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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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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]

PCM briefing: BASF expands R&D presence in South Asia; Viessmann, Aldi Nord team up on ice-based TES system

Ben Welter - Friday, March 10, 2017

BASF Group opened its Innovation Campus Asia Pacific in Mumbai this week, dramatically expanding its research and development presence in India. BASF expects to invest 50 million euros in the campus, making it the company's largest R&D investment in South Asia. BASF Venture Capital, meanwhile, is investing in the U.S. renewable chemistry firm P2 Science

• The heating and cooling technology company Viessmann and the food retailer Aldi Nord have developed a new cooling and heating system that employs propane heat pumps, photovoltaics and ice storage. The ESyCool system, designed to reduce energy costs by 15 percent and reduce life-cycle costs, will be installed in 10 Aldi Nord stores in Germany. 

• Registration is open for the 2017 New Product Development and Innovation in the Chemical Industry summit, to be held April 26-27 in Berlin. Speakers include Stephan Altmann, head of innovation excellence at BASF, and Olivier Magnin, technology director for Europe, the Middle East and Africa at DuPont Performance Materials.

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.

PCM briefing: Sunamp, University of Glasgow partner on Chinese power plant project; Reaxys PhD Prize entries due March 13

Ben Welter - Monday, March 06, 2017

Sunamp Ltd. is teaming up with Glasgow University and partners in China to boost the performance of Organic Rankine Cycle power plants that use renewable heat sources for distributed heat and power supply in China. The joint project has been awarded 2 million pounds in funding from the China-UK Research and Innovation Bridges program. Sunamp's PCM heat batteries will be integrated with ORC plants to store heat energy for power generation when the sun doesn’t shine. 

• Submissions for the 2017 Reaxys PhD Prize close on March 13. The international competition is open to Ph.D. students or recent graduates conducting innovative research in synthetic chemistry. Forty-five finalists will present their research at the Reaxys Prize Symposium in Shanghai in October. Three winners will be selected, with each earning a $2,000 award.

• In an interview with Energy Storage Report, Ice Energy CEO Mike Hopkins says his company is looking to tie up partnerships with solar installers in regions where net metering is being phased out.

• Global chemicals production started the first quarter on a strong note, according to the American Chemistry Council. The council’s Global Chemical Production Regional Index showed that that headline global production rose 0.6 percent in January after a similar gain in December.

• Packaging giant Sonoco has again made Fortune magazine's list of most-admired companies, ranking second in the packaging/containers category. 

Alexium International has appointed Dirk Van Hyning as CEO, effective June 30. He will replace Nicholas Clark, who remains on the board and assumes a new role as executive director strategy. Former U.S. congresswoman Karen Thurman has joined Alexium's board as a non-executive director.  

Carnegie Mellon researchers have developed a thermally conductive rubber material that they’ve nicknamed “thubber.” The new material, which can stretch more than six times its initial length, is an electrically insulating composite. Potential applications include soft robotics and athletic wear.

• New from Wise Guy Reports: "Global Thermal Energy Storage (TES) Market Research Report 2017"

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]

A look inside an undergraduate team's solar thermal storage project

Ben Welter - Friday, February 17, 2017

The Solar Owl team

From left: Brandon Koyanagi, Will Wilson, Gerardo Rojo and Michelle Zdanowski

For their senior undergraduate project, four engineering students at Southern Illinois University Edwardsville developed a heat storage system designed to collect thermal energy from the sun and release it at night.

The Solar Owl combines water-based sensible heat storage in an insulated tank and latent heat storage through use of a hydrated salt phase change material. The PCM is contained in a continuous, multiple-coil vessel within the tank.

SIUE TES tankThe team – Brandon Koyanagi, Will Wilson, Gerardo Rojo and Michelle Zdanowski – designed, analyzed, built and tested a scale prototype of the apparatus.

“At full size,” Wilson says, “the tank would be capable of heating an average American home through the evening and night, fourteen hours, using heat accumulated from solar thermal collectors during a typical St. Louis-area winter day. The Solar Owl reduces the size of the heat storage tank by 40 percent when compared to a sensible-only storage solution.”

The team earned an A on the project and will continue to develop the system in graduate studies. Aside from securing a patent on the design elements and a trademark on the name, the team has no immediate plans to commercialize the system.

Here’s a Q&A with Wilson, who was selected as Outstanding Senior in the university’s Mechanical Engineering Department this year.

Q: Why did the team choose sodium acetate trihydrate as the phase change material? 

A: SAT fit our needs in four important ways. (1) SAT's latent heat of fusion is high enough to keep tank size adequately small. (2) SAT, and the necessary additives, are readily availability at low to mid cost. (3) SAT exhibits low toxicity and is environmentally friendly. (4) The melting point of 58 C lends itself well to our application. This melting point is low enough to be completely melted by heat collected from a standard flat-plate solar thermal collector, while also providing a good temperature delta for most hydronic loop appliances.

Q: What is the source of the SAT you're using? 

A: We utilized SIUE chemistry lab space to synthesize a custom solution of lab-grade hydrated sodium acetate crystals with a small amount of additional water to slightly lower the temperature needed for complete melting. Carboxymethyl cellulose (CMC) was added to mitigate phase separation and potassium sulfate to minimize supercooling.

Q: SAT typically exhibits supercooling. Is that a problem in your application? 

A: As the system is not intended to be a long-term heat store, supercooling was not desirable for our design. To reduce supercooling, we added potassium sulfate to the solution as a nucleating agent.

Q. Unmodified SAT's latent heat of fusion is typically 264–289 joules per gram, with a melt point of 58 C. Does your SAT fit those specs? 

A: Our SAT did fit within that range per gram of SAT in solution. Of course, the latent heat of fusion for the solution overall, including the extra water and additives, was somewhat lower.

Q: What triggers the release of the heat?

A: Heat is released as the tank temperature falls below the melting point (plus a correction for minimal supercooling, approximately 5 degrees Celsius).

Q: What heat transfer fluid is used between the solar collectors and the tank?

A: I should note that, since the storage tank was the focus of our project, our prototype simulated solar collectors using an electrically heated water bath with submerged heat transfer coil. The transfer fluid from the “collector” to the tank, and between the tank and the testing radiators, is a solution of propylene glycol. This was chosen for (1) its low environmental toxicity and (2) its sensible heat capacity, which is high enough to help maintain tank temperature, but low enough to facilitate an appropriate heat transfer rate.

Q: What are the key design elements of the container, and what material is it made of?

A: The PCM container is a set of interconnected concentric helical coils constructed from standard PEX tubing. A set of likewise interconnected helical heat transfer coils is interspersed between the PEX coils, allowing proximity of the heat source to melt the PCM during the day, with enough space between coils to allow free convective heat transfer to the surrounding water in the tank. This configuration has the following advantages:

• It holds a relatively large amount of PCM with large surface area for heat transfer to the water in the tank.

• The tubing diameter is small enough to allow for an adequate heat rejection rate from the PCM (given SAT’s low heat conductivity).

• The thermal conductivity of PEX is higher than many plastics, such that it does not present a bottleneck to the release of PCM heat. 

As far as our research informs us, our design also stands out in that the PCM solution may be readily drained and filled for system maintenance. According to the data we could locate, an SAT solution experiencing daily phase cycling has a predicted useful life of around 10 years. Allowing easy access to flush the PCM container and refill is therefore critical for long-term maintenance and also for the case where the SAT formulation fails early, becomes contaminated, or requires testing or monitoring.

For more on the project, see:

http://www.theintelligencer.com/news/article/Students-design-heat-storage-system-10865688.php

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 Amazon.in 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.

Biznews.com 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. 

Research roundup: PU-PCM in refrigerated vehicle; indirect solar dryer; triplex tube heat exchangers; more

Ben Welter - Thursday, February 02, 2017

Experimental and numerical study of insulation walls containing a composite layer of PU-PCM and dedicated to refrigerated vehicle [Applied Thermal Engineering]

Development and experimental validation of a CFD model for PCM in a vertical triplex tube heat exchanger [Applied Thermal Engineering]

Recycled additions for improving the thermal conductivity of concrete in preparing energy storage systems [Construction and Building Materials]

Thermal behavior of indirect solar dryer: nocturnal usage of solar air collector with PCM [Journal of Cleaner Production]

Solar still with latent heat energy storage: A review [Innovative Food Science & Emerging Technologies]

2-D numerical investigation of melting of an impure PCM in the arbitrary-shaped annuli [International Journal of Thermal Sciences]

Melting enhancement in triplex-tube latent heat energy storage system using nanoparticles-metal foam combination [Applied Energy]

A concept of a thermal comfort system with energy storage in structure of the building [Problemy Eksploatacji]

Impact of Sodium Silicate Pentahydrate as Phase Change Material in Concrete Cubes for Enhancing the Thermal Comfort [pdf]
[International Journal of Civil Engineering and Technology]