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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 monthly PCM newsletter. Or join the discussion on LinkedIn.




Research roundup: Micro/nano PCM for solar thermal applications; photovoltaic cooling; beeswax emulsions; more

Ben Welter - Thursday, March 21, 2019

From Renewable Energy:

Review on micro/nano phase change materials for solar thermal applications

From Jordan Journal of Mechanical and Industrial Engineering :

Photovoltaic Cooling Using Phase Change Material

From Advanced Materials Interfaces:

Phase Change Materials: Superhydrophobic Coatings from Beeswax‐in‐Water Emulsions with Latent Heat Storage Capability

From Energy Storage:

Experimental Observations on the Interface Front of Phase Change Material inside Cylindrical Cavity

From Applied Energy:

Effect of different dimensional carbon materials on the properties and application of phase change materials: A review

Research roundup: Poly (methyl methacrylate) shell; calcium carbonate shell; macroscopic composite cement mortars; more

Ben Welter - Tuesday, March 19, 2019

From Energy Procedia:

Development of microencapsulated phase change material with poly (methyl methacrylate) shell for thermal energy storage
Supercooling study of erythritol/EG composite phase change materials
Thermal performance of pouch Lithium-ion battery module cooled by phase change materials
Active cooling based battery thermal management using composite phase change materials
Investigation on Thermal Performance of an Integrated Phase Change Material Blind System for Double Skin Facade Buildings
Experimental study on preparation of a novel foamed cement with paraffin/ expanded graphite composite phase change thermal energy storage material

From Colloids and Surfaces A: Physicochemical and Engineering Aspects:

Synthesis and performance evaluation of paraffin microcapsules with calcium carbonate shell modulated by different anionic surfactants for thermal energy storage

From Journal of Materials Chemistry A:

A novel shape-stabilization strategy for phase change thermal energy storage

From Journal of Molecular Liquids:

Melting of phase change materials in a trapezoidal cavity: Orientation and nanoparticles effects

From Energy and Buildings:

Development of new nano-enhanced phase change materials (NEPCM) to improve energy efficiency in buildings: lab-scale characterization

From Applied Sciences:

Efficient Characterization of Macroscopic Composite Cement Mortars with Various Contents of Phase Change Material

From Solar Energy:

Modelling and performance analysis of a new concept of integral collector storage (ICS) with phase change material

Research roundup: Personal cooling system; optimization of active wall system; cement mortar; asphalt pavement; more

Ben Welter - Friday, March 15, 2019

From International Journal of Refrigeration:

Experimental study of enhanced PCM exchangers applied in a thermal energy storage system for personal cooling

JMR illustration of microencapsulated n-octadecane with silk From Journal of Materials Research:

Fabrication and characterization of microencapsulated n-octadecane with silk fibroin–silver nanoparticles shell for thermal regulation

From IOP Conference Series: Earth and Environmental Sciences:

Simple Thermal Energy Storage Tank for Improving the Energy Efficiency of an Existing Air-conditioning System
An optimization study into thermally activated wall system with latent heat thermal energy storage
Simulation of operation performance of a solar assisted ground heat pump system with phase change thermal storage for heating in a rural building in Xi'an
Experimental Study on the Demand Shifting Effects of PCM Integrated Air-Conditioning Duct

From International Journal of Energy Research:

Efficiency optimisation of the thermal energy storage unit in the form of the ceiling panel for summer conditions

From Materials Research Express:

Experimental study on thermal conductivity of composite phase change material of fatty acid and paraffin

From Energies:

Design Optimization of a Hybrid Steam-PCM Thermal Energy Storage for Industrial Applications

From Construction and Building Materials:

Analysis of thermoregulation indices on microencapsulated phase change materials for asphalt pavement

From Applied Thermal Engineering:

Experimental and numerical characterization of an impure phase change material using a thermal lattice Boltzmann method

From Energy Conversion and Management:

Experimental and numerical study of a vertical earth-to-air heat exchanger system integrated with annular phase change material

From Materials:

Thermal and Structural Characterization of Geopolymer-Coated Polyurethane Foam—Phase Change Material Capsules/Geopolymer Concrete Composites

From Applied Sciences:

Microstructure and Mechanical Properties of Cement Mortar Containing Phase Change Materials

PCM briefing: Boston food bank installs Viking Cold TES system; 2-day workshop on microencapsulation

Ben Welter - Friday, March 08, 2019

The Greater Boston Food Bank is reporting a 75 percent reduction in energy use during targeted peak hours since the beginning of the year after installing a Viking Cold Solutions thermal energy storage system for the refrigeration units at its 117,000 square-foot, high-efficiency Yawkey Distribution Center.

Maria Telkes• To mark Women's History Month, 24/7 Wall St. has compiled a list of "50 Things You Never Knew Were Invented by Women." MIT researcher Maria Telkes, a pioneer in the field of solar thermal storage, is on the list at No. 30. She created the first solar-heated system for her home in Dover, Mass., in 1947. The system used a phase change material, sodium sulfate decahydrate, to store solar heat.

• Researchers at the Chinese Academy of Sciences say they have developed an inexpensive, flexible film that renders the objects it covers virtually invisible in infrared light. The film's main components are DuPont's Kevlar, a synthetic fiber with high tensile strength, and polyethylene glycol, a phase change material that can store heat. 

• French utility ENGIE has begun production at one of South Africa’s largest renewable energy projects, the 100MW Kathu Solar Park. The concentrated solar plant's molten salt storage system provides up to 4.5 hours of thermal energy storage.

• The Southwest Research Institute is hosting a two-day workshop on microencapsulation March 25-26 in San Antonio, Texas. The introductory course will cover topics such as atomization (spray drying, spray chilling, spray congealing) and spray coating (fluid bed coating, granulation). The cost is $950.

• The University of California is winning praise for its decision to end its subscription deal with Elsevier, the world’s biggest publisher of scientific journals. UC is the first major university system to push for open-access publishing. UC, which had been paying $11 million a year to Elsevier in subscription fees, generates about 10 percent of the research produced in the United States. “It’s ridiculous that, in this age of the internet, researchers are paying huge fees for access to academic papers and for publication of their own work,” the San Jose Mercury News said in a March 6 editorial.   

Research roundup: PCM wallboard; cement mortars; electric load shifting; red-mud geopolymer composite; more

Ben Welter - Wednesday, February 27, 2019

From Renewable Energy:

Phase Change Material Wallboard (PCMW) melting temperature optimisation for passive indoor temperature control

From Cement and Concrete Research:

Multiphysics analysis of effects of encapsulated phase change materials (PCMs) in cement mortars

From Journal of Molecular Liquids:

Preparation and characterization of sodium sulfate pentahydrate/sodium pyrophosphate composite phase change energy storage materials

From Energy and Buildings:

Performance of heat pump integrated phase change material thermal storage for electric load shifting in building demand side management
Indoor thermal comfort assessment using PCM based storage system integrated with ceiling fan ventilation: Experimental design and response surface approach

From International Journal of Photoenergy:

Experimental Study on the Performance of a Phase Change Slurry-Based Heat Pipe Solar Photovoltaic/Thermal Cogeneration System

From Solar Energy:

Effects of sodium nitrate concentration on thermophysical properties of solar salts and on the thermal energy storage cost
Red-mud geopolymer composite encapsulated phase change material for thermal comfort in built-sector [pdf]

From Energies:

A Novel Encapsulation Method for Phase Change Materials with a AgBr Shell as a Thermal Energy Storage Material

From Advanced Composites and Hybrid Materials:

Latent heat and thermal conductivity enhancements in polyethylene glycol/polyethylene glycol-grafted graphene oxide composites

From International Journal of Refrigeration:

Preparation and performance of form-stable TBAB hydrate/SiO2 composite PCM for cold energy storage

From Solar Energy Materials and Solar Cells:

Delignified wood/capric acid-palmitic acid mixture stable-form phase change material for thermal storage
Molten salt corrosion mechanisms of nitrate based thermal energy storage materials for concentrated solar power plants: A review

From Buildings:

Thermal Performance of Hollow-Core Slab Ventilation System with Macro-Encapsulated Phase-Change Materials in Supply Air Duct

From International Journal of Heat and Mass Transfer:

Heat transfer performance of the finned nano-enhanced phase change material system under the inclination influence

From Journal of the Electrochemical Society:

Effect of High Temperature Circumstance on Lithium-Ion Battery and the Application of Phase Change Material

From Energy:

High-temperature PCM-based thermal energy storage for industrial furnaces installed in energy-intensive industries

PCM mats helped lift Virginia Tech to first place in Solar Decathlon

Ben Welter - Monday, February 18, 2019

FutureHAUS, front elevation

The Virginia Tech team that won first place in the 2018 Solar Decathlon Middle East credits a good share of its success to the deft use of phase change material donated by Insolcorp LLC of New London, N.C.

