Phase Change Matters

Matteo D’Antoni, a senior researcher at the European Academy of Bozen/Bolzano in Italy, talked with youris.com about installing energy-saving technologies in existing buildings. He lists three important planning steps:

1. Evaluate the building's existing energy consumption.
   
2. Evaluate the integration of passive technologies, such as phase change material.
   
3. Evaluate the integration of active technologies, such as solar energy. 
   

"It is a complex approach," he explained. "One the one hand, we have to calculate how much primary energy can we save; on the other, how much it costs. Technologies have to be easy to install and maintain and [incur] a limited investment cost. If they are expensive, we have to understand whether it makes sense to install them. And this analysis has to take into account the energy concept of a specific building replaced in its own environmental context."

Using a novel modeling tool for concentrated solar power, Spanish researchers have designed a more efficient storage system employing multilayered phase change material. The CSP system has a theoretical thermal efficiency of more than 74 percent and requires only a third of the molten salt needed in traditional two-tank systems.

The system was first described in "A New Thermocline-PCM Thermal Storage Concept for CSP Plants. Numerical Analysis and Perspectives," a paper presented at SolarPACES 2013. "The key aspect of this new concept," the researchers wrote, "is the inclusion of PCM layers at both ends of the tank, whose fusion temperatures are conveniently chosen to be inside the 'admissible' temperature ranges for the outlet of both charge and discharge processes."