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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.




Thermal energy storage is at the heart of net-zero milking system

Ben Welter - Thursday, February 18, 2016

Dairy farms consume a surprising amount of energy. Electricity is needed to run milking machines, to heat water to clean the equipment and to cool milk to safe temperatures for storage and consumption. 

The West Central Research and Outreach Center in Morris, Minn., is developing a dairy system that collects more energy from renewable sources than it uses. The key components: two wind turbines, a solar thermal array, a heat pump, three heat exchangers and a 2,000-gallon water tank. The Morris Sun Tribune describes the system:

WCROC dairy herd"The central component of the new net-zero dairy will be a heat pump designed to collect the heat from the cow's milk and store it in a 2,000 gallon thermal storage tank custom built by Custom Fabrication and Repair of Morris.

"Water will also be heated using solar thermal collectors already built along the east side of the dairy barn, adding another source for preheated water. This reduces the amount of energy needed to warm the water to the necessary temperature.

They've also installed three heat exchangers — devices that transfer heat between a warm substance and a cold substance — that will be used to chill the milk and help move heat into and out of the thermal storage unit. From the storage unit, the water will flow through an electric, tankless water heater system to get up to the final temperature needed for cleaning."

In an interview with Phase Change Matters, renewable energy scientist Eric Buchanan shared more details on the tank: "The tank is partitioned into three sections in such a way to promote temperature stratification. The inlets and outlets on the cold and hot sides of the tank also incorporate radial diffusers designed to slow the flow and minimize vertical mixing. The tank will be insulated with spray foam to about R-80."

PCM briefing: Georgia Tech selected for Solar Decathlon; Arizona company to outsource operations of 'Near Zero Carbon' greenhouse

Ben Welter - Monday, February 08, 2016

• A team from Georgia Tech is one of 16 chosen to participate in the U.S. Energy Department's 2017 Solar Decathlon. The team will explore concepts such as heat recovery systems, phase change materials, solar technology and direct current microgrids. Northwestern, Rice and Syracuse universities are among the other schools selected. 

Sustainable Energy and Agriculture Technology LLC is looking to outsource the operations of a “Near Zero Carbon” solar greenhouse in Sahuarita, Ariz. Phase change material will be used to control temperature in the 1,160-square-meter greenhouse.

EnergyNest reports that its concrete thermal energy storage system at the Masdar Institute's solar plant in Abu Dhabi is performing as well as or better than simulations suggested it would.

• A growing number of researchers are contacting reporters directly to alert them to upcoming papers, The Scientist magazine reports.

• The National Renewable Energy Laboratory has obtained a U.S. patent for a method that rapidly characterizes specialized materials during the manufacturing process.

PCM briefing: Upward pressure on palm oil prices; lab technician opening at CIC Energigune

Ben Welter - Wednesday, February 03, 2016

Global palm oil production is expected to be lower in 2016 than forecast due to the El Niño phenomenon, the Malaysian Palm Oil Council said Tuesday. The council projects an average price of $621 per metric ton and says the price is not likely fall below $480.

CIC Energigune, an energy research center in Spain's Basque Country, has an opening for a lab technician in its thermal energy storage group.

Johnson & Johnson and va-Q-tec Ltd. won first-place awards at the annual temperature controlled logistics conference in Frankfurt last month. Katharina Wuensche, va-Q-tec's director of business development, won the Cold Chain IQ Newcomer Award.  

• Among cold chain specialist Gary Hutchinson's predictions for 2016: Specialized packaging for specific drugs and tighter controls on clinical trial operations in extreme environments.

• In an interview with Health Care Packaging, cold chain consultant Geoff Glauser talks about the challenges of transporting the Ebola vaccine to West Africa. Intellectual Ventures' Arktek passive cooling device was adapted for use in clinical trials of the vaccine, using a specially formulated phase change liquid that freezes at -80º C.

Research roundup: Graphene nanoplatelets and expanded graphite; natural convective heat transfer; freeze protection for crops; more

Ben Welter - Monday, February 01, 2016

Thermal performance enhancement of palmitic-stearic acid by adding graphene nanoplatelets and expanded graphite for thermal energy storage: A comparative study [Energy]

Experimental study on natural convective heat transfer of tube immersed in microencapsulated phase change material suspensions [Applied Thermal Engineering]

Phase change material’s (PCM) impacts on the energy performance and thermal comfort of buildings in a mild climate [Building and Environment]

On the Use of Encapsulated Phase Change Materials Pebbles and Pellets as Freeze Protection Method for Low-Stature Plants/Crops [Engineering in Agriculture, Environment and Food]

Research roundup: Shape-stabilized PCM derived from potato; flat micro-heat pipe array; self-assembly fabrication of n-octadecane; more

Ben Welter - Friday, January 29, 2016

Preparation and thermal properties of shape-stabilized composite phase change materials based on polyethylene glycol and porous carbon prepared from potato [RSC Advances]

Experimental study on the thermal performance of a new type of thermal energy storage based on flat micro-heat pipe array [Energy Conversion and Management]

Self-assembly fabrication of microencapsulated n-octadecane with natural silk fibroin shell for thermal-regulating textiles [Applied Thermal Engineering]

The Implementation of Phase Changing Materials in Energy-efficient Buildings. Case Study: EFdeN Project [Energy Procedia]

PCM Selection Using AHP Method to Maintain Thermal Comfort of the Vehicle Occupants [Energy Procedia]

PCMs show promise in citrus greenhouse in Canada

Ben Welter - Thursday, January 28, 2016

Becky Mason put phase change material to the test at Carmenia Farm in Duncan, British Columbia, last year. The goal: Keep her 200-square-foot greenhouse running all winter, using the heat of the sun to grow lemons, limes and avocados without electricity. 

Carmenia Farm greenhouseAfter securing government funding to support the project, she ordered eutectic salts from PCM maker RGEES of Arden, N.C. The PCM has a melt point of 6º C and a storage capacity of 260 joules per gram. She deployed the PCM in 89 1-liter bottles stacked around the raised beds in the greenhouse. She disconnected the strings of incandescent lights that had kept the trees warm the previous winter. The initial result? Not good. When the temperature plummeted outside, it also plummeted inside, falling to -4º C. Her fruit suffered frost burn. The PCM had failed to recharge.

Writing in Small Farm Canada, Mason explains how she addressed the problem by adding insulation, placing the PCM bottles side-by-side and putting a barrel of water in the greenhouse to provide a reserve of thermal energy to help the PCM recharge. In the end, she found the results encouraging:

"Based on advice from the manufacturer and other project partners, I tried a number of fixes, until at last the PCM product worked as intended by early January of 2015. From early January through the end of April, when the data collection ended, the PCM kept the inside of the greenhouse continually above 32F (O Celsius), even when the outside temperature went below freezing on over 20F (-6C) nights, sometimes as low as 26F (-3C). Even more significantly, the soil temperature never went below 50F (10C) throughout the entire trial period.  Despite the early setbacks, all of the citrus, as well as the avocado tree, made it through the winter and are flourishing. Winter production with an air temperature above freezing and a 50F (10C) soil temperature offers year round farming."

India's new high-altitude shelters use PCM, water tanks to store thermal energy

Ben Welter - Monday, October 05, 2015

Chang La research station, northern India

India's Defense Research and Development Organization (DRDO) has established the highest research station on Earth. The Chang La station, near Pangong Lake in northern India, stands at 17,500 feet above sea level. Along with the station, DRDO is also introducing a new technology for solar-heated shelters. According to the Tribune of India:

"DRDO has also developed a unique green energy based micro-climate-controlled shelter for use in high-altitude areas that traps and utilises solar energy to maintain the temperature inside. DRDO scientists said while power generated from solar energy could be stored in batteries, it is very difficult to store heat energy derived from the sun for later use. The new shelter, called Dhruv, uses phase change materials for night applications, heat trapping roof design, freeze-resistant underground water storage tanks and solar energy based thermal budgeting."

Rare and endangered plants will be preserved at the Chang La station, where temperatures can fall as low as -40º C. The station will also be used to conduct extreme-altitude research on plants, animals and bio-medical material. The station will house up 20 scientists and support staff. Solar power will be the primary source of energy.

Research roundup: Phase change cold storage; gypsum-based composites; root zone heating system; more

Ben Welter - Thursday, August 06, 2015

Influencing factors on the energy saving performance of battery storage and phase change cold storage in a PV cooling system [Energy and Buildings]

Development and thermal characterization of innovative gypsum-based composites incorporating phase change material as building energy storage system [Energy and Buildings]

LCA & LCCA of a PCM application to control root zone temperatures of hydroponic crops in comparison with conventional root zone heating systems [Renewable Energy]

Consolidated microcapsules with double alginate shell containing paraffin for latent heat storage [Solar Energy Materials and Solar Cells]

Investigation of the corrosion behavior of NiVAl multilayer coatings in hot salt melts [Surface and Coatings Technology]

Geopolymer-based composite materials containing PCM for thermal energy storage [Ceramics for Energy conference paper]

Exergy analysis of the solar still integrated nano composite phase change materials [Applied Solar Energy]

Thermal properties of C17H36/MCM-41 composite phase change materials [Computational Materials Science]

Novel solid-solid phase change materials with biodegradable trihydroxy surfactant for thermal energy storage [RSC Advances]

Heat capacity enhancement of water tanks by use of phase change materials for domestic purposes [Instal]

Solar desalination system in California uses thermal storage to run 24x7

Ben Welter - Friday, June 26, 2015

The Panoche Water District in California's parched San Joaquin Valley is working to clean up and reuse irrigation water tainted by salts, selenium, boron and other minerals.

WaterFX desalination systemThe pilot project uses solar collectors to concentrate heat on water in clear piping. The evaporation process removes most of the minerals, leaving behind potable water that contains less than 5 parts per million of dissolved salts. 

"Because the process relies on solar energy, and we store heat during the day in thermal storage units, we operate 24 hours a day," treatment plant coordinator Betty Hurley Lindeman told Ag Alert, the weekly newspaper of the California Farm Bureau Federation. "The plant requires very little commercial power and has very low air emissions."

The technology, developed by San Francisco start-up WaterFX, features solar-collector mirrors, an absorption heat pump, a multi-stage distillation system and thermal storage units. The company says the system will eventually be capable of producing up to 1.6 billion gallons of freshwater a year and help the district to stop discharging agricultural water into the San Joaquin River by 2019. 

I haven't been able to reach WaterFX to get details on the thermal storage units. CSP Today, in a story posted in February 2014, said the units are designed for temperatures between 165º C and 235º C and utilize "a specially formulated thermal concrete with embedded heat exchanger tubes."