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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.

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Research roundup: N-octadecane/polystyrene/expanded graphite composites; decorative wood-based panels for thermal energy storage; more

Ben Welter - Monday, June 11, 2018

From Energy:

Experimental investigation on n–octadecane/polystyrene/expanded graphite composites as form–stable thermal energy storage materials

From Green Energy and Environment:

Thermal characterization of bio-based phase changing materials in decorative wood-based panels for thermal energy storage

From Chemical Engineering Science:

Melt-Front Propagation and Velocity Profiles in Packed Beds of Phase-Change Materials Measured by Magnetic Resonance Imaging

From Thermal Science and Engineering Progress:

Employment of Finned PCM Container in a Household Refrigerator as a Cold Thermal Energy Storage System

From Energy Conversion and Management:

Melting and solidification of PCM embedded in porous metal foam in horizontal multi-tube heat storage system
Evaluation of paraffin infiltrated in various porous silica matrices as shape-stabilized phase change materials for thermal energy storage

From Construction and Building Materials:

Potential applications of phase change materials to mitigate freeze-thaw deteriorations in concrete pavement
A practical ranking system for evaluation of industry viable phase change materials for use in concrete
Experimental and numerical study of thermal performance of the PCM wall with solar radiation
Utilizing blast furnace slags (BFS) to prepare high-temperature composite phase change materials (C-PCMs) 

From International Journal of Thermophysics:

Behavior of a PCM at Varying Heating Rates: Experimental and Theoretical Study with an Aim at Temperature Moderation in Radionuclide Concrete Encasements

PCM briefing: Ecozen Solutions wins Ashden Award; Fraunhofer researchers among winners in Imagine Chemistry challenge

Ben Welter - Monday, June 11, 2018

Ecozen cold storage unit

Ecozen Solutions of India, which makes portable solar cold rooms for use on small farms, is one of six international winners in the 2018 Ashden Awards competition. The Ecofrost system's thermal storage unit can store power for more than 36 hours in case of cloudy or rainy weather. The organizations will be honored at a ceremony at the Royal Geographical Society in London on Thursday, June 14. 

Axel Kraft and Martin Peters of Fraunhofer UMSICHT are among the winners of the 2018 AkzoNobel Imagine Chemistry challenge. Kraft and Peters will receive support from LuxResearch to further develop a catalytic process for making alcohols from more sustainable raw materials. Overall, 10 startups and researchers were chosen as winners from a group of 20 finalists at a three-day event held at Chalmers University in Gothenburg, Sweden.

A call for papers has been issued for the 10th International Conference on Indoor Air Quality, Ventilation and Energy Conservation in Buildings. Topics include ventilation strategies and measurement techniques; HVAC systems; smart technologies for zero-energy buildings; and design and energy modeling. Abstracts are due by Nov. 1. The conference will be held Sept. 5-7, 2019, in Bari, Italy.  

• Researchers at the Jülich Solar Tower test facility in Germany have reached a milestone in the development of a new receiver concept for solar tower power plants. During a test of the centrifugal receiver CentRec for the generation and storage of solar high temperature heat, an average particle temperature of 965 degrees Celsius has been measured at the receiver outlet. The bauxite particles used in the system are available at prices that enable cost-effective thermal storage. “The proof of the high operating temperature is an essential condition for the targeted commercialization of this new receiver concept,” said Dr. Reiner Buck, head of solar tower systems at the DLR Institute of Solar Research

• June 15 is the last day to get the early bird rate for this year's Advancements in Thermal Management Conference (Denver, Aug. 8-9). Topics include thermal materials, thermal imaging, thermal characterization, modeling, battery cooling and thermal simulation. Joe Kelly, senior materials scientist at Outlast Technologies, is among the speakers. His topic: "Enhancing Thermal Stability and Performance of Lithium-ion Batteries using Latent Heat Storage (LHS) Technology."

Alexium says it's working to establish wide acceptance of new testing protocol

Ben Welter - Friday, June 08, 2018

Alexium International Group Ltd. announced in April that it had developed an "innovative thermal analytical testing methodology" to measure the cooling capacity of PCM-enhanced products used in pillows, sheets and mattresses.

Alexium interim CEO Robert BrookinsAlexium, based in Greer, S.C., and Perth, Australia, makes flame-retardant and PCM-enhanced fabric treatments. Dr. Robert Brookins, Alexium’s executive vice president of research and development and newly appointed interim CEO, responded to questions about the new protocol this week.

