The award recognizes the Vacaville project’s NightSky™ system as the most outstanding technology achievement in the Alternative and/or Renewable Energy Use category within ASHRAE Region 10, which includes California, Hawaii, Arizona, and most of Nevada.
Monitoring for the Vacaville NightSky system shows 74% energy savings and 88% peak demand reduction compared to a typical system. Energy cost savings will amortize incremental system costs in three years.
All-Weather owner Lance Porter was impressed with the energy savings and comfort of the new system.
“In the future, many commercial buildings will use this system,” he said. “The energy cost savings help our bottom line, and will increase the value of my building over the long term. But more importantly, the comfort helps keep our offices productive.”
The All-Weather project uses ICI’s NightSky technology to deliver “natural cooling” from water chilled by spraying it on the roof at night. Dick Bourne, system designer and ICI vice president, accepted the award at a recent ASHRAE regional conference.
“Because the clear night sky is so cold, a low-slope roof is the coolest place to be on a summer night,” he said. “Through radiation to the night sky, we can spray-cool a large volume of water to 55Â°F on a typical valley night, and to 50Â° in the mountains.
“This is enough to cool a commercial building through the next day when the temperature is up to 95Â°.”
The processAfter the water is cooled, it drains from the roof through a filter to a storage tank. The filter is automatically backwashed to remove collected dirt. This “roof-washing” function keeps white roofs cooler under the hot sun, and helps improve outdoor air quality.
The Vacaville system stores cooling in a water tank and in the concrete slab floors. For hot weather, a 50% downsized chiller is programmed to supplement roof-spray cooling of the tank water. The chiller does not add to electric utility generation requirements because it never operates during peak load hours.
The chilled floor slab steadily delivers cooling through the day, and is supplemented by an air-delivery system controlled by thermostats. The slab is also used to deliver radiant floor heating comfort in winter.
“The cooling performance and features are a bonus,” Porter said. “What first attracted me to the system was the radiant floor heating. We like the building’s high-ceiling architecture, but we wouldn’t be able to keep these offices comfortable in winter without warm floors.”
ICI has designed and implemented a variety of new and retrofit NightSky systems on public and private buildings in three Midwest and Western states. A number of different governmental groups and utilities have partially supported development and testing of the system.
ICI was recently formed through a merger of Roof Science Corp., Davis, and Performance Controls, El Dorado. Paul Passantino, ICI president and founder of Performance Controls, is optimistic about his company’s future.
For more information on the NightSky system, contact ICI at 530-757-4844.