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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.




PCM insulation additive wins $35,000 MIT Clean Energy Prize

Ben Welter - Tuesday, June 09, 2015

Insulation additiveCoolFlux, an insulation technology that uses phase change material to improve a building’s cooling performance, won $35,000 at last month's MIT Clean Energy awards.

CoolFlux was developed by graduate students Alan Ransil and Wenhao Sun in an MIT materials design challenge. The developers describe it as an additive "that improves the effectiveness of insulation without changing how those panels look, feel or could be installed." The patent-pending technology promises to improve a building's cooling performance by up to 40 percent. ...

Economist says energy efficiency is overlooked factor in measuring productivity

Ben Welter - Tuesday, June 09, 2015

Greentech Media's latest "Energy Gang" podcast includes a segment with Skip Laitner, an economist who says we've been measuring energy productivity all wrong. As measured by all energy available for use, he said, the U.S. economy is running at only 15 percent efficiency. 

Economist Skip Laitner"Whether it's light, whether it's thermal energy, an industrial process, whether it's powering up the Internet or maintaining a cold beer in the refrigerator, what is actually going on as work, to provide the cooling, to provide the heat and provide the light?" said Laitner, right. "When we [measure energy productivity] that way we find that we're wasting more than 80 percent of that energy, and that's nothing but a set of costs that really clamp down on the economy."

In another segment, starting at 25:30, the group talks about the Energy Storage Association's expo in Dallas last month. Among the takeaways: Ice-based storage and phase change material are gaining traction in the discussion of energy storage.

"Storage is everything from batteries all the way through ice storage and thermal storage units, all the way through to some of these phase change materials and other things," said energy futurist Jigar Shah. "I was pitched a couple times by folks who had much different definitions of storage, which I thought was fascinating."

Research roundup: Bischofite as PCM for thermal energy storage; phase change composite; solar fresh air system

Ben Welter - Monday, June 08, 2015

Use of polyethylene glycol for the improvement of the cycling stability of bischofite as thermal energy storage material [Applied Energy]

High thermal conductivity phase change composite with percolating carbon fiber network [Applied Energy]

Thermal storage exchanger based on phase change material applying to solar fresh air system [Materials Research Innovations]

Industrial Surplus Heat Utilization through Mobile Thermal Energy Storage with Enhanced Operating Strategy [Greenstock 2015 conference paper]

Halotechnics CEO urges development of scalable storage-only technology for CSP

Ben Welter - Friday, June 05, 2015

The development of scalable storage-only technology, using electricity to heat molten salts, would help reduce costs for concentrating solar power projects, Justin Raade, CEO of energy storage systems supplier Halotechnics, tells CSP Today.

“If we can build more projects that use thermal energy storage technology for this electrical storage application then people will get more familiar with it. Those designs will improve, the costs will come down, and that will benefit future CSP plants with molten salt storage,” Raade said. 

Solar Decathlon entry uses rainwater to shift cooling to off-peak hours

Ben Welter - Friday, June 05, 2015


Builder Online takes an in-depth look at NexusHaus, one of 20 entries in the U.S. Department of Energy's Solar Decathlon 2015. Net zero energy use and water conservation are integral to the house, a co-production of a team of students from the University of Texas, Austin, and Technische Universitat Munchen, Germany. One goal is to reduce peak energy consumption by 80 percent through thermal energy storage. In summer, a rainwater-collecting tank will serve as a thermal storage unit for a system that will shift cooling to off-peak hours. 

"The home will capture enough rainwater to supply all of its potable water needs, although it will be connected to the municipal water supply for backup during long dry spells," Builder Online reports. "Rainwater will hit the 2,000-square-foot canopy between the home's two modules and flow down a system of gutters into under-deck bladder tanks that can hold up to 5,000 gallons. Before being used in the house for drinking, bathing, and clothes and dish washing, the rainwater will be run through a two-state filtration system: a carbon filter for particulates and a UV light filter to treat it to the National Sanitation Foundation's Standard 61 for potable water."

The Solar Decathlon will take place Oct. 8-18 in Irvine, Calif. Entries will be judged on energy efficiency, design, affordability and consumer appeal.

Research roundup: Ground source heat pump with PCM; vertical shell and tube; novel mPCM slurry; more

Ben Welter - Thursday, June 04, 2015

Numerical study on ground source heat pump integrated with phase change material cooling storage system in office building [Applied Thermal Energy]

Numerical investigation of heat transfer mechanism in a vertical shell and tube latent heat energy storage system [Applied Thermal Energy]

Theoretical investigation of the energy performance of a novel MPCM (Microencapsulated Phase Change Material) slurry based PV/T module [Energy]

Hydrated salts/expanded graphite composite with high thermal conductivity as a shape-stabilized phase change material for thermal energy storage [Energy Conversion and Management]

Aluminum and silicon based phase change materials for high capacity thermal energy storage [Applied Thermal Engineering]

Little Lotus raises $130,000 on Kickstarter to help bring baby blankets, swaddles to market

Ben Welter - Thursday, June 04, 2015

Little Lotus sleeping bagLittle Lotus, Embrace Innovations' line of PCM-powered baby blankets, sleeping bags and swaddles, has completed its fund-raising campaign on Kickstarter, gathering more than $130,000 in pledges from 676 backers. Embrace Innovations is the for-profit social-enterprise arm of Embrace Global, a nonprofit whose low-cost infant warmer has helped more than 150,000 at-risk infants in India, Afghanistan and other developing nations. 

Little Lotus and the Embrace warmer both use phase change material to regulate body temperature. The Kickstarter campaign, intended to raise money to help bring the Little Lotus to market, tied the two products together: For every Little Lotus purchase over $100, Embrace Innovations pledged to donate $25 toward an infant warmer for a baby in a developing country. The swaddles ($150 a pair) and sleeping bags ($150 a pair) are available in limited quantities at

The Little Lotus line uses PCM embedded in a layer of fabric. Through a public relations representative, Embrace Innovations declined to discuss the PCM or the company's manufacturing plans. The Embrace warmer includes a pouch containing PureTemp 37 phase change material.

Massachusetts launches $10 million energy storage initiative

Ben Welter - Wednesday, June 03, 2015

Massachusetts Gov. Charlie BakerMassachusetts' new energy storage initiative includes $10 million in investments and could lead to policy and regulatory changes. Some of the money will fund studies to analyze market opportunities and supply state policymakers with cost-benefit analysis and policy recommendations.

Gov. Charlie Baker says he wants Massachusetts to be an energy storage leader.

“The Commonwealth’s plans for energy storage will allow the state to move toward establishing a mature local market for these technologies that will, in turn, benefit ratepayers and the local economy,” Baker said. “Massachusetts has an exciting opportunity to provide a comprehensive approach to support a growing energy storage industry with this initiative's analysis, policy and program development.”

Research roundup: Thermal stability testing; nanofibers composite; barium-based PCM; domestic hot water tanks

Ben Welter - Monday, June 01, 2015

Review on the methodology used in thermal stability characterization of phase change materials [Renewable and Sustainable Energy Reviews]

Fabrication and characterization of capric–lauric–palmitic acid/electrospun SiO2 nanofibers composite as form-stable phase change material for thermal energy storage/retrieval [Solar Energy]

Effect of Barium-based Phase Change Material (PCM) to Control the Heat of Hydration on the Mechanical Properties of Mass Concrete [Thermochimica Acta]

An experimental and numerical investigation on the use of phase change materials in building elements: The case of a flat roof in Istanbul [Energy and Buildings]

Integration of PCM in Domestic Hot Water Tanks: Optimization for Shifting Peak Demand [Energy and Buildings]

Research roundup: Storage evaporator for vehicle energy management; Heisler chart; PCM applications in building environment; more

Ben Welter - Friday, May 29, 2015

Modeling Air Conditioning System with Storage Evaporator for Vehicle Energy Management [Applied Thermal Engineering]

Expanding Heisler Chart to Characterize Heat Transfer Phenomena in a Building Envelope Integrated With Phase Change Materials [Applied Thermal Engineering]

Experimental evaluation at pilot plant scale of multiple PCMs (cascaded) vs. single PCM configuration for thermal energy storage [Renewable Energy]

Virtual Special Issue - PCM applications in building environment [Building and Environment]

Synthesis and Characteristics of Hygroscopic Phase Change Material: Composite Microencapsulated Phase Change Material (MPCM) and Diatomite [Energy and Buildings]

Design and calculation of a new storage tank for concentrating solar power plant [Energy Conversion and Management]

Microfluidic fabrication and thermal characteristics of core-shell phase change microfibers with high paraffin content [Applied Thermal Engineering]

Synthesis and characterization of thermal energy storage microencapsulated n-dodecanol with acrylic polymer shell [Energy]

Exergy analysis of discharging multi-tank thermal energy storage systems with constant heat extraction [Applied Energy]