Cityline Sunnyvale

Location: Sunnyvale, CA
The Property
Cityline Sunnyvale is a newly created, mixed-use neighborhood in the heart of Silicon Valley. The development possesses two enclosed garages: One on Taaffe Street; the other on Murphy Avenue. This case study focuses on the Murphy Avenue facility, a multi-level facility totaling 230,000 square feet which accommodates approximately 1,000 vehicles.
The Savings Opportunity
The Cityline Garage is ventilated 24/7 by seven exhaust fan motors comprising 50 horsepower. With no means of control in place, they consume more than 281,400-kilowatt hours (kWh) per year. Correlating peak kilowatt (kW) demand is greater than 32 kW. The property's utility rate is $0.17/kWh, including fees and taxes, so after factoring for fan runtimes (24/7) and total HP, the annual cost to ventilate the garage amounts to more than $47,800 – not including future utility rate increases.
The NES Solution
NES deployed its Digital TR 8025 Series system at the Murphy Avenue Garage, including 48 BACnet-communicating, CO sensors mounted throughout three levels of the garage, plus a total of seven (7) Danfoss VLT® VFDs to control the garage exhaust-fan motors. The NES system controls the rate of ventilation based on CO concentrations at any given juncture, with the sensors providing