FutureHAUS, the lone U.S. entry, topped 13 other finalists and more than 60 total entrants in the competition organized by the U.S. Department of Energy and the United Arab Emirates’ Dubai Electricity & Water Authority. Australia's University of Wollongong finished second. The finals took place in November in the desert heat of Dubai.

Insolcorp donated 400 square feet of two types of Infinite R PCM mats. Both are salt hydrates, one with a melt point of 21 degrees Celsius, the other a melt point of 22 degrees C. The phase change material acts as a thermal battery, absorbing and releasing thermal energy as it solidifies and melts.

The Virginia Tech team deployed the mats in the plenum of its 900-square-foot solar-powered house. The PCM allowed the team to take advantage of a rule that limited the use of solar energy to 8kw at any one time, with one exception: Unlimited use of solar energy for air conditioning was allowed during daily inspection periods to assure visitor comfort. The PCM mats, solidified during those periods, helped keep the house comfortable at other times. That helped the FutureHAUS achieve the highest score in net energy use, a key metric in the competition.

Joseph Wheeler, AIA"Every team struggled with the 8kw limit," said Joseph Wheeler, right, lead faculty on FutureHAUS and co-director of Virginia Tech's Center for Design Research. "Typically, during peak energy, you would be generating lots and lots of power, which you could easily charge your batteries with, which you could easily run all your tasks, and you could feed the grid, and build up quite a bit of surplus so that you would remain energy positive throughout the two weeks of competition.

"But, since they limited inverter use at any one time to 8kw, it really put a limit to what our energy budget was. We saw phase change as batteries. A massive ton of batteries. ... It's more of a strategy for a competition than it is for a realized situation. But in a realized situation, we know the value of the PCM. Heat energy, cost of power being cheaper at night than during the day where you can charge your systems and load shift. Practically, PCMs make a lot of sense. And we wanted to have the PCMs in this house for practical reasons, not just for competition reasons. ...

"In simple terms, we eased the demand for the HVAC every afternoon. It was the hottest time of the day and it was also the time when we were getting less power from the solar panels because the sun was moving down. It was a critical time because we knew that once the sun went down, we had to survive on battery. And we had a limit. They limited every house to 15kw of battery."

FutureHAUS, kitchenThe FutureHAUS team finished in the top three in eight of the competition's 10 categories: first place in Architecture, House Functioning and Sustainable Transportation; second place in Sustainability and Innovation; and third place in Engineering/Construction, Energy Efficiency and Comfort Conditions.

The FutureHAUS entry was a two-year university-wide effort. More than 100 Virginia Tech students helped design and build the structure, with help from faculty members in architecture, urban studies, science, engineering and other departments.

The house consists of 18 modular  "cartridges" built inside a Virginia Tech research facility. It was first assembled on campus in Blacksburg, Va., last summer. After testing, it was disassembled, shipped to Dubai and then reassembled at the competition site in just two days. It has since been shipped back to Blacksburg, where it will undergo testing to measure its various energy-saving components.

"We now have a system in place where we can collect data and can truly test the performance," Wheeler said. "We know the PCM worked for us during the competition because we did have some temperature sensors in the ceiling. And so we were able to prove that we were reaching the pre-state when those PCMs were being charged. But we really want to collect a lot more data and look at it in real-world situations."

Research roundup: Thermal conductivity; decarbonization potential of compact heat storage; liquid desiccant cooling systems; more

Ben Welter - Wednesday, February 06, 2019

From Energy:

Effects of thermal conductivity and density on phase change materials-based thermal energy storage systems

From Renewable Energy:

Melting process investigation of phase change materials in a shell and tube heat exchanger enhanced with heat pipe

From Applied Thermal Engineering:

Compact latent heat storage decarbonisation potential for domestic hot water and space heating applications in the UK
Numerical and experimental study of phase-change temperature controller containing graded cellular material fabricated by additive manufacturing
A novel composite phase change material with paraffin wax in tailings porous ceramics
Characterisation and evaluation of a new phase change enhanced working solution for liquid desiccant cooling systems
Thermal properties enhancement and application of a novel sodium acetate trihydrate-formamide/expanded graphite shape-stabilized composite phase change material for electric radiant floor heating

From Environmental Research:

Latent heat storage biocomposites of phase change material-biochar as feasible eco-friendly building materials

From Colloids and Surfaces A:

A facile microencapsulation of phase change materials within silicone-based shells by using glass capillary devices

From Microporous and Mesoporous Materials:

Phase change in modified metal organic frameworks MIL-101(Cr): Mechanism on highly improved energy storage performance

From Applied Energy:

Role of porous metal foam on the heat transfer enhancement for a thermal energy storage tube
Energy saving performance assessment and lessons learned from the operation of an active phase change materials system in a multi-storey building in Melbourne

From Building and Environment:

Comparative analysis of the PCM application according to the building type as retrofit system

From Construction and Building Materials:

Evaluation of the potential use of form-stable phase change materials to improve the freeze-thaw resistance of concrete

From Results in Physics:

Application Research of Nano-storage Materials in Cold Chain Logistics of E-commerce Fresh Agricultural Products

From Journal of Energy Storage:

Using PCM as energy storage material in water tanks: Theoretical and experimental investigation

Research roundup: Micro environmental control system; alkali nitrate salts; sodium thiosulfate pentahydrate; more

Ben Welter - Tuesday, January 22, 2019

From Journal of Thermal Science and Engineering :

Phase Change Material Freezing in an Energy Storage Module for a Micro Environmental Control System
Phase Change Material Melting in an Energy Storage Module for a Micro Environmental Control System

From Renewable Energy:

Form-stable oxalic acid dihydrate/glycolic acid-based composite PCMs for thermal energy storage
Molecular simulation of the structure and physical properties of alkali nitrate salts for thermal energy storage

From Applied Energy:

Effect of inclination on the thermal response of composite phase change materials for thermal energy storage

From Solar Energy Materials and Solar Cells:

Characterization and thermal performance of microencapsulated sodium thiosulfate pentahydrate as phase change material for thermal energy storage
Fabrication and applications of dual-responsive microencapsulated phase change material with enhanced solar energy-storage and solar photocatalytic effectiveness

From Energy:

Numerical investigations of optimal phase change material incorporated into ventilated walls

From Polymer Degradation and Stability:

EG-based coatings for flame retardance of shape stabilized phase change materials

From Construction and Building Materials:

Freeze-thaw performance of phase change material (PCM) incorporated pavement subgrade soil


Patent application: Radiative cooling with solar spectrum reflection

Ben Welter - Tuesday, January 22, 2019

U.S. patent application 20190017758 (applicant Board of Trustees of Stanford University, Stanford, Calif.):

"Aspects of the present disclosure are directed toward radiative cooling with solar spectrum reflection. In certain more specific embodiments, a structure facilitates far-field radiation at particular wavelengths while blocking radiation at solar wavelengths. Additionally, aspects of the present disclosure allow for twenty-four hour cooling of buildings and similar structures, and for cooling through a heat exchange to other liquid, gases, or solids. ... The heat exchange interface may further interface with phase-change materials either directly or indirectly to allow for thermal storage driven by the radiative properties of the plurality of different materials."

Research roundup: Solar storage tank; concentric PCM module; supercooling degree improvement; more

Ben Welter - Monday, January 21, 2019

From Journal of Thermal Science:

Energy Storage Performance of a PCM in the Solar Storage Tank

From International Journal of Applied Engineering Research:

Numerical assessment of suitability of phase-change materials in a concentric PCM-module for thermal storage applications [pdf]

From International Journal of Energy Research:

Experimental measurements and numerical computation of nanofluid and microencapsulated phase change material in porous material

From IOP Conference Series: Materials Science and Engineering:

Nano-enhanced phase change material effects on the supercooling degree improvement: A review

From Renewable Energy:

Potential of ventilation systems with thermal energy storage using PCMs applied to air conditioned buildings

From Journal of Mechanical Engineering and Technology:

Thermal performance analysis of nano enhanced paraffin wax and myristic acid

From Solar Energy:

Synthesis and characterization of microencapsulated phase change materials with comb-like acrylic co-polymer shell as thermal energy storage materials
Sensible and latent heat energy storage systems for concentrated solar power plants, exergy efficiency comparison

From Solar Energy Materials and Solar Cells:

Thermal energy storage characteristics of myristic acid-palmitic eutectic mixtures encapsulated in PMMA shell

From Thermal Science and Engineering Progress:

Parametric analysis and optimization of an underfloor solar assisted heating system with phase change materials

From International Journal of Heat and Mass Transfer:

The improved enthalpy-transforming based lattice Boltzmann model for solid-liquid phase change

From Applied Energy:

Innovative design of superhydrophobic thermal energy-storage materials by microencapsulation of n-docosane with nanostructured ZnO/SiO2 shell

From AIP Conference Proceedings:

Preparation and characterization of nanoparticle blended polymers for thermal energy storage applications