Phase Change Matters

• Ice Energy, the Santa Barbara, Calif., company that made and distributed ice-based thermal energy storage systems, has filed for bankruptcy. The company's Ice Bear system makes ice at night when demand for electricity is low and capacity is abundant. During the day, the stored ice is used to provide cooling. Details of the Chapter 7 bankruptcy, filed in December, are sparse. The company's website is no longer active. Over the years, Ice Energy had won several major energy storage and distribution contracts with utilities, and had begun marketing a smaller version of the Ice Bear system aimed at retail customers. 

• Viking Cold Solutions has an opening for a chemical/thermal engineer in Houston. The engineer will "conduct research in Thermal Science, Storage/Heat Transfer and Phase Change Materials (PCM) for low temperature applications (<10⁰C)."

• Axiom Exergy has secured more than $1 million in orders for the Axiom Cloud, a software platform that helps manage energy consumption in supermarkets and cold storage facilities that use the company's PCM-powered thermal storage systems.

• The 2020 Advancements in Thermal Management conference, to be held Aug. 6-7 in Denver, has issued a call for presentations. Topics include thermal materials, thermal modeling and characterization and measurement of thermal materials. Abstracts are due Feb. 12.

• EnergyNest will install a large thermal energy storage battery at a Senftenbacher brick factory in Austria. The system will temporarily store excess energy in the form of hot air from a tunnel furnace. The stored heat be converted to steam and later reused in production.

• Devan Chemicals, the Belgium-based developer of finishing technologies for textiles, introduced its Tones of Cool Bio technology at the Heimtextil trade show in Frankfurt, Germany, last month. The technology "stimulates the textile to dissipate redundant heat from the body and to instantly reduce the body temperature," the company says. The phase change materials "are derived from sustainable, natural sources.

• Registration is open for the 23rd Microencapsulation Industrial Convention to be held June 8-11 in Rotterdam, Netherlands.

U.S. patent application 20200011583 (applicant LG Electronics Inc., Seoul, South Korea):

"A refrigerator includes a cabinet, a first inner case that defines a freezing compartment, a second inner case that defines a refrigerating compartment, a thermal siphon unit that is configured to carry a working fluid for heat transfer and that has a closed loop shape that includes a first part arranged at an outer side of the first inner case and a second part arranged at an outer side of the second inner case, and a cool air storage unit arranged in a space partitioned in the first inner case. The cool air storage unit is configured to accommodate cool air of the freezing compartment and transfer the cool air to the first part of the thermal siphon unit arranged outside of the first inner case. ... [The] cool air storage unit [shown above] includes a housing that defines an external appearance of the cool air storage unit and that is configured to store a phase change material."

http://www.freepatentsonline.com/20200011583.pdf

U.S. patent application 20200009520 (applicant Vorwerk & Co. Interholding GmbH, Wuppertal, Germany):

"A preparation vessel, in particular for a food processor, has a vessel wall and a preparation area surrounded by the vessel wall. The vessel wall has a cooling device that contacts the vessel wall in a heat-conducting manner for cooling a preparation item present in the preparation area. The vessel wall in at least a partial area has a double-walled design, with an inner wall bordering the preparation area and an outer wall that is formed separately from the inner wall and spaced apart from the inner wall by a gap, wherein the gap has the cooling device and a phase change material located between the cooling device and the outer wall as viewed in a direction from the preparation area to the outer wall."

http://www.freepatentsonline.com/20200009520.pdf

U.S. patent application 20200008623 (applicant Curators of the University of Missouri, Columbia, Mo.):

"A drinking container system with multiple temperature zones, wherein the container system includes a main body having a sidewall and a bottom that define a phase change material (PCM) module receptacle, and a phase change material (PCM) module having a sidewall that defines a beverage chamber. The PCM module is disposable within the PCM module receptacle such that a beverage egress flow path is defined between the main body sidewall and the PCM module sidewall. The flow path formed in the container can make the beverage achieve the desired drinking temperature. The PCM module sidewall is at least partially filled with a phase change material and is structured and operable to provide a plurality temperature zones within the beverage chamber. Each temperature zone is operable to maintain a temperature of a respective portion of a liquid disposed within the beverage chamber within a respective temperature range."

