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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.

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PCM battery shows promise in home heating system

Ben Welter - Tuesday, September 15, 2020

A home heating system equipped with a PCM battery put up encouraging numbers in a small trial in northern Italy earlier this year. The monthlong test “shows that is possible [for such a system] to supply the whole heating demand of a house reducing close to zero the costs,” says Domenico Feo, who developed the system. The full report, prepared by ThermaLink, a trademark of Sunservice Srl of Treviso, Italy, is available here.

ThermaCubeThe system is composed of a 6 kW solar array, an air/water heat pump and a thermal battery filled with BioPCM Q42, a biobased phase change material supplied by Phase Change Energy Solutions of Asheboro, N.C. A control unit, PCDCube, monitors temperatures and manages energy flow to optimize system performance. In an interview with Phase Change Matters, Feo answered questions about the heat battery, recently rebranded as ThermaCube.

Q: Thermal conductivity has proven to be a challenge in thermal energy storage across most types of PCM. Was conductivity an issue with the required charge/discharge cycles?

A: "As already known, the thermal conductivity of the PCM, especially of the organic one that we use, is low. This is, at the same time, a disadvantage and an advantage. The disadvantage has been minimized in using a heat exchanger made with a flat aluminum panel with the various layers just over 1 inch of distance; in this way we are able to make the entire volume of material work in a very efficient way. Vice versa this is an advantage for the very low heat losses during the non-work phases; in conditions of installations inside the buildings, the temperatures can be maintained for several days."

Q: If faster heat transfer is required, do you envision a redesign of the heat exchanger or a modification of the PCM to meet the demand of the energy transfer?

A: "As manufacturer, we can customize the heat exchanger dimensions and shape in order to achieve our goals, but as always in the industrial scalability, the quantities are mandatory for a good price. We designed a single heat exchanger dimension and multiply it in order to be able to produce the different storage capacities and realize a complete modular range. The transfer of energy can be however accelerated by increasing the flow rate of the fluid and the delta T between the fluid and the melting point, of course there is always a limit to this possibility. There are still studies around this point that need to be better understood."

Q: Would implementing several PCMs of different melting temperatures aid in the overall performance of the TES?

A: "Let's say that we expect a slight drop in performance at lower temperatures, but we don't have many other tests to give you a more general opinion."

Q: How is the PCM temperature measured throughout the entire storage to provide input to the PCDCube? Since the melting/solidification of PCM is not a homogenous process, are multiple measurements necessary to get a realistic status of the PCM?

A: "In the documents that we have published, we do not specify that we have installed two temperature probes, one in the center and another one near the walls and it is evident that, when the final phase of the  discharge of the PCM approaches, the perimeter probe shows a decrease of more sudden temperature than the central one. We, however, assume that the fact of having installed our thermal battery outside the building in a very cold climate, has exaggerated the heat loss despite the low heat transmission."

Q: Have you considered other PCM suppliers/products, since many are located in Europe and the RAL quality organization is based there?

A: "This is a possibility, at least for the distribution of our products in Europe and Asia. Currently we try to separate the supply of the case with exchangers (that we manufacture) from the PCM with direct purchase of the client from the supplier, especially in the larger units."

Q: What is the customer value proposition for this product? What is the expected return on investment/payback period?

A: "This is a $1 million question; the proposal is certainly into the growing wave of the storage market, even the electrical ones for PV systems. (A Tesla Powerwall is cool but not economically advantageous if you don’t pay attention at the payback that is higher than the life of the battery). The best value proposition is to separate production from the consumption of the energy and take advantage of renewable energies which, unfortunately, are linked to the day / night cycle and the outdoor temperature conditions. We see perfect the combination HP + Thermal Battery because we can concentrate the HP working hours during the best outdoor conditions that, for many reasons, are affecting and reducing the performances.  Furthermore, we also see a large market in the use of these thermal batteries in all these existing systems which are undersized or which, due to specific situations of changing use of the building, are no longer able to provide the necessary heating or cooling to the whole plant. About the ROI, this really varies a lot country by country because the cost of the electricity has different rates and peak hours schedules. The industrial needs are sometimes much more interesting and attractive than the residential ones."

Q: What are your plans for a commercial rollout?

A: "We are completing the Italian sales force and are looking for international distributors. Our goal is to propose the range of products at an international level with distribution agreements for the case only with exchangers; it will obviously be our responsibility to direct the partner to some reliable and high-quality PCM manufacturers. Obviously, those who will quickly give us the opportunity to build pilot plants, demonstrating the technology, will have an advantage in introducing them into the market and in the exclusivity of the contractual relationship."

