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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.




Patent application: Portable temperature controlled container

Ben Welter - Thursday, August 25, 2016

DeltaTrak patent application drawing

U.S. patent application 20160243000 (applicant Deltatrak Inc., Pleasanton, Calif.):

"This invention relates to a portable temperature controlled container comprising a body having a storage compartment, an opening to permit access to the storage compartment and an insulated lid. The container comprises a fan, a heat sink and a thermoelectric device, as well as a first phase change material and a thermoelectric device in thermal communication with both the first phase change material and the storage compartment. The thermoelectric device in thermal communication with both the first phase change material and the storage compartment is operable to remove energy in the form of heat from one of the storage compartment and the first phase change material and transfer that energy in the form of heat to the other of the storage compartment and the first phase change material. In this way, the device will require less power, be highly robust, will operate across a range of temperatures, and will be cost effective to manufacture."

PCM briefing: TES tank cuts cooling costs at Shippensburg; flow chart shows how all energy in U.S. is used

Ben Welter - Friday, August 12, 2016

• Inventor-entrepreneur Saul Griffith has developed a really, really detailed flow chart showing how all the energy in the United States is used. "This is really the first time that all of this data is brought together in one flow diagram, which is important if you really want to understand the consequences through the whole economy of things like defense," Griffith says.

Bill Gould, chief technology officer at SolarReserve, explains why he believes in the future of concentrating solar power with thermal energy storage. "CSP with storage is set to realize falling installation costs as global deployment accelerates," he writes. "It is a relatively young technology, with a strong roadmap for performance improvements, optimization and cost reduction. Future projects are already seeing 30 percent reductions in capital costs."

Viking Cold Solutions, maker of a PV/PCM cooling system, is generating sales leads with an offer of a free energy analysis to owners of supermarkets and cold storage warehouses.

• The new 3,000-ton high-efficiency cooling plant at Shippensburg University in Pennsylvania features a 1.7-million-gallon thermal energy storage tank. The tank stores water chilled during off-peak hours and provides up to four hours of full-load capacity without mechanical cooling. The system cut energy consumption during last year's cooling season by 12 percent — despite an 11 percent increase in cooling degree days.

PCM briefing: EU research focuses on energy retrofits; Axiom Exergy raises $2.5 million

Ben Welter - Tuesday, August 02, 2016

• A European Union research project focused on retrofitting old buildings to meet EU efficiency standards is taking a close look at PCMs built into walls. “By using a phase change material which freezes at 18°C and melts at 25°C,” says Dr. Jürgen Frick, project coordinator, “we can regulate the temperature fluctuations of a room. If the temperature falls to 18°C, the PCM freezes and heats the room. When it rises to 25°, the PCM melts, energy is absorbed, and the room is cooled.”

Rally by Diamond Mattress• The latest entry in the bed-in-a-box mattress competition features open-cell foam infused with copper gel and phase change material to regulate temperature. Diamond Mattress of Rancho Dominguez, Calif., says the company's new Rally line will be sold online and in retail stores.

Eric Buchanan of the West Central Research and Outreach Center in Morris, Minn., has posted an update on his net-zero dairy project. The system's key components so far include solar thermal panels, a heat pump, three heat exchangers and a 2,000-gallon water tank. Fifty-four kilowatts of solar PV and two 10-kW wind turbines are now being added to the system.

Axiom Exergy has raised $2.5 million from investors to help bring its refrigeration battery to supermarkets and cold storage facilities across the United States. The system uses a salt-based phase change material to reduce peak power usage by up to 40 percent and provide backup cooling during power outages.

• The University of Birmingham's Birmingham Centre for Energy Storage is setting up a joint lab on energy storage research with Global Energy Interconnection Research Institute Europe, an organization founded by China's state-run utility. The lab will focus on thermal and cryogenic energy storage systems and their application in energy networks.

• New from Accuray Research: "Global Advanced Phase Change Material (PCM) Market Analysis & Trends - Industry Forecast to 2025"

• A research team at Camosun College in Victoria, British Columbia, has selected PureTemp phase change material for use in a study of greenhouse thermal storage systems. "One of the engineering students is focusing on designing racks for the PCM bottles that will be specifically engineered to slow release and speed recharge of the bottles," writes Becky Mason, an instructor at Camosun who helped organize the research project. "This is intended to optimize use of PCM in off-grid greenhouses where electric fans are not used to circulate air around the PCM."

PCM/PV system cuts energy use at San Diego food bank

Ben Welter - Wednesday, June 01, 2016

Viking Cold Solutions has installed one of its hybrid cooling systems at a food bank in San Diego, Calif. 

The system combines rooftop photovoltaic panels and thermal energy storage to efficiently cool Jacobs & Cushman San Diego Food Bank's 80,000-square-foot warehouse. 

San Diego Food Bank TES Plastic cells filled with a salt-hydrate phase change material are arranged in modules installed above food storage racks. Solar-powered chillers solidify the PCM during the day. When the chillers are idle, the PCM absorbs heat as it melts, keeping the warehouse within its target temperature range. 

The Houston-based company says the system provides sufficient cooling capacity to cut grid consumption dramatically. "Between the hours of 7 p.m. to 7 a.m.," Viking says of one six-week period, "grid consumption dropped from 168 KWh to 8.1 KWh, a 95% reduction. And peak demand from refrigeration dropped from a high of 46 kW at midday to 1 kW overnight." 

The warehouse is the central food distribution hub for San Diego County, serving an average of 400,000 people each month. Last year, the food bank distributed 22 million pounds of food. ....

Patent application: Device for conserving, transporting fresh or frozen products

Ben Welter - Thursday, May 19, 2016

U.S. patent application 20160109187 (applicant Thermo King Corp., Bloomington, Minn.):

Thermo King patent application drawing"An apparatus for a thermally insulated container is disclosed. The apparatus includes one or more heat accumulators. Each of the thermal accumulators includes a plurality of longitudinal heat accumulation modules. Each of the longitudinal modules includes a casing forming a cavity therein. The cavity is configured to receive a phase change material. A first wall of the casing includes a substantially flat surface and a second wall includes a heat transfer enhanced surface portion. The longitudinal modules include a heat exchanger having at least a portion disposed within the cavity that is configured to supply a heat transfer fluid. The plurality of longitudinal heat accumulation modules are securely connected to each other and are in thermal communication with each other."


Research roundup: Expanded vermiculite composites; stearic acid/iron-oxide/titanium-oxide ternary; condensation heat recovery; more

Ben Welter - Thursday, May 12, 2016

Preparation of stearic acid/modified expanded vermiculite composite phase change material with simultaneously enhanced thermal conductivity and latent heat [Solar Energy Materials and Solar Cells]

Comparative Study of Stearic Acid/Iron-Oxide Binary and Stearic Acid/Iron-Oxide/Titanium-Oxide Ternary for Use as Energy Storage Material [pdf] [Journal of Physics]

Cost-optimal thermal energy storage system for a residential building with heat pump heating and demand response control [Applied Energy]

Cold storage condensation heat recovery system with a novel composite phase change material [Applied Energy]

Energy and economic analysis of building integrated with PCM in different cities of China [Applied Energy]

Patent application: Apparatus for the storage, transport and distribution of refrigerated or frozen goods

Ben Welter - Thursday, April 21, 2016

U.S. patent application 20160109186 (applicant Thermo King Corp., Bloomington, Minn.):

"An apparatus for the storage, transport and distribution of refrigerated or frozen goods, in particular for thermally insulated containers of refrigerated vehicles, cold rooms and the like, including one or more thermal storage devices, each including a housing defining a cavity for holding a phase change material. The cavity contains a heat exchanger that may be supplied with a heat exchange fluid. The housing includes a substantially flat wall portion and a heat transfer enhanced wall portion. The apparatus includes ventilator in communication with the thermal storage device."

Research roundup: Thermal inertia of PCM envelopes; heating system with PCM plate heat exchanger; n-eicosane-filled microcapsules; more

Ben Welter - Monday, April 11, 2016

Indicators evaluating thermal inertia performance of envelopes with phase change material [Energy and Buildings]

Thermal performance of a heating system working with a PCM plate heat exchanger and comparison with a water tank [Energy and Buildings]

Preparation and thermal energy storage studies of CH3COONa·3H2O-KCl composites salt system with enhanced phase change performance [Applied Thermal Engineering]

Discharging process of a finned heat pipe–assisted thermal energy storage system with high temperature phase change material [Energy Conversion and Management]

Performance analysis of a innovative PCM-based device for Cold Storage in the Civil Air Conditioning [Energy and Buildings]

Thermal performance of latent heat storage: phase change material melting in horizontal tube applied to lightweight building envelopes [Composite Structures]

Properties of n-eicosane-filled microcapsules with different morphology. Phase Change Materials studied by positron spectroscopy and complementary methods [Materials Chemistry and Physics]

Development of graphite foam infiltrated with MgCl2 for a latent heat based thermal energy storage (LHTES) system [Renewable Energy]

Air–PCM heat exchanger for peak load management: Experimental and simulation [Solar Energy]

Melting and solidification of PCM enhanced by radial conductive fins and nanoparticles in cylindrical annulus [Energy Conversion and Management]

Preparation of palygorskite paraffin nanocomposite suitable for thermal energy storage [Applied Clay Science]

Effect of phase change material roof layer on cooling and heating loads of a residential building in Melbourne [Energy and Buildings]

Research roundup: Finned spherical capsule; review of PCM-based cold thermal storage; macroencapsulation of metallic PCM; more

Ben Welter - Wednesday, March 09, 2016

An experimental and numerical investigation of constrained melting heat transfer of a phase change material in a circumferentially finned spherical capsule for thermal energy storage [Applied Thermal Engineering]

Physical-chemical properties evolution and thermal properties reliability of a paraffin wax under solar radiation exposure in a real-scale PCM window system [Energy and Buildings]

Phase change material based cold thermal energy storage: materials, techniques and applications - a review [International Journal of Refrigeration]

An investigation into the use of the heat pipe technology in thermal energy storage heat exchangers [Energy]

Macro-encapsulation of metallic phase change material using cylindrical-type ceramic containers for high-temperature thermal energy storage [Applied Energy]

Phase change materials based on polyethylene glycol supported by graphene-based mesoporous silica sheets [Applied Thermal Engineering]

Bermuda food distributor uses PCM thermal storage to cut refrigeration costs

Ben Welter - Friday, March 04, 2016

Thermal cells made by Viking Cold Solutions of Houston, Texas, have helped a food distributor in Bermuda reduce refrigeration costs by 40 percent. 

The thermal cells were installed in the ceiling of Butterfield and Vallis' 10,000-square-foot warehouse freezer in 2015. The cells consist of a salt hydrate solution contained in conductive thermal plastic tubes. The phase change material solidifies when the chillers are running. The PCM absorbs heat as it melts, allowing the chillers to run less frequently and still keep the warehouse within a few degrees of -18º Celsius. 

The system is among 20 built and installed by Viking in cold storage warehouses in Puerto Rico, Bermuda, St. Thomas, California, New Mexico and Texas. Collin Coker, Viking's vice president for sales and marketing, said his company is working on pilot grocery store installations in Texas and California.

Spencer Butterfield, chief operating officer at Butterfield and Vallis, says a 2013 tax break on the importation of energy-saving technology helped make the system economically feasible. He estimated that the system will pay for itself in four years. 

The design of Viking's thermal cells continues to evolve. Below: The system installed at New Mexico Foods in 2015 consists of film pouches suspended in steel racks. Bottom: The company's newest design consists of blow-molded HDPE bottles mounted on steel tubing.

Viking Cold Solutions installation in New Mexico  

Vikings Cold Solutions' newest thermal cell design (2016)