http://www.freepatentsonline.com/20200008623.pdf

The Phase Change Matters newsletter is celebrating its fifth anniversary with the publication of issue No. 224. Only a handful of folks received issue No. 1; the first issue of 2020 was e-mailed to 1,303 subscribers. More than 40,000 people from more than 160 countries visited puretemp.com last year. Here are the most-viewed newsletter posts from 2019:

1. PureTemp introduces temperature-control fabric coating (Jan. 23)

2. New dorm at Massachusetts college features 18,000+ square feet of PCM mats (Aug. 15)

3. Croda began work on new microencapsulated PCM four years ago (July 26)

4. PCM-equipped infant warming mat set for large-scale trial in Rwanda (Jan. 7)

5. Novel PCM microspheres keep new therapy pack flexible when frozen (June 15)

6. Croda adds 2 biobased phase change materials to its lineup (May 17)

7. PCM system inefficiencies blamed on design flaws, operator errors (March 25)

8. Sunamp signs agreement with Chinese heat pump maker (March 18)

9. PureTemp shows energy-saving potential in EnergyPlus simulations (Aug. 28)

10. Microtek introduces new PCM built with nextek encapsulation technology (March 11)

From Waste Management:

• Evaluation of carbonized waste tire for development of novel shape stabilized composite phase change material for thermal energy storage

From Journal of Energy Storage:

• Development of polyurethane foam incorporating phase change material for thermal energy storage
• Facile synthesis and thermal performance of cetyl palmitate/nickel foam composite phase change materials for thermal energy storage
• Optimal sizing design and operation of electrical and thermal energy storage systems in smart buildings

From Energy Conversion and Management:

• Numerical investigation of the effects of the nano-enhanced phase change materials on the thermal and electrical performance of hybrid PV/thermal systems
• Thermal storage and thermal management properties of a novel ventilated mortar block integrated with phase change material for floor heating: an experimental study

From Applied Energy:

• Wood-based composite phase change materials with self-cleaning superhydrophobic surface for thermal energy storage

From Renewable Energy:

• Corrosion assessment of promising hydrated salts as sorption materials for thermal energy storage systems
• Experimental study on latent thermal energy storage system with gradient porosity copper foam for mid-temperature solar energy application
• Selection of a phase change material and its thickness for application in walls of buildings for solar-assisted steam curing of precast concrete
• Experimental assessment of Phase Change Material (PCM) embedded bricks for passive conditioning in buildings

From Applied Thermal Engineering:

• Analysis of energy retrofit system using latent heat storage materials applied to residential buildings considering climate impacts
• Experimental and numerical simulation of phase change process for paraffin/expanded graphite/ethylene-vinyl acetate ternary composite
• An experimental investigation on the evaporation of polystyrene encapsulated phase change composite material based nanofluids

From Solar Energy Materials and Solar Cells:

• Lightweight mesoporous carbon fibers with interconnected graphitic walls for supports of form-stable phase change materials with enhanced thermal conductivity

From Energies:

• The Effects of Fin Parameters on the Solidification of PCMs in a Fin-Enhanced Thermal Energy Storage System

From Journal of Materials Science:

• Graphene aerogel-based phase changing composites for thermal energy storage systems

From Journal of Mechanical Science and Technology:

• A study on development of the thermal storage type plate heat exchanger including PCM layer

From Journal of Power Sources:

• Delayed liquid cooling strategy with phase change material to achieve high temperature uniformity of Li-ion battery under high-rate discharge

From Scientific Reports:

• Modification of asphalt mixtures for cold regions using microencapsulated phase change materials

From ASES National Solar Conference:

• A Study on the Thermal Energy Storage System Using Multiple PCMs [pdf]

From Molecules:

• Assessment of Thermal Performance of Textile Materials Modified with PCM Microcapsules Using Combination of DSC and Infrared Thermography Methods

From Energy and Buildings:

• Experimental study on thermal performance of a mobilized thermal energy storage system: A case study of hydrated salt latent heat storage

From Chemical Engineering Journal:

• Shape-stabilized hydrated salt/paraffin composite phase change materials for advanced thermal energy storage and management

From International Journal of Heat and Mass Transfer:

• A conjugate heat transfer model for unconstrained melting of macroencapsulated phase change materials subjected to external convection

Advanced Cooling Technologies of Lancaster, Pa., has been awarded a U.S. patent for a phase change material with a tunable melting point.

