The Phase Change Matters e-mail newsletter is a weekly summary of the latest news and research on phase change materials and thermal energy storage. To subscribe, visit www.puretemp.com/subscribe. For more frequent updates, follow @puretemp on Twitter or visit the Phase Change Matters blog, www.puretemp.com/pcmatters.
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.
The 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 meet its goal 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.”
PHASE CHANGE MATERIAL
Cooling research focuses on paraffin beads in ‘rotary heat exchanger’
Drexel University offers a detailed look at the novel dry-cooling technology being studied to reduce water use at thermoelectric plants. The research team, which includes Drexel, the University of Memphis, Evapco, WorleyParsons and the Electric Power Research Institute, is focusing on phase change material in the form of tiny wax beads:
“The group’s design uses large mesh disks, 20 meters in diameter, woven from quarter-inch-thick tubes filled with tiny bead-like capsules of paraffin just a few millimeters in diameter. The discs would be stacked 15 meters high in a cylinder the team calls a ‘rotary heat exchanger unit.’ With the look of a sophisticated water wheel, the unit will have openings on the top and bottom for hot water to flow in, cooled water to drain out and ambient air to keep the system moving.
“As the hot water enters the unit from the steam condenser, the beads in the mesh will absorb the heat. The discs will continue to rotate as the water enters the unit. When the heated portion of the disc reaches the cooling side of the unit, ambient air is pumped in to let the beads release the heat before returning to the atmosphere outside the plant. The cooled beads spin back to the other side as the disc rotates, ready to repeat the process.”
Thermal energy storage system
U.S. patent application 20150176920: “A device including first and second heat accumulators, each including thermal energy storage containers. Each container includes an insulating enclosure containing earth crossed by at least one first line for the circulation of a first heat transfer fluid and at least one second line for the circulation of a second heat transfer fluid.”
PCMs keep headache-relief wrap cooler longer
Wrap your head around this: Phase change materials are being used to relieve headache pain. Hammacher Schlemmer says PCM gel packs allow the new Superior Headache Relieving Wrap to “stay cool 200% longer than typical models.”
For our full list of recent academic research, see puretemp.com/academic. Here are highlights from the past week:From Applied Energy:
• CO2 mitigation accounting for Thermal Energy Storage (TES) case studies [Applied Energy]
From Energy and Buildings:
• Application of Phase Change Materials to Improve the Thermal Performance of Cementitious Material
From Composites Part A: Applied Science and Manufacturing:
• Study on the phase change thermal storage performance of palmitic acid/carbon nanotubes composites
From Thermochimica Acta:
• Positive influence of expanded graphite on the physical behavior of phase change materials based on linear low-density polyethylene and paraffin wax
From Fluid Phase Equilibria:
• Binary Solid-Liquid Equilibrium Systems Containing Fatty Acids, Fatty Alcohols and Triolein by Differential Scanning Calorimetry
More than 220 of your colleagues have joined a new LinkedIn group devoted to the discussion of phase change material and thermal energy storage. The Phase Change Matters group is an interactive complement to the blog and newsletter of the same name.
You are invited to join the group and connect with PCM and TES experts from around the world. New members this week include Project Exergy founder Lawrence Orsini. He writes:
Hi folks, I’m a long time energy industry vet with a background in refrigeration systems, utilities, and energy policy. I’ve been proposing progressive PCM storage projects for many years in the grocery industry. Most recently we’ve started developing a combined heat and computing platform that uses computers as a primary heat source for buildings and are looking to PCM to dramatically shrink the size of the thermal storage systems as well as balance the thermal load on the compute systems to keep them alive longer.
Two Entropy Solutions advisors, Dr. Mohammed Farid of the University of Auckland and Lucas B. Hyman of Goss Engineering, are ready to answer your questions about phase change material and thermal energy storage. We’ll select the best questions sent to email@example.com and post the answers here each Friday.