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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 bwelter@puretemp.com. We'll select the best and post the answers here each week.

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PCM briefing: Tessol featured in Forbes India; Terrafore Technologies selected for Argonne program

Ben Welter - Monday, June 05, 2017

Thermal Energy Service Solutions, maker of a PCM-based "plug-and-chill" refrigeration system for delivery trucks, is profiled in this month's issue of Forbes India. The system's heat exchanger is designed to keep the refrigerator on the truck within the optimal temperature range for a full day’s operation without drawing power from the engine. The heat exchanger can be fully charged in about six hours at any power outlet.

C-Therm Technologies will be among the exhibitors the Techtextil North America trade show in Chicago June 20-22. The company will demonstrate its non-destructive TCi Property Analyzer, which is designed to characterize the thermal performance (the “warm feel” or “cool touch”) of textiles, fabrics and apparels.

Terrafore Technologies of Minneapolis is one of seven small businesses recently selected to collaborate with researchers at Argonne National Laboratory as part of the Department of Energy's Small Business Vouchers program. Terrafore and Argonne will test the reliability of phase change salt capsules for a compact high-temperature thermal energy storage system for concentrated solar power.

SpecialChem is offering an online course titled "How to Search & Map U.S. Patents for Patentability." The 90-minute course, scheduled for June 28, is designed to for R&D people "looking to avoid patent infringement by enhancing their patent searching and mapping skills." The cost for three attendees on one connection is 300 euros.

PCM briefing: Pluss VP honored as 'Innovator under 35'; BASF partners with Hewlett Packard Enterprise on new supercomputer

Ben Welter - Tuesday, March 21, 2017

Ankit Jhanwar, VP for corporate planning and strategy at Pluss Advanced Technologies, was honored as one of 10 "Innovators under 35" at EmTech India 2017.

Sunamp Ltd., maker of PCM-based heat batteries, is one of eight finalists for an Ashden UK Award. Winners will be announced at a ceremony in London on June 15. The competition recognizes excellence in the field of green energy.

Hewlett Packard Enterprise will work with BASF to develop a supercomputer that will sharply reduce the time it takes to run simulations and modeling in chemical research. "The new supercomputer will promote the application and development of complex modeling and simulation approaches, opening up completely new avenues for our research at BASF,” said Dr. Martin Brudermueller, chief technology officer at BASF.

McKinsey & Co. analysts say a slowdown in the chemical industry's financial performance over the past five years reflects important changes in the industry’s fundamentals. One of their recommendations: "Incumbent specialty-chemical players must prepare for further encroachment of commoditization and erosion of their historical advantages when attackers from developing markets gain more experience and become increasingly technologically savvy."

California lawmakers have introduced legislation to encourage more clean energy resources to address peak load. The bills would require utilities to deploy clean energy during peak demand in order to meet the state's aggressive greenhouse gas and renewable energy goals. 

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.

Dutch-led consortium develops calculation model for industrial heat storage

Ben Welter - Friday, December 16, 2016

LOCOSTO PCM test tankA consortium led by the Energy Research Center of the Netherlands (ECN) has developed a calculation model to predict the performance of a phase change material buffer for industrial heat storage in the 100-250° C temperature range. The model is used to optimize the design of a heat exchanger to achieve the required performance in the most cost-effective way. According to the ECN:

"A test installation with around 100 liters of PCM (see photo) is used to measure the performance of the storage and compare it with the model calculations. There is a high level of consistency between the experimental and model outcomes, providing a basis for the further development and scaling of PCM heat storage technology."

The consortium continues to work on the selection of PCMs with the desired attributes for industrial heat storage. 

"We consider salt hydrates as most feasible option for industrial heat storage," said Robert de Boer, thermal systems project manager at ECN. "I wouldn’t say it is ideal, but the best we can get at this moment."

Members of the LOCOSTO consortium are end-users DOW, Perstorp and EMMTEC; system suppliers IEE and Bronswerk Heat Transfer; materials suppliers PCM Technology and Nedmag; and Dutch research institutes TNO and ECN. "LOCOSTO" stands for "LOw COst STOrage" of heat.

https://www.ecn.nl/news/item/ecn-develops-energy-saving-and-cost-effective-technology-for-industrial-heat-storage/

PCM, foam insulation combine to reduce heat transfer through walls

Ben Welter - Monday, December 12, 2016

Researchers at the Fraunhofer Institute for Chemical Technology in Germany say they have successfully integrated phase change material in foam insulation for use in walls.

What's new about the technology?

"Instead of a few micrograms, several grams of the phase change materials have been integrated. Therefore the thickness of the wall is not changing by increasing the thermal mass," says Sandra Pappert, a scientist at Fraunhofer.

Details of the research will be presented at the BAU trade fair in Munich, Jan. 16-21, 2017. Researchers will use two climatic chambers to demonstrate the extent to which the foam sheets can help manage temperature fluctuations in buildings.

https://www.fraunhofer.de/content/dam/zv/en/press-media/2016/Dezember/ForschungKompakt/rn_12_2016_ICT_Combination%20of%20Isolation%20and%20thermal%20mass.pdf

Patent application: HVAC system for electric vehicle with driving range extension

Ben Welter - Thursday, September 01, 2016

U.S. patent application 20160250906 (applicant Mahle International GmbH, Stuttgart, Germany):

"A heat pump cooling and heating system for an electric vehicle includes a range extending PCM heat exchanger, with a single acting phase change material with a melt temperature between the two comfort temperatures associated with cooling and heating, respectively. In a charging mode, as the vehicle batteries are charged, the same exterior current source runs the compressor, charging the PCM exchanger with heat or 'cold.' During an initial range extending mode, the PCM exchanger/reservoir serves as the heat source or heat sink. The PCM material does not directly heat or cool the air, as is conventional, allowing a single reservoir material to be used in both heating and cooling modes."

http://www.freepatentsonline.com/20160250906.pdf

PCM briefing: EU research focuses on energy retrofits; Axiom Exergy raises $2.5 million

Ben Welter - Tuesday, August 02, 2016

• A European Union research project focused on retrofitting old buildings to meet EU efficiency standards is taking a close look at PCMs built into walls. “By using a phase change material which freezes at 18°C and melts at 25°C,” says Dr. Jürgen Frick, project coordinator, “we can regulate the temperature fluctuations of a room. If the temperature falls to 18°C, the PCM freezes and heats the room. When it rises to 25°, the PCM melts, energy is absorbed, and the room is cooled.”

Rally by Diamond Mattress• The latest entry in the bed-in-a-box mattress competition features open-cell foam infused with copper gel and phase change material to regulate temperature. Diamond Mattress of Rancho Dominguez, Calif., says the company's new Rally line will be sold online and in retail stores.

Eric Buchanan of the West Central Research and Outreach Center in Morris, Minn., has posted an update on his net-zero dairy project. The system's key components so far include solar thermal panels, a heat pump, three heat exchangers and a 2,000-gallon water tank. Fifty-four kilowatts of solar PV and two 10-kW wind turbines are now being added to the system.

Axiom Exergy has raised $2.5 million from investors to help bring its refrigeration battery to supermarkets and cold storage facilities across the United States. The system uses a salt-based phase change material to reduce peak power usage by up to 40 percent and provide backup cooling during power outages.

• The University of Birmingham's Birmingham Centre for Energy Storage is setting up a joint lab on energy storage research with Global Energy Interconnection Research Institute Europe, an organization founded by China's state-run utility. The lab will focus on thermal and cryogenic energy storage systems and their application in energy networks.

• New from Accuray Research: "Global Advanced Phase Change Material (PCM) Market Analysis & Trends - Industry Forecast to 2025"

• A research team at Camosun College in Victoria, British Columbia, has selected PureTemp phase change material for use in a study of greenhouse thermal storage systems. "One of the engineering students is focusing on designing racks for the PCM bottles that will be specifically engineered to slow release and speed recharge of the bottles," writes Becky Mason, an instructor at Camosun who helped organize the research project. "This is intended to optimize use of PCM in off-grid greenhouses where electric fans are not used to circulate air around the PCM."

Research roundup: Refrigerated display cabinet; MA/HDPE composites with nano-additives; incinerator ash; more

Ben Welter - Sunday, July 31, 2016

The novel use of phase change materials in an open type refrigerated display cabinet: A theoretical investigation [Applied Energy]

Reducing cell-to-cell spacing for large-format lithium ion battery modules with aluminum or PCM heat sinks under failure conditions [Applied Energy]

Synthesis and thermal properties of the MA/HDPE composites with nano-additives as form-stable PCM with improved thermal conductivity [Applied Energy]

An experimental study of thermal management system using copper mesh-enhanced composite phase change materials for power battery pack [Energy]

Novel Multiphase Change Materials for Energy Storage Application in Buildings [14th International Energy Conversion Engineering Conference, Propulsion and Energy Forum]

MSWI bottom ash for thermal energy storage: An innovative and sustainable approach for its reutilization [Renewable Energy]

Response surface method optimization of V-shaped fin assisted latent heat thermal energy storage system during discharging process [Alexandria Engineering Journal]

Entropy Solutions develops shape-stabilized versions of 2 PureTemp PCMs

Ben Welter - Wednesday, July 13, 2016

Entropy Solutions has developed shape-stabilized versions of two of its PureTemp biobased phase change materials. These "gelled" PCMs maintain their shape even as the PCM cycles between solid and liquid form, absorbing, storing and releasing thermal energy as needed in temperature-control applications. Potential uses include building materials, underfloor electric heating systems and shipping containers.

Shape-stabilized PureTemp 4The gelled PureTemp 4, right, has a latent heat of 159.4 joules per gram, a melt point of 4.81º Celsius and a freeze point of 1.07º Celsius. The gelled PureTemp 20 has a latent heat of 149.3 J/g, a melt point of 21.39º C and a freeze point of 16.85º C. The addition of polymers accounts for the observed reductions in latent heat compared to the ungelled versions.

The gelled forms ensure even distribution of PCMs contained in thin films. The PCM does not leak from the polymer matrix after thermal cycling. Other properties of these lab-scale versions include:

• Moldable
• Narrow melting range
• Soft when the PCM is in the liquid state
• Stiff/hard when the PCM is in the solid state
• Minimized leakage if enclosing film is punctured

Entropy Solutions is exploring scale-up and commercialization options for the new material.

2016 Presidential Green Chemistry Challenge Award winners named

Ben Welter - Thursday, June 23, 2016

Verdezyne of Carlsbad, Calif., which developed a greener way to make high-performance nylon, is among this year's Presidential Green Chemistry Challenge Award winners. Verdezyne's process uses a plant-based feedstock and does not employ high temperatures or concentrated nitric acid. The nylon is used in hairbrushes, toothbrushes, adhesives, coatings, fragrances and other products. It has qualified for the USDA Certified Biobased label.

The U.S. Environmental Protection Agency award recognizes innovative technologies "that turn climate risk and other environmental problems into business opportunities, spurring innovation and economic development." The awards were present last week at the annual Green Chemistry & Engineering Conference in Portland, Ore. This year's other winners:

• Professor Paul Chirik of Princeton University discovered a new class of catalysts to produce silicones without the use of platinum.

Newlight Technologies of Costa Mesa, Calif., developed a plastic made from methane-based greenhouse gas. 

• Texas-based CB&I and Albemarle Corp. of Baton Rouge, La., developed and commercialized a safer technology to produce alkylate, a clean gasoline component.

Dow AgroSciences of Indianapolis developed and commercialized Instinct, an additive that reduces the leaching of fertilizer nitrate into ground and surface waters. 

Dr. William R. Sutterlin, Entropy Solutions' chief science officer, was a member of a University of Missouri team that won the academic award in 2006 for developing an inexpensive method to convert waste glycerin, a byproduct of biodiesel fuel production, into propylene glycol.

https://www.epa.gov/newsreleases/epa-honors-winners-2016-presidential-green-chemistry-challenge-awards-0