Q: Your company's news release (https://alexiuminternational.com/8401-2/) says the protocol allows for "facile adoption by the industry." Is a detailed description of the protocol publicly available, so that results can be replicated and a new industry standard established? 

A: "At this point, the protocol has been openly shared with people in the industry, and Alexium has educated them on how to use this method. This work has been in conjunction with our customers. For more general usage, Alexium is working to introduce this as a formal test method through a standards organization."

Q: What retail pillows were evaluated (by type, if not by brand)? Do they contain microencapsulated phase change materials? 

A: "All of the pillows were purchased from general retail stores and were all based on the application of the PCM to a textile component. Based on the marketing included with the pillows and the apparent method of application, microencapsulated phase change materials were used on all of these. To clarify, none of the products specifically stated that PCMs were used."

Q: What is the MPCM load in each of the four Alexium-treated pillows shown in the chart? 

A: "We supply the analytical data as a testament to performance, but do not provide public information about the specific MPCM loading for products treated with our products."

Q: Are the four Alexium-treated pillows commercially available, as tested?

A: "These products represent four models that have gone into full production for commercialization by our customers."

Q: How do the results you obtained compare to other known methods used for quantifying cooling capacity, such as ASTM Standard D7984?

A: "We have used D7984 to test fabrics treated with different levels of PCM and found that MTPS provides no meaningful data. For this reason, Alexium undertook the work to develop this new test method. Based on our research, ASTM D7984 is effective for thermal effusivity and by our assessment provides insight related to sensible heat transfer; however, due to the test protocol for D7984, the thermal properties due to latent heat (i.e., PCM) are not effectively tested by that method. For our work, established DSC protocols were used as the starting place for the new method, because DSC has proven very effective at studying PCM-based materials."

Q: Do you use the DSC to measure the treated fabric’s thermal conductivity and specific heat capacity, so you can calculate the thermal effusivity?

A: "Our method is used to measure the latent heat absorbed by the PCM-treated fabric. This is important because this is the basis of the cooling effects provided by the PCM. The critical advance made with this test method is adapting established DSC methods so that they can be used reliably with PCM-treated textiles. We believe that building on an established test method is critical for the wide spread acceptance of this method."

Patent application: Thermal management device using phase change material

Ben Welter - Monday, June 04, 2018

U.S. patent application 20180149437 (applicant Boeing Co., Chicago, Ill.):

"A device manages thermal energy applied to a composite patch on a structure having a heat sink. The device includes an enclosure configured to be placed on the structure overlying the composite patch, and a phase change material within the enclosure for absorbing the thermal energy."

http://www.freepatentsonline.com/20180149437.pdf

Patent application: Method for controlling the release of heat by a temperature control unit

Ben Welter - Monday, June 04, 2018

U.S. patent application 20180147916 (applicant Thermo King Corp., Bloomington, Minn.):

"[An] HVAC circuit for a temperature control unit, the HVAC circuit comprising: a phase change material (PCM) reservoir; wherein the HVAC circuit is configured to operate in a heat storage mode, whereby heat generated by the temperature control unit for providing temperature control within the internal space is stored in the PCM reservoir, and wherein the HVAC circuit is configured to operate in a heat release mode, whereby the heat generated by the temperature control unit for providing temperature control within the internal space is released to an ambient environment outside of the internal space."

http://www.freepatentsonline.com/20180147916.pdf

PCM briefing: DowDuPont shifts to small-scale R&D projects; Viking Cold Solutions has opening for business development manager

Ben Welter - Monday, June 04, 2018

Arktek vaccine carrierWired takes a close look at Arktek, "the Ebola vaccine's high-tech thermos." The World Health Organization is using the PCM-equipped container to transport the temperature-sensitive vaccine to wherever it's needed, whatever the conditions. The container is designed keep payloads colder than -65 C for five days.

• With an eye toward increased profits, CEO Edward Breen says DowDuPont is moving away from large-scale R&D projects in favor of less risky initiatives of $30 million or less.

Viking Cold Solutions has posted an opening for a business development manager for the Northeastern United States.

ASHRAE has published a new standard describing a methodology to apply building energy modeling throughout the design process. ASHRAE Standard 209-2018 defines minimum requirements for providing energy design assistance using building energy simulation and analysis.

Pelican BioThermal is opening its first Canadian drop point for the Credo on Demand rental program. The new drop point, at ATS Healthcare headquarters in Toronto, offers customers an additional location to return temperature-control pallet and bulk shippers. 

Patent application: Compositions comprising PCM and methods of making the same

Ben Welter - Monday, June 04, 2018

U.S. patent application 20180148621 (applicant Phase Change Energy Solutions Inc., Asheboro, S.C.):

"In one aspect, compositions are described herein. In some embodiments, a composition comprises a phase change material, a hydrophobic sorption material, and a viscosity modifier. In some embodiments, a composition comprises a foam and a latent heat storage material dispersed in the foam, the latent heat storage material comprising a phase change material and a hydrophobic sorption material."

http://www.freepatentsonline.com/20180148621.pdf

Alexium International CEO Dirk Van Hyning resigns

Ben Welter - Friday, June 01, 2018

Alexium International Group Ltd. said its chief executive officer, Dirk Van Hyning, resigned this week for personal reasons. He was appointed CEO in June 2017.

Robert Brookins, Alexium’s executive vice president of research and development, has been appointed interim CEO. Alexium, based in Greer, S.C., and Perth, Australia, makes flame-retardant and PCM-enhanced fabric treatments.

In April, Alexium announced that it had developed an "innovative thermal analytical testing methodology" to measure the cooling capacity of PCM-enhanced products used on pillows, sheets and mattresses.

In an April 23 news release, the company said:

"Alexium developed a testing protocol using a standard industry tool to quantify the cooling capacity, or enthalpic cooling, of PCM products when applied to pillows and other bedding fabrics. As a result, using this testing protocol, pillows treated with Alexium’s Alexicool PCM solution were shown to deliver over 500% greater cooling capacity than commercially available pillows treated with other PCM products.

"Testing was conducted on microencapsulated octadecane-based PCM in a controlled lab environment using a differential scanning calorimetry method developed by Alexium scientists with a TA Instrument DSC 250. The method was developed to be applicable across a wide range of fiber composition, fabric construction, and types of PCM." 

Alexium said the protocol allows for "facile adoption by the industry." But the company has not responded to questions about whether a detailed description of the protocol would be made public so that results can be replicated and a new industry standard established. It is not clear how the protocol compares to other known methods used for quantifying cooling capacity, such as ASTM Standard D7984.

Phase change composite shows potential to double AC compressor efficiency

Ben Welter - Friday, June 01, 2018

Using a phase change composite material, researchers at the University of Illinois at Chicago have developed a novel thermal energy storage system that has the potential to downsize conventional air-conditioner compressors by 50 percent and double compressor efficiency during off- and mid-peak hours.

The research is described in a paper titled “Design and optimization of a hybrid air conditioning system with thermal energy storage using phase change composite,” recently accepted for publication in Energy Conversion and Management. One of the authors, Said Al-Hallaj, a research professor of chemical engineering at UI-Chicago and CEO of AllCell Technologies LLC, answered a few questions by e-mail.

Q: Who led the research team, and how long did the project take?

A: “It is an ongoing project since 2015 at the University of Illinois at Chicago, where I work as a Research Professor of Chemical Engineering, and part of the PhD thesis for my graduate student Ahmed Aljehani.”

Q: Who funded the project? 

A: “Ahmed has a scholarship from his government in Saudi Arabia and we get technical support from our industry partners NETenergy and AllCell Technologies LLC.”

Q: Who supplied the PCM?

A: “I believe it is n-tetradecane (C14H30) PCM that we bought from a distributor and not sure about actual source.”

28 slabs of phase change composite materialQ: What is its peak melting point? 

A: “4-6 degrees Celsius.”

Q: What is its thermal storage capacity?

A: “180 kJ/kg (78% PCM, 22% graphite).”

Q: Describe the benchtop PCC/TES system size, components and functionality.

A: “The actual 4 kWh PCC-TES structure is made of 28 slabs of PCC [right]. The whole PCC-TES structure is thermally insulated with building insulation materials. Each slab represents a graphite structure that has been soaked into n-tetradecane for at least 24 h until impregnated with n-tetradecane. The slabs are numbered from top to bottom; top being number 1. The second component is the copper tubes or the copper coils, which pass back and forth in between the 28 slabs. The copper tubes enter the PCC-TES structure from the top and exits from the bottom of the structure.”

Q: Is the concept intended mainly for commercial AC systems, or could it be adapted for residential use?

A: “It should work for both, but commercial AC applications are more economically beneficial due to rate structure and peak demand requirements.”

Q: What are the next steps in developing this concept?

A: “NETenergy, our technology commercialization partner, is partnering with National Renewable Energy Laboratory and a major OEM to build and test a full-scale prototype at NREL facilities in the next year or so.”


https://www.sciencedirect.com/science/article/pii/S019689041830517X