Plant helps university cut water, energy use
Stanford University cut its water use by 15 percent and is projected to save $420 million in operational costs, thanks to a new central energy facility developed with help from Johnson Controls.
The new plant helps Stanford make substantial progress to meet California’s statewide goal to reduce water use by 25 percent. Officials say the facility operates efficiently in any weather condition, thanks to ultra-efficient green HVAC building technologies, including heat recovery chillers, hot and cold water thermal energy storage, and a patented smart technology system that uses weather and electricity pricing forecasts to optimize operations.
“Nothing goes to waste inside this facility. We are recycling heat that is typically released by cooling towers and putting it to good use to keep students and staff comfortable,” said Trent Nevill, vice president and general manager at Johnson Controls’ building efficiency division. “All this is accomplished while helping Stanford reduce its carbon emissions by 50 percent compared to levels during the 1990s.”
Together with Affiliated Engineers Inc., Johnson Controls worked with Stanford engineers to design a custom-engineered heat-recovery process that is 70 percent more efficient than the co-generation process Stanford had used since 1987. Company officials say York heat-recovery chillers will meet more than 90 percent of campus heating demands by capturing almost two-thirds of the waste heat generated by the campus cooling system to produce hot water for the heating system.
Along with a Metasys building automation system, Johnson Controls also developed the Enterprise Optimization System, a predictive control software system to optimize cost and energy use based on the 10-day weather forecast and future grid electricity prices. The software is designed to predict hourly campus heating and cooling needs, and then determine how to best run the HVAC equipment inside. It also will determine how much hot and cold water to store in the system’s water thermal storage tanks for later use, the company says.
“There’s a great comparison to autopilot technology on an aircraft. The system continuously monitors plant equipment, predicts campus energy loads and grid electricity prices, and steers the system to optimal efficiency,” Nevill said.