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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.




PCM battery shows promise in home heating system

Ben Welter - Tuesday, September 15, 2020

A home heating system equipped with a PCM battery put up encouraging numbers in a small trial in northern Italy earlier this year. The monthlong test “shows that is possible [for such a system] to supply the whole heating demand of a house reducing close to zero the costs,” says Domenico Feo, who developed the system. The full report, prepared by ThermaLink, a trademark of Sunservice Srl of Treviso, Italy, is available here.

ThermaCubeThe system is composed of a 6 kW solar array, an air/water heat pump and a thermal battery filled with BioPCM Q42, a biobased phase change material supplied by Phase Change Energy Solutions of Asheboro, N.C. A control unit, PCDCube, monitors temperatures and manages energy flow to optimize system performance. In an interview with Phase Change Matters, Feo answered questions about the heat battery, recently rebranded as ThermaCube.

Q: Thermal conductivity has proven to be a challenge in thermal energy storage across most types of PCM. Was conductivity an issue with the required charge/discharge cycles?

A: "As already known, the thermal conductivity of the PCM, especially of the organic one that we use, is low. This is, at the same time, a disadvantage and an advantage. The disadvantage has been minimized in using a heat exchanger made with a flat aluminum panel with the various layers just over 1 inch of distance; in this way we are able to make the entire volume of material work in a very efficient way. Vice versa this is an advantage for the very low heat losses during the non-work phases; in conditions of installations inside the buildings, the temperatures can be maintained for several days."

Q: If faster heat transfer is required, do you envision a redesign of the heat exchanger or a modification of the PCM to meet the demand of the energy transfer?

A: "As manufacturer, we can customize the heat exchanger dimensions and shape in order to achieve our goals, but as always in the industrial scalability, the quantities are mandatory for a good price. We designed a single heat exchanger dimension and multiply it in order to be able to produce the different storage capacities and realize a complete modular range. The transfer of energy can be however accelerated by increasing the flow rate of the fluid and the delta T between the fluid and the melting point, of course there is always a limit to this possibility. There are still studies around this point that need to be better understood."

Q: Would implementing several PCMs of different melting temperatures aid in the overall performance of the TES?

A: "Let's say that we expect a slight drop in performance at lower temperatures, but we don't have many other tests to give you a more general opinion."

Q: How is the PCM temperature measured throughout the entire storage to provide input to the PCDCube? Since the melting/solidification of PCM is not a homogenous process, are multiple measurements necessary to get a realistic status of the PCM?

A: "In the documents that we have published, we do not specify that we have installed two temperature probes, one in the center and another one near the walls and it is evident that, when the final phase of the  discharge of the PCM approaches, the perimeter probe shows a decrease of more sudden temperature than the central one. We, however, assume that the fact of having installed our thermal battery outside the building in a very cold climate, has exaggerated the heat loss despite the low heat transmission."

Q: Have you considered other PCM suppliers/products, since many are located in Europe and the RAL quality organization is based there?

A: "This is a possibility, at least for the distribution of our products in Europe and Asia. Currently we try to separate the supply of the case with exchangers (that we manufacture) from the PCM with direct purchase of the client from the supplier, especially in the larger units."

Q: What is the customer value proposition for this product? What is the expected return on investment/payback period?

A: "This is a $1 million question; the proposal is certainly into the growing wave of the storage market, even the electrical ones for PV systems. (A Tesla Powerwall is cool but not economically advantageous if you don’t pay attention at the payback that is higher than the life of the battery). The best value proposition is to separate production from the consumption of the energy and take advantage of renewable energies which, unfortunately, are linked to the day / night cycle and the outdoor temperature conditions. We see perfect the combination HP + Thermal Battery because we can concentrate the HP working hours during the best outdoor conditions that, for many reasons, are affecting and reducing the performances.  Furthermore, we also see a large market in the use of these thermal batteries in all these existing systems which are undersized or which, due to specific situations of changing use of the building, are no longer able to provide the necessary heating or cooling to the whole plant. About the ROI, this really varies a lot country by country because the cost of the electricity has different rates and peak hours schedules. The industrial needs are sometimes much more interesting and attractive than the residential ones."

Q: What are your plans for a commercial rollout?

A: "We are completing the Italian sales force and are looking for international distributors. Our goal is to propose the range of products at an international level with distribution agreements for the case only with exchangers; it will obviously be our responsibility to direct the partner to some reliable and high-quality PCM manufacturers. Obviously, those who will quickly give us the opportunity to build pilot plants, demonstrating the technology, will have an advantage in introducing them into the market and in the exclusivity of the contractual relationship."

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

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.

ACT is awarded a U.S. patent for PCM with tunable melt point

Ben Welter - Friday, January 10, 2020

Advanced Cooling Technologies of Lancaster, Pa., has been awarded a U.S. patent for a phase change material with a tunable melting point.

The hydration level of the PCM, a salt hydrate consisting primarily of salt and water, is altered to change the melting point to a desired set point using changes in humidity of the system.

“In an ARPA-E ARID funded program, we showed that you could change the melting point of salt hydrate phase change materials by changing the hydration levels of the salt hydrate in-situ,” Richard Bonner, ACT’s vice president for R&D, wrote in a LinkedIn post. “We also applied this technology to power plant cooling, where the seasonal variations in ambient temperature necessitate different melting points. Congratulations to the inventors: Dr. Ying Zheng, Dr. Chien-hua Chen, Dr. Howard Pearlman, and Dr. Fangyu Cao."

ACT worked with Lehigh University and the University of Missouri to develop the PCM. The idea was prompted by ACT’s interest in utilizing seasonal shifts in weather for the company’s day/night thermal storage application. A tunable melt point allows the PCM to be more easily solidified in cold and hot seasons.

The targeted melt temperatures in the project were from 25° C to 45° C for low-grade thermal energy storage, but could be extended to higher temperatures with other salt hydrates, the company said.

The project was funded, in part, with a $3.2 million ARPA-E ARID grant, awarded in 2015. ARID stands for "Advanced Research in dry Cooling." The project teams were challenged to "develop innovative, high-performance air-cooled heat exchangers and supplemental cooling systems and/or cool-storage systems" for use in thermoelectric power plants, to replace existing technologies that use a substantial amount of water to cool plant condensers.

The ARID project was completed in 2018. ACT's invention is now at the lab-scale testing phase. The most difficult hurdle, the company said, will be to scale up to commercialization level.  “From a manufacturing standpoint, shifting of the hydration level would require a large infrastructure for altering the humidity,” the company said.

“The concept could also be applied to the HVAC industry (building comfort) to provide day/night load shifting,” the company said, “as well as PCM synthesis and preparation for a consistent product. “

Sunamp's UniQ heat storage product earns RAL certification

Ben Welter - Monday, December 16, 2019

The RAL Quality Association PCM has awarded the RAL Quality Mark to Sunamp Ltd. for its UniQ line of thermal batteries.

RAL quality markThe product, which has been installed in thousands of homes across Europe, uses a specially formulated phase change material to store large amounts of energy from renewable and other sources and release it as heat to deliver hot water and space heating as needed. The PCM is sodium acetate trihydrate-based with a patented formulation giving a melt point of 58 degrees Celsius. 

In independent testing conducted by ZAE Bayern, the PCM was successfully melted and solidified in a UniQ heat battery for 10,000 cycles. At the end of the test, no significant differences in stored thermal energy capacity were found between the cycled samples and an uncycled sample of the PCM. The product, which also passed leak testing, earned the association's highest level of certification, Grade A. 

Over 3,000 UniQ units are now in service, with Sunamp projecting a tenfold growth in sales next year. The quality mark will be featured on Sunamp’s website and in other marketing materials, UniQ manuals and product labels.

“We are delighted that our thermally charged UniQ product range of heat batteries has been awarded a globally recognized mark of quality,” said Kate Fisher, Ph.D., a materials integration scientist at Sunamp, which is based in Edinburgh, Scotland. “RAL certification is a huge accolade and cements Sunamp’s position as world leaders at the forefront of the technology.”

Sunamp UniQ heat batteriesThe RAL Quality Association PCM was established in 2004 to develop standards for the PCM industry. Members include Axiotherm, Microtek Laboratories, Rubitherm, Croda Europe, va-Q-tec, PCM Technology, Global-Systems Europe, Sasol, Sunamp, Pluss Advanced Technologies and PureTemp LLC.

Members and non-members alike can submit their products to the association for independent testing and earn the RAL Quality Mark. To qualify for the mark, products and materials must meet standards for energy storage capacity and phase transition temperature and stability, as defined in RAL-GZ 896.

“I am delighted that more and more products with PCM technology can be awarded the RAL Quality Mark as meaningful and transparent proof of quality and longevity,” said Stefan Thomann, the association’s managing director. “The great thing about Sunamp´s UniQ heat batteries is that they can be installed and used in homes very easily and save a lot of energy costs and carbon emissions immediately. The fact that they passed more than 10,000 cycles make sure that users will be able to profit from these benefits for decades.”

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.

PCM briefing: Viking Cold is finalist for innovation award; Sonoco launches sustainable packaging initiative

Ben Welter - Friday, September 20, 2019

Viking Cold Solutions is a finalist for an Energy Storage of North America Innovation Award. The behind-the-meter thermal energy storage systems up for the award are part of an Eversource demand management program in Massachusetts. 

A thermal storage project in Northamptonshire, England, is expected to provide 47 new homes with hot water and heat via renewable energy sources such as solar power. The borehole technology, developed by Caplin Solar of Leicester, stores heat in the ground in warmer months for later use in colder periods.

• Packaging giant Sonoco of Hartsville, S.C., has announced the creation of its EnviroSense sustainable packaging initiative. EnviroSense products are designed to incorporate a number of elements associated with more sustainable packaging, including optimized package-to-product ratio; increased use of recycled and recyclable content; fiber sourcing; compostability; and the use of bio-based materials.

• Registration is open for Sonoco ThermoSafe's next Leading Minds Seminar, "Collaborative Learning that FUELS Your Temperature Sensitive Healthcare Products," to be held Nov. 14 in Amsterdam. The seminar is designed for European supply chain, logistics, quality and packaging professionals responsible for the protection and management of temperature sensitive healthcare clinical supplies and finished products. 

Hydrostor, a Canadian developer of advanced compressed air energy storage projects, has announced the closing of $37 million (USD) in growth financing. Hydrostor has three projects in operation or under construction in Canada and Australia 

• A projected tripling of heat-related deaths in the United Kingdom over the next 30 years will require a drastic rethinking of ways to cool buildings, a parliamentary select committee warns. “The risk of overheating in terms of minimising risks to health and safety of occupants should be enshrined into regulations for new build homes and retrofits," the Environmental Audit Committee said. "This should be considered alongside an integrated review of energy efficiency and ventilation, and be included in the government’s planned Future Homes Standard, to include improvement in the measurement of current and future overheating risk and prioritise passive cooling measures.”

• The most entertaining obituary of a self-taught chemist you will read this month. Rest in peace, Joe Heller.

PCM briefing: Glacier Tek sponsors wheelchair cyclists in Kenya fundraiser; CCT closer to commercializing silicon battery

Ben Welter - Monday, September 09, 2019

Dom Coleman, Regain trustee and grants officerGlacier Tek LLC of Minneapolis is sponsoring seven quadriplegic cyclists taking part in a fundraising ride in Kenya's Rift Valley next month. The Kenya Cycle Challenge 2019, organized by Regain, a U.K.-registered charity, is on track to raise 80,000 pounds to support quadriplegic athletes in Great Britain. More than 50 riders are expected to participate. The seven sponsored riders will be wearing PureTemp-powered Glacier Tek cooling vests to help them handle the 32º C heat they will likely encounter on the five-day ride. People with spinal cord injuries are vulnerable to heat stress because their bodies cannot send the signals needed to initiate sweating in response to hot conditions. 

• Heat battery manufacturer Sunamp Ltd. is among the exhibitors at the InstallerSCOTLAND trade show in Glasgow, Scotland, on Thursday.

CCT Energy Storage is on track to install its first commercial thermal energy device at a mobile phone base station in Adelaide, South Australia, before the end of the year following an agreement in principle with an Australian infrastructure provider. CCT unveiled its first 24kW device in March, describing it as the world’s first working thermal battery using silicon as a phase change material.  

• Hundreds of Australia’s most environmentally advanced homes will open their doors to visitors on Sunday, Sustainable House Day 2019. At least two of the homes – Farrell’s House in Narara, New South Wales, and the 10 Star Home in Cape Paterson, Victoria – feature phase change technology. More than 33,000 people visited 226 homes across Australia last year.  

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: