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 monthly PCM newsletter. Or join the discussion on LinkedIn.




Research roundup: Ricinoleic acid as PCM; estimating temperature distribution of PCM; enthalpy-temperature curves; more

Ben Welter - Tuesday, January 05, 2016

Study on Characteristics of Ricinoleic Acid as a Phase Change Material [Applied Mechanics and Materials]

Method for Estimating the Temperature Distribution in a Phase Change Material with a Broad Phase-change-temperature Range [Energy Procedia]

Thermal Behavior Mapping of a Phase Change Material Between the Heating and Cooling Enthalpy-temperature Curves [Energy Procedia]

Thermal Change for Heat Exchanger Cooling System of PCM [European Journal of Engineering and Natural Sciences]

Applications of Active Hollow Core Slabs and Insulated Concrete Foam Walls as Thermal Storage in Cold Climate Residential Buildings [Energy Procedia]

Modelling of an Active PCM Thermal Energy Storage for Control Applications [Energy Procedia]

Second-law design of a latent heat thermal energy storage with branched fins [International Journal of Numerical Methods for Heat & Fluid Flow]

Phase Change Materials Applications to Optimize Cooling Performance of Buildings in the Mediterranean Area: A Parametric Analysis [Energy Procedia]

Research roundup: Energy-efficient concrete; graphite exfoliation; micro PCM slurries; PCM window system; more

Ben Welter - Wednesday, December 30, 2015

Energy efficient concrete with n-octadecane/xGnP SSPCM for energy conservation in infrastructure [Construction and Building Materials]

Exfoliation of graphite by solar irradiation and investigate their thermal property on capric–myristic–palmitic acid/exfoliated graphite composite as phase change material (PCM) for energy storage [Journal of Energy Storage]

Review on microencapsulated phase change materials slurries (mPCMS) properties [Applied Thermal Engineering]

Dynamic Thermal Performance of a PCM Window System: Characterization Using Large Scale Measurements [Energy Procedia]

Synthesis and Characterization of Composite Phase Change Material (CPCM) with SiO2 and Diatomite as Endothermal-hygroscopic Material [Energy Procedia]

Mortars with incorporation of PCM based in different binders: mechanical and thermal behavior [European Mortar Summit 2015]

Review of development of phase change cold storage technology for food cold chain application [pdf] [International Forum on Energy, Environment Science and Materials]

Modeling of Solidification of CCHH (CaCl2, 6H2O) in a Shell-and-Tube PCM based Heat Storage Unit [Procedia Engineering]

Research roundup: Xylitol penta myristate; melting of PCM in horizontal annulus; hybrid photovoltaic module; more

Ben Welter - Thursday, December 17, 2015

Thermal Energy Storage Properties of Xylitol Penta Myristate and Xylitol Penta Laurate as Novel Solid-liquid Phase Change Materials [Energy Sources]

Melting of a Phase Change Material in a Horizontal Annulus With Discrete Heat Sources [pdf] [Thermal Science]

Development of a thermal model for a hybrid photovoltaic module and phase change materials storage integrated in buildings [Solar Energy]

Exergy analysis of solar desalination still combined with heat storage system using phase change material (PCM) [Desalination]

Energy-Efficient Building Envelopes: use of Phase Change Materials in Cement-Based Composites [International Association for Bridge and Structural Engineering]

PureTemp phase change material is now available in high-performance Vesl devices

Ben Welter - Tuesday, December 15, 2015

In partnership with Entropy Solutions, Vesl LLC now offers PureTemp phase change material in encapsulated form. Three new patent-pending containment solutions – BlockVesl, MacroVesl and MicroVesl – feature an enhanced surface-area-to-mass ratio. That means faster energy exchange and superior PureTemp performance.


The stackable BlockVesl is a precisely engineered PCM device with more than 3,200 square centimeters of surface area. It is suited to a wide range of applications, including refrigeration, air conditioning, heat recovery and heat storage. One BlockVesl can store up to 200,000 joules of energy depending on the PCM selected.


The 305mm-diameter MacroVesl is a multi-chambered, high-capacity sphere with more than 24,600 square centimeters of surface area. That’s more than 16 times the surface area of a typical sphere of the same diameter. It is suited to a wide range of applications, including air conditioning, heat recovery and thermal energy storage.


