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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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Patent application: Even carbon number paraffin composition

Ben Welter - Thursday, October 11, 2018

U.S. patent application 20180290946 (applicant REG Synthetic Fuels LLC, Ames, Iowa):

"Paraffin compositions including mainly even carbon number paraffins, and a method for manufacturing the same, is disclosed herein. In one embodiment, the method involves contacting naturally occurring fatty acid/glycerides with hydrogen in a slurry bubble column reactor containing bimetallic catalysts with equivalent particle diameters from about 10 to about 400 micron. The even carbon number compositions are particularly useful as phase change material."

http://www.freepatentsonline.com/20180290946.pdf

Research roundup: Ternary hydrated salt mixture; earth-air heat exchanger; shape-stabilized fly ash composite PCM; more

Ben Welter - Monday, October 01, 2018

From Energy Conversion and Management:

Two types of composite phase change panels containing a ternary hydrated salt mixture for use in building envelope and ventilation system
Research on cooling performance of phase change material-filled earth-air heat exchanger
An experimental investigation of the phase change process effects on the system performance for the evacuated tube solar collectors integrated with PCMs

From Solar Energy:

Carbon based material included-shaped stabilized phase change materials for sunlight-driven energy conversion and storage: An extensive review

From Applied Thermal Engineering:

Experimental Study of Water Solidification Phenomenon for Ice-on-Coil Thermal Energy Storage Application Utilizing Falling Film

From Powder Technology:

Preparation and thermal properties of stearic acid-benzamide eutectic mixture/expanded graphite composites as phase change materials for thermal energy storage

From International Communications in Heat and Mass Transfer:

Experimental and numerical study of melting of the phase change material tetracosane

From Particuology:

Effect of particle size on the thermal performance of NaNO3/SiO2/C composite phase-change materials

From Materials Chemistry and Physics:

Low-cost, shape-stabilized fly ash composite phase change material synthesized by using a facile process for building energy efficiency

From Construction and Building Materials:

Preparation and thermal properties of encapsulated ceramsite-supported phase change materials used in asphalt pavements

From Applied Energy:

Research roundup: Heat capacities of potential organic PCMs; asphalt binders; novel smart textile; modeling hysteresis; more

Ben Welter - Tuesday, September 18, 2018

From Journal of Chemical Thermodynamics:

Heat capacities of potential organic phase change materials

From Renewable Energy:

Effects of microencapsulated phase change materials on the performance of asphalt binders
An improved, generalized effective thermal conductivity method for rapid design of high temperature shell-and-tube latent heat thermal energy storage systems
Multi-objective optimisation of thermal energy storage using phase change materials for solar air systems

From Energy:

A comprehensive study of properties of paraffin phase change materials for solar thermal energy storage and thermal management applications
Evaluation of a novel solar driven sorption cooling/heating system integrated with PCM storage compartment

From Chemical Engineering Journal:

Shape-stabilized phase change materials based on porous supports for thermal energy storage applications
Novel smart textile with phase change materials encapsulated core-sheath structure fabricated by coaxial electrospinning

From International Journal of Heat and Mass Transfer:

Experimental research on the effective heating strategies for a phase change material based power battery module
Modeling hysteresis in the phase transition of industrial-grade solid/liquid PCM for thermal energy storages

From Applied Thermal Engineering:

Determination of heat transfer coefficients in direct contact latent heat storage systems

Research roundup: Thermoplastic polyurethane blends; simulation of supercooling and convection; battery thermal management; more

Ben Welter - Tuesday, September 11, 2018

From Frontiers in Materials:

Thermoplastic polyurethane blends with thermal energy storage/release capability

From Energies:

Review of Reactors with Potential Use in Thermochemical Energy Storage in Concentrated Solar Power Plants

From Progress in Computational Fluid Dynamics:

Towards the simulation of supercooling and convection in phase change materials using a thermal lattice Boltzmann method

From Nanomaterials:

Palm Kernel Shell Activated Carbon as an Inorganic Framework for Shape-Stabilized Phase Change Material

From Journal of Power Sources:

A comprehensive review on a passive (phase change materials) and an active (thermoelectric cooler) battery thermal management system and their limitations

From Applied Energy:

Process integration of thermal energy storage systems – Evaluation methodology and case studies

From Journal of Nanomaterials:

Effects of Biceramic AlN-SiC Microparticles on the Thermal Properties of Paraffin for Thermal Energy Storage

Research roundup: Microencapsulated paraffin; PCM plasterboard; palmitic acid ethyl ester; more

Ben Welter - Tuesday, August 21, 2018

From Experimental Thermal and Fluid Science:

Thermal–hydraulic characteristics of ethylene glycol aqueous solutions containing microencapsulated paraffin

From Applied Thermal Engineering:

Three-dimensional numerical and experimental investigation of the behavior of solar salts within thermal storage devices during phase change

From Renewable Energy:

Numerical investigation on the effect of different parameters in enhancing heat transfer performance of photovoltaic thermal systems

From Energy Conversion and Management:

Development of a calorific value controller using bimetal fin channel for PCM heat storage
Experimental and numerical investigation for improving the thermal performance of a microencapsulated phase change material plasterboard

From Polymers:

Fabrication and Performance of Composite Microencapsulated Phase Change Materials with Palmitic Acid Ethyl Ester as Core

From Cement and Concrete Composites:

Elucidating the influences of compliant microscale inclusions on the fracture behavior of cementitious composites

From AIP Conference Proceedings:

Simulation and validation of PCM melting in concentric double pipe heat exchanger
Modeling and experimental validation of the thermal behavior of PCM using DSC input data
Thermal behavior of melting paraffin wax process in cylindrical capsule by experimental study

From Energy and Buildings:

A novel building material with low thermal conductivity: Rapid synthesis of foam concrete reinforced silica aerogel and energy performance simulation

Research roundup: Dynamic behavior of PCM-27; Al2O3, SiO2 and TiO2 nano-inclusions; coacervation microencapsulation; more

Ben Welter - Tuesday, August 14, 2018

From International Journal of Thermal Sciences:

An experimental and a numerical analysis of the dynamic behavior of PCM-27 included inside a vertical enclosure: Application in space heating purposes

From Journal of Molecular Liquids:

Thermal conductivity enhancement in organic phase change material (phenol-water system) upon addition of Al2O3, SiO2 and TiO2 nano-inclusions

From Applied Thermal Engineering:

Experimental and numerical investigations of nano-additives enhanced paraffin in a shell-and-tube heat exchanger: A comparative study
Three-dimensional numerical and experimental investigation of the behavior of solar salts within thermal storage devices during phase change

From Energy Conversion and Management:

Formulation of a model predictive control algorithm to enhance the performance of a latent heat solar thermal system
Performance assessment of a new hydrogen cooled prismatic battery pack arrangement for hydrogen hybrid electric vehicles

From Carbohydrate Polymers:

Chitosan composite microencapsulated comb-like polymeric phase change material via coacervation microencapsulation

From Renewable Energy:

Analytical Considerations on Optimization of Cascaded Heat Transfer Process for Thermal Storage System with Principles of Thermodynamics

From Proceedings of Microscopy & Microanalysis 2018:

In-Situ TEM Observation of Crystallization in Phase-Change Material

From International Journal of Energy Research:

Research roundup: Humidity control material; solar water heaters; nanomaterials; flow-through wall elements; more

Ben Welter - Monday, July 09, 2018

From Energy and Buildings:

A Review on Enhancement of Phase Change Materials - A Nanomaterials Perspective
Phase change humidity control material and its impact on building energy consumption

From Solar Energy:

Optimization of melting and solidification processes of PCM: Application to integrated collector storage solar water heaters

From Applied Thermal Engineering:

Experimental Investigation on the Heat Transfer Enhancement in a Novel Latent Heat Thermal Storage Equipment
Recent advancements on thermal management and evaluation for data centers
Heat Transfer Characteristics of an Expanded Graphite/Paraffin PCM-Heat Exchanger used in an Instantaneous Heat Pump Water Heater

From Thermal Science and Engineering Progress:

Numerical simulation of the melting of a NePCM due to a heated thin plate with different positions in a square enclosure

From Journal of Building Engineering:

Numerical study of flow-through wall elements with phase–change materials

From Journal of Energy Storage:

Exploratory investigation of a new thermal energy storage system with different phase change materials having distinct melting temperatures

From Renewable Energy:

Optimization assessment of the energy performance of a BIPV/T-PCM system using Genetic Algorithms

From Sustainable Cities and Society:

Coupled cooling method and application of latent heat thermal energy storage combined with pre-cooling of envelope: Temperature control using phase-change chair

Solar-powered concept camper uses PCM to keep passengers comfortable

Ben Welter - Monday, July 02, 2018

Dethleffs' e.home concept camperDethleffs GmbH & Co.'s solar-powered concept camper, introduced last year, is one of four winners in the transportation category of the German Innovation Award 2018. The "e.home" features 334 square feet of thin solar panels and a heating system that uses phase change materials to absorb heat when the outside temperature rises above 79° F. Fully equipped, its driving range on a full charge is just over 100 miles.

Christoph Gawalleck, technical director at Dethleffs, oversaw the two-year development of the e-home. He answered a few question via email:

Q: Describe the phase change material used in the vehicle.

A: “The PCM is Micronal from BASF. But BASF sold this business unit to Microtek Laboratories in May 2017. It is a paraffin. The melting point is 26°C, the solidification takes place at 23° C.”

Cross section of PCM panel used in Dethleffs e.homeQ: How is the PCM contained?

A: “The PCM is in aluminum plates that are shaped like corrugated cardboard [right]. So the heat can be passed very quickly to the PCM. The plate contains 4 kilograms of Micronal per square meter.”

Q: How much PCM is used in the camper?

A: “Approximately 35 kilograms.”

Q: Have you collected data on how well the PCM manages temperatures in the camper? Has it met expectations?

A: “The vehicle was at many shows last year, so the tests are still running at the moment.”

Q: What was the development team's great challenge?

A: “The biggest challenge was to get access to the battery capacity of the vehicle in addition to the solar cells.”

Q: Are there plans to commercialize the e.home camper?

A: “The vehicle was meant to present our ideas to customers and match them with their wishes. Of course, various individual elements, such as connectivity, will be incorporated into production vehicles.”

Q: Are there plans to use PCM technology in other Dethleffs campers?

A: “This is not known until the tests have been completed.”

PCM-equipped personal air conditioner set for commercial release in 2019

Ben Welter - Tuesday, June 26, 2018

Developers of a personal air conditioner designed to reduce energy use in office buildings say they’re on track for commercial release next year. The “μX” micro climate system features a phase change material that solidifies at about 18 degrees C to store cooling generated at night for use during the day.

mX early version
The evolution of the μX: an early design ...
Dr. H. Ezzat Khalifa of Syracuse University led the development team, which includes Air Innovations, Cornell University, United Technologies Research Center and Bush Technical LLC. The team has been working on the system since 2015, funded in large part by a $3.2 million grant from the U.S. Energy Department’s Advanced Research Projects Agency-Energy. The New York State Energy Research and Development Authority provided $400,000 in follow-on funding in 2016.

Sam Brown, OEM custom director at Air Innovations, is in charge of bringing the product to market. He and Michael Wetzel, president and CEO at Air Innovations, talked about their company’s role in the project.

Q: Describe the μX system size, components and functionality.

Brown: “The current unit is about twice size of a standard PC computer tower. The unit utilizes a phase change material that melts over time. We then run a fan over the material to create an active cooling effect. A compressor then re-solidifies the PCM in the off-peak hours for future on-demand needs.”

Q: Describe the phase change material used in the system: type, melt point, thermal storage capacity, amount used in each unit.

Brown:Rubitherm, 68F, 8-10 hours, 40 pounds.”

mX early version
... a version displayed at a recent conference ...
Q: Were different PCMs tested, or did the team focus on one from the start?

Wetzel: “Many PCMs were considered and analyzed before settling on Rubitherm, but no others were tested in operating systems.”

Q: Preliminary tests indicate the prototype can remove more than 32W of heat, surpassing the ARPA-E grant target of 23W. Is the final production model likely to hit that higher number?

Wetzel: “23 watts is the target heat removal directly from a person. Our manikin results showed us exceeding that number in all tests. We tested three different diffuser methods. Some achieved as high as 32 watts removed from the manikin. In all cases we are actually generating more than 500 watt-hours of cooling, enough to cool the airstream 8 degrees F for 10 hours.”

Q: The system is now known as "μX." Will that name be used for the commercial product?

Brown: “No, the commercialized name will more closely reflect the manner in which it's utilized.”

Q: What was the greatest technical hurdle the team faced in developing this product?

Wetzel: “There were many challenges on this project. Part of the program required the development of the world’s smallest scroll compressor. This also means that there was no performance data or design simulation data with which to develop the rest of the system. Our partners on the project had to develop simulation tools based on testing each new component. At Air Innovations our main challenges are designing for manufacturability and the integration and testing of off-the-shelf components as alternatives, as some of the elements of the ARPA-E units are not yet commercially available.”

mX early version
... and, finally, says Brown, "where we think the unit will potentially go in final production."
Q: What is happening with the project right now? Is it at the pilot stage?

Brown: “Currently, we are working through ARPA-E and New York State Energy grants to fully develop the technology. We are developing the unit for two scenarios. The primary is for 8-10 hours of cooling in any office environment. The other is for four hours to off-load the grid in metropolitan areas with peak power capacity concerns. Several units have been built and tested in controlled environments. We are currently seeking grant opportunities to support larger field trials.”

Q: Can you offer any details on the timeline, projected price, target market and sales projections?

Brown: “Further human testing will be necessary in order to right-size the final product. The unit will likely be ready for market sometime in 2019. The initial price point of the unit will be higher, and then come down based on quantity and market demand, settling around $2,500. It is our goal to bring to market 250-500 units in the first year.

“The exciting opportunity with the μX technology is that it further expands upon our existing Micro Environments product line. The commercialized unit will be able to control the users’ complete environment while not only offering active cooling and heating, but to control their entire surroundings as seen in our other models. Furthermore, our customers will see an ROI with the μX technology by allowing set points in the summer to run higher and temps to run cooler in the winter, reducing building HVAC power needs with a more personal temperature control directly at the desk. We believe this technology can improve worker productivity by allowing individual control, at all times, of their specific environment.”

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