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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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New dorm at Massachusetts college features 18,000+ square feet of PCM mats

Ben Welter - Thursday, August 15, 2019

Garfield passive house elements

A new dormitory at Williams College in Massachusetts is equipped with 18,200 square feet of mats filled with phase change material.

Garfield House, completed in time for the first students to move in this month, is designed to achieve Passive House PHIUS+ certification and LEED Gold certification. It features R-38 walls, R-60 roofs, triple-pane windows, high-efficiency energy recovery ventilation units, drainwater heat recovery and a 50 kw photovoltaic array.

The Infinite R PCM mats, made by Insolcorp LLC of New London, N.C., will help keep the passively cooled building comfortable when the weather is warm. The PCM is a salt hydrate with a peak melting point of 73 degrees F and a thermal storage capacity of about 170 joules per gram. The mats are deployed within Garfield's interior walls and above ceilings.

Jacob Higginbottom Jacob Higginbottom, director of higher education design at SGA Architects in Boston, was project manager. He first learned about the potential use of phase change material in building envelopes and interiors in March 2018.

"A member of our team had run across the Infinite R product at a trade show and our client was looking for ways to introduce passive cooling techniques since it’s their campus standard to build residence halls without active cooling," said Higginbottom, right. "Upon research we convinced the client that this could help and they decided to give it a try."

Garfield House has no active cooling system. Did that present any special challenges?

"The fact that Garfield did not have cooling wasn’t necessarily a challenge for the PCM, but perhaps was more of an opportunity for the project itself," said Mick Dunn, Insolcorp president. "The project wasn’t without a cooling source altogether. The design team implemented well-designed ERV/ventilation to leverage cool overnight temperatures. As part of the Passive House design process, some issues were identified with cooling and being able to maintain comfort without the introduction of A/C. So we worked with them to analyze a suitable amount of PCM to help address that cooling issue and help negate the need for investment in mechanical cooling other than ventilation.

"We’ve had numerous applications where the PCM has been used with no active cooling. Most of these have been very large industrial applications where the PCM has been used to control peak plant temperatures in buildings with very high internal heat loads. The results have been very good, and we’ve seen reductions as much as 10 to 15F compared with baseline temps. Sometimes we’ll be using a higher temp PCM to promote natural re-freezing. In more conventional occupied office/housing applications we’d typically still be looking for some kind of mechanical cooling mechanism such as ventilation if air conditioning is not present. And we’d probably be more likely to consider this as a viable strategy in climates such as California or New England than say Florida where humidity and overnight temperatures are very high."

The engineering firm Thornton Tomasetti of New York conducted whole building energy modeling in WUFI Passive, the program required by the Passive House Institute US (PHIUS). The models project cooling demand of 0.74 kBtu per square foot per year and a cooling load of 1.64 Btu per hour per square foot. A PCM thermal simulation model projects a peak cooling reduction of 10 degrees F.

Will the building's actual performance be measured against these metrics in the first year of occupancy?

Elsa Mullin, senior sustainability consultant at Thornton Tomasetti, says PHIUS "does not require post-occupancy measurement and verification after initial occupancy."

Higginbottom said LEED certification for the design portion is completed. All construction requirements have been submitted and he expects a LEED Gold certificate from the U.S. Green Building Council by the end of the month.

He said the use of PCM won't be a factor in the certification process.

"A building like this can easily achieve LEED Gold without the use of this material," he said. "PCM was introduced to address thermal comfort. Active cooling does not dramatically affect the building energy consumption in a use type like this (most loads come from domestic HW and plug loads and ventilation fans which are still required irrespective of cooling design)."

It's the first time Higginbottom has used PCM in a project. He hopes to use it in future projects.

"The interesting part about this product is the ability to fine-tune a building towards net zero or net positive and also to flatten out the demand for cooling and possibly downsize equipment in the future and save money on operating and up front costs," he said. "We would like to have more research to back that up, but it’s a speculation on our part that this would be a benefit to building owners’ first costs and life-cycle costs."

