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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.




Contributions sought for new database on thermal storage materials

Ben Welter - Monday, April 16, 2018

A new database for thermal energy storage materials is being developed within the framework of the International Energy Agency’s Energy Conservation through Energy Storage group, Annex 29 and SHC Task 42.

The database is designed to provide characteristic data for phase change, sorption and thermochemical materials. The website,, also offers a wiki with definitions related to thermal energy storage. Both areas are open for contributions.

The phase transition data provided for PCMs must be measured according to a DSC-measurement standard. To ensure the quality of the submitted data, contributors must provide a reference measurement using a PCM provided by Fraunhofer ISE.

Stefan Gschwander, head of Group Heat and Cold Storage at Fraunhofer ISE in Freiburg, Germany, said all submitted data will undergo a review process. “If the data is in line with our requirements it can be published in the public area,” he said.

So far, 15 PCMs are listed in the public area. A restricted area of the database is limited to  independently measured materials.

“The data stored is high-quality data which can be used for research, for example
simulation or to design a system,” Gschwander said. “So for our database, the manufacturers normally do not provide data but sample material that is measured from the institutions that are able to measure according the definitions. So far we have measured PCM from Rubitherm, Sasol and BASF. …

“So far we have about 20 different materials in the restricted area and, as we have used it for the development of the measurement standard, many of the materials have been measured several times by different laboratories so that we have a lot more measurements stored in the database.”

Fraunhofer ISE offers independent characterization of PCM, with fees depending on the material and the DSC required to do the measurement.

The ECES is a technology collaboration group that supports the development of electrical energy storage, thermal energy storage, distributed energy storage and borehole thermal energy storage. For more information on the material database project and characterization services, contact Gschwander at

Research roundup: Microcapsule with SiO2-TiO2 hybrid shell; finned rectangular enclosures; glazed roof with PCM; more

Ben Welter - Wednesday, April 11, 2018

Synthesis and properties of phase change microcapsule with SiO2-TiO2 hybrid shell [Solar Energy]

Experimental investigation of melting behaviour of phase change material in finned rectangular enclosures under different inclination angles [Experimental Thermal and Fluid Science]

Phase change material based cooling of photovoltaic panel: A simplified numerical model for the optimization of the phase change material layer and general economic evaluation [Journal of Cleaner Production]

Influence of glazed roof containing phase change material on indoor thermal environment and energy consumption [Applied Energy]

Thermal field and heat storage in a cyclic phase change process caused by several moving melting and solidification interfaces in the layer [International Journal of Thermal Sciences]

A phase change microactuator based on paraffin wax/expanded graphite/nickel particle composite with induction heating [Sensors and Actuators A: Physical]

Research roundup: Personal cooling device; China's cold chain; prismatic lithium ion batteries; more

Ben Welter - Friday, March 16, 2018

"Preparation and Characterization of Modified Porous Wood Flour/Lauric-Myristic Acid Eutectic Mixture as a Form-Stable Phase Change Material" [Energy & Fuels]

A novel phase based cooling system for prismatic lithium ion batteries [Institut International du Froid]

Optimization of solar photovoltaic system integrated with phase change material [Solar Energy]

A novel heat transfer enhancement technique for performance improvements in encapsulated latent heat storage system [Solar Energy]

Experimental and numerical investigation of a solar collector/storage system with composite phase change materials [Solar Energy]

Enhanced thermal conductivity of phase change material nanocomposites based on MnO2 nanowires and nanotubes for energy storage [Solar Energy Materials and Solar Cells]

Enhancing the Thermosiphon-Driven Discharge of a Latent Heat Thermal Storage System used in a Personal Cooling Device [International Journal of Refrigeration]

An Overview of Current Status of Cold Chain in China [International Journal of Refrigeration]

Applications of Thermal Analysis to the Study of Phase-Change Materials [Handbook of Thermal Analysis and Calorimetry]

Thermo-physical characteristics, mechanical performance and long-term stability of high temperature latent heat storages based on paraffin-polymer compounds [Thermochimica Acta]

High thermal conductive paraffin/calcium carbonate phase change microcapsules based composites with different carbon network [Applied Energy]

Research roundup: Acrylic PCM microcapsules; paraffin-water nanoemulsion; two-tank molten salt TES; more

Ben Welter - Wednesday, February 14, 2018

Non-linear system identification of a latent heat thermal energy storage system [Applied Thermal Engineering]

Tailoring of bifunctional microencapsulated phase change materials with CdS/SiO2 double-layered shell for solar photocatalysis and solar thermal energy storage [Applied Thermal Engineering]

Preparation of acrylic PCM microcapsules with dual responsivity to temperature and magnetic field changes [European Polymer Journal]

Paraffin wax–water nanoemulsion: A superior thermal energy storage medium providing higher rate of thermal energy storage per unit heat exchanger volume than water and paraffin wax [Energy Conversion and Management]

Preparation and characterization of stearic acid/polyurethane composites as dual phase change material for thermal energy storage [Journal of Thermal Analysis and Calorimetry]

Efficiency analyses of high temperature thermal energy storage systems of rocks only and rock-PCM capsule combination [Solar Energy]

Thermal performance analysis of PCM wallboards for building application based on numerical simulation [Solar Energy]

Thermal energy storage in district heating: Centralised storage vs. storage in thermal inertia of buildings [Energy Conversion and Management]

Two-tank molten salts thermal energy storage system for solar power plants at pilot plant scale: lessons learnt and recommendations for its design, start-up and operation [Renewable Energy]

Research roundup: Eutectic organic PCMs; diatomite/CNTs/PEG composites; cellulose insulation; more

Ben Welter - Tuesday, February 06, 2018

From Data in Brief:

Prediction of the Properties of Eutectic Organic Phase Change Materials

From Energy and Buildings:

Diatomite/CNTs/PEG composite PCMs with shape-stabilized and improved thermal conductivity: Preparation and thermal energy storage properties

From Solar Energy:

Thermal performance of phase change materials (PCM)-enhanced cellulose insulation in passive solar residential building walls

From Energy Procedia:

A Parametric Study about the Potential to Integrate Phase Change Material into Photovoltaic Panel
Investigations on thermal environment in residential buildings with PCM embedded in external wall
Passive Cooling Using Phase Change Material and Insulation for High-rise Office Building in Tropical Climate
A Study on Latent Heat Energy Storage Performance of Tetradecane
Erythritol-Vermiculite form-stable phase change materials for thermal energy storage

From Applied Thermal Engineering:

Modification of expanded graphite and its adsorption for hydrated salt to prepare composite PCMs

From Renewable Energy:

Experimental Investigation of Solar Chimney with Phase Change Material (PCM)
Effect of retrofitting a silver/water nanofluid-based photovoltaic/thermal (PV/T) system with a PCM-thermal battery for residential applications

From International Journal of Thermal Sciences:

Thermal charging performance of enhanced phase change material composites for thermal battery design

From Colloids and Surfaces A: Physicochemical and Engineering Aspects:

Preparation and characterization of high-temperature non-flowing SiO2/EG/paraffin composites by high-temperature refining

From Materials Today: Proceedings:

Experimental analysis of thermal energy storage by phase change material system for cooling and heating applications

From Materials & Design:

Thermal conductivity enhancement of phase change materials with form-stable carbon bonded carbon fiber network

From Sustainable Cities and Society:

Experimental study on thermal performance improvement of building envelopes by integrating with phase change material in an intermittently heated room

From International Journal of Refrigeration:

Phase-change thermal energy storage using spherical capsules: performance of a test plant

Research roundup: Review of latent heat storage systems; triple-glazed window with PCM; myristic acid; more

Ben Welter - Wednesday, January 17, 2018

Design of a Latent Thermal Energy Storage System From Constructal Approach [ASME 2017 International Mechanical Engineering Congress and Exposition]

Latent Heat Thermal Energy Storage Systems with Solid–Liquid Phase Change Materials: A Review [Advanced Engineering Materials]

Simulation Research on the Dynamic Thermal Performance of a Novel Triple-glazed Window Filled with PCM [Sustainable Cities and Society]

Charging and Discharging Period Analysis of Myristic Acid as Phase Change Material [pdf] [International Journal of Current Engineering and Technology]

Solid-liquid phase equilibria of stearic acid and dicarboxylic acids binary mixtures as low temperature thermal energy storage materials [Journal of Chemical Thermodynamics]

Comparative study on the solar still performance utilizing different PCM [Desalination]

Temperature stabilization using salt hydrate storage system to achieve thermal comfort in prefabricated wooden houses [Energy and Buildings]

Multiobjective optimization of a building envelope with the use of phase change materials (PCMs) in Mediterranean climates [International Journal of Energy Research]

Experimental research in the phase change materials based on paraffin and expanded perlite [Phase Transitions]

Enhanced Thermal Conductivity and Thermal Performance of Polyethylene Glycol (PEG)/Modified SiO2 Composite Phase Change Material [Science of Advanced Materials]

Research roundup: Eutectic fatty acids; review of automotive applications; expanded graphite composites; more

Ben Welter - Wednesday, January 03, 2018

Prediction of the Properties of Eutectic Fatty Acid Phase Change Materials [Thermochimica Acta]

Phase-change materials (PCM) for automotive applications: A review [Applied Thermal Engineering]

A polymer-coated calcium chloride hexahydrate/expanded graphite composite phase change material with enhanced thermal reliability and good applicability [Composites Science and Technology]

Synthesis and characterization of beeswax-tetradecanol-carbon fiber/expanded perlite form-stable composite phase change material for solar energy storage [Composites Part A: Applied Science and Manufacturing]

An energy-efficient composite by using expanded graphite stabilized paraffin as phase change material [Composites Part A: Applied Science and Manufacturing]

Synthesis and characterization of PEG/ZSM-5 composite phase change materials for latent heat storage [Renewable Energy]

Fabrication and characteristics of composite phase change material based on Ba(OH)2·8H2O for thermal energy storage [Solar Energy Materials and Solar Cells]

Silica fume/capric acid-palmitic acid composite phase change material doped with CNTs for thermal energy storage [Solar Energy Materials and Solar Cells]

Hybridizing graphene aerogel into three-dimensional graphene foam for high-performance composite phase change materials [Energy Storage Materials]

Phase Change in Spiral Coil Heat Storage Systems [Sustainable Cities and Society]

Thermal management performance of phase change materials with different thermal conductivities for Li-ion battery packs operated at low temperatures [Energy]

Geocooling with integrated PCM thermal energy storage in a Mediterranean climate [Energy]

RAL Quality Association PCM approves updated quality and testing specifications

Ben Welter - Thursday, December 14, 2017

Members of the RAL Quality Association PCM have unanimously approved revised versions of two documents governing the association’s quality testing program.

The association, formed in 2004, promotes the use of high-quality phase change material and oversees independent testing of PCMs. Members include Croda, va-Q-tec, Pluss Advanced Technologies and Entropy Solutions. Members and non-members alike can submit their products to the association for independent testing and earn the RAL Quality Mark.

RAL PCM quality markThe first document, “Quality and Testing Specifications for Phase Change Materials,” also known as RAL-GZ 896, sets out the general principles for PCM. The document defines PCM, PCM composites, PCM objects and PCM systems; establishes performance requirements; and outlines the nature and scope of monitoring measures.

Improvements to RAL-GZ 896 include:

Clearer structure and wording, less text. The prior edition was judged to be strongly fragmented, hard to read and too long. At the same time some definitions, especially those in the glossary, required clarification.

Heat flow meter measurements are now permissible. This will make measuring larger PCM products much easier.

Reduced testing frequency during cycling. The prior edition required testing the quality criteria at fixed intervals during cycling. The new edition recommends testing at intervals during cycling (to reduce the risk that cycling is continued until the end despite the sample has already failed) and the intervals are wider. These changes are designed to reduce the cost of testing.

Including segregation. Segregation is an important criterion for salt hydrates especially and was included as additional quality requirement.

Better explanation of monitoring.

The second document provides detailed provisions and references to the certification of PCM, PCM composites, PCM objects and PCM systems. Improvements to this document include more detailed descriptions of measuring methods and guidance on which methods are appropriate for different types of PCM.

The revised documents will be submitted to the German RAL Institute for Quality Assurance and Certification, the PCM association’s governing body, for final review and approval. The revised documents are expected to take effect in early spring.

Patent application: Lubricating composition with phase change material

Ben Welter - Monday, December 11, 2017

U.S. patent application 20170349850 (applicant Total Marketing Services, Puteaux, France):

"Disclosed is a monophasic lubricating composition including a base oil, an oil chosen from the polyalkylene glycols (PAG) and a phase-change material, in particular water. The monophasic lubricating composition can be used, in particular, for lubricating a vehicle engine. It has improved thermal performance relative to the lubricant compositions of the prior art. It also helps reduce fouling of the engine parts."

Research roundup: Erythritol in spheres; triplex-tube TES system enhancement; spray freezing of PCM; more

Ben Welter - Tuesday, December 05, 2017

Theoretical and numerical analysis on phase change materials (PCM): A case study of the solidification process of erythritol in spheres [International Journal of Heat and Mass Transfer]

Optimisation analysis of PCM-enhanced opaque building envelope components for the energy retrofitting of office buildings in Mediterranean climates [Applied Energy]

Solidification enhancement of PCM in a triplex-tube thermal energy storage system with nanoparticles and fins [Applied Energy]

System-Level Analysis of a Novel Air-Cooled Condenser using Spray Freezing of Phase Change Materials [Applied Thermal Energy]

Analysis of operational performance of a mechanical ventilation cooling system with latent thermal energy storage [Energy and Buildings]

Evaluation of two cooling devices for construction workers by a thermal manikin [Fashion and Textiles]

Study on improving the heat storage property of Ba(OH)2 • 8H2O with paraffin [Materials Research Express]