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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.




Research roundup: Thermal performance of PCM wallboards; baby incubator; characterization of desert sand; more

Ben Welter - Thursday, February 22, 2018

• An Innovative Apparatus for Simulating Daily Temperature for Investigating Thermal Performance of Wallboards Incorporating PCMs [Energy and Buildings]

Application of Combined Materials for Baby Incubator [Procedia Manufacturing]

Characterization of desert sand to be used as a high-temperature thermal energy storage medium in particle solar receiver technology [Applied Energy]

Use of partial load operating conditions for latent thermal energy storage management [Applied Energy]

Melting phenomenon in a finned thermal storage system with graphene nano-plates for medium temperature applications [Energy Conversion and Management]

Ca(NO3)2-NaNO3/expanded graphite composite as a novel shape-stable phase change material for mid- to high-temperature thermal energy storage [Energy Conversion and Management]

Cumulative energy demand and global warming potential of a building-integrated solar thermal system with/without phase change material [Journal of Environmental Management]

Research roundup: Enhanced bulk-organic PCMs; cementitious composites; business clothing incorporating PCMs; more

Ben Welter - Wednesday, February 21, 2018

New formulation and characterization of enhanced bulk-organic phase change materials [Energy and Buildings]

Numerical analysis of the freeze-thaw performance of cementitious composites that contain phase change material (PCM) [Materials & Design]

Thermal Properties of Lauric Acid Filled in Carbon Nanotubes as Shape-stabilized Phase Change Materials [Physical Chemistry Chemical Physics]

Thermo-physiological comfort of business clothing incorporating phase change materials in a cold environment [International Journal of Clothing Science and Technology]

Phase change material thermal energy storage for a large scale ammonia chiller/heat pump system [International Institute of Refrigeration]

Case Study of Load Shifting Using Thermal Energy Ice Storage in Public Facilities [Journal of Facility Management]

Microencapsulated phase change materials with composite titania-polyurea (TiO2-PUA) shell [Applied Energy]

Numerical study on the effects of fins and nanoparticles in a shell and tube phase change thermal energy storage unit [Applied Energy]

Novel thermal resonator draws power from daily temperature swings

Ben Welter - Friday, February 16, 2018

MIT thermal resonator test device

Researchers at the Massachusetts Institute of Technology have developed a system that uses phase change material and graphene to convert daily fluctuations in ambient temperature into electrical power. 

The system, called a thermal resonator, is described in a paper published in the journal Nature Communications.

“We basically invented this concept out of whole cloth,” one of the authors, professor Michael Strano, told MIT News. “We’ve built the first thermal resonator. It’s something that can sit on a desk and generate energy out of what seems like nothing. We are surrounded by temperature fluctuations of all different frequencies all of the time. These are an untapped source of energy.”

MIT News writes:

"The researchers realized that to produce power from temperature cycles, they needed a material that is optimized for a little-recognized characteristic called thermal effusivity — a property that describes how readily the material can draw heat from its surroundings or release it. Thermal effusivity combines the properties of thermal conduction (how rapidly heat can propagate through a material) and thermal capacity (how much heat can be stored in a given volume of material). In most materials, if one of these properties is high, the other tends to be low. Ceramics, for example, have high thermal capacity but low conduction.

"To get around this, the team created a carefully tailored combination of materials. The basic structure is a metal foam, made of copper or nickel, which is then coated with a layer of graphene to provide even greater thermal conductivity. Then, the foam is infused with a kind of wax called octadecane, a phase-change material, which changes between solid and liquid within a particular range of temperatures chosen for a given application.

"A sample of the material made to test the concept showed that, simply in response to a 10-degree-Celsius temperature difference between night and day, the tiny sample of material produced 350 millivolts of potential and 1.3 milliwatts of power — enough to power simple, small environmental sensors or communications systems."

The researchers say the system could be used, for example, to continuously power remote sensing systems for years.

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]

Patent application: PCM compositions and methods of making the same

Ben Welter - Thursday, February 08, 2018

U.S. patent application 20180037788 (applicant Phase Change Energy Solutions, Asheboro, N.C.):

"In one aspect, compositions are described herein. In some embodiments, a composition comprises a phase change material, a hydrophobic sorption material, and a viscosity modifier. In some embodiments, a composition comprises a foam and a latent heat storage material dispersed in the foam, the latent heat storage material comprising a phase change material and a hydrophobic sorption material."

Inspired by nature, 'active energy building' takes wing in Liechtenstein

Ben Welter - Thursday, February 08, 2018

Marxer Haus, west side

The Marxer building on a rare sun-splashed January morning in Vaduz.

An “active energy building” bristling with new technology has officially spread its sophisticated wings in Vaduz, Liechtenstein.

The six-year project was directed by Anton Falkeis and his wife, Cornelia Falkeis-Senn, world-renowned architects based in Vienna. Their client, Liechtenstein attorney and banker Peter Marxer, challenged them to design a sustainable apartment building that relies as much as possible on renewable energy.

A team that included energy experts from the Lucerne University of Applied Sciences and Arts was assembled for the complex task. Countless hours of planning, research, design work, computer modeling and prototyping produced a number of innovations used in the 12-unit Marxer building, including:

• An array of 13 photovoltaic panels that rise from the roof and track the sun’s path across the sky, optimizing the collection of solar energy.

• Load-bearing structures that mimic nature in appearance and function.

• “Acoustically active” three-dimensional interior lighting elements that act as sound diffusors and absorbers.

Anton Falkeis and climate wing
Anton Falkeis and one of the PCM-filled climate wings.
• Seven “climate wings” that fold out of the building facade and absorb, store and release thermal energy as needed to keep the interior comfortable.

The computer-controlled solar panels, which measure up to 14 square meters, rise from the roof at sunrise and turn with the sun during the day. When night falls or inclement weather approaches, the panels automatically fold back into the roof. The system is said to collect nearly three times the solar energy of stationary panels.

Anton Falkeis described the project as a “prototype for a decentralized urban energy production system that’s part of a bigger network.”

“We created an energy cluster with the surrounding buildings, some of which are owned by the same client,” he said. “We share the energy generated by our PV trackers embedded in the roof structure first with the cluster. We sell any surplus to the grid. The utility can use the surplus to refill the hydro power plant storage.”

The climate wings contain 1.4 metric tons of Rubitherm PCM enclosed in aluminum tubes.

Climate wing detail
Each climate wing contains rows of PCM-filled aluminum tubes.

Four wings on the building’s western side are dedicated to heating. They are filled with PCM that has a melting point of 31 degrees Celsius. In cold months, these wings open during the day, exposing the PCM to solar radiation that melts the material. Each wing folds back at night and connects to ventilation systems in the adjoining apartments. The tubes release heat as the PCM solidifies, and low-power fans move the warm air throughout the apartments.

Three wings on the eastern side are dedicated to cooling. The PCM in these has a melting point of 21 degrees C. In summer, the wings open at night, allowing cool air to solidify the PCM. Each wing folds back against the building during the day and connects to the adjoining ventilation systems. Indoor air is cooled as it flows past the frozen PCM in the wing.

Climate wing detail
Ducts carry air warmed by PCM into the apartments.
With a surface area of 24 square meters, the western wings are said to generate about 10 percent of heating capacity. The eastern wings, with a surface of 15 square meters, generate around 16 percent of cooling capacity.

How did the team address flammability issues associated with biobased PCM?

“We developed the encapsulation so that no oxygen can come in contact with the PCM,” Falkeis said. “The whole thing was tested to 300 degrees Celsius, heating up, cooling down, heating up. And finally we got permission by the building commission, a Swiss testing certificate, to use it in the building envelope. Swiss testing accreditation is valid all over Europe.”

Aside from patent applications, what’s next for all this ground-breaking technology? 

“We need to reduce complexity and try to produce more standardized building envelope panels or systems that could be part of a regular building system,” Falkeis said. “This is our next step: Reducing the complexity in terms of form.”

He also hopes to spread awareness. "Active energy building" technology was on display at a New York City exhibition that ended in January. The exhibit opens in Los Angeles on March 1; after that, it will be on display in Vienna and Berlin.

Now that the complex project is complete and the first tenants have moved in, the architect says he is "very happy" with the results.

“There’s a lot of architectural and technological detailing,” he said. “There are more than 800 drawings just on detail. It’s very precise. It’s very well done. Very high standards. It’s really crazy how finally everything came out like we planned it.  It was six years of hard work, being on site, checking everything. …  It was a sort of never-ending ongoing research project. It was really exciting to be part of this.”

Marxer Haus, east side

The east side of Marxer building faces a small park, a biking trail and a creek.

Research roundup: Heat transfer model based on energy asymmetry; smart concretes; traction transient cooling; more

Ben Welter - Wednesday, February 07, 2018

A new heat transfer model of phase change material based on energy asymmetry [Applied Energy]

Multifunctional smart concretes with novel phase change materials: Mechanical and thermo-energy investigation [Applied Energy]

The melting of salt hydrate phase change material in an irregular metal foam for the application of traction transient cooling [Thermal Science and Engineering Progress]

Solar Energy Latent Thermal Storage by Phase Change Materials (PCMs) in a Honeycomb System [Thermal Science and Engineering Progress]

Fabrication and characterization of diethylene glycol hexadecyl ether-grafted graphene oxide as a form-stable phase change material [Thermochimica Acta]

One-dimensional model of a stratified thermal storage tank with supercritical coiled heat exchanger [Applied Thermal Engineering]

Using silicagel industrial wastes to synthesize polyethylene glycol/silica-hydroxyl form-stable phase change materials for thermal energy storage applications [Solar Energy Materials and Solar Cells]

Steam-PCM heat exchanger design and materials optimization by using Cr-Mo alloys [Solar Energy Materials and Solar Cells]

Sodium acetate trihydrate-chitin nanowhisker nanocomposites with enhanced phase change performance for thermal energy storage [Solar Energy Materials and Solar Cells]

Preparation and thermal properties of fatty acid/diatomite form-stable composite phase change material for thermal energy storage [Solar Energy Materials and Solar Cells]

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

PCM briefing: Israeli startup introduces IceBrick; Ulster University launches energy storage research project

Ben Welter - Monday, February 05, 2018

Nostromo Energy of Israel has introduced the IceBrick, an energy storage system designed to store and discharge an amount of energy equivalent to 25 kWh of electricity consumed by cooling systems at peak demand hours. The 2,000-pound IceBrick contains plain water and a proprietary nucleate.

• A new report from Environment New York, an advocacy organization, says rising renewable energy production means that energy storage is ready for prime time. Thermal storage, utility-scale batteries and pumped-storage hydro are among the technologies discussed in the report, "Making Sense of Energy Storage: How Storage Technologies Can Support a Renewable Energy Future."

Ulster University of Northern Ireland has announced 6.7-million-euro cross-border research project to develop energy storage ideas for consumers. The European Union-funded project will explore energy storage methods such as thermochemical material storage and heat pump design. 

• The European Parliament has voted in favor of a proposal that would remove palm oil-based biodiesel from the European Union's list of renewable fuels by 2021. Indonesia and Malaysia, two of the world’s largest palm oil producers, have been increasingly critical of EU’s plans to phase out palm oil biodiesel, with both countries threatening retaliation in trade and taking the matter to the World Trade Organization.

• A CALMAC thermal energy storage system has helped Kings County Courthouse in Hanford, Calif., achieve LEED Silver Certification and reduce annual energy costs by more than $100,000. 

AkzoNobel is accepting submissions for its 2018 Imagine Chemistry initiative. The company's specialty chemicals unit is seeking to partner with startups and academics to bring innovative ideas to market.

• New in 2018: Membership in the American Oil Chemists' Society now includes free online access to three AOCS publications: the Journal of the American Oil Chemists' Society; the Journal of Surfactants and Detergents; and Lipids.

Pluss Advanced Technologies of India, maker of the MiraCradle neonate cooler, has signed a collaboration agreement with Dräger, a German-based medical and safety technology company, to spread use of the PCM-enabled device in Asia and Africa.

• Netherland's Eindhoven University of Technology has openings for three Ph.D. positions involved in the study of crystal hydrate heat storage.  

• A Spanish university that has developed new biobased phase change materials with enhanced thermal properties is looking for industrial partners interested in a technical cooperation or a license agreement. 

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]