Patent application: PCM-based enhancement for reversed-cycle defrosting

Ben Welter - Thursday, July 25, 2019

U.S. patent application 20190226735 (applicant Sunamp Ltd., Lothian, Great Britain):

"A thermal energy storage system in the form of a reverse-cycle defrosting vapour compression system suitable for use with systems adapted to transfer heat from at least one heat source to at least one heat sink (heat transfer system), wherein said thermal energy storage system comprises: at least two thermal energy storage units; said thermal energy storage units comprise a thermal store comprising a heat exchanger with the storage units comprising a primary coil and a secondary coil; the primary coil is dedicated for use with refrigerant fluids and is adapted for inter-connection to both a condenser and a pressure-lowering device for use with a heat transfer system; the secondary coil is dedicated for use with heat transfer fluids and wherein said secondary coils are adapted to exchange heat with the phase change material in each thermal storage unit; said primary and secondary coils are surrounded by a suitable phase change material."

http://www.freepatentsonline.com/20190226735.pdf

Research roundup: Diatomite‐based hydrated salt composites; zinc oxide coating of hermetically encapsulated paraffins; more

Ben Welter - Thursday, July 25, 2019

From International Journal of Energy Research:

Design of diatomite‐based hydrated salt composites with low supercooling degree and enhanced heat transfer for thermal energy storage

From Journal of Physical Chemistry B:

Clusters in Liquid Fatty Acids: Structure and Role in Nucleation

From Construction and Building Materials:

Development of thermal energy storage lightweight structural cementitious composites by means of macro-encapsulated PCM
Preparation of microencapsulated phase change materials used graphene oxide to improve thermal stability and its incorporation in gypsum materials

From Journal of Power and Energy:

Numerical modelling of phase change material melting process embedded in porous media: Effect of heat storage size

From Advanced Materials Interfaces:

Phase Change Materials: Doubly Coated, Organic–Inorganic Paraffin Phase Change Materials: Zinc Oxide Coating of Hermetically Encapsulated Paraffins

From NASA Technical Reports Server:

Utilization of Micro Tube Heat Exchanger for Next Generation Phase Change Material Heat Exchanger Development

From SN Applied Sciences:

Encapsulation of paraffin wax by rigid cross-linked poly (styrene divinylbenzene-acrylic acid) and its thermal characterization

From Energy Conversion and Management:

Transient performance of a Peltier super cooler under varied electric pulse conditions with phase change material

From Applied Thermal Engineering:

Thermal optimization of a kirigami-patterned wearable lithium-ion battery based on a novel design of composite phase change material
An experimental and theoretical study of the solidification process of phase change materials in a horizontal annular enclosure

From Journal of Energy Storage:

Enhancement of the thermal energy storage capacity of a parabolic dish concentrated solar receiver using phase change materials

From Renewable Energy:

Numerical simulation on the thermal performance of a PCM-containing ventilation system with a continuous change in inlet air temperature

From Energy Fuels:

Graphene modified hydrate salt/UV-curable resin form-stable phase change materials: continuously adjustable phase change temperature and ultrafast solar-to-thermal conversion

From Journal of Industrial and Chemical Engineering:

Thermal performance enhancement of a phase change material with expanded graphite via ultrasonication

From Chemistry Select:

Microencapsulation of Stearic Acid into Strontium Titanate Shell by Sol‐Gel Approach for Thermal Energy Storage

Patent application: Method for making PCM products and system therefor

Ben Welter - Thursday, July 18, 2019

U.S. patent application 20190217553 (inventor Peter Horwath, New London, N.C.):

Horwath patent drawing"A method for processing phase change material includes providing pieces of phase change material having a transition temperature, the pieces of phase change material being in a solid phase. A medium is provided which is transformable from a liquid state to a solid state, the medium is in the liquid state and at a temperature which is below the transition temperature of the pieces of phase change material. The pieces of phase change material are combined with the medium to form a mixture. The mixture is supplied to a tool which forms a phase change material product. The medium is then transformed to the solid state."

http://www.freepatentsonline.com/20190217553.pdf

Research roundup: Thermally conductive HDPE; pentaerythritol; RT44HC; epoxy resin composites; more

Ben Welter - Thursday, July 18, 2019

From Journal of Applied Polymer Science:

Thermally conductive high-density polyethylene as novel phase-change material: Application-relevant long-term stability
Reliable phase‐change polyurethane crosslinked by dynamic ionic‐bond crosslinking for thermal energy storage

From International Journal of Heat and Mass Transfer:

A molecular dynamics study of the effects of crystalline structure transition on the thermal conductivity of pentaerythritol as a solid-solid phase change material
A comparative study of the effect of varying wall heat flux on melting characteristics of phase change material RT44HC in rectangular test cells
High thermal response rate and super low supercooling degree microencapsulated phase change materials (MEPCM) developed by optimizing shell with various nanoparticles

From Materials Research Express:

