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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.

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INUTEQ donates hundreds of cooling vests to Dutch hospitals

Ben Welter - Monday, May 11, 2020

Hundreds of INUTEQ cooling vests developed for use by Dutch athletes at the Tokyo Olympics this summer have been donated for use in Dutch hospitals during the COVID-19 pandemic.

INUTEQ PCM pulloverThe PCM-equipped pullovers, designed to help athletes cope with heat stress, became available when the Tokyo Games were postponed until 2021. The pullovers can be worn under the heavy, heat-trapping protective gear used by doctors and nurses.

The pullovers are manufactured in Netherlands. The cooling material is Croda's CrodaTherm 21, a biobased PCM with a melting temperature of 21 degrees C. The 1.3-kg pullover is a simple "one-size-fits-most" garment, with two adjustable buckles and no fabric shell. 

“Doctors and nurses at the ICU, who are treating corona patients, can work comfortably for up to three hours longer thanks to this cooling vest," said Dr. Thijs Eijsvogels, physiologist at Radboud University Medical Center, Nijmegen. "The cooling vests ensure a stable body temperature, less sweating, maintenance of concentration and a faster recovery after each intensive work session.”

The pullover is marketed as "PCM CoolOver" on the INUTEQ website. It can be worn "under military combat gear, hazardous materials suits, mascot costumes and other professional apparel."   

https://inuteq.com/pcm-coolover-medical-nl/pcm-coolover-medical-eng/

Research roundup: Polythioether-based PCMS; alginate encapsulation; temperature stresses in concrete pavement; more

Ben Welter - Friday, May 08, 2020

From European Polymer Journal:

Extremely fast synthesis of polythioether based phase change materials (PCMs) for thermal energy storage

From Journal of Building Engineering:

Thermal behavior analysis of hollow bricks filled with phase-change material (PCM)

From Energies:

FEM Applied to Building Physics: Modeling Solar Radiation and Heat Transfer of PCM Enhanced Test Cells

From Iranian Polymer Journal:

Encapsulation of phase change materials with alginate modified by nanostructured sodium carbonate and silicate

From Energy & Fuels:

Aluminium ammonium sulfate dodecahydrate with multiple additives as composite phase change materials for thermal energy storage

From Materials Today: Proceedings:

Evaluation and reduction of temperature stresses in concrete pavement by using phase changing material
Optimization of Heat Energy Based on Phase Change Materials used in Solar Collector using Taguchi Method
Experimental and Theoretical Investigations on Thermal Conductivity of the Paraffin Wax using CuO Nanoparticles

From Journal of Energy Storage:

Novel synthesis of silica coated palmitic acid nanocapsules for thermal energy storage
Recent progress in phase change materials storage containers: Geometries, design considerations and heat transfer improvement methods
Effect of phase separation and supercooling on the storage capacity in a commercial latent heat thermal energy storage: Experimental cycling of a salt hydrate PCM
Energy efficiency optimization of the waste heat recovery system with embedded phase change materials in greenhouses: A thermo-economic-environmental study
Characterization of innovative mortars with direct incorporation of phase change materials

From Applied Thermal Engineering:

A trade study of a phase change system in a stratospheric airship based on a triple gasbag concept
Experimental evaluation of structural insulated panels outfitted with phase change materials
Lattice Boltzmann simulation of melting heat transfer in a composite phase change material

From Geothermics:

Parametric modeling and simulation of low temperature energy storage for cold-climate multi-family residences using a geothermal heat pump system with integrated phase change material storage tank

From Energy:

Multi-level uncertainty optimisation on phase change materials integrated renewable systems with hybrid ventilations and active cooling
A novel solar thermal system combining with active phase-change material heat storage wall (STS-APHSW): Dynamic model, validation and thermal performance

From Advances in Energy Research:

Theoretical Modeling of Phase Change Material-Based Space Heating Using Solar Energy

From Chemical Engineering Journal:

High latent heat and recyclable form-stable phase change materials prepared via a facile self-template method

From Composites Part B: Engineering:

In situ one-step construction of monolithic silica aerogel-based composite phase change materials for thermal protection

From Solar Energy:

Effects of external insulation component on thermal performance of a Trombe wall with phase change materials

From Journal of Architectural Engineering:

Experimental and Numerical Thermal Properties Investigation of Cement-Based Materials Modified with PCM for Building Construction Use

From Energy Conversion and Management:

Experimental and numerical study on the thermal performance of ventilated roof composed with multiple phase change material (VR-MPCM)

From Construction and Building Materials:

Multi-scale analysis on thermal properties of cement-based materials containing micro-encapsulated phase change materials

From Applied Energy:

D-mannitol@silica/graphene oxide nanoencapsulated phase change material with high phase change properties and thermal reliability
Novel bio-based phase change materials with high enthalpy for thermal energy storage

From Materials Today Energy:

A detailed review on heat transfer rate, supercooling, thermal stability and reliability of nanoparticle dispersed organic phase change material for low-temperature applications

From International Journal of Thermal Sciences:

Experimental study and assessment of high-tech thermal energy storing radiant floor heating system with latent heat storage materials

From Advanced Powder Technology:

Paraffin core-polymer shell micro-encapsulated phase change materials and expanded graphite particles as an enhanced energy storage medium in heat exchangers

Research roundup: Corn oil PCM in frozen food cooling machine; portable solar box cooker; expanded graphite/1-octadecanol composite; more

Ben Welter - Saturday, March 21, 2020

From Journal of Physics:

Corn oil phase change material (PCM) in frozen food cooling machine to improve energy efficiency

From Materials Today: Proceedings:

Investigating thermal properties of Nanoparticle Dispersed Paraffin (NDP) as phase change material for thermal energy storage

From Energy:

Effects of fluctuating thermal sources on a shell-and-tube latent thermal energy storage during charging process

From Solar Energy:

Design, realization, and tests of a portable solar box cooker coupled with an erythritol-based PCM thermal energy storage
Diversiform microstructure silicon carbides stabilized stearic acid as composite phase change materials

From International Journal of Thermofluids:

Investigating the performance of a thermal energy storage unit with paraffin as phase change material, targeting buildings’ cooling needs: an experimental approach

From Journal of Cleaner Production:

Energy and exergy analysis of wind farm integrated with compressed air energy storage using multi-stage phase change material

From Powder Technology:

Effect of nano-SiC on thermal properties of expanded graphite/1-octadecanol composite materials for thermal energy storage

From Journal of Energy Storage:

A multi-objective optimal design method for thermal energy storage systems with PCM: A case study for outdoor swimming pool heating application
Reducing PV module temperature with radiation based PV module incorporating composite phase change material
Numerical investigation on the effect of fin design on the melting of phase change material in a horizontal shell and tube thermal energy storage

From Journal of Thermal Analysis and Calorimetry:

Characterization of form-stable phase-change material for solar photovoltaic cooling

From International Journal of Thermophysics:

Thermophysical Properties of a Novel Nanoencapsulated Phase Change Material

From International Journal of Heat and Mass Transfer:

Lattice Boltzmann simulation of forced convection melting of a composite phase change material with heat dissipation through an open-ended channel
High power density thermal energy storage using additively manufactured heat exchangers and phase change material

From Energies:

Evaluation of the State of Charge of a Solid/Liquid Phase Change Material in a Thermal Energy Storage Tank [pdf]
Novel Simulation Algorithm for Modeling the Hysteresis of Phase Change Materials [pdf]

From Energy & Fuels:

Novel shape-stabilized phase change materials based on paraffin/EPDM@graphene with high thermal conductivity and low leakage rate

From Polymers and Polymer Composites:

Regulating phase-change temperatures of form-stable phase-change ternary composite fibrous membranes consisting of polystyrene nanofibers and fatty acid eutectics via co-electrospinning method

From Applied Energy:

A design protocol for enhanced discharge exergy in phase change material heat battery
Fabrication of heat storage pellets composed of microencapsulated phase change material for high-temperature applications
A high-thermal-conductivity, high-durability phase-change composite using a carbon fibre sheet as a supporting matrix

From Journal of Building Engineering:

Preparation and characterization of metal-organic framework /microencapsulated phase change material composites for indoor hygrothermal control

From Indoor and Built Environment:

Numerical and experimental investigation on dynamic thermal performance of floor heating system with phase change material for thermal storage

From Applied Clay Science:

A triply synergistic method for palygorskite activation to effectively impregnate phase change materials (PCMs) for thermal energy storage

From Chemical Engineering Journal:

Lignin-fatty acid hybrid nanocapsules for scalable thermal energy storage in phase-change materials

From Construction and Building Materials:

Phase change materials for pavement applications: A review

From Carbohydrate Polymers:

Shape-stabilization of polyethylene glycol phase change materials with chitin nanofibers for applications in “smart” windows

PCM briefing: Ice Energy files for bankruptcy; Viking Cold has opening for thermal engineer

Ben Welter - Monday, February 10, 2020

Ice Energy, the Santa Barbara, Calif., company that made and distributed ice-based thermal energy storage systems, has filed for bankruptcy. The company's Ice Bear system makes ice at night when demand for electricity is low and capacity is abundant. During the day, the stored ice is used to provide cooling. Details of the Chapter 7 bankruptcy, filed in December, are sparse. The company's website is no longer active. Over the years, Ice Energy had won several major energy storage and distribution contracts with utilities, and had begun marketing a smaller version of the Ice Bear system aimed at retail customers. 

Viking Cold Solutions has an opening for a chemical/thermal engineer in Houston. The engineer will "conduct research in Thermal Science, Storage/Heat Transfer and Phase Change Materials (PCM) for low temperature applications (<10⁰C)."

Axiom Exergy has secured more than $1 million in orders for the Axiom Cloud, a software platform that helps manage energy consumption in supermarkets and cold storage facilities that use the company's PCM-powered thermal storage systems.

• The 2020 Advancements in Thermal Management conference, to be held Aug. 6-7 in Denver, has issued a call for presentations. Topics include thermal materials, thermal modeling and characterization and measurement of thermal materials. Abstracts are due Feb. 12.

EnergyNest will install a large thermal energy storage battery at a Senftenbacher brick factory in Austria. The system will temporarily store excess energy in the form of hot air from a tunnel furnace. The stored heat be converted to steam and later reused in production.

Devan Chemicals, the Belgium-based developer of finishing technologies for textiles, introduced its Tones of Cool Bio technology at the Heimtextil trade show in Frankfurt, Germany, last month. The technology "stimulates the textile to dissipate redundant heat from the body and to instantly reduce the body temperature," the company says. The phase change materials "are derived from sustainable, natural sources.

Registration is open for the 23rd Microencapsulation Industrial Convention to be held June 8-11 in Rotterdam, Netherlands.

Research roundup: Carbonized waste tires; cetyl palmitate/nickel foam; hydrated salt corrosion assessment; more

Ben Welter - Tuesday, January 14, 2020

From Waste Management:

Evaluation of carbonized waste tire for development of novel shape stabilized composite phase change material for thermal energy storage

From Journal of Energy Storage:

Development of polyurethane foam incorporating phase change material for thermal energy storage
Facile synthesis and thermal performance of cetyl palmitate/nickel foam composite phase change materials for thermal energy storage
Optimal sizing design and operation of electrical and thermal energy storage systems in smart buildings

From Energy Conversion and Management:

Numerical investigation of the effects of the nano-enhanced phase change materials on the thermal and electrical performance of hybrid PV/thermal systems
Thermal storage and thermal management properties of a novel ventilated mortar block integrated with phase change material for floor heating: an experimental study

From Applied Energy:

Wood-based composite phase change materials with self-cleaning superhydrophobic surface for thermal energy storage

From Renewable Energy:

Corrosion assessment of promising hydrated salts as sorption materials for thermal energy storage systems
Experimental study on latent thermal energy storage system with gradient porosity copper foam for mid-temperature solar energy application
Selection of a phase change material and its thickness for application in walls of buildings for solar-assisted steam curing of precast concrete
Experimental assessment of Phase Change Material (PCM) embedded bricks for passive conditioning in buildings

From Applied Thermal Engineering:

Analysis of energy retrofit system using latent heat storage materials applied to residential buildings considering climate impacts
Experimental and numerical simulation of phase change process for paraffin/expanded graphite/ethylene-vinyl acetate ternary composite
An experimental investigation on the evaporation of polystyrene encapsulated phase change composite material based nanofluids

From Solar Energy Materials and Solar Cells:

Lightweight mesoporous carbon fibers with interconnected graphitic walls for supports of form-stable phase change materials with enhanced thermal conductivity

From Energies:

The Effects of Fin Parameters on the Solidification of PCMs in a Fin-Enhanced Thermal Energy Storage System

From Journal of Materials Science:

Graphene aerogel-based phase changing composites for thermal energy storage systems

From Journal of Mechanical Science and Technology:

A study on development of the thermal storage type plate heat exchanger including PCM layer

From Journal of Power Sources:

Delayed liquid cooling strategy with phase change material to achieve high temperature uniformity of Li-ion battery under high-rate discharge

From Scientific Reports:

Modification of asphalt mixtures for cold regions using microencapsulated phase change materials

From ASES National Solar Conference:

A Study on the Thermal Energy Storage System Using Multiple PCMs [pdf]

From Molecules:

Assessment of Thermal Performance of Textile Materials Modified with PCM Microcapsules Using Combination of DSC and Infrared Thermography Methods

From Energy and Buildings:

Experimental study on thermal performance of a mobilized thermal energy storage system: A case study of hydrated salt latent heat storage

From Chemical Engineering Journal:

Shape-stabilized hydrated salt/paraffin composite phase change materials for advanced thermal energy storage and management

From International Journal of Heat and Mass Transfer:

A conjugate heat transfer model for unconstrained melting of macroencapsulated phase change materials subjected to external convection

Research roundup: Passive cooling in buildings; honeycomb carbon fibers; leak-free aggregates; more

Ben Welter - Monday, October 14, 2019

From Applied Energy:

Passive cooling through phase change materials in buildings. A critical study of implementation alternatives

From Applied Thermal Engineering:

Honeycomb carbon fibers strengthened composite phase change materials for superior thermal energy storage

From e-Polymers:

Fabrication and characterization of conductive microcapsule containing phase change material

From Construction and Building Materials:

Preparation and characterization of nano-SiO2/paraffin/PE wax composite shell microcapsules containing TDI for self-healing of cementitious materials
Development of leak-free phase change material aggregates
Behavior of cementitious mortars with direct incorporation of non-encapsulated phase change material after severe temperature exposure

From Advanced Functional Materials:

Engineering the Thermal Conductivity of Functional Phase‐Change Materials for Heat Energy Conversion, Storage, and Utilization

From Journal of Energy Storage:

A numerical investigation of the effects of metal foam characteristics and heating/cooling conditions on the phase change kinetic of phase change materials embedded in metal foam
Applications of combined/hybrid use of heat pipe and phase change materials in energy storage and cooling systems: A recent review
Innovative composite sorbent for thermal energy storage based on a SrBr2·6H2O filled silicone composite foam

From ACS Applied Nano Materials:

Concentrated Ag Nanoparticles in Dodecane as Phase Change Materials for Thermal Energy Storage

From Materials Research Express:

Preparation of 1-dodecanol microcapsules with cellulose nanofibers-modified melamine-formaldehyde resin as a potential phase change material

From IOP Conference Series: Earth and Environmental Science:

Optimisation of Parameters in Thermal Energy Storage System by Enhancing Heat Transfer in Phase Change Material

From International Journal of Heat and Mass Transfer:

Thermal transport properties at interface of fatty acid esters enhanced with carbon-based nanoadditives

From Journal of Solar Energy Engineering:

Using a Novel Phase Change Material-Based Cooling Tower for a Photovoltaic Module Cooling

From Solar Energy:

Experimental investigation on micro-scale phase change material based on sodium acetate trihydrate for thermal storage

From RSC Advances:

A novel forced separation method for the preparation of paraffin with excellent phase changes

From Energy Conversion and Management:

Experimental characterisation of a novel thermal energy storage based on open-cell copper foams immersed in organic phase change material

PCM briefing: Acumen invests in Promethean Power Systems; Viking Cold wins Cleanie award

Ben Welter - Monday, October 14, 2019

• Social venture capital investor Acumen has invested an undisclosed amount in Promethean Power Systems Inc., which makes PCM-based refrigeration systems for cold-storage and milk chilling applications in off-grid and partially electrified areas of developing countries. Jiten Ghelani, chief executive of Promethean, which is based in Boston, Mass., and Pune, India, said the investment would help the company accelerate the adoption of its products across India and other markets, and also expand its cooling-as-a-service offerings. 

Air New Zealand pillow• Two new consumer products featuring temperature-control fabrics from Outlast Technologies hit the market recently: A pillow designed to improve the quality of sleep for passengers on Air New Zealand's long-haul flights and a Calloway pullover designed to keep golfers cool in warm weather and warm in cold weather

Viking Cold Solutions of Houston, Texas, won a Platinum Cleanie Award last month for a PCM-based storage and demand management project in Massachusetts. The Cleanie Awards, presented at this year's North America Smart Energy Week in Salt Lake City, Utah, recognize companies and individuals shaping the clean-tech and renewable energy industries. The Viking Cold project involved the installation and commissioning of TES systems to store refrigeration energy and facilitate 1.3 MW of energy demand reduction across eight customer facilities, including the Greater Boston Food Bank.

Sonoco ThermoSafe of Arlington Heights, Ill., has introduced a new temperature-controlled box rental service. "The new Orion r product line is based on the existing ChillTech product," said Ben VanderPlas, manager of engineering and product management at Sonoco. "We’ve made changes to make the product more reusable (added EPP) and have increased the VIP insulation. The PCMs remain the same, using paraffin-based materials. ChillTech was developed by Laminar Medica in the UK prior to their acquisition and integration into the ThermoSafe business. Solutions will exist for 2-8, 15-25 and frozen temperatures."

Sonoco ThermoSafe has posted an opening for a Senior Account Manager Europe, to be based in Netherlands.

Microtek Laboratories Inc. of Dayton, Ohio, has introduced a new line of PCM-equipped pouches and panels for use in temperature-controlled shipping.

Research roundup: Mesoporous silica; nanoencapsulation of oleic acid PCM; flexible crosslinking; more

Ben Welter - Friday, September 20, 2019

From International Journal of Energy Research:

Facile functionalized mesoporous silica using biomimetic method as new matrix for preparation of shape‐stabilized phase‐change material with improved enthalpy
Binary mixtures of fatty alcohols and fatty acid esters as novel solid‐liquid phase change materials

From Journal of Applied Polymer Science:

Phase change material with flexible crosslinking for thermal energy storage

From Journal of Thermal Analysis and Calorimetry:

Nanoencapsulation of oleic acid phase change material with Ag2O nanoparticles-based urea formaldehyde shell for building thermal energy storage

From Renewable Energy:

Enhanced properties of diatomite-based composite phase change materials for thermal energy storage

From Energy:

Perspectives for short-term thermal energy storage using salt hydrates for building heating
Design and construction of mesoporous silica/n-eicosane phase-change nanocomposites for supercooling depression and heat transfer enhancement
Numerical investigations on performance of phase change material Trombe wall in building

From Energy and Buildings:

Potential of energy flexible buildings: evaluation of DSM strategies using building thermal mass
Numerical analysis in a full-scale thermal energy storage tank with dual PCM capsules

From Applied Thermal Engineering:

Experimental determination and fractal modeling of the effective thermal conductivity of autoclave aerated concrete (AAC) impregnated with paraffin for improved thermal storage performance
Preparation and characterization of new nano-particle mixed as thermal storage material
Numerical investigation on integrated thermal management for a lithium-ion battery module with a composite phase change material and liquid cooling

From Chemical Engineering Journal:

Fatty Amines/Graphene Sponge Form-Stable Phase Change Material Composites with Exceptionally High Loading Rates and Energy Density for Thermal Energy Storage

From MATEC Web of Conferences:

Thermal conductivity of aerated concrete (AC) composites containing micro-encapsulated phase change materials [pdf]
Overheating mitigation in buildings: a computational exploration of the potential of phase change materials [pdf]

From Solar Energy:

Experimental study on the thermal performance of capric acid-myristyl alcohol/expanded perlite composite phase change materials for thermal energy storage

From Solar Energy Materials and Solar Cells:

Graphitization as efficient inhibitor of the carbon steel corrosion by molten binary nitrate salt for thermal energy storage at concentrated solar power
A strategy for designing microencapsulated composite phase change thermal storage materials with tunable melting temperature

From Institute of Electronics and Information Engineers 2019 Summer Conference:

Thermal Management System in Electric vehicle Battery Pack Using Phase Change Material

From Materials Chemistry and Physics:

Preparation and thermal properties of n-eicosane/nano-SiO2/expanded graphite composite phase-change material for thermal energy storage

From Sustainable Cities and Society:

Simulative optimization on energy saving performance of phase change panels with different phase transition temperatures

From Thermochimica Acta:

The stability and thermophysical properties of a thermal fluid containing surface-functionalized nanoencapsulated PCM

From International Journal of Heat and Mass Transfer:

Functionalized mesoporous silica as matrix for shape-stabilized phase change materials

From Applied Energy:

Synthesis and characterization of microencapsulated sodium sulfate decahydrate as phase change energy storage materials

From Energy Conversion and Management:

Prototype latent heat storage system with aluminum-silicon as a phase change material and a Stirling engine for electricity generation

From Journal of Solar Energy Engineering:

Experimental Investigation and Numerical Modeling of Room Temperature Control in Buildings by the Implementation of Phase Change Material in the Roof
Suitability Assessment and Experimental Characterization of Phase Change Materials for Energy Conservation in Indian Buildings

Research roundup: Corrosion effect of Micronal PCMs; photovoltaic-thermal system optimization; diatomite-based composite; more

Ben Welter - Monday, September 09, 2019

From Renewable Energy and Sustainable Buildings:

Study of Corrosion Effect of Micronal® Phase Change Materials (PCM) with Different Metal Samples
Use of Phase Change Materials for Solar Systems Applications
Performance Optimization of Concentrated Photovoltaic-Thermal (CPV-T) System Employing Phase Change Material (PCM) in Hot Climate

From Asia International Symposium on Mechatronics:

Investigation for a Phase Change Immersion Cooling System

From Energy Conversion and Management:

Experimental study of active phase change cooling technique based on porous media for photovoltaic thermal management and efficiency enhancement

From Renewable Energy:

Enhanced properties of diatomite-based composite phase change materials for thermal energy storage
Hybrid thermal energy storage with phase change materials for solar domestic hot water applications: Direct versus indirect heat exchange systems

From Journal of Applied Polymer Science:

Surface modification of MWCNT and its influence on properties of paraffin/MWCNT nanocomposites as phase change material

From Energy and Buildings:

Energy and emissions analysis of ice thermal energy storage in the western US
Thermal energy storage characterization of cementitious composites made with Recycled Brick Aggregates containing PCM

From Solar Energy:

Innovative passive heat-storage walls improve thermal performance and energy efficiency in Chinese solar greenhouses for non-arable lands

From Construction and Building Materials:

Development of structural thermal energy storage concrete using paraffin intruded lightweight aggregate with nano-refined modified encapsulation paste layer

From Applied Energy:

A comprehensive review on positive cold energy storage technologies and applications in air conditioning with phase change materials

From International Journal of Energy Research:

Preparation and characterization of nano‐enhanced myristic acid using metal oxide nanoparticles for thermal energy storage
Performance comparison of different combined heat and compressed air energy storage systems integrated with organic Rankine cycle

From xPRESS Polymer Letters:

Editorial corner – a personal view / Thermal management with polymer composites

From International Symposium on Asphalt Pavement & Environment:

Impregnation of Lightweight Aggregate Particles with Phase Change Material for Its Use in Asphalt Mixtures

From Journal of Sol-Gel Science and Technology:

Development of new inorganic shape stabilized phase change materials with LiNO3 and LiCl salts by sol-gel method

From Advanced Functional Materials:

Functional Soft Composites As Thermal Protecting Substrates for Wearable Electronics

PureTemp shows energy-saving potential in EnergyPlus simulations

Ben Welter - Wednesday, August 28, 2019

In EnergyPlus simulations using hysteresis data, the integration of PureTemp phase change materials in a building's suspended ceiling tiles showed potential savings in cooling energy ranging from 5.5 percent to 37.4 percent.

Ceiling tile drawingThe PCM modeling research, conducted at University of Manitoba, also found a reduction in "discomfort hours" from 10 percent to 29 percent, depending on the zone and PCM type.

The researchers set out to investigate the feasibility of integrating PCMs within a suspended ceiling using the hysteresis method in EnergyPlus 8.9. The hysteresis effect, wherein a PCM has different melting/freezing temperature curves, complicates the simulation of PCM use in buildings. The EnergyPlus modeling software was updated in 2017 to include the effect of hysteresis.

Minneapolis-based PureTemp LLC provided the researchers with the thermo-physical properties of PCMs required for modeling in EnergyPlus. Five types of PCMs, namely PCM20 (PureTemp 20), PCM21, PCM22, PCM23 (PureTemp 23), and PCM24, were tested and analyzed. The melting and freezing temperatures of the five PCMs fall within the thermal comfort range and operation of the HVAC system of the building the researchers chose as a case study: the University of Manitoba's new Stanley Pauley Engineering Building.

Miroslava KavgicThe number of each PCM represents the material's peak melting temperature in degrees Celsius. The theoretical properties of PCM21, PCM22 and PCM24 were derived from the actual properties of PureTemp 20, PureTemp 23 and PureTemp 25.

One of the study's authors, Dr. Miroslava Kavgic, right, is an assistant professor of civil engineering at the university. She answered questions about the research by email.

Q: What do you think is the most important finding, as far as impact on manufacturers of PCMs and PCM products?

A: "The findings of our research study suggest a promising future for the applications of PCMs in buildings located in cold climates. Furthermore, our study showed that in addition to already proven cooling energy-saving potential, PCMs can be very efficient in reducing heating energy demand. As a result, the findings from our study can increase application of PCMs in buildings located in the dominant heating climates, and therefore increase the demand for these unique building materials. We also hope that higher demand for PCMs will bring down their price which currently hinders the more extensive application of PCMs in areas with the lower energy prices such as Manitoba."

Q: Why did you choose to use PureTemp data? Was there a preference to use a biobased PCM? Or was data on other products hard to obtain?

EnergyPlus model: enthalpy-temperature method
EnergyPlus PCM model, enthalpy-temperature method
A: "PureTemp shares valuable thermo-physical properties of its PCM products on its website. Furthermore, upon our request PureTemp provided additional information required for the modeling of PCMs in EnergyPlus using hysteresis method. PureTemp also provides other useful information related to various applications and experimental testing of PCMs. Finally, PureTemp’s PCM products are produced from agricultural sources, and they are readily biodegradable and non-toxic. These positive characteristics of the PureTemp’s PCM products can enable the development of environmentally friendly solutions that can significantly reduce buildings’ energy consumption while improving their indoor thermal comfort."

Q: Given the impact of a PCMs hysteresis the final simulation results, is there a standard you’d like the industry to establish for consistent data from the PCM manufacturers?

EnergyPlus model: hysteresis method
EnergyPlus PCM model, hysteresis method

A: "Consistent data from the PCM manufacturers would increase confidence in the modeling results, and this applies to both hysteresis and temperature-enthalpy methods. Moreover, the consistent PCM properties could also be beneficial for the manufacturers as they will allow the end-user to test multiple PCMs and purchase several different materials for real-world implementation. This is particularly important considering the need for numerical analysis before the real-world implementation due to both complex behavior of PCMs and their relatively high price. The sensitivity analysis of the hysteresis input parameters suggests that manufacturers should pay partial attention to the parameters that have high impact on the simulation results."

Q: For future work, is there interest in comparing the same PCM measured with different methods, such as T-history and DSC?

A: "The t-history method is relatively inexpensive and straightforward to measure the phase-change enthalpy of PCM products using considerably larger sample sizes compared to DSC, and therefore for non-uniform PCMs it is a good testing alternative to DSC."

Table 3. Thermo-physical properties of the tested PCM:

Hysteresis properties PCM20 PCM21 PCM22 PCM23 PCM24
Latent heat during the entire phase change process (J/kg) 171,000 189,000 208,000 227,000 207,000
Peak melting temperature (°C) 20 21 22 23 24
Peak freezing temperature (°C) 18 19 20 21 22
Liquid-state thermal conductivity (W/(m∙K)) 0.14 0.143 0.146 0.15 0.15
Solid-state thermal conductivity (W/(m∙K)) 0.23 0.236 0.243 0.25 0.25
Liquid-state density (kg/m3) 680 730 780 830 840
Solid-state density (kg/m3) 950 936 923 910 930
Liquid-state specific heat (J/(kg∙K)) 2150 2096 2043 1990 2140
Solid-state specific heat (J/(kg∙K)) 2070 1993 1916 1840 1915

 

The full version of the paper is available here through the end of September 2019:

https://authors.elsevier.com/a/1ZZ3u4r6KuzlE4