Phase Change Matters RSS


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.

Two Entropy advisors, Dr. Mohammed Farid and Lucas B. Hyman, are pleased to take your questions about PCMs and thermal energy storage. Send your questions to We'll select the best and post the answers here each week.




Research roundup: Rubber sealing materials; pork fat as novel PCM; thermal inertia of buildings; more

Ben Welter - Wednesday, September 20, 2017

Feasibility of Using Microencapsulated Phase Change Materials as Filler for Improving Low Temperature Performance of Rubber Sealing Materials [Soft Matter]

Evaluation of the nanofluid and nano-PCM based photovoltaic thermal (PVT) system: An experimental study [Energy Conversion and Management]

Investigation of pork fat as potential novel phase change material for passive cooling applications in photovoltaics [Journal of Cleaner Production]

Superwetting polypropylene aerogel supported form-stable phase change materials with extremely high organics loading and enhanced thermal conductivity [Solar Energy Materials and Solar Cells]

Polyethylene glycol-enwrapped silicon carbide nanowires network/expanded vermiculite composite phase change materials: Form-stabilization, thermal energy storage behavior and thermal conductivity enhancement [Solar Energy Materials and Solar Cells]

Solar desalination using solar still enhanced by external solar collector and PCM [Applied Thermal Engineering]

Using Thermal Inertia of Buildings with Phase Change Material for Demand Response [Energy Procedia]

Preparation of microencapsulated phase change materials (MEPCM) for thermal energy storage [Energy Procedia]

Study of thermal conductive enhancement mechanism and selection criteria of carbon-additive for composite phase change materials [International Journal of Heat and Mass Transfer]

PCM briefing: Three molten salt projects projects move forward in U.S., Germany

Ben Welter - Tuesday, September 19, 2017

Terrafore salt encapsulation• The U.S. Department of Energy has released funding to the Argonne National Laboratory for a scaled-up round of independent testing of Terrafore Technologiesencapsulated thermal energy storage in phase change salts. The materials, shown at right, are designed to operate in temperatures to greater than 800° C in a single tank that acts as both storage and heat exchanger.

• The Department of Energy has invited Terrestrial Energy USA to submit the second part of its application for a federal loan guarantee to support the licensing and construction of its Integrated Molten Salt Reactor

DLR has fired up the TESIS thermal storage facility in Cologne, Germany. One hundred tons of molten salt is alternately heated and cooled from 250 to 560 degrees Celsius in the test facility, which is designed to allow industrial-scale testing of temporary storage methods for renewable energy and waste heat. 

• Va-Q-tec AG is reporting a strong increase in its service business in the first half of 2017, up 54 percent to 8.8 million euros. The company, based in Würzburg, Germany, develops, manufactures and sells vacuum insulation panels and phase change materials. 

• New from Zion Market Research: "Global thermal storage market is expected to reach USD 5.7 billion in 2022, growing at a CAGR of 10.7% between 2017 and 2022"

Advanced combat clothing featuring "four-way stretch phase-change material" was on display last week at the annual Defense and Security Equipment International show in London. Royal College of Art researchers and designers collaborated with the Ministry of Defense on the prototypes, which are designed to be easy to run in and comfortable to wear.  

Research roundup: PCM wallboard; composite Trombe solar wall; indoor thermal comfort; more

Ben Welter - Friday, September 15, 2017

Energetic performance of two different PCM wallboards and their regeneration behavior in office rooms [Energy Procedia]

Correlation between energy efficiency in buildings and comfort of the users [Energy Procedia]

Numerical study of a composite Trombe solar wall integrating microencapsulated PCM [Energy Procedia]

Design of High Temperature Thermal Energy Storage for High Power Levels [Sustainable Cities and Society]

Numerical analysis of heat transfer processes in a low-cost, high-performance ice storage device for residential applications [Applied Thermal Engineering]

Solid-liquid phase change investigation through a double pipe heat exchanger dealing with time-dependent boundary conditions [Applied Thermal Engineering]

Evaluation of energy efficient hybrid hollow plaster panel using phase change material/xGnP composites [Applied Energy]

Indoor thermal comfort assessment using different constructive solutions incorporating PCM [Applied Energy]

The experimental phase diagram study of the binary polyols system erythritol-xylitol [Solar Energy Materials and Solar Cells]

Multifunctional poly (melamine-urea-formaldehyde)/graphene microcapsules with low infrared emissivity and high thermal conductivity [Materials Science and Engineering: B]

PCM briefing: Solar-powered micro cold rooms; Axiom Exergy's jazz connection

Ben Welter - Wednesday, September 13, 2017

• The German company Covestro is providing technology for use in solar-powered micro cold rooms in India. The cold rooms employ phase change material to keep produce cool until it can be transported from farm to market. Eight hundred units will be built in the Indian state of Telangana over the next two years. 

• In an interview with the San Jose Mercury News, Anthony Diamond talks about the musical connection he shares with Axiom Exergy co-founder Amrit Robbins. They met as undergrads at Stanford University. "I play saxophone, he’s actually a trumpet player," Diamond said. "He was like, the best jazz trumpet player on campus. So whenever I had a gig, I would call him, and vice-versa. We had an opportunity to collaborate a lot within that context. I knew that I worked really well with him and we were a really great team."

• Heat battery maker Sunamp Ltd. is one of 15 European scaleups selected to give presentations in California next week at Startup Europe Comes to Silicon Valley

Pelican BioThermal has opened a service center in Puerto Rico. The center will serve as a depot for the company’s Credo on Demand rental program and enable customers to receive and return reusable temperature controlled packaging systems.

Facebook has announced that its cloud campus in Odense, Denmark, will be connected to a neighborhood district heating system. The company expects the system will warm 6,900 homes.

Evelyn Wang, director of MIT’s Device Research Laboratory and an internationally recognized leader in phase change heat transfer on nanostructure surfaces, has been named associate department head of operations in the school's Department of Mechanical Engineering.  

Long-Qing Chen, professor of engineering science, mechanics and mathematics at Penn State University, has been awarded a Humboldt Research Award by the Alexander von Humboldt Foundation of Germany. Chen will work with Jürgen Rödel, professor of materials science and engineering at the Technische Universität Darmstadt, on areas of mutual interest, including multiferroic thin films and phase change materials.

MIT researchers are taking a look at 3,000-year-old technology that could help reduce the use of fossil fuels. Under the proposal, electric resistance heaters would convert excess electricity into heat. The heat would be stored in a large mass of firebricks, which can retain heat for long periods if they are enclosed in an insulated casing. The heat could be used directly for industrial processes, or it could feed generators that convert it back to electricity when the power is needed.  

Research roundup: Supercooling in paraffin slurry; double-composition microencapsulation; encapsulated nitrates; more

Ben Welter - Thursday, September 07, 2017

Reduction of supercooling in paraffin phase change slurry by polyvinyl alcohol [International Journal of Refrigeration]

Preparation, characterization, and thermal stability of double-composition shell microencapsulated phase change material by interfacial polymerization [Colloid and Polymer Science]

Heat transfer characteristics of a hybrid thermal energy storage tank with Phase Change Materials (PCMs) during indirect charging using isothermal coil heat exchanger [Solar Energy]

Hybrid network structure of boron nitride and graphene oxide in shape-stabilized composite phase change materials with enhanced thermal conductivity and light-to-electric energy conversion capability [Solar Energy Materials and Solar Cells]

Encapsulated Nitrates Phase Change Material Selection for Use as Thermal Storage and Heat Transfer Materials at High Temperature in Concentrated Solar Power Plants [Energies 2017]

Research roundup: Influence of nanoparticle morphology; battery thermal management; concrete pavement; more

Ben Welter - Wednesday, September 06, 2017

Influence of nanoparticle morphology and its dispersion ability regarding thermal properties of water used as Phase Change Material [Applied Thermal Engineering]

The optimal allocation of the PCM within a composite wall for surface temperature and heat flux reduction: an experimental approach [Applied Thermal Engineering]

An innovative practical battery thermal management system based on phase change materials: Numerical and experimental investigations [Applied Thermal Engineering]

Using phase change material in under floor heating [Energy Procedia]

Incorporating phase change materials in concrete pavement to melt snow and ice [Cement and Concrete Composites]

Dynamics of phase change in a vertical PCM capsule in the presence of radiation at high temperatures [Applied Energy]

Experimental study on thermal performance of phase change material passive and active combined using for building application in winter [Applied Energy]

Thermodynamics behavior of phase change latent heat materials in micro-/nanoconfined spaces for thermal storage and applications [Renewable and Sustainable Energy Reviews]

Advancement in phase change materials for thermal energy storage applications [Solar Energy Materials and Solar Cells]

Study on solidification process of sodium acetate trihydrate for seasonal solar thermal energy storage [Solar Energy Materials and Solar Cells]

Patent application: Building integrated PV roofing assemblies with PCM

Ben Welter - Thursday, August 17, 2017

U.S. patent application 20170237387 (SolarCity Corp., San Mateo, Calif):

"A solar roof assembly, comprising: a support material covering a portion of a roof surface; a plurality of standing seam metal roof pans arranged in columns on the roof deck over the support material at a first height above the roof surface; a plurality of support pans arranged in columns on the roof surface adjacent to at least one column of standing seam metal roof pan, each support pan comprising a pair of standing seams running a length of each side edge thereof and having a plurality of ridges and valleys and between each side edge; a plurality of photovoltaic modules arranged end to end in columns over the plurality of support pans on the plurality of ridges. ... The solar roof assembly [may include] a heat storage material positioned between at least one pairing of the photovoltaic modules and support pans, wherein the heat storage material comprises at least one compartment having a phase change material can transition from a first phase to a second phase at a transition temperature."

Research roundup: Stearyl alcohol/ HDPE /expanded graphite composite PCM; perlite-based PCM wallboard; more

Ben Welter - Thursday, August 17, 2017

Improved thermal properties of stearyl alcohol/high density polyethylene/expanded graphite composite phase change materials for building thermal energy storage [Energy and Buildings]

Development and thermal performance of an expanded perlite-based phase change material wallboard for passive cooling in building [Energy and Buildings]

Numerical and experimental investigation of an insulation layer with phase change materials (PCMs) [Energy and Buildings]

Polyurethane foams with microencapsulated phase change material: Comparative analysis of thermal conductivity characterization approaches [Energy and Buildings]

Flammability assessment of Phase Change Material wall lining and insulation materials with different weight fractions [Energy and Buildings]

Thermal analysis of nanoparticle-enhanced phase change material solidification in a rectangular latent heat storage unit including natural convection [Energy and Buildings]

A portable solar-powered air-cooling system based on phase-change materials for a vehicle cabin [Energy Conversion and Management]

Thermal performance and economic evaluation of a newly developed phase change material for effective building encapsulation [Energy Conversion and Management]

Fabrication of three-dimensional metal-graphene network phase change composite for high thermal conductivity and suppressed subcooling phenomena [Energy Conversion and Management]

Researches of composite phase change material cooling/resistance wire preheating coupling system of a designed 18650-type battery module [Applied Thermal Engineering]

The impact of the heating/cooling rate on the thermoregulating properties of textile materials modified with PCM microcapsules [Applied Thermal Engineering]

Fatty acids/1-dodecanol binary eutectic phase change materials for low temperature solar thermal applications: Design, development and thermal analysis [Solar Energy]

An Experimental Evaluation of Direct Flow Evacuated Tube Solar Collector Integrated with Phase Change Material [Energy]

Heat capacities of some sugar alcohols as phase change materials for thermal energy storage applications [Journal of Chemical Thermodynamics]

Research roundup: Geopolymer concrete; octyl, decyl, dodecyl and tetradecyl stearates; supercooling suppression of erythritol; more

Ben Welter - Thursday, August 03, 2017

From Cement and Concrete Research:

Mechanical properties and microscale changes of geopolymer concrete and Portland cement concrete containing micro-encapsulated phase change materials

From Applied Energy:

Impact of pressure on the dynamic behavior of CO2 hydrate slurry in a stirred tank reactor applied to cold thermal energy storage

From International Journal of Refrigeration:

Parametric analysis of domestic refrigerators using PCM heat exchanger

From American Institute of Physics:

Utilization of the PCM Latent Heat for Energy Savings in Buildings [pdf]

From Journal of Cleaner Production:

LCA perspective to assess the environmental impact of a novel PCM-based cold storage unit for the civil air conditioning

From Renewable Energy:

A calcium chloride hexahydrate/expanded perlite composite with good heat storage and insulation properties for building energy conservation
Ionic compounds derived from crude glycerol: Thermal energy storage capability evaluation
Comparative study of the thermal performance of four different shell-and-tube heat exchangers used as latent heat thermal energy storage systems

From Materials Today: Proceedings:

Viscoelastic characterization of multifunctional composites incorporated with microencapsulated phase change materials

From Applied Thermal Engineering:

Effect of phase change material wall on natural convection heat transfer inside an air filled enclosure
A numerical study of building integrated with CaCl2·6H2O/expanded graphite composite phase change material
Study of the thermal behavior of the composite phase change material (PCM) room in summer and winter

From Applied Polymer Science:

Emulsion-electrospinning n-octadecane/silk composite fiber as environmental-friendly form-stable phase change materials

From Journal of Materials Chemistry A:

Versatility of polyethylene glycol (PEG) in designing solid-solid phase change materials (PCMs) for thermal management and their application to innovative technologies

From Materials:

Influence of Microencapsulated Phase Change Material (PCM) Addition on (Micro) Mechanical Properties of Cement Paste
Investigation of the Dynamic Melting Process in a Thermal Energy Storage Unit Using a Helical Coil Heat Exchanger

From Energy and Buildings:

Experimental analysis of thermal performance in buildings with shape-stabilized phase change materials
Preparation and thermal properties of octyl, decyl, dodecyl and tetradecyl stearates as phase change materials for thermal energy storage
Effect of PCM application inside an evacuated tube collector on the thermal performance of a domestic hot water system

From Solar Energy:

Experimental investigation of water based photovoltaic/thermal (PV/T) system with and without phase change material (PCM)
Heat transfer studies of building brick containing phase change materials
Experimental investigations on stable supercooling performance of sodium acetate trihydrate PCM for thermal storage

From Solar Energy Materials and Solar Cells:

Supercooling suppression and thermal behavior improvement of erythritol as phase change material for thermal energy storage
MgCl2·6H2O-Mg(NO3)2·6H2O eutectic/SiO2 composite phase change material with improved thermal reliability and enhanced thermal conductivity

Extremely high-temperature TES prototype under development in Europe

Ben Welter - Thursday, August 03, 2017

At seven locations around Europe, a consortium of universities, R&D centers and an Italian company is investigating materials and devices for thermal energy storage at temperatures of up to 2000º C, well beyond the maximum operating temperatures of systems in use today.

The AMADEUS project, funded by the European Union’s Horizon 2020 program, aims to build a prototype of a system that stores electricity in the form of extremely dense heat, using a solid state device known as a hybrid thermionic-photovoltaic converter. The project’s success hinges on the development of novel silicon and boron alloys with melting temperatures well above 1000º C and energy densities of more than 1 kilowatt hour per liter.

Alejandro DatasAlejandro Datas, a research scientist at the Technical University of Madrid’s Institute of Solar Energy, is the project’s scientific coordinator. He responded to questions about the project by email.

Q: What is your role as scientific coordinator?

A: My role is to coordinate the project activities and make them converge at the end in a single prototype, which will demonstrate the feasibility of this new concept. I’m also involved in the development of the infrared-sensitive PV cell (or thermophotovoltaic cell) that will be used to convert radiant heat into electricity in these systems.

Q: Work on the project began about seven months ago and is scheduled to continue through 2019. What important milestones have you reached so far, and what are the next important milestones?

A: During the first six months of the project, we have characterized some Si-B alloys with different compositions to determine their most important thermophysical parameters, such as latent heat and thermal conductivity. By means of solubility and wettability experiments, we have also studied the interaction of these alloys with some nitride- and carbide- refractories that are intended to be used for the container walls. Also, we have fabricated an experimental setup that will enable the characterization of the energy converters at very high temperatures. The next expected milestones will be the fabrication of the first generation of hybrid thermionic-photovoltaic converters, as well as the determination of the optimal Si-B alloy composition based on an exhaustive analysis of their thermophysical properties and their reactivity with the container walls.

Q: Can you describe, briefly, the PCM you are developing, and what is meant by "the silicon-boron system"?

A: The Si-B system refers to an alloy containing silicon and boron elements in some specific proportions. Silicon and boron have two of the highest latent heats among all the elements in the periodic table. But they show some important drawbacks: in the case of silicon, it expands upon solidification (like water) which leads to very severe constraints for the vessel design; in the case of boron, it has a high cost. The Si-B system is expected to exploit the best of both elements. For instance, the eutectic composition of this alloy (having only 5% of boron) is expected to notably improve the properties of pure silicon PCM at a reasonable cost increment. In brief, Si-B alloys have potential to meet the main requirements for being considered an ideal PCM: low cost, high latent heat and high thermal conductivity. Surprisingly, very little attention has been paid to this system so far, and to our knowledge, AMADEUS is the very first project to investigate these materials in detail for energy storage applications.

Q: What are some of the PCM containment materials and structures under consideration?

A: One advantage of Si-B PCMs is their high thermal conductivity. Thus, they could be stored in relatively large containers without needing very advanced encapsulation arrangements. This minimizes the impact of the container in the final cost of the system. In order to achieve the minimum interaction between the container and the Si-B PCM, we are investigating several kinds of vessel liners based on nitrides (e.g. BN or Si3N4), carbides (e.g. SiC) and oxides (e.g. SiO2).

Q: How does AMADEUS differ from the molten silicon storage technology under development by 1414 Degrees in Australia?

A: Apparently, 1414 Degrees uses pure silicon PCM and “conventional” dynamic engines to transform latent heat into electricity. 1414 Degrees probably needs to reach the market soon, so that they must use reliable and mature technologies. In AMADEUS we are exploring new technologies with greater potential that still require further development. This is the case of Si-B alloys, which may enable higher energy densities and more efficient vessel designs. This is also the case of the thermionic and thermophotovoltaic converters, which will eventually enable more efficient, compact and simpler systems, not requiring working fluids or moving parts. We certainly hope that companies such as 1414 Degrees, and others that could start activities in the near future, could benefit from the results of AMADEUS project.