioThermal's Credo ProMed pack to keep insulin at the right temperature. The pair topped the 10,000-kilometer mark this week. They've pedaled across 16 countries, averaging 44 km per day. "We just realized that maybe we forgot to make a postcard from Nepal," the pair said in a Facebook post from Myanmar. "We might consider to cycle back to do it." Their final destination is Singapore.

• Organizers of a one-day symposium at Brunei University on the efficient use of waste heat have issued a call for abstracts. The symposium, "Heat Recovery and Efficient Conversion and Utilisation of Waste Heat," will be held April 20, 2017. Abstracts must be submitted by Jan. 31.

Pelican BioThermal has completed a $1.65 million expansion of the manufacturing facilities at its U.S. headquarters in Plymouth, Minn. The company now has 70,000 square feet of manufacturing space in the Minneapolis suburb, up from 54,000 square feet. The expansion will support production of single-use temperature-controlled shippers in the United States.

Weise's Outlast Houston motorcycle jacket• New from Weise Motorcycle Clothing: The Outlast Houston, a fully armored waterproof jacket with a removable lining that features Outlast phase change material to regulate temperature. 

Serta is touting “breakthrough cooling technology” in the new version of its iComfort memory foam mattresses. Phase change material is embedded in the fabric and on the surface of the gel memory foam.

• The United Kingdom plans to spend £28 million ($35 million) on reducing the cost of energy storage, advancing demand side response technologies and improving energy efficiency measures for industry. Up to one-third of the money will be spent on a competition to reduce the cost of energy storage, including thermal storage.

• The EU-funded Heat4Cool research project is developing a novel retrofit planning tool to help retrofit companies, architects, manufacturers, building administrators and residents weigh the potential benefits of three main technologies: gas and solar thermally driven adsorption heat pumps; PV-assisted DC-powered heat pumps connected to advanced modular PCM heat and cold storage systems; and energy recovery from sewage water with high performance heat exchangers. You are invited to help in this effort by completing a five-minute survey online.

• A Florida startup is calling its PCM-infused TempPro fabric “a gamechanger for luxury lingerie.” Giapenta, which launched a Kickstarter campaign this week, uses the temperature-regulating fabric in its line of bras, panties and sleep masks. The campaign has already met its modest target of raising $25,000. I've contacted the company and hope to have technical details on TempPro in time for next week's newsletter..