The MicroVesl features a multi-layered polymer structure chosen for its ideal barrier properties. The MicroVesl, now available in a diameter of 18.5 mm, can be made in a range of sizes and is ideal for use in refrigeration, air conditioning, thermal energy storage and many other applications.

To learn more, visit

Research roundup: Stearic acid/graphene core-shell composite; binary mixtures of fatty acid methyl esters; ice TES system design; more

Ben Welter - Thursday, December 10, 2015

A Pickering emulsion route to a stearic acid/graphene core–shell composite phase change material [Carbon]

Binary mixtures of fatty acid methyl esters as phase change materials for low temperature applications [Applied Thermal Engineering]

Identification of Design Criteria for District Cooling Distribution Network with Ice Thermal Energy Storage System [Energy Procedia]

Numerical simulation of phase change materials for building applications: a review [Advances in Building Energy Research]

RAL Quality Association PCM works to spread the word on phase change material

Ben Welter - Wednesday, November 25, 2015

Stefan ThommanThe RAL Quality Association PCM was established in 2004 to develop standards for the phase change material industry. Its European focus is reflected in its member list: BASF, Rubitherm, EMCO and va-Q-tec (Germany), Salca and global-E-systems (Netherlands), and Croda (United Kingdom). Sasol (South Africa) and Pluss Advanced Technologies (India) are also members.

The annual membership fee is 4,000 euros plus a one-time admission fee of 2,000 euros. Members and non-members alike can submit their products to the association for independent testing and earn the RAL Quality Mark.

But the RAL Quality Association PCM does more than establish performance standards and conduct tests. We asked Stefan Thomann, the association's managing director, to speak in detail about the organization’s objectives and the benefits of membership. He kindly responded by e-mail:

“Generally speaking," he explained, "our association has two key objectives":

1. Influencing the political landscape in the EU in favor of PCM

“The EU have set ambitious targets in their 2020 Energy Strategy: reducing [greenhouse gas] emissions by 20%, increasing the share of renewable energy to 20% of consumption and achieve energy savings of 20% as minimum targets. The buildings sector is the one in which the largest savings in energy consumption and [greenhouse gas] emissions could be achieved. The Energy Performance of Buildings Directive (EPBD; from 2010 was certainly a step into the right direction, requiring Member States to set minimum energy performance requirements for new buildings and buildings undergoing deep-renovation.

“One of our key points of criticism is that the EPBD and its national transpositions do pay a lot attention on insulation and efficient heating systems, but do not (sufficiently) address the problem of overheating and thermal comfort in summer. With the modern way of lightweight building these problems will undoubtedly increase or require cooling systems that will spend parts of the saved energy. Both you and I know that PCM would be a perfect solution via passive cooling systems or by combining HVAC systems with PCM. But unfortunately neither the EPBD nor 95% of its national transpositions allow to count PCM as an appropriate means of saving energy and getting incentives for them. We are intensively working on changing this at the moment, both on EU and national level.

“Another interesting aspect in terms of the Energy Strategy is promoting the use of thermal storages based on PCM. Since heat (or cold) is usually the form in which energy is needed, it makes sense to efficiently store thermal energy instead of inefficiently store electricity. This would help increasing the use of renewable energy by storing it from when it is available until when it is actually needed.

2. Promoting the use of high-quality PCM

“The other key objective is to provide high-quality PCM for the various applications, independently certified by the RAL Quality Mark. If customers decide to use PCM in their applications, they want to be 100% sure that the products perform in the way the supplier promised they would and continuously do over their anticipated lifetime. For this reason, we developed Quality and Testing specifications (RAL-GZ 896) for PCM and PCM composites, objects and systems.

RAL Quality Association PCM logo “If manufacturers of PCM comply with the Quality and Testing specifications and can prove the continuous quality with an internal and external monitoring systems, they can use the RAL Quality Mark for their products as a well-acknowledged and independent proof of quality. …

“In my opinion, there is no better way to convince customers of the [value of] high-quality products compared to inferior but cheaper ones than having their long-lasting effectiveness independently confirmed and documented by the RAL Quality Mark. Although the RAL Quality Association is located in Germany, it is open for companies from all over the world and the Quality Mark can just as well be used in all countries – it is not limited to the German market.

“Apart from the actual use of the Quality Mark, I would say that the biggest benefit of being member is the close contact to some of the leading companies producing and applying high-quality PCM and products with PCM and to the European research facilities that are active in this area. [Members] have the right to attend all our General Assembly Meetings – which are about 3 per year at the moment – and to vote on all decisions … [and] shape the future of the Quality Mark and PCM in general. 

“The annual membership fee is 4,000 EUR plus a one-time admission fee of 2,000 EUR in the first year of membership. This is some sort of a compensation payment because the foundation members had to bear the costs for the whole establishment of the association, the Quality and Testing Specifications and all other documents and services like the homepage for example. This amount is only invoiced once and will be strictly used for the association’s objectives.

“The annual membership fee entitles you to attend all General Assembly meetings and to vote on all decisions. There will be no extra fees for using the Quality Mark no matter for how many products you would like to use it – apart from the mere testing costs for the initial test and the external testing.”

University of Washington expands use of PCM in science complex walls, ceilings

Ben Welter - Friday, November 20, 2015

ZGF drawing of UW nanoengineering building

Phase change material will be used in walls and ceiling panels at the University of Washington's new Nanoengineering and Sciences Building. The 78,000-square-foot building is the second phase of a science complex at the center of campus. The first was the 90,000-square-foot Molecular Engineering and Sciences Building, completed in 2012.

Writing in Seattle's Daily Journal of Commerce, Nicole Cooper of ZGF Architects explains how PCMs performed in phase one: 

"The PCM is developed from vegetable oil and is 'charged' at night when windows to office spaces are automatically opened to provide a flush of cool air. With the completion of phase one, the design team was able to set up temperature monitoring in the spaces, wall cavities and ceilings to quantify the effects of the PCM.

"It was determined through two years of data collection that the PCM reduces the temperature around 1.5 to 2 degrees during peaks times on the hottest days of the year. This provided significant savings in the design of the mechanical systems for both phases as well as a beneficial cost savings to UW."

Entropy Solutions adds PureTemp 7 to its line of biobased PCMs

Ben Welter - Friday, November 06, 2015

Entropy Solutions has added PureTemp 7 to its lineup of more than two dozen biobased, renewable phase change materials. With a melt point of 7º Celsius and a heat storage capacity of 185 joules per gram, PureTemp 7 is designed to fully solidify in a refrigerator, making it suitable for use in freezer-less settings. Potential applications include shipping, cold storage and air conditioning. PureTemp 7 will be available beginning in December 2015.

Research roundup: Emulsion co-polymerization encapsulation; underfloor heating; cellulose/graphene aerogel phase change composites; more

Ben Welter - Thursday, November 05, 2015

Microcapsulation and Macrocapsulation of Phase Change Materials by Emulsion Co-polymerization Method [Progress in Clean Energy]

The Energy Conservation Potential of Using Phase-Change Materials as Thermal Mass Material for Air Source Heat Pump-Driven Underfloor Heating System in a Building [Progress in Clean Energy]

Cellulose/graphene aerogel supported phase change composites with high thermal conductivity and good shape stability for thermal energy storage [Carbon]

Simulated Aging and Characterization of Phase Change Materials for Thermal Management of Building Envelopes [pdf]  [U.S. Army Corps of Engineers]

Synthesis and Performance of Thermoplastic Polyurethane-Based Solid–Solid Phase-Change Materials for Energy Storage [Science of Advanced Materials]

Research roundup: Supercooling of salt hydrates; lauric acid/expanded perlite; ice thermal energy storage; more

Ben Welter - Monday, October 26, 2015

Experimental characterisation of sub-cooling in hydrated salt phase change materials [Applied Thermal Engineering]

Research on the preparation and properties of lauric acid/expanded perlite phase change materials [Energy and Buildings]

The potential of lightweight low-energy houses with hybrid adaptable thermal storage: comparing the performance of promising concepts [Energy and Buildings]

Ice thermal energy storage (ITES) for air-conditioning application in full and partial load operating modes [International Journal of Refrigeration]

Reproducibility of solidification and melting processes in a latent heat thermal storage tank [International Journal of Refrigeration]