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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 version of EnergyPlus features updated PCM module

Ben Welter - Tuesday, October 17, 2017

The latest version of EnergyPlus modeling software includes an updated module for measuring the impact of phase change material on energy use in buildings.
 
Developed by the U.S. Department of Energy, EnergyPlus is an energy simulation program that can be used to calculate heating and cooling load in a building, based on detailed information about the building’s physical make-up and mechanical systems.
 
With the support of a $100,000 grant from the Department of Energy, Jeremiah Crossett, chief technology officer of NRGsim Inc., worked with Dr. Edwin Lee of the National Renewable Energy Laboratory to incorporate the updated PCM module into EnergyPlus.
 
The PCM module was originally developed more than five years ago by Ramprasad Chandrasekharan, then a graduate student in mechanical engineering at Oklahoma State University. Crossett assumed responsibility for the module soon after, debugging the FORTRAN code and modifying the logic to include the effects of subcooling and hysteresis. He began using the module in a customized version of EnergyPlus on all PCM modeling projects he worked on. The module, however, was not compatible with public versions of EnergyPlus, which was converted to the C++ programming language in 2014.
 
Jeremiah CrossettCrossett, right, sought the DOE grant to fund the conversion of the PCM module to C++ so that it could be incorporated into EnergyPlus. The module features two major improvements to the original PCM module.
 
“The new model includes the effects of hysteresis,” Crossett said. “The input object is called Material Property Phase Change Hysteresis and includes two [temperature/enthalpy] curves. Instead of going up and down in the slope of a single curve, the model either stores the energy in the storage range and then releases it when the model hits the heating curve. Or the model hits the heating curve immediately, depending on the properties of the actual phase change material. This model takes into account the histories of building surface temperatures, on into the current. It does a better job of accounting for the phase change material’s performance over time.
 
“In the previous version, what would happen is any time temperatures would fall and then rise again, and rise and then fall again, any time temperatures were not fully linear, [the module] would show additional energy consumption. Essentially, you had this single curve and as it would get cooler it would drop the heat back into the space. So say your material’s melting at 74, 75 Fahrenheit, and you’re saving on cooling energy, and then it drops down to 73, and now it drops all the heat right back into the space. So now you’ve got more energy you’ve got to deal with in your cooling system. That’s not how it actually works in the real world. …
 
“That caused a whole lot of studies, done by many, many different people over the years, to be wrong. It essentially gave a false indication that phase change materials don’t work nearly as well as they really do. …
 
“[The new module also] models subcooling and supercooling. Each PCM has a theoretical melt and freeze point. That’s normally how these products are rated. Some companies call it a Q-value. Other companies just say it as a number, such as a phase change 23 or a phase change 29 in degrees Celsius. But in the real world, how these products actually perform is that there’s some amount of subcooling: the freezing point is not identical to the melting point. You can have supercooling as well, where once your material is frozen, you have to reach a point above the theoretical melting point in order to melt it. This model allows the thermal simulation to have different melting and freezing points. ...         

"Now that EnergyPlus can accurately model PCM's performance in real buildings," Crossett said, "it is well-suited for evaluation of PCM technologies for energy codes such as California's Title 24 and green building standards such as ASHRAE 189.1."

Here's a screen grab of a portion of the new EnergyPlus PCM module:

Crossett and Lee completed work on the module in August. Version 8.8.0, released on Sept. 30, is available for free at https://energyplus.net/downloads. They plan to publish a paper on their work later this year.

Over the next six months NRGsim plans to work with PCM manufacturers to add their products to a database for the EnergyPlus program, based on the ASTM C1784-14 protocol, "Standard Test Method for Using a Heat Flow Meter Apparatus for Measuring Thermal Storage Properties of Phase Change Materials and Products."

PCM briefing: Solar-powered micro cold rooms; Axiom Exergy's jazz connection

Ben Welter - Wednesday, September 13, 2017

• The German company Covestro is providing technology for use in solar-powered micro cold rooms in India. The cold rooms employ phase change material to keep produce cool until it can be transported from farm to market. Eight hundred units will be built in the Indian state of Telangana over the next two years. 

• In an interview with the San Jose Mercury News, Anthony Diamond talks about the musical connection he shares with Axiom Exergy co-founder Amrit Robbins. They met as undergrads at Stanford University. "I play saxophone, he’s actually a trumpet player," Diamond said. "He was like, the best jazz trumpet player on campus. So whenever I had a gig, I would call him, and vice-versa. We had an opportunity to collaborate a lot within that context. I knew that I worked really well with him and we were a really great team."

• Heat battery maker Sunamp Ltd. is one of 15 European scaleups selected to give presentations in California next week at Startup Europe Comes to Silicon Valley

Pelican BioThermal has opened a service center in Puerto Rico. The center will serve as a depot for the company’s Credo on Demand rental program and enable customers to receive and return reusable temperature controlled packaging systems.

Facebook has announced that its cloud campus in Odense, Denmark, will be connected to a neighborhood district heating system. The company expects the system will warm 6,900 homes.

Evelyn Wang, director of MIT’s Device Research Laboratory and an internationally recognized leader in phase change heat transfer on nanostructure surfaces, has been named associate department head of operations in the school's Department of Mechanical Engineering.  

Long-Qing Chen, professor of engineering science, mechanics and mathematics at Penn State University, has been awarded a Humboldt Research Award by the Alexander von Humboldt Foundation of Germany. Chen will work with Jürgen Rödel, professor of materials science and engineering at the Technische Universität Darmstadt, on areas of mutual interest, including multiferroic thin films and phase change materials.

MIT researchers are taking a look at 3,000-year-old technology that could help reduce the use of fossil fuels. Under the proposal, electric resistance heaters would convert excess electricity into heat. The heat would be stored in a large mass of firebricks, which can retain heat for long periods if they are enclosed in an insulated casing. The heat could be used directly for industrial processes, or it could feed generators that convert it back to electricity when the power is needed.  

Colorado's first certified passive house 'has gone well past expectations'

Ben Welter - Wednesday, January 04, 2017

Colorado's first certified International Passive House is nestled in the foothills of the Rocky Mountains north of Denver. The 1,200-square-foot MARTaK house, designed by architect and author Andrew Michler, is used primarily as an off-the-grid workspace. The structure has now been occupied continuously for six months. Has it met Michler's energy expectations?

MARTaK passive house photo by Andrew Michler"Yes," Michler says, "it's gone well past my expectations. ... We haven't turned on the heating system this year." 

A solar array shared with a neighboring home provides all electrical power and most of the heating, with a propane-powered hydronic system serving as backup. Passive House Planning Package software was used to find the most efficient mix of insulation, windows and shading. Natural, nontoxic and recycled materials are used throughout the house. 

Biobased phase change material with a melt point of 23º C is used to help even out temperature spikes. The PCM is contained in 500 square feet of ENRG Blankets made by Phase Change Energy Solutions. Most of the material is installed a south-facing interior wall. 

Is it possible to measure the PCM's impact on overall performance?

"That's the question that I haven't found anybody able to answer," Michler says. "It's more about experiential. It's hard to isolate the PCM performance. There's no good modeling software for this. ...

"Overheating has been the biggest issue with passive houses, and we're seeing some anecdotal success with PCMs. We had a really warm fall, and the PCM did seem to level out the interior temperature, leveling out at 78 degrees Fahrenheit."

Has Michler used PCM in other projects? "No, this is the first. I do have interest in trying it again."

http://www.archello.com/en/project/martak-passive-house

PCM briefing: Dulas introduces 52.5-liter solar fridge; Argonne's Dileep Singh is named ASM International fellow

Ben Welter - Thursday, October 27, 2016

Dulas VC50SDD refrigeratorDulas Ltd. has added a 52.5-liter model to its line of solar-powered refrigerators. The VC50SDD is powered by the British company's Solar Direct Drive technology and uses paraffin-based phase change material to keep vaccines and other payloads at temperatures ranging from 5°C to 43°C. With an optional "integrated solar socket," the refrigerator can also be used to charge cellphones or temperature-monitoring equipment. The World Health Organization earlier this month approved the refrigerator for purchase by UNICEF and other U.N. agencies. 

Dr. Dileep Singh of Argonne National Laboratory has been named a fellow of ASM International for his work on concentrating solar power and other energy innovations. Singh and his team developed a latent heat-based thermal energy storage system that enhances the performance of phase change material using high-conductivity graphite foam.

• Two new reports from QYResearch: "Global Thermal Energy Storage (TES) Market Professional Survey Report 2016" and "Europe Advanced Phase Change Materials (PCM) Market Report 2016."

• A handful sessions scheduled for the 2017 Energy Storage World Forum and Residential Energy Storage Forum are related to thermal energy storage: "Niche Energy Storage Technologies," led by Pierre-Guy Therond, director of new technologies at EDF Energies Nouvelles of France; "Synergistic Combinations of Energy Storage Technologies," led by John Hatton, chief commercial officer at Alpheon Energy, United Kingdom; and "Integrating Storage to Improve Renewable Generation Capacity Factor," led by Martin Wilcox, senior consultant at Mott MacDonald, United Kingdom. The conferences will be held May 8-12 in Berlin.

MatériO has opened its new materials library in Shanghai, with more than 1,000 materials on display. MatériO, based in France, lists more than 7,400 "cutting edge" materials and technologies in its database, including Entropy Solutions' PureTemp phase change material.

• U.S. chemical production is thriving, according to a American Chemistry Council analyst, but several factors threaten long-term growth, including equipment shortages and a lack of skilled workers.

PCM briefing: Alexium adds clients in bedding industry; new research on temperature-controlled pharma packaging

Ben Welter - Tuesday, June 07, 2016

Alexium International has announced an agreement to sell its new flame-retardant phase change material to a U.S.-based textile finisher serving the bedding industry. Alexium, based in Perth, Australia, and Greer, S.C., announced in May that it had reached a PCM sales agreement with one of the world's largest producers of mattress ticking. "Alexium is now in production or full-scale trials with six global mattress fabric finishers," said CEO Nicholas Clark "and for the first time, a major manufacturer in apparel is evaluating our flame retardant phase change material technology." 

• New from Research and Markets: "Temperature Controlled Pharmaceutical Packaging Solutions (TCPPS) Market: Global Industry Analysis and Opportunity Assessment, 2016-2026."

TheM dining mat• Months after falling short of raising $30,000 on IndieGoGo, developers of a PCM-powered thermal dining placemat called TheM said in January that they hoped to develop a successful design by the end of February. The team is now apologizing again, telling backers: "The PCM material did not work as intended and [we are] trying to develop a solution that can still add value to the innovation. Please bear with us and within the next 60 days [we hope] to have a product with which [we] can reward your support and patience."

Ira Smith, director of strategic development for global transport and biologistics at Pelican BioThermal, is among the panelists at the FlyPharma conference in Brussels this week. The topic: The increasing appeal of inter-continental rail freight services and sea freight.

Glacier Tek cooling vests are profiled in the June issue of OR Today magazine. The vests, which use PureTemp bio-based phase change material to maintain thermal comfort, are being marketed as a way to address heat stress among surgeons and operating room staff, who endure "bright lights, sterile gowns, lead aprons, physical exertion and time stress."

GreenCE is offering a free hourlong webinar, "Reinventing Green Building: Focus on Carbon & Leverage Technology," at 1 p.m. June 14. Instructors will discuss the limitations of LEED certification in various U.S. market segments and identify alternatives to LEED certification. 

• The National Renewable Energy Laboratory has named Peter Green as the new deputy laboratory director for science and technology. Green is a professor of materials science and engineering, chemical engineering and applied physics at the University of Michigan.  

Monodraught's Cool-Phase cooling and ventilation system has been specified for Harrogate's new civic headquarters, now under construction in County Durham, England. The system combines a phase change material thermal energy store with an intelligently controlled air handling unit to actively ventilate and cool buildings without the use of refrigerants. The company says the system contributes credits toward BREEAM standards for lifecycle costs, indoor air quality and low- and zero-carbon technologies. 

Research roundup: Simplified method for modeling TES performance; influence of chain extender on polyurethane-based PCMs; more

Ben Welter - Wednesday, December 02, 2015

A simplified method for modeling the thermal performance of storage tanks containing PCMs [Applied Thermal Engineering]

The influence of chain extender on properties of polyurethane-based phase change materials modified with graphene [Applied Energy]

The State of the Art for Technologies Used to Decrease Demand in Buildings: Thermal Energy Storage [Energy Performance of Buildings]

Performance analysis of a solar air heating system with latent heat storage in a lightweight building [Applied Thermal Engineering]

Research roundup: Thermal characteristics of microencapsulated PCM; expanded graphite and paraffin; problems associated with PCMs; more

Ben Welter - Thursday, November 05, 2015

Micro-Encapsulated Phase-Change Materials for Latent-Heat Storage: Thermal Characteristics [pdf] [Materials and Technology]

Improvement of thermal conductivity of paraffin by adding expanded graphite [Journal of Composite Materials]

Figure of Merit for the Thermal Performance of Cementitious Composites Containing Phase Change Materials [Cement and Concrete Composites]

SigmaPipe as an Education Tool for Engineers [Education for Chemical Engineers]

Experimental study on crystallization process and prediction for the latent heat of ice slurry generation based sodium chloride solution [Applied Energy]

Review on Latent Heat Storage and Problems Associated With Phase Change Materials [pdf] [International Journal of Research in Engineering and Technology]

Smart Building: Decision Making Architecture for Thermal Energy Management [Sensors]