Phase Change Matters

The Naval Postgraduate School in Monterey, Calif., is seeking bids on a thermal storage system for its Turbo Propulsion Laboratory.

"As part of the ONR funded ESTEP (Energy Systems Technology Evaluation Program) a heating system with thermal storage is being set up. The ESTEP program is designed to implement technologies that have the capability of reducing Navy and wider DoD facilities energy costs.

"The system is designed to match demand with available renewable supply and store the excess heating in a thermal storage system for use later. The technology that will be investigated uses solid inert materials rather than liquids as they are potentially simpler to use.

"The system forms an integral part of the Naval Postgraduate School’s energy curriculum. It is being used as a thesis project and will also be used in a planned renewable energy course within the [Mechanical and Astronautical Engineering Department] department."

https://www.neco.navy.mil/synopsis/detail.aspx?id=422272

In December, a U.S. Army Corps of Engineers office building in Seattle was one of nine projects recognized for innovative design with an ASHRAE Technology Award. Federal Center South received first place in the new commercial buildings category. 

The Seattle Daily Journal of Commerce takes a closer look at the project, including the months of tweaking needed to reach the energy-use guarantees made by the general contractor, Sellen Construction.

“This is not your father's 1960s pickup truck,” said Tom Boysen, senior project manager. “This thing has at least four gears of cooling and two gears of heating.”

The complex system includes heat-recovery chillers that extract heat from a thermal storage tank to warm the building in the morning, when demand is high. The rooftop tank is filled with 2-foot-long panels containing phase change material that freezes and thaws at 55 degrees, serving as a battery for storing heat.

https://www.djc.com/news/en/12074091.html