Location: San Francisco
The Japan Center Garage is the hub of San Francisco’s Japantown. It was constructed in 1968, and it’s divided into two, primary parking facilities: The Main Garage, which is a two-level, 235,000 square-foot structure; and the Annex Garage, a single-level, below-grade facility measuring 60,000 square feet.
The Savings Opportunity
With no means of controlling motors running 21 hours a day, seven (7) days a week, the Main Garage’s newly installed mechanical ventilation system would consume more than 970,000 kilowatt-hours (kWh) per calendar year. The correlating annual peak kilowatt (kW) demand would amount to more than 125 kW. Calculations for the Annex Garage reflected a 19/7 runtime schedule consuming more than 280,000 kWh per year, with an annual peak kW demand amounting to more than 40kW.
NES installed its Digital TR50 Series system in the Main Garage and the its TR25 Series system in the Annex Garage. The NES system controls the rate of ventilation in the Main and Annex garages based on carbon monoxide (CO) concentrations at a given juncture. 71 BACnet-communicating NES CO sensors provide instantaneous feedback to NES controllers, which then relay speed commands — via VFDs — to the garage’s exhaust and supply fan motors, increasing and decreasing motor speeds in proportion to CO readings.
Even after a >500% increase in fan-motor runtimes, the NES System reduced the baseline of energy consumption from the year prior to retrofit
Since NES system commissioning, the energy consumed by 45, new electric motors running a combined average of 20 hours per day and possessing a combined 225 horsepower amounts to just 38,300 kWh annually – a 97% reduction from the 1.25 million kWh per year the same mechanical system would otherwise consume with no means of fan-motor control in place. The NES system provides a recurring operational-cost savings greater than $250,000 a year — not including future utility rate increases.