Evaluation of thermophysical properties of shaped inorganic hydrated salt-based phase change materials for wall energy storage

From Construction and Building Materials:

Measurement and analysis of thermophysical parameters of the epoxy resin composites shape-stabilized phase change material
Thermal enhanced cement-lime mortars with phase change materials (PCM), lightweight aggregate and cellulose fibers

From Energy and Buildings:

Properties of concretes enhanced with phase change materials for building applications

From Hong Kong Polytechnic University:

Development of encapsulation methods for organic-based phase change materials in water

From Journal of Energy Storage:

Recent developments in the synthesis of microencapsulated and nanoencapsulated phase change materials

From Energy Conversion and Management:

Experimental and modeling study on thermal performance of hydrated salt latent heat thermal energy storage system

From Energies:

Thermal Response of Mortar Panels with Different Forms of Macro-Encapsulated Phase Change Materials: A Finite Element Study

From Renewable Energy:

Influence of the location of discrete macro-encapsulated thermal energy storage on the performance of a double pass solar plate collector system

From IOP Conference Series: Earth and Environmental Science:

Simulation and Analysis of Fuel Tank Heat Exchanger Based on Phase Change Material
Simulation Analysis of Thermal Storage Process of Phase Change Energy Storage Materials

From Nano-Structures & Nano-Objects:

Synthesis of organic phase change materials by using carbon nanotubes as filler material

From Processes:

Preparation and Performance Analysis of Graphite Additive/Paraffin Composite Phase Change Materials

From International Conference on Human-Computer Interaction:

Thermoregulating and Hydrating Microcapsules: Contributions of Textile Technology in the Design of Wearable Products for Wheelchair Dependents

From Materials Today:

Experimental study on hybrid natural circulation type solar air heater with paraffin wax based thermal storage

From Thermal Science and Engineering Progress:

Numerical and Experimental Investigation of Melting Characteristics of Phase Change Material-RT58

Research roundup: Foamed cement blocks; polyethylene glycol/wood flour composites; radiant ceiling panels; more

Ben Welter - Thursday, July 11, 2019

From Trends in Food Science & Technology:

Micro/nano-encapsulated phase change materials (PCMs) as emerging materials for the food industry

From Solar Energy Materials and Solar Cells:

A foamed cement blocks with paraffin/expanded graphite composite phase change solar thermal absorption material
Solvent-free preparation of bio-based polyethylene glycol/wood flour composites as novel shape-stabilized phase change materials for solar thermal energy storage
Spray-graphitization as a protection method against corrosion by molten nitrate salts and molten salts based nanofluids for thermal energy storage applications
Preparation and characterization of microencapsulated phase change materials containing inorganic hydrated salt with silica shell for thermal energy storage
Enhancing thermal conductivity of paraffin wax 53–57 °C using expanded graphite

From Solar Energy:

Simultaneous charging and discharging of phase change materials: Development of correlation for liquid fraction

From Energy and Buildings:

Numerical study of the electrical load shift capability of a ground source heat pump system with phase change thermal storage

From International Conference on Materials, Environment, Mechanical and Industrial Systems:

Simulation-based analysis of the use of PCM and shading devices to improve the thermal comfort in buildings

From Applied Thermal Engineering:

Experimental study of a pilot-scale fin-and-tube phase change material storage
On-demand Intermittent Ice Slurry Generation for Subzero Cold Thermal Energy Storage: Numerical Simulation and Performance Analysis
Atomistic modelling of water transport and adsorption mechanisms in silicoaluminophosphate for thermal energy storage

From Clima 2019, 13th REHVA World Congress:

Experimental comparison of radiant ceiling panels and ceiling panels containing phase change material (PCM)

From Journal of Energy Storage:

Review of stability and thermal conductivity enhancements for salt hydrates
Characterisation of promising phase change materials for high temperature thermal energy storage

From Journal of Cleaner Production:

Self-assembly of 3D-graphite block infiltrated phase change materials with increased thermal conductivity

From Sustainable Cities and Society:

Thermal Performance Difference of Phase Change Energy Storage Units Based on Tubular Macro-encapsulation

From Renewable and Sustainable Energy Reviews:

State-of-technology review of water-based closed seasonal thermal energy storage systems

From Applied Energy:

Thermal energy storage in district heating and cooling systems: A review

From Polymers:

Fabrication and Characterization of Novel Shape-Stabilized Phase Change Materials Based on P(TDA-co-HDA)/GO Composites 

Research roundup: Spent coffee grounds; tropical tree fruit oils; natural rubber composites; more

Ben Welter - Friday, July 05, 2019

From Chemosphere:

Spent coffee grounds as supporting materials to produce bio-composite PCM with natural waxes

From Biotechnology Reports:

Novel phase change materials for thermal energy storage: evaluation of tropical tree fruit oils

From Construction and Building Materials:

Compressive strength and hygric properties of concretes incorporating microencapsulated phase change material
Thermal enhanced cement-lime mortars with phase change materials (PCM), lightweight aggregate and cellulose fibers

From Case Studies in Thermal Engineering:

Optimal fin parameters used for enhancing the melting and solidification of phase-change material in a heat exchanger unite

From Materials Chemistry and Physics:

Porous geopolymer as a possible template for a phase change material

From Journal of Physics: Conference Series:

Thermophysical Characteristics of VCO-Soybean Oil Mixture as Phase Change Material (PCM) using T-History Method

From Rubber Chemistry and Technology:

Phase-Change Material: Natural Rubber Composites for Heat Storage Applications

From Powder Technology:

An enthalpy based discrete thermal modelling framework for particulate systems with phase change materials

From Chemistry Select:

Carbon Soot/n–carboxylic Acids Composites As Form‐stable Phase Change Materials For Thermal Energy Storage

From International Journal of Heat and Mass Transfer:

Experimental study of thermo-physical properties and application of paraffin-carbon nanotubes composite phase change materials
High thermal response rate and super low supercooling degree microencapsulated phase change materials (MEPCM) developed by optimizing shell with various nanoparticles

From Applied Thermal Engineering:

Design optimization of the phase change material integrated solar receiver: A numerical parametric study

From Solar Energy Materials and Solar Cells:

Synthesis and characterization of ditetradecyl succinate and dioctadecyl succinate as novel phase change materials for thermal energy storage

From Advanced Materials Interfaces:

Doubly Coated, Organic–Inorganic Paraffin Phase Change Materials: Zinc Oxide Coating of Hermetically Encapsulated Paraffins

From Journal of Energy Storage:

Heat transfer enhancement of charging and discharging of phase change materials and size optimization of a latent thermal energy storage system for solar cold storage application

Research roundup: Form-stable PCM; polyethylene glycol/quartz composites; fuzzy clustering; more

Ben Welter - Tuesday, June 18, 2019

From Renewable Energy:

A N-octadecane/hierarchically Porous TiO2 Form-Stable PCM for Thermal Energy Storage

From International Journal of Energy Research:

Hybrid solar parabolic dish power plant and high‐temperature phase change material energy storage system

From Journal of Applied Polymer Science:

Thermal and dynamic mechanical properties of polyethylene glycol/quartz composites for phase change materials

From Journal of Cleaner Production:

Using fuzzy clustering and weighted cumulative probability distribution techniques for optimal design of phase change material thermal energy storage

From Construction and Building Materials:

Thermoregulation effect analysis of microencapsulated phase change thermoregulation agent for asphalt pavement

From Applied Energy:

Residential cooling using separated and coupled precooling and thermal energy storage strategies

Sunamp signs its first major UK contract

Ben Welter - Friday, June 07, 2019

Sunamp Ltd. has signed a memo of understanding to supply its PCM-based heat batteries to Fischer Future Heat under an original equipment manufacturer contract. Sunamp, based in Edinburgh, Scotland, says the deal involves "many thousands" of units and will be worth seven figures as sales ramp up. Leicester-based Fischer began selling the product, dubbed the Aquafficient, in February.

Andrew BissellIn an email interview, Sunamp CEO Andrew Bissell filled in a few details on the deal.

Q: Can you tell me about the PCM aspects of this product?

A: "Sunamp’s success in making a super-stable (40,000+ cycles tested) salt hydrate PCM (very energy dense) at 58C and combining it (in a highly insulated, cuboid enclosure) with a very high power heat exchanger (high power, high flow rate hot water) made a whole class of heat battery devices possible. Not least electric water heaters, with about 4x the energy density of a classic electric hot water tank and 5+ gallon per minute performance. A key innovation (patent pending around the details) was to use electric elements immersed inside the PCM to melt the PCM and charge the heat battery."

Q: What can you tell me about the manufacturing process?

A: "Because Aquafficient by Fischer Future Heat is based on Sunamp UniQ, it’s effectively been in production at Sunamp Factory for nearly a year. 

"By going down this OEM white label route, Fischer Future Heat could hit the ground running with Aquafficient - which they did! Sunamp’s manufacturing has had to scale already this year from 75 units a month to 75 units a week, with 75 a day on the near horizon. This to keep up with exponentially rising combined demand from Fischer, other OEMs, and large housing and regeneration projects.

“We keep scaling production and the demand keeps outpacing us! We're working really hard on scaling up production and appreciate our partners’ and their customers patience when they sometimes have to wait quite a number of weeks for the product they want.”

https://www.insider.co.uk/news/heat-storage-battery-pioneer-sunamp-16252849

PCM in stadium seating: For fans on the hot seat, it's a pretty cool idea

Ben Welter - Saturday, May 25, 2019

Dustin Schafer of Henderson EngineersDustin Schafer, senior vice president and director of engineering at Henderson Engineers of Lenexa, Kansas, first became familiar with phase change material when he read an ASHRAE article about conference room air conditioning.

The method struck him as a small-scale version of a stadium or arena. "From there," he says, "I began I began devising a plan for us to implement this into our large-scale venues we design." 

Schafer developed the idea of using PCM inside the hollow portions of seats and seating structures to keep open-air stadiums cooler on hot days. The concept underwent testing at Kansas State University and was awarded a U.S. patent, "Stadium Ambient Temperature Control System," in 2017. He is giving a presentation on the concept June 12 at an event sponsored by AIA Kansas City at the Center for Architecture & Design in Kansas City, Mo. In an email interview, he discussed the development process. 

Q: How long have you worked at your company?

A: "I joined Henderson in 2008 and have nearly 20 years of industry experience."

Q: Can you briefly describe the process of testing the concept?

A: "In looking to develop an innovative, cost effective, and energy efficient option, we began conducting research on the potential implementation of PCM on venue seats to increase the thermal mass in the space and extend the length of time occupants are comfortable. Essentially, the material could be frozen (the material we used has a freezing point of 70° F) prior to the event, then as the PCM reaches its melting point, it would absorb some of the heat brought on by the human and/or solar load, prolonging the time the space is comfortable for attendees.

Henderson patent application drawing"I led a team in conducting a variety of tests to determine the efficacy of this idea. We worked with Kansas State University and utilized their Institute for Environmental Research to complete our testing. We set up a lab that included actual stadium seats arranged in a layout consistent with typical venues. Each seat in the testing area had 10 pounds of PCM attached to the back and a dummy in the seat equipped with electric resistance heaters that produced an amount of heat equivalent to that of a human being. The layout also included suspended wires with thermocouples to create the temperature sensor array around the dummy occupant.

"We conducted two tests to evaluate the impact this technology could have, each with two test value temperatures, 90° F and 100° F. In both tests we took measurements in an environmental chamber that simulated different ambient conditions during an event and compared both a control chamber and a chamber with PCM attached to the chairs. The tests ran until the effect of PCM was no longer noticeable."

Q: Can you provide a summary of the test results?

A: "In our research, we determined that PCM could be an impactful option for open stadiums situated in mild climates where the night temperatures drop low enough to freeze the material. To have an even greater impact, application of PCM should be seriously considered in enclosed arenas. Because the HVAC system could be used to pre-charge the bowl and freeze the material, this application could be even more significant. Additionally, the cooling result could materially affect the peak load needs for the HVAC systems in these spaces, saving the owner on energy costs.

"We also identified areas where PCM would not make sense a part of the temperature control solution, such as in climates with high winds that would simply blow away the cooled air, areas where the temperature does not drop below 70° F and thus doesn’t allow the PCM to freeze, or areas where the temperature rises too far above the melting point prior to the event meaning the cooling effect is lost before it is needed. Finally, we’ve found it necessary to note that this process only impacts spaces that need to be cooled – it cannot be used in heating conditions.

"We determined that phase change material does have a significant and sustained impact on occupant comfort. While it is not the whole solution, it can be a meaningful portion of the overall answer."

Q: Can you provide information on the PCM used in testing?

A: "We used InsolCorp’s Infinite-R phase change material." 

Q: Is Henderson now working on any projects that include the use of PCMs in this manner?

A: "We are not working on any projects that include the use of PCM."

Q: What interests you most about the use of PCM in building and construction?

A: "It’s a sustainable solution that is relatively low cost. It’s not the end all, be all, but it’s a small step that can have a nice impact. Professional sports teams focus heavily on the fan experience and this is a difference maker when it comes to their in-venue comfort."