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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: Carbonized wood-based composite; inclined photovoltaic system; nanoparticle-enriched PCM; more

Ben Welter - Monday, July 02, 2018

From Energy:

Low-cost, three-dimension, high thermal conductivity, carbonized wood-based composite phase change materials for thermal energy storage
Coupled Cooling Method for Multiple Latent Heat Thermal Storage Devices Combined with Pre-cooling of Envelope: Model Development and Operation Optimization
Latent and sensible heat analysis of PCM incorporated in a brick for cold and hot climatic conditions, utilizing computational fluid dynamics

From International Journal of Heat and Mass Transfer:

Study on a PEG/epoxy shape-stabilized phase change material: Preparation, thermal properties and thermal storage performance

From Journal of Cleaner Production:

Research on the Application of Phase-change Heat Storage in Centralized Solar Hot Water System

From Applied Thermal Engineering:

Numerical study of an inclined photovoltaic system coupled with phase change material under various operating conditions

From Solar Energy:

Effect of MOF derived hierarchical Co3O4/expanded graphite on thermal performance of stearic acid phase change material
Numerical analysis of a new thermal energy storage system using phase change materials for direct steam parabolic trough solar power plants

From Applied Energy:

Cyclic performance of cascaded and multi-layered solid-PCM shell-and-tube thermal energy storage systems: A case study of the 19.9 MWe Gemasolar CSP plant

From Journal of Energy Storage:

Experimental investigation of transient melting and heat transfer behavior of nanoparticle-enriched PCM in a rectangular enclosure

From Desalination:

Theoretical study on the performance of a solar still system integrated with PCM-PV module for sustainable water and power generation

From Solar Energy Materials and Solar Cells:

Graphene Aerogels Enhanced Phase Change Materials prepared by one-pot method with high thermal conductivity and large latent energy storage
Facile approach to improve solar thermal energy storage efficiency using encapsulated sugar alcohol based phase change material

PCM briefing: Cash infusion for Ice Energy; ASHRAE's new energy audit standard now available

Ben Welter - Monday, July 02, 2018

Ice Energy, make of the Ice Bear and other ice-based energy storage systems, is getting an infusion of cash from a private equity manager. The California startup will receive $40 million from Argo Infrastructure Partners to finance the delivery of its residential and commercial thermal storage contracts.

• "Chemistry for the Non-Chemist," a four-part online course offered by Chemical Watch, promises "a solid introduction to chemistry." The cost: $450.  

ASHRAE Standard 211 is now available for download. The standard "establishes consistent practices for conducting and reporting energy audits for commercial buildings. The standard defines the procedures required to perform Energy Audit Levels 1, 2, and 3; provides a common scope of work for these audit levels for use by building owners and others; c. establishes consistent methodology and minimum rigor of analysis required; and establishes minimum reporting requirements for the results of energy audits." 

Purchase College of New York will get a free replacement for its aging central heating plant, thanks to a collaborative thermal energy storage project from the New York Power Authority and Brenmiller Energy. The R&D project will investigate sensible thermal energy storage as a way to increase the efficiency of a standard combined heat and power system. The new system could save State University of New York $100,000 a year.

Fifty-four academic papers were presented at PCM 2018, the 12th IIR International Conference on Phase Change Materials and Slurries for Refrigeration and Air Conditioning, held in Orford, Canada, last month. "Investigations on the stability of metallic cans for PCM macro-encapsulation," "Investigation of compatibility of organic and inorganic PCMs with the materials of containers" and "Life cycle assessment phase changes of materials, component and system concept" are among the papers posted on the International Institute of Refrigeration website. 

John Lerch, vice president of sales and marketing at thermal energy storage company Axiom Exergy, writes about "5 things utilities should consider for energy storage." 

Wilmar International said it has ceased sourcing from palm oil suppliers allegedly associated with Gama, a company that was accused by Greenpeace of causing deforestation in Indonesia. 

• The Roundtable on Sustainable Palm Oil and Canadian supply chain consultancy Ulula are collaborating to introduce a mobile phone app to report potential workers’ incidents and abuses on palm oil plantations. 

PCM-equipped personal air conditioner set for commercial release in 2019

Ben Welter - Tuesday, June 26, 2018

Developers of a personal air conditioner designed to reduce energy use in office buildings say they’re on track for commercial release next year. The “μX” micro climate system features a phase change material that solidifies at about 18 degrees C to store cooling generated at night for use during the day.

mX early version
The evolution of the μX: an early design ...
Dr. H. Ezzat Khalifa of Syracuse University led the development team, which includes Air Innovations, Cornell University, United Technologies Research Center and Bush Technical LLC. The team has been working on the system since 2015, funded in large part by a $3.2 million grant from the U.S. Energy Department’s Advanced Research Projects Agency-Energy. The New York State Energy Research and Development Authority provided $400,000 in follow-on funding in 2016.

Sam Brown, OEM custom director at Air Innovations, is in charge of bringing the product to market. He and Michael Wetzel, president and CEO at Air Innovations, talked about their company’s role in the project.

Q: Describe the μX system size, components and functionality.

Brown: “The current unit is about twice size of a standard PC computer tower. The unit utilizes a phase change material that melts over time. We then run a fan over the material to create an active cooling effect. A compressor then re-solidifies the PCM in the off-peak hours for future on-demand needs.”

Q: Describe the phase change material used in the system: type, melt point, thermal storage capacity, amount used in each unit.

Brown:Rubitherm, 68F, 8-10 hours, 40 pounds.”

mX early version
... a version displayed at a recent conference ...
Q: Were different PCMs tested, or did the team focus on one from the start?

Wetzel: “Many PCMs were considered and analyzed before settling on Rubitherm, but no others were tested in operating systems.”

Q: Preliminary tests indicate the prototype can remove more than 32W of heat, surpassing the ARPA-E grant target of 23W. Is the final production model likely to hit that higher number?

Wetzel: “23 watts is the target heat removal directly from a person. Our manikin results showed us exceeding that number in all tests. We tested three different diffuser methods. Some achieved as high as 32 watts removed from the manikin. In all cases we are actually generating more than 500 watt-hours of cooling, enough to cool the airstream 8 degrees F for 10 hours.”

Q: The system is now known as "μX." Will that name be used for the commercial product?

Brown: “No, the commercialized name will more closely reflect the manner in which it's utilized.”

Q: What was the greatest technical hurdle the team faced in developing this product?

Wetzel: “There were many challenges on this project. Part of the program required the development of the world’s smallest scroll compressor. This also means that there was no performance data or design simulation data with which to develop the rest of the system. Our partners on the project had to develop simulation tools based on testing each new component. At Air Innovations our main challenges are designing for manufacturability and the integration and testing of off-the-shelf components as alternatives, as some of the elements of the ARPA-E units are not yet commercially available.”

mX early version
... and, finally, says Brown, "where we think the unit will potentially go in final production."
Q: What is happening with the project right now? Is it at the pilot stage?

Brown: “Currently, we are working through ARPA-E and New York State Energy grants to fully develop the technology. We are developing the unit for two scenarios. The primary is for 8-10 hours of cooling in any office environment. The other is for four hours to off-load the grid in metropolitan areas with peak power capacity concerns. Several units have been built and tested in controlled environments. We are currently seeking grant opportunities to support larger field trials.”

Q: Can you offer any details on the timeline, projected price, target market and sales projections?

Brown: “Further human testing will be necessary in order to right-size the final product. The unit will likely be ready for market sometime in 2019. The initial price point of the unit will be higher, and then come down based on quantity and market demand, settling around $2,500. It is our goal to bring to market 250-500 units in the first year.

“The exciting opportunity with the μX technology is that it further expands upon our existing Micro Environments product line. The commercialized unit will be able to control the users’ complete environment while not only offering active cooling and heating, but to control their entire surroundings as seen in our other models. Furthermore, our customers will see an ROI with the μX technology by allowing set points in the summer to run higher and temps to run cooler in the winter, reducing building HVAC power needs with a more personal temperature control directly at the desk. We believe this technology can improve worker productivity by allowing individual control, at all times, of their specific environment.”

PCM briefing: Neck collar uses Outlast to keep wearer cool; thermally responsive bandage heals wounds quickly

Ben Welter - Monday, June 25, 2018

A new neck collar designed for people living with motor neurone disease features Outlast phase change technology to keep the wearer cool. The Heads Up collar supports the collection of small muscles in the neck that are vulnerable to the wasting effects of the disease.

• A Northwestern University team has developed a thermally responsive bandage that quickly heals painful, hard-to-treat sores in people with diabetes. The bandage features a hydrogel that rapidly solidifies when exposed to body temperature, conforming to the shape of the wound.

• In the short term, analysts say crude palm oil prices have likely hit rock bottom. But a Rabobank analyst is projecting reduced production - and higher prices - from 2022 to 2025. 

•  A call for papers has been issued for the Advanced Automotive Battery Conference Europe, to be held in Strasbourg, France, Jan. 27-31, 2019. "Thermal modeling" and "preventing thermal runaway" are among the topics. The deadline for priority consideration is June 29.

Emily Liu, a professor at Rensselaer Polytechnic Institute, was recently selected by the U.S. Department of Energy's Solar Energy Technologies Office to receive a $1.8 million award to study high-temperature molten-salt properties and corrosion mechanisms.

Dr. Robert Brookins, interim CEO at Alexium International Group Ltd., will present an hourlong webinar, "Phase Change Materials: How Can They Help Set Your Company Apart," on June 28. The free event is sponsored by the Industrial Fabrics Association International.  

• Swedish solar company Azelio has launched a demonstrator of its solar energy storage technology. The system uses an aluminum alloy as a thermal storage material. 

In a new directive, the European Commission is calling for at least 32 percent of total EU energy use to come from renewable sources by 2030. The directive, which will require the formal approval of the European Parliament, sets specific annual targets for cooling and heating installations. 

• The agenda is taking shape for the 13th International Conference on Advanced Building Skins, to be held Oct. 1-2 in Bern, Switzerland. Topics include "Energy buffering with phase change materials" and "Thermal performance of phase change materials for the building skin."

Va-Q-tec AG is expanding its Kölleda location in Thuringia, Germany. The company manufactures vacuum isolation panels, phase change materials and passive thermal packaging systems at two plants there.

• MIT Technology Review reports that Alphabet Inc. (Google's parent company) appears to be in talks to spin out Project Malta, a molten-salt energy storage project, in a transaction involving Breakthrough Energy Ventures, Bill Gates’ $1 billion investment fund.

Research roundup: Natural convection heat transfer; simulation of hysteresis effects; PCM in roofs; more

Ben Welter - Wednesday, June 20, 2018

From Energy Conversion and Management:

Effect of using nanoparticles on the performance of thermal energy storage of phase change material coupled with air-conditioning unit
Numerical study on the effect of non-uniform magnetic fields on melting and solidification characteristics of NEPCMs in an annulus enclosure
Solidification behavior of binary eutectic phase change material in a vertical finned thermal storage system dispersed with graphene nano-plates

From International Communications in Heat and Mass Transfer:

A method to evaluate natural convection heat transfer in microencapsulated phase change material (MPCM) slurry: An experimental study
Dynamic of plumes and scaling during the melting of a Phase Change Material heated from below

From Applied Thermal Engineering:

Experimental investigation of the thermal performance of heat pipe assisted phase change material for battery thermal management system
Low-temperature macro-encapsulated phase change material based thermal energy storage system without air void space design

From Energy and Buildings:

Modeling and experimental validation of an algorithm for simulation of hysteresis effects in phase change materials for building components
Thermal performance and numerical simulation of geopolymer concrete containing different types of thermoregulating materials for passive building applications

From Solar Energy:

How to enhance thermal energy storage effect of PCM in roofs with varying solar reflectance: Experimental and numerical assessment of a new roof system for passive cooling in different climate conditions

From Energy:

A facile approach to synthesize microencapsulated phase change materials embedded with silver nanoparticle for both thermal energy storage and antimicrobial purpose

From Reference Module in Materials Science and Materials Engineering:

Materials, Design and Development of Latent Heat Storage Systems for Medium and Large-Scale Applications: Issues and Challenges

From Physica A: Statistical Mechanics and its Applications:

Melting process in porous media around two hot cylinders: Numerical study using the lattice Boltzmann method

From Solar Energy Materials and Solar Cells:

Synthesis and characterization of chain-extended and branched polyurethane copolymers as form stable phase change materials for solar thermal conversion storage

From Construction and Building Materials:

Investigation of different materials for macroencapsulation of salt hydrate phase change materials for building purposes

From Journal of Energy Storage:

CFD thermal energy storage enhancement of PCM filling a cylindrical cavity equipped with submerged heating sources
Performance analysis of industrial PCM heat storage lab prototype

Research roundup: Heat transfer enhancement of PCMs; CuO/palmitic acid composite; cooking applications; more

Ben Welter - Tuesday, June 12, 2018

From Materials Today: Proceedings:

Investigation of thermal performance by applying a solar chimney with PCM towards the natural ventilation of model house under Climate of Thailand
Study of Solar– PCM Walls for domestic hot water production under the tropical climate of Thailand
Improved Performance of Composite Phase Change Material for Thermal Energy Storage
Experimental investigation on freezing/melting characteristics of two different phase change materials
Review on Heat Transfer Enhancement of Phase Change Materials (PCMs)
Experimental Investigation of Improved Thermal Characteristics of Al2O3/Barium Hydroxide Octa Hydrate as Phase Change Materials (PCMs)
Improved Thermal Energy Storage Behavior of CuO/Palmitic acid Composite as Phase Change Material

From Applied Thermal Engineering:

An Experimental Investigation of the Melting Process of a Bio-based Nano-PCM filled Vertical Cylindrical Thermal Energy Storage System

From International Journal of Heat and Mass Transfer:

Experimental investigation of the effects of mass fraction and temperature on the viscosity of microencapsulated PCM slurry

From Journal of the Brazilian Society of Mechanical Sciences and Engineering:

Rapid thermal cycling of three phase change materials (PCMs) for cooking applications

From 3rd Thermal and Fluids Engineering Conference:

Use of Wood/Phase Change Material Composite in the Building Envelope for Building Thermal Control and Energy Savings

Research roundup: N-octadecane/polystyrene/expanded graphite composites; decorative wood-based panels for thermal energy storage; more

Ben Welter - Monday, June 11, 2018

From Energy:

Experimental investigation on n–octadecane/polystyrene/expanded graphite composites as form–stable thermal energy storage materials

From Green Energy and Environment:

Thermal characterization of bio-based phase changing materials in decorative wood-based panels for thermal energy storage

From Chemical Engineering Science:

Melt-Front Propagation and Velocity Profiles in Packed Beds of Phase-Change Materials Measured by Magnetic Resonance Imaging

From Thermal Science and Engineering Progress:

Employment of Finned PCM Container in a Household Refrigerator as a Cold Thermal Energy Storage System

From Energy Conversion and Management:

Melting and solidification of PCM embedded in porous metal foam in horizontal multi-tube heat storage system
Evaluation of paraffin infiltrated in various porous silica matrices as shape-stabilized phase change materials for thermal energy storage

From Construction and Building Materials:

Potential applications of phase change materials to mitigate freeze-thaw deteriorations in concrete pavement
A practical ranking system for evaluation of industry viable phase change materials for use in concrete
Experimental and numerical study of thermal performance of the PCM wall with solar radiation
Utilizing blast furnace slags (BFS) to prepare high-temperature composite phase change materials (C-PCMs) 

From International Journal of Thermophysics:

Behavior of a PCM at Varying Heating Rates: Experimental and Theoretical Study with an Aim at Temperature Moderation in Radionuclide Concrete Encasements

PCM briefing: Ecozen Solutions wins Ashden Award; Fraunhofer researchers among winners in Imagine Chemistry challenge

Ben Welter - Monday, June 11, 2018

Ecozen cold storage unit

Ecozen Solutions of India, which makes portable solar cold rooms for use on small farms, is one of six international winners in the 2018 Ashden Awards competition. The Ecofrost system's thermal storage unit can store power for more than 36 hours in case of cloudy or rainy weather. The organizations will be honored at a ceremony at the Royal Geographical Society in London on Thursday, June 14. 

Axel Kraft and Martin Peters of Fraunhofer UMSICHT are among the winners of the 2018 AkzoNobel Imagine Chemistry challenge. Kraft and Peters will receive support from LuxResearch to further develop a catalytic process for making alcohols from more sustainable raw materials. Overall, 10 startups and researchers were chosen as winners from a group of 20 finalists at a three-day event held at Chalmers University in Gothenburg, Sweden.

A call for papers has been issued for the 10th International Conference on Indoor Air Quality, Ventilation and Energy Conservation in Buildings. Topics include ventilation strategies and measurement techniques; HVAC systems; smart technologies for zero-energy buildings; and design and energy modeling. Abstracts are due by Nov. 1. The conference will be held Sept. 5-7, 2019, in Bari, Italy.  

• Researchers at the Jülich Solar Tower test facility in Germany have reached a milestone in the development of a new receiver concept for solar tower power plants. During a test of the centrifugal receiver CentRec for the generation and storage of solar high temperature heat, an average particle temperature of 965 degrees Celsius has been measured at the receiver outlet. The bauxite particles used in the system are available at prices that enable cost-effective thermal storage. “The proof of the high operating temperature is an essential condition for the targeted commercialization of this new receiver concept,” said Dr. Reiner Buck, head of solar tower systems at the DLR Institute of Solar Research

• June 15 is the last day to get the early bird rate for this year's Advancements in Thermal Management Conference (Denver, Aug. 8-9). Topics include thermal materials, thermal imaging, thermal characterization, modeling, battery cooling and thermal simulation. Joe Kelly, senior materials scientist at Outlast Technologies, is among the speakers. His topic: "Enhancing Thermal Stability and Performance of Lithium-ion Batteries using Latent Heat Storage (LHS) Technology."

Phase change composite shows potential to double AC compressor efficiency

Ben Welter - Friday, June 01, 2018

Using a phase change composite material, researchers at the University of Illinois at Chicago have developed a novel thermal energy storage system that has the potential to downsize conventional air-conditioner compressors by 50 percent and double compressor efficiency during off- and mid-peak hours.

The research is described in a paper titled “Design and optimization of a hybrid air conditioning system with thermal energy storage using phase change composite,” recently accepted for publication in Energy Conversion and Management. One of the authors, Said Al-Hallaj, a research professor of chemical engineering at UI-Chicago and CEO of AllCell Technologies LLC, answered a few questions by e-mail.

Q: Who led the research team, and how long did the project take?

A: “It is an ongoing project since 2015 at the University of Illinois at Chicago, where I work as a Research Professor of Chemical Engineering, and part of the PhD thesis for my graduate student Ahmed Aljehani.”

Q: Who funded the project? 

A: “Ahmed has a scholarship from his government in Saudi Arabia and we get technical support from our industry partners NETenergy and AllCell Technologies LLC.”

Q: Who supplied the PCM?

A: “I believe it is n-tetradecane (C14H30) PCM that we bought from a distributor and not sure about actual source.”

28 slabs of phase change composite materialQ: What is its peak melting point? 

A: “4-6 degrees Celsius.”

Q: What is its thermal storage capacity?

A: “180 kJ/kg (78% PCM, 22% graphite).”

Q: Describe the benchtop PCC/TES system size, components and functionality.

A: “The actual 4 kWh PCC-TES structure is made of 28 slabs of PCC [right]. The whole PCC-TES structure is thermally insulated with building insulation materials. Each slab represents a graphite structure that has been soaked into n-tetradecane for at least 24 h until impregnated with n-tetradecane. The slabs are numbered from top to bottom; top being number 1. The second component is the copper tubes or the copper coils, which pass back and forth in between the 28 slabs. The copper tubes enter the PCC-TES structure from the top and exits from the bottom of the structure.”

Q: Is the concept intended mainly for commercial AC systems, or could it be adapted for residential use?

A: “It should work for both, but commercial AC applications are more economically beneficial due to rate structure and peak demand requirements.”

Q: What are the next steps in developing this concept?

A: “NETenergy, our technology commercialization partner, is partnering with National Renewable Energy Laboratory and a major OEM to build and test a full-scale prototype at NREL facilities in the next year or so.”

Research roundup: Nanofluid-based PCMs; microencapsulation of n-alkanes; finned solar PV PCM; more

Ben Welter - Thursday, May 31, 2018

From Chemical Engineering Journal:

Glycolysis of Advanced Polyurethanes Composites containing Thermoregulating Microcapsules

From Applied Thermal Engineering:
From Applied Energy:

From International Journal of Thermal Sciences:

From Chemical Engineering Science: