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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: 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:

Fraunhofer LBF develops composite PCM to lower dashboard temperature

Ben Welter - Monday, August 13, 2018

Structure of Fraunhofer's Smart Cover Panel.

Researchers at the Fraunhofer Institute for Structural Durability and System Reliability LBF in Darmstadt, Germany, have developed a new phase change composite material designed to reduce the surface temperature of dashboards in vehicles. 

Springer Professional of Germany has a good summary [translated from the German original]:

"The composite is suitable for a temperature phase transition and consists of a carrier material made of polyethylene, which can store energy. The filler graphite, on the other hand, ensures rapid heat dissipation. In a cyclic process of heating and cooling phases, the scientists were able to achieve a temperature reduction of 46 percent or 41 degrees Celsius compared to a conventional polypropylene-talc compound dashboard."

Fraunhofer, of course, offers a more detailed look [also translated from German]:

"To demonstrate the benefits of the new material, the scientists built this component into the dashboard of an electric vehicle to subsequently create a cycle of heating and cooling phases. The cooling was provided by Peltier elements. These electrothermal transducers are in turn cooled by external fans. The energy for Peltier elements and coolers comes from an additional 12 V battery powered by photovoltaic power.

"The energy released during the phase transition was used by the LBF researchers to switch on the Peltier elements only for a certain period of time. In this way, the fans do not have to constantly run at maximum power. By appropriate regulation, the cooling system is coupled to the temperature in the material. This should lead to a higher life expectancy of the electronic components. Thanks to a clever setting of the starting point of the working group, the Smart Cover Panel is controlled by the sunlight itself. This means that cooling only starts in hot summer days, and in winter the coveted warmth stays in the dashboard."

https://www.lbf.fraunhofer.de/de/presse/presseinformationen/phase-changing-material-mehr-komfort-und-reichweite-elektromobilitaet.html

Research roundup: Octadecanol/expanded perlite; PV/T system design; macroencapsulated PCM for pavement; more

Ben Welter - Friday, August 10, 2018

From Renewable Energy:

Experimental investigation on thermal properties and thermal performance enhancement of octadecanol/expanded perlite form stable phase change materials for efficient thermal energy storage
Effect of graphite mass concentrations in a mixture of graphite nanoparticles and paraffin wax as hybrid storage materials on performances of solar still

From Renewable and Sustainable Energy Reviews:

A review on recent development for the design and packaging of hybrid photovoltaic/thermal (PV/T) solar systems

From Materials:

Mechanical and Thermal Performance of Macro-Encapsulated Phase Change Materials for Pavement Application

From International Journal of Heat and Mass Transfer:

Heat transfer behavior of elemental sulfur for low temperature thermal energy storage applications
A novel method for determining the melting point, fusion latent heat, specific heat capacity and thermal conductivity of phase change materials
Effect of microstructure on melting in metal-foam/paraffin composite phase change materials

From Chemical Engineering Journal:

Flexible phase change materials for thermal storage and temperature control

From Construction and Building Materials:

Experimental investigation of thermal and mechanical properties of magnesium oxychloride cement with form-stable phase change material

From Solar Energy:

New insights into the corrosion mechanism between molten nitrate salts and ceramic materials for packed bed thermocline systems: A case study for steel slag and solar salt


Research roundup: Solar thermal modeling; finned multitube storage; solid-solid PCM: more

Ben Welter - Wednesday, August 01, 2018

From Applied Thermal Engineering:

Modelling and experimental study of latent heat thermal energy storage with encapsulated PCMs for solar thermal applications

From Journal of Energy Storage:

Estimation of thermal performance and design optimization of finned multitube latent heat thermal energy storage

From Engineering Science and Technology:

Experimental study on heat transfer performance of neopentyl glycol/CuO composite solid-solid PCM in TES based heat sink

From Solar Energy:

Synthesis and characterization of stearic acid/silicon dioxide nanoencapsules for solar energy storage

C-Therm offers free webinar on characterizing PCMs for TES and thermal management of batteries

Ben Welter - Tuesday, July 31, 2018

C-Therm Technologies is hosting a free webinar this week on recent research on composite phase change materials for thermal energy storage and battery thermal management. C-Therm’s MTPS method for thermal conductivity characterization of PCMs was used in the research. The webinar, "Characterizing Phase Change Materials for Thermal Energy Storage and Improved Battery Thermal Management," will be held at 1 p.m. EDT Thursday, Aug. 2. 

http://ctherm.com/resources/webinars/upcoming_webinars#PCM

Research roundup: Alum/expanded graphite composite; geopolymeric mortars; flexible PCMs; more

Ben Welter - Monday, July 30, 2018

From Energy:

Experimental investigations of Alum/expanded graphite composite phase change material for thermal energy storage and its compatibility with metals

From International Journal of Thermal Sciences:

Numerical study on the effect of phase change materials on heat transfer in asphalt concrete

From The Open Construction & Building Technology Journal:

Thermal Performance of Resource-Efficient Geopolymeric Mortars Containing Phase Change Materials

From Chemical Engineering Journal:

Flexible Phase Change Materials for Thermal Storage and Temperature Control

From Journal of Materials Chemistry A:

Nanoconfinement of phase change materials within carbon aerogels: phase transition behaviours and photo-to-thermal energy storage

From Materiales de Construcción:

Identification of best available thermal energy storage compounds for low-to-moderate temperature storage applications in buildings

Ph.D. candidate digs deep into the T-history method

Ben Welter - Friday, July 27, 2018

The lab folks at PureTemp have had a keen interest in the T-history method since our days as a tech startup with a small budget. T-history is a relatively simple, low-cost way to determine the heat of fusion, specific heat and thermal conductivity of phase change materials.

Pepe TanNew research on the topic turned up in one of our automated searches earlier this month: “Characterizing phase change materials using the T-History method: On the factors influencing the accuracy and precision of the enthalpy-temperature curve.” The lead author, Pepe Tan, is a pursuing a Ph.D. at Chalmers University of Technology in Sweden. I contacted him to find out more. 

Q: What prompted your interest in studying the T-history method?

A: “When I started my Ph.D. at Chalmers, T-history was a good complement to the available DSC instrument in our research group. And it was a nice opportunity to collaborate with ZAE Bayern and learn the method. While implementing the method, we found it was very worth studying certain aspects of it in parallel, because of how different the method has been presented so far in the scientific community.”

Q: Do you envision T-history replacing DSC for characterizing and validating PCMs as an industry standard? If not for PCM validation, perhaps for application engineering and thermal modeling?

A: “I definitely consider T-history and DSC as complementary methods since their limitations for finding the intrinsic PCMs properties are still subject to research. With this uncertainty, any measurement available from different sources would be useful for the engineer to carefully estimate the actual behavior of the PCM in its application.”   

Q: When do you believe T-history will be studied and validated sufficiently to become adopted as a commercially available piece of equipment?

T-history chamberA: “To reach that goal, a systematic assessment of different implementations of the method (setup and data evaluation) would be necessary. But spending this effort also depends on the current needs for accurate PCM properties in typical applications.”

Q: Will the mathematical model of the method become open-source and available for laboratories?

A: “The data evaluation method in the paper should be seen as one proposal on how to calculate the enthalpy from real experimental data. And it is presented in detail, so that it can be recreated.

“The challenge in our experiments was to negate the noise amplification when differentiating the temperature over time data. But this could be done in many different ways, which will in turn affect the enthalpy results. We made the raw experimental data available so that other data evaluation methods can be tested.”

Q: What do you view as the most significant challenge with T-history? How does this compare to the challenges associated with DSC?

A: “That would be to perform a rigorous measurement uncertainty analysis in order to specify a reliable limit for accuracy and precision in terms of an uncertainty. Since this strongly depends on the individual implementation of the method and the chosen data evaluation, the DSC is in my opinion one step ahead.”

Q: Is T-history capable of accurate and precise measurement with thermal conductivity additives or nucleating agents?

A: “This depends on the material and the actual implementation of the method. And this would be an example where the possibility to use complementary methods that utilize different sample sizes like DSC and T-history will be helpful to filter out the intrinsic material behavior. The larger sample sizes of the T-history setup should increase the chance to actually have representative samples, meaning samples containing a representative amount of the nucleating agent and/or the thermal conductivity additives."  

Q: What are your postdoctoral plans?

A: “I expect to graduate by June 2020. At the moment, I plan to wait and see what options are available when the graduation date comes a bit closer.”

Research roundup: Silicon carbide for battery thermal management; Stefan moving boundary models; alkali nitrate/nitrite salts; more

Ben Welter - Tuesday, July 24, 2018

From Renewable Energy:

Using Renewables Coupled with Thermal Energy Storage to Reduce Natural Gas Consumption in Higher Temperature Commercial/Industrial Applications

From Solar Energy:

Development of a solar thermal storage cum cooking device using salt hydrate

From Applied Energy:

One-step fabrication of fatty acids/nano copper/polyester shape-stable composite phase change material for thermal energy management and storage
Palmitic acid/polyvinyl butyral/expanded graphite composites as form-stable phase change materials for solar thermal energy storage

From Chinese Journal of Chemical Engineering:

Preparation and phase change performance of Na2HPO4·12H2O@poly(lactic acid) capsules for thermal energy storage

From Applied Thermal Engineering:

Thermal performance of sodium acetate trihydrate based composite phase change material for thermal energy storage
Performance improvement and energy consumption reduction in refrigeration systems using phase change material (PCM)
A thermal conductive composite phase change material with enhanced volume resistivity by introducing silicon carbide for battery thermal management
Numerical and Experimental study on the performance of a new two -layered high-temperature packed-bed thermal energy storage system with changed-diameter macro-encapsulation capsule

From Colloids and Surfaces A: Physicochemical and Engineering Aspects:

Green Nano-encapsulation Technique for Preparation of Phase Change Nanofibers Mats with Core-Sheath Structure
From International Journal of Thermal Sciences:

Analytical and numerical analysis of PCM solidification inside a rectangular finned container with time-dependent boundary condition

From Construction and Building Materials:

Elaboration and properties of a composite bio-based PCM for an application in building envelopes

From International Journal of Heat and Mass Transfer:

Lorentz forces effect on NEPCM heat transfer during solidification in a porous energy storage system
A translucent honeycomb solar collector and thermal storage module for building façades

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

PCM briefing: New EU energy standard takes effect; new research on inorganic phase change material

Ben Welter - Monday, July 09, 2018

• The new version of the European Union's Energy Performance of Buildings Directive takes effect July 9. The directive is the EU's main legislative instrument designed to promote improved energy performance of buildings. Member states will have 20 months to transpose the new elements into national law.

• A proposal to use microencapsulated phase change material to help motor vehicles run smoothly in extreme cold has won the ClimateLaunchpad competition in Azerbaijan. A team of chemical engineering students from Baku Higher Oil School developed the concept. The team will represent Azerbaijan at the ClimateLaunchpad finals in Scotland Nov. 1-2, 2018.

• New from Research Reports: "2018 Global Inorganic PCMs Industry Report – History, Present and Future"