The hydration level of the PCM, a salt hydrate consisting primarily of salt and water, is altered to change the melting point to a desired set point using changes in humidity of the system.

“In an ARPA-E ARID funded program, we showed that you could change the melting point of salt hydrate phase change materials by changing the hydration levels of the salt hydrate in-situ,” Richard Bonner, ACT’s vice president for R&D, wrote in a LinkedIn post. “We also applied this technology to power plant cooling, where the seasonal variations in ambient temperature necessitate different melting points. Congratulations to the inventors: Dr. Ying Zheng, Dr. Chien-hua Chen, Dr. Howard Pearlman, and Dr. Fangyu Cao."

ACT worked with Lehigh University and the University of Missouri to develop the PCM. The idea was prompted by ACT’s interest in utilizing seasonal shifts in weather for the company’s day/night thermal storage application. A tunable melt point allows the PCM to be more easily solidified in cold and hot seasons.

The targeted melt temperatures in the project were from 25° C to 45° C for low-grade thermal energy storage, but could be extended to higher temperatures with other salt hydrates, the company said.

The project was funded, in part, with a $3.2 million ARPA-E ARID grant, awarded in 2015. ARID stands for "Advanced Research in dry Cooling." The project teams were challenged to "develop innovative, high-performance air-cooled heat exchangers and supplemental cooling systems and/or cool-storage systems" for use in thermoelectric power plants, to replace existing technologies that use a substantial amount of water to cool plant condensers.

The ARID project was completed in 2018. ACT's invention is now at the lab-scale testing phase. The most difficult hurdle, the company said, will be to scale up to commercialization level.  “From a manufacturing standpoint, shifting of the hydration level would require a large infrastructure for altering the humidity,” the company said.

“The concept could also be applied to the HVAC industry (building comfort) to provide day/night load shifting,” the company said, “as well as PCM synthesis and preparation for a consistent product. “
 

The RAL Quality Association PCM has awarded the RAL Quality Mark to Sunamp Ltd. for its UniQ line of thermal batteries.

The product, which has been installed in thousands of homes across Europe, uses a specially formulated phase change material to store large amounts of energy from renewable and other sources and release it as heat to deliver hot water and space heating as needed. The PCM is sodium acetate trihydrate-based with a patented formulation giving a melt point of 58 degrees Celsius. 

In independent testing conducted by ZAE Bayern, the PCM was successfully melted and solidified in a UniQ heat battery for 10,000 cycles. At the end of the test, no significant differences in stored thermal energy capacity were found between the cycled samples and an uncycled sample of the PCM. The product, which also passed leak testing, earned the association's highest level of certification, Grade A. 

Over 3,000 UniQ units are now in service, with Sunamp projecting a tenfold growth in sales next year. The quality mark will be featured on Sunamp’s website and in other marketing materials, UniQ manuals and product labels.

“We are delighted that our thermally charged UniQ product range of heat batteries has been awarded a globally recognized mark of quality,” said Kate Fisher, Ph.D., a materials integration scientist at Sunamp, which is based in Edinburgh, Scotland. “RAL certification is a huge accolade and cements Sunamp’s position as world leaders at the forefront of the technology.”

The RAL Quality Association PCM was established in 2004 to develop standards for the PCM industry. Members include Axiotherm, Microtek Laboratories, Rubitherm, Croda Europe, va-Q-tec, PCM Technology, Global-Systems Europe, Sasol, Sunamp, Pluss Advanced Technologies and PureTemp LLC.

Members and non-members alike can submit their products to the association for independent testing and earn the RAL Quality Mark. To qualify for the mark, products and materials must meet standards for energy storage capacity and phase transition temperature and stability, as defined in RAL-GZ 896.

“I am delighted that more and more products with PCM technology can be awarded the RAL Quality Mark as meaningful and transparent proof of quality and longevity,” said Stefan Thomann, the association’s managing director. “The great thing about Sunamp´s UniQ heat batteries is that they can be installed and used in homes very easily and save a lot of energy costs and carbon emissions immediately. The fact that they passed more than 10,000 cycles make sure that users will be able to profit from these benefits for decades.”

• Presentations given at the 14th Conference on Advanced Building Skins in Switzerland in October are available via download for 80 euros. Among the topics: "Thermal performance of engineered wood flooring impregnated with phase-change materials," Damien Mathis, University LAVAL, Fontenay-sous-Bois, France; "Thermal comfort modelling and its impact on building energy performance," Vikram Sami, Olson Kundig, Seattle, Wash.; and "Integrated solar electric/thermal cooling system with storage," Mohannad Bayoumi, King Abdulaziz University, Jeddah, Saudi Arabia.

• Loughborough University researchers have been awarded funding to help with the design and development of a four-wheeled electric vehicle for research, teaching and outreach in India. Engineers at Vellore Institute of Technology and PSG College of Technology, both located in Tamil Nadu, will work with Loughborough researchers to explore the use of phase change material and other technologies to manage battery heat. The high ambient temperatures in south India and similar climates can significantly reduce battery life in electric vehicles.  

• Energy storage specialist 1414 Degrees has announced plans to acquire SolarReserve Australia II, which owns the Aurora Solar Energy Project in South Australia and two solar sites in New South Wales. The Adelaide, Australia, company plans to use the Aurora site to build a 400 MW solar farm with thermal storage capacity of several thousand megawatt hours. The technology stores electricity as thermal energy by heating and melting containers full of silicon.

• Agritech startup Ecozen of Pune, India, which makes portable solar cold rooms for use on small farms, has raised a total of $6 million to fuel its growth phase. The cold rooms feature a PCM-equipped thermal storage unit that can store power for more than 36 hours in case of cloudy or rainy weather.  

• Advanced Cooling Technologies Inc. of Lancaster, Penn., is seeking qualified research and development engineers at various experience and education levels to work on space, defense and energy-related applications. 

• Andreas Hauer, head of the energy storage department at ZAE Bayern (the Bavarian Center for Applied Energy Research) has joined the board of directors at the International Solar Energy Society.

One of the challenges faced by PCM manufacturers is a negative perception of the material fed by occasional reports of PCM systems that do not perform as well as expected. To address that concern, the RAL Quality Association PCM is recommending that member companies inform potential customers about the performance standards established by RAL. Potential customers may not be aware that such standards exist.

While RAL certification of PCM products and systems is available, the objective of the RAL recommendation is not to suggest to customers that RAL certification is required, but rather to increase awareness that standards exist to distinguish between good and bad quality products.

An excerpt from the association's letter to members:

"The Quality Association PCM (Gütegemeinschaft PCM e.V.) was founded to develop meaningful and transparent quality specifications for phase change materials, monitor compliance with these specifications and award the RAL Quality Mark Phase Change Materials to those products that do comply. The overall objective is to build up customer confidence in phase change materials and to make sure that the products live up to the customers´ expectations with regards to performance and longevity. ...

"In order to achieve full customer satisfaction and raise confidence in our technology, we recommend pointing to the criteria laid down in Quality Assurance RAL-GZ 896 whenever you participate in a tender or talk to potential clients. It is the customers´ decision if they want to apply these criteria, but they should be aware of them at least. The latest version of RAL-GZ 896 is available to the public on our website (https://www.pcm-ral.org/pcm/en/quality-testing-specifications-pcm/)."

The RAL Quality Association PCM was established in 2004 to develop standards for the PCM industry. Members include Axiotherm, Microtek Laboratories, Rubitherm, Croda Europe, va-Q-tec, PCM Technology, Global-Systems Europe, Sasol, Sunamp, Pluss Advanced Technologies and PureTemp LLC. The association will hold its next meeting Nov. 5 in Dusseldorf, Germany.

TOPIC