Patent application: Mattress assemblies including panel with PCMs

Ben Welter - Sunday, September 06, 2020

U.S. patent application 20200260882 (applicant Dreamwell Ltd., Atlanta, Ga.):

"A mattress assembly comprising: at least one layer proximate to a sleeping surface of the mattress assembly spanning at least a portion of the length and/or width of the sleeping surface comprising: a two-ply preformed capsulate sheet comprising a plurality of cells; and a phase change material within at least a portion of the plurality of cells."

http://www.freepatentsonline.com/20200260882.pdf

PCM briefing: ThermoSafe-ACL Airshop agreement; new CEO at Phase Change Energy Solutions

Ben Welter - Sunday, September 06, 2020

Pegasus ULDSonoco ThermoSafe and ACL Airshop have announced a global agreementfor the handling and repair of ThermoSafe’s Pegasus ULD bulk temperature-controlled containers ACL Airshop, of Greenville, S.C., provides cargo support equipment and logistics solutions for airlines and air cargo carriers. Sonoco says the unit load device is made of composite materials that are lighter and more damage-resistant than traditional metal containers. It uses a gelled phase change material to maintain pharmaceutical-safe temperatures for five days or more, depending on the PCM used.

Has long-term thermal energy storage come of age? That's the premise of a recent advertorial sponsored by Viking Cold Solutions on Greentech Media's website. The Houston company says its PCM-based system, designed for use in cold storage facilities, stores enough energy to cycle off refrigeration for up to 13 hours per day and reduce energy consumption by more than 25 percent. Not much new in the article, but the reader comment section might be of interest to people who are familiar with the technology.

• A cycling club in Great Britain teamed up with Peli BioThermal this summer to deliver temperature-sensitive prescriptions to housebound people. The company supplied Banbury Star Cyclists with CrÄ“do ProMed temperature-controlled medical transport bags. The PCM-equipped bags are designed to transport pharmaceutical samples and medical supply payloads within two ranges, 2-8°C and 15-25°C.

Phase Change Energy Solutions of Asheboro, N.C., has a new chief executive officer. Govi Rao, co-founder and managing partner at CARBON Group Global, joined the company in April. His predecessor, Dennis McGill, had held the position since December 2018.

Sunamp Ltd. of Scotland has raised 4.5 million pounds in a Series A financing round led by Chilean venture capital firm Aurus Capital. Sunamp says it will use the funds to support commercial scaling in the United Kingdom and expansion in Central Europe, Asia and North America.

• The 15th Conference on Advanced Building Skins will be held as scheduled Oct. 26-27 in Bern, Switzerland. "In the unlikely event that the conference will not take place, or the participant may not be able to travel," organizers say, "paid registration will be credited to our conference next year." The 12 sessions, with over 70 presentations, will also be available online.

• A four-man canoe team put Glacier Tek's PCM-powered cooling vests to the test last month at the Missouri 340, a 340-mile paddle race from Kansas City to St. Charles, Mo. Team Mississippi, led by Scott Miller, 44, of Minneapolis, finished 11th overall in the race, completing the course in 44 hours, 38 minutes. The race drew more than 350 entries. Team members used the vests to cool down at checkpoints. Miller, second from left in the photo, plans to use the vests to battle the heat in the Great Alabama 650, which bills itself as the world's longest annual paddle race. That event begins Sept. 26 on the Coosa River in northern Alabama.

Research roundup: Hysteresis; reflective roof coating; optimizing energy balance of nearly zero energy buildings; more

Ben Welter - Monday, August 31, 2020

From Journal of Molecular Liquids:

The research progress on phase change hysteresis affecting the thermal characteristics of PCMs: A review

From Journal of Building Engineering:

Thermal behavior of a phase change material in a building roof with and without reflective coating in a warm humid zone

From Renewable Energy:

A comprehensive study on thermal storage characteristics of nano-CeO2 embedded phase change material and its influence on the performance of evacuated tube solar water heater

From Sustainable Cities and Society:

Numerical analysis of phase change materials for optimizing the energy balance of a nearly zero energy building

From Journal of Energy Storage:

Multi-objective optimization of cooling and heating loads in residential buildings integrated with phase change materials using the artificial neural network and genetic algorithm
Assessing corrosive behaviour of commercial phase change materials in the 21–25 ºC temperature range
Exergy and economic analyses of nanoparticle-enriched phase change material in an air heat exchanger for cooling of residential buildings
Experimental and numerical investigation on enhancing heat transfer performance of a phase change thermal storage tank
The effect of ultraviolet coating on containment and fire hazards of phase change materials impregnated wood structure

From Energy Conversion and Management:

Application of granular materials for void space reduction within packed bed thermal energy storage system filled with macro-encapsulated phase change materials

From Chemical Engineering Journal:

Simultaneous solar-thermal energy harvesting and storage via shape stabilized salt hydrate phase change material

From Solar Energy:

Characterization and cooling effect of a novel cement-based composite phase change material
Effect of polymer-derived silicon carbonitride on thermal performances of polyethylene glycol based composite phase change materials

From Case Studies in Thermal Engineering:

Effect of porosity and pore density of copper foam on thermal performance of the paraffin-copper foam composite Phase-Change Material

From Renewable and Sustainable Energy Reviews:

A critical assessment on synergistic improvement in PCM based thermal batteries

From Journal of Energy Resources Technology:

Experimental Analysis of Salt Hydrate Latent Heat Thermal Energy Storage System With Porous Aluminum Fabric and Salt Hydrate as Phase Change Material With Enhanced Stability and Supercooling

From Energy Sources:

Experimental study on thermal management and performance improvement of solar PV panel cooling using form stable phase change material
Experimental investigation of thermal performance of indirect mode solar dryer with phase change material for banana slices

From Aalto University:

Experimental design and investigation on a thermal energy storage system using phase change materials [thesis]

From Journal of Applied Physics:

Development of eco-sustainable plasters with thermal energy storage capability

From Chemical Engineering Transactions:

Thermal Performance of Phase Change Material Wallboard with Typical Structure: Artificial Controlled Condition Experimental Investigation

From Materials Research Express:

Fabrication of thermal energy storage wood based on graphene aerogel encapsulated polyethylene glycol as phase change material
Preparation and characterization of acrylic resin encapsulated n-dodecanol microcapsule phase change material

From ACS Sustainable Chemical Engineering:

Synthesis and Characterization of Fatty Acid Amides from Commercial Vegetable Oils and Primary Alkyl Amines for Phase Change Material Applications

From Carbohydrate Polymers:

Fibrous form-stable phase change materials with high thermal conductivity fabricated by interfacial polyelectrolyte complex spinning

From Materials Today: Proceedings:

Effect of various phase change materials (paraffin wax/hydrogenated vegetable oil) packed in a fabricated shell and tube type heat exchanger

From Solar Energy Materials and Solar Cells:

Composite phase change materials with heat transfer self-enhancement for thermal energy storage
Novel network structural PEG/PAA/SiO2 composite phase change materials with strong shape stability for storing thermal energy

From International Journal of Refrigeration:

Improving the performance of household refrigerating appliances through the integration of phase change materials in the context of the new global refrigerator standard IEC 62552:2015

From Advances in Colloid and Interface Science:

Nanoencapsulation of phase change materials (PCMs) and their applications in various fields for energy storage and management

From Building and Environment:

Space heating performance of novel ventilated mortar blocks integrated with phase change material for floor heating

From Energy:

A promising form-stable phase change material composed of C/SiO2 aerogel and palmitic acid with large latent heat as short-term thermal insulation

From Journal of Cleaner Production:

Enhanced thermal storage capacity of paraffin/diatomite composite using oleophobic modification

From International Conference on Renewable Energies for Developing Countries:

Storage efficiency of paraffin-LDPE-MWCNT phase change material for industrial building applications

4-man canoe team will test Glacier Tek cooling vests in 340-mile race

Ben Welter - Sunday, August 02, 2020

A four-man canoe team will put Glacier Tek cooling vests to the test this week at the Missouri 340, a 340-mile paddle race from Kansas City to St. Charles, Mo.

Competitors have 88 hours to complete the Missouri River course. The race, first held in 2005, typically draws hundreds of canoeists and kayakers. The event record, set by a two-person canoe team in 2018, is 34 hours, 34 minutes.

Team Mississippi, led by Scott Miller, 44, of Minneapolis, will be paddling a 23-foot Wenonah Minnesota IV.

Scott Miller“The MR340 is usually held in July or August and is famous for being hot,” said Miller, right. “This year, however, the forecast looks shockingly mild, with highs in the upper 70s. We will be working hard, however, and expect to be in the bright sun much of the time and still generating plenty of body heat, so we anticipate the vests still being very useful during the sunniest and hottest times of the day.”

Glacier Tek cooling vests are designed to maintain a microclimate of 59 degrees F for up to 2.5 hours in 100 F heat. The cooling packs are powered by PureTemp, a phase change material certified as 100 percent biobased by the U.S. Department of Agriculture. The packs can be recharged in as little as 20 minutes in ice water. A support crew will supply Team Mississippi with fully charged packs as needed.

About the paddlers:

Rod Price, 60, of Winter Garden, Fla., has won approximately 300 canoe races in his 40 years of competition. He is the only paddler to complete North America's three longest distance races: the 1,200-mile Ultimate Florida Challenge (2012), the Yukon 1000-mile canoe race (2009) and the 750-mile Race to Alaska (2017). In 2019 Rod was selected for the Team USA Senior Dragon Boat Squad that competed in Thailand and won three gold medals. He has written three books about his racing adventures: “Racing to the Yukon” (2009), “Racing Around Florida” (2012) and “Have Paddle Will Travel” (2019).

How he copes with extreme heat: “Constantly hydrates with cold fluids containing electrolytes, wears light clothing and a sun hat and puts on sunscreen several times each day.

Oliver Simes, 27, of Cornucopia, Wis., has spent the last few years as a sea kayak guide in the Apostle Islands National Lakeshore. Paddled the length of the Mississippi River solo in a kayak in 2016.

How he copes with extreme heat:  “Keep ice in an insulated bottle. Going for swims.”

Bobby Johnson, 42, of Dunedin, Fla., has been been kayak racing for four years.

How he copes with extreme heat: “Depends on race. Clothing , hats, energy output. I run along shore under trees. Use the water I’m paddling on. Deal with it. Train hard.”

Scott Miller, 44, Minneapolis, Minn. In 2005, he paddled over 2,000 miles from Minneapolis to Hudson Bay (where the polar bears live), to celebrate the 75th anniversary of the trip taken by Eric Sevareid and Walter Port in 1930.

How he copes with extreme heat: “Dip hat or headband in water, hydrate before, during and after paddling, wear body-covering clothing to protect skin from the sun.”

About Glacier Tek

Glacier Tek LLC of Minneapolis, Minn., has been making high-tech garments that help defend the wearer from heat stress in extreme environments for more than 20 years. Glacier Tek’s first product, the Original Cool Vest, was among the earliest completely self-contained body cooling vests on the market. Our satisfied repeat customers include Dow Chemical, General Electric, General Mills, Kaiser Permanente and the FBI.

BioPreferred labelGlacier Tek cooling vests feature PureTemp phase change material, a biobased technology designed to absorb heat generated by the wearer. Glacier Tek vests maintain a comfortable 59 degrees for up to 2.5 hours, even in the most extreme heat, and never over-cool. Our vests offer better safety and cooling duration than that of evaporative, ice or gel-cooled vests.

Each Glacier Tek vest includes a set of cooling packs powered by PureTemp, a safe and effective biobased material. All Glacier Tek cooling packs have earned the USDA Certified BioPreferred® label, verification that the amount of renewable biobased material in the product meets or exceeds levels set by the U.S. Department of Agriculture.

INUTEQ donates hundreds of cooling vests to Dutch hospitals

Ben Welter - Monday, May 11, 2020

Hundreds of INUTEQ cooling vests developed for use by Dutch athletes at the Tokyo Olympics this summer have been donated for use in Dutch hospitals during the COVID-19 pandemic.

INUTEQ PCM pulloverThe PCM-equipped pullovers, designed to help athletes cope with heat stress, became available when the Tokyo Games were postponed until 2021. The pullovers can be worn under the heavy, heat-trapping protective gear used by doctors and nurses.

The pullovers are manufactured in Netherlands. The cooling material is Croda's CrodaTherm 21, a biobased PCM with a melting temperature of 21 degrees C. The 1.3-kg pullover is a simple "one-size-fits-most" garment, with two adjustable buckles and no fabric shell. 

“Doctors and nurses at the ICU, who are treating corona patients, can work comfortably for up to three hours longer thanks to this cooling vest," said Dr. Thijs Eijsvogels, physiologist at Radboud University Medical Center, Nijmegen. "The cooling vests ensure a stable body temperature, less sweating, maintenance of concentration and a faster recovery after each intensive work session.”

The pullover is marketed as "PCM CoolOver" on the INUTEQ website. It can be worn "under military combat gear, hazardous materials suits, mascot costumes and other professional apparel."   

https://inuteq.com/pcm-coolover-medical-nl/pcm-coolover-medical-eng/

Phase Energy announces a new shape-stable PCM

Ben Welter - Monday, May 11, 2020

Phase Energy Ltd. has announced the development of shape-stable technology for organic wax-based PCMs.

The company, based in Hull, United Kingdom, said a tetradecane-based shape-stable material would typically contain more than 90% PCM; the new technology has achieved levels of up to 96%. "Initial tests indicate that little, if any, enthalpy is lost, possibly due to the very low level of additives required," the company said.

The technology was jointly developed with Rainer Busch of IBC Europe, Germany.

"So far, the technology has been used for paraffins, esters etc. and on a range of PCMs with [melt points] of up to 53 degrees Centigrade," Phase Energy said in a LinkedIn post. "The technology permits the production of leak-resistant packs/pouches using very simple process technology." 

"We’re currently working with some companies in the cold chain area; looking at cold packs/pouches, pallet covers etc.," Ian Biggin, director at Phase Energy, said in an e-mail. "As the technology can be adapted to higher temperature PCMs we are also interested in those areas as well but we decided that cold chain was the obvious place to start."

The photo below illustrates the material's flexibility. According to the company, it "shows a shape stable sample, 100 x 30 x 12mm, containing 92% tetradecane and 8% additives, being stretched to >700mm. When released the sample returned to its original size."

http://phase-energy.com/new-shape-stable-pcm-development/

PCM briefing: Ph.D. opening at University of Twente; Denver thermal conference moves online

Ben Welter - Monday, May 11, 2020

• The University of Twente, Netherlands, has an opening for a four-year Ph.D. position in phase change materials for heat storage. "This research project will try to introduce a smart composite material which can store the heat for both short and long-term storage time," according to the posting. "This smart material will be based on inorganic salt hydrates having controllable discharging speed which is very advantageous for future smart heat batteries." The starting salary is 2,325 euros per month, plus an annual 8.3% year-end bonus.

• Because of uncertainties associated with the COVID-19 pandemic, the 2020 Advancements in Thermal Management conference, scheduled for Aug. 6-7 in Denver, will be held as a virtual event on the same dates. According to the conference website: "Thermal 2020 presentations will be webcast with live slide presentations, audio, and real-time Q&A. Attendees may revisit these presentations after the event via recordings delivered directly to them. Exhibit booths feature rich, virtual profiles. Networking is done all-day via video conference rooms and though scheduled 1x1 meetings." A full conference pass costs $295 through June 12.

Peli BioThermal says air ambulance crews in Europe are transporting blood products via the company's Credo ProMed transport bags. The temperature-controlled bags are designed to protect blood products needed for transfusions at emergency scenes.

 • Researchers at the U.S. Department of Energy's Argonne National Laboratory are working to integrate a new thermal energy storage technology within CHP systems from Capstone Turbine Corp. to boost heat recovery. In the Argonne system, high-temperature PCMs are embedded within highly thermally conductive foam. The foam is then sealed with inert gas inside a module, preventing moisture or oxygen from getting inside and degrading the components.

Patent application: Cosmetic holographic wearable ocular devices

Ben Welter - Sunday, May 10, 2020

U.S. patent application 20200132897 (applicant TruIris LLC, Columbus, Ohio):

"Wearable ocular devices (such as ocular prostheses or contact lenses) utilizing diffraction gratings to produce color, as well as methods for producing such devices, are provided. A diffraction grating on the device may diffract the incident light to the observer. The result may be colored light that appears to originate from the wearer's eyes. The diffraction grating may achieve a look or feeling that is qualitatively or quantitatively different from the look or feeling achieved by previous devices that use dyes or inks."

http://www.freepatentsonline.com/20200132897.pdf

More U.S. patent applications:

Temperature management bedding systems | Graphene oxide aerogel beads | Thermal material with high capacity and high conductivity | Self-healing metal structures | Heat exchanger for three fluids | Steam power plant | Lightweight thermal battery                            

Patent application: Thermal management systems including multiple phase changing materials

Ben Welter - Sunday, May 10, 2020

Toyota patent drawingU.S. patent application 20200136209 (applicant Toyota Motor Engineering & Manufacturing North America Inc., Plano, Texas):

"A battery module including a battery cell and a thermal management system for removing heat from the battery cell. The thermal management system includes two or more unit cells in an array. Each unit cell includes a primary shell comprising a primary phase change material (PCM), and a secondary shell comprising a secondary PCM that is thermally coupled to the primary shell. The battery cell is thermally coupled to the primary shell at a heat transfer interface and the secondary shells of adjacent unit cells in the array are separate."

http://www.freepatentsonline.com/20200136209.pdf