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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 monthly PCM newsletter. Or join the discussion on LinkedIn.




Patent application: Device and method for drug delivery

Ben Welter - Friday, February 14, 2020

U.S. patent application 20200038600 (applicant Insuline Medical Ltd., Jerusalem, Israel):

Insuline patent drawing"A drug delivery control apparatus (e.g. a treatment apparatus) may be configured to control an amount of drug contained in a drug depot delivered or otherwise perfused or diffused into the circulatory system of a patient comprising a cooling element configured for cooling a treatment area by removing heat from the treatment area. The cooling element may be arranged above or near the treatment area. A heat disposal assembly is in thermal communication with the cooling element and configured for directing the removed heat to a heat zone away from the treatment area. A power source, a controller and a housing may be configured to at least partially house at least the cooling element and the heat disposal assembly. ... the heat disposal assembly comprises a phase change material configured to absorb at least some heat from the treatment area."

Patent application: Temperature controlled product shipper

Ben Welter - Friday, February 14, 2020

U.S. patent application 20200033045 (applicant Packaging Technology Group Inc., Fall River, Mass.):

"A temperature-controlled product shipper includes a phase change material bladder which can be filled at the point of packaging. The shipper includes an internal product box and an outer box where the product box is received within the outer box. The phase change material bladder is received within a cavity defined between the outer surface of the product box and the inner surface of the outer box. The shipper may also include an insulated liner which is received between the product box and the bladder."

Cubesat propulsion concept wins $225,000 National Science Foundation grant

Ben Welter - Friday, February 14, 2020

A Cubesat propulsion system that uses phase change material to store solar thermal energy for use when needed has been awarded a $225,000 National Science Foundation SBIR grant. The ThermaSat concept, developed by Howe Industries of Tempe, Ariz., is designed to provide propulsion for a typical 15kg cubcubesat for 10 years.

Cubesats are tiny satellites — weighing as little as 200 grams — that orbit close to Earth’s atmosphere. They are cheaper to develop and launch than larger satellites. Cubesats have a wide range of purposes, including the collection of mapping and weather data. More than 1,100 have been successfully deployed.

Troy Howe, owner of Howe Industries, answered questions about the ThermaSat propulsion system.

Q: How long has your company been working on the concept?

A: "We have been working on this topic for only about a year in preparation for our NSF proposal, but have experience with optical systems and phase change materials going back about five years."

Q: Can you briefly describe how the system works?

A: "The ThermaSat works by heating liquid water propellant to high temperature steam using incident sunlight. Normally, it is difficult to reach high enough temperatures to use water as propellant, but our optical filtration system is designed to reject long wavelengths of light and only transmit short wavelengths- similar to the greenhouse effect. The phase change materials in the thermal capacitor store the solar energy over a period of hours and then heat the propellant during a 'burn' phase.

ThermaSat cutaway drawing"The PCM will be distributed throughout a graphite matrix in the form of small beads. Flow channels will run axially down the length of the cylinder for the propellant to pass through. The design is based loosely on the old NERVA fuel elements from the nuclear rocket program in the 1970s, with the UC kernels being replaced with our PCM. The drawing here shows a cutaway of the thermal capacitor surrounded by the optical system.

"The system is very conceptual at this point and has not been tested, although the propulsion characteristics are well understood. Our task at this point is to show that the optical system works as predicted and can reach the desired temperatures. Phase II will address the effects of a vacuum environment on a prototype."

Q: What type of PCM is used?

A: "We chose a salt (80LiOH+20LiF) as our PCM, it melts at 700K and has a latent heat of fusion of 1163 J/g. The material was selected based on a study performed by NASA in 1986 on space energy storage. The paper was called 'Technology for Brayton-Cycle Space Powerplants Using Solar and Nuclear Energy' by Robert English.""

Q: How much PCM would be used in a system powering a typical Cubesat?

A: "The standard design includes 0.62 kg of PCM. "

Q: Are you working with any Cubesat manufacturers at this point?

A: "We received letters of interest from Pumpkin Space Systems, Aster Labs, and Arizona State University. They all expressed interest in having a safe and reliable Cubesat propulsion system but we have not formally formed collaboration with any manufacturers at this point.”

Q: How will you use the NSF SBIR grant?

A: "Our goals for this topic include demonstrating the optical system in a lab bench test, fabricating photonic crystals, and performing computational analysis on the thermal, structural, and propulsion systems."

Q: What's the next major step in commercializing the system?

A: "Our commercialization strategy right now is to build a functioning prototype and demonstrate operation on earth. From that point we will aim to do a flight test which performs a set of orbital maneuvers and successfully de-orbits itself. From there we will work with Cubesat manufacturers to move forward."

Q: What excites you most about this project?

A: "We are excited about how near term and effective this technology will be for the upcoming Cubesat revolution. We hope to provide a safe, reliable, and effective propulsion solution that can be used with thousands of different satellites and drastically increase the performance of new technologies in space in the timeframe of just a few years.”

PCM briefing: Ice Energy files for bankruptcy; Viking Cold has opening for thermal engineer

Ben Welter - Monday, February 10, 2020

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.

Patent application: Refrigerator with phase change material

Ben Welter - Tuesday, January 14, 2020

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

Patent drawing of LG refrigerator"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."

Patent application: Preparation vessel with a cooling device

Ben Welter - Tuesday, January 14, 2020

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."

Patent application: Drinking container with different temperature zones

Ben Welter - Tuesday, January 14, 2020

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

Patent drawing of PCM mug"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."

PCM newsletter marks 5th anniversary

Ben Welter - Tuesday, January 14, 2020

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 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)

Research roundup: Carbonized waste tires; cetyl palmitate/nickel foam; hydrated salt corrosion assessment; more

Ben Welter - Tuesday, January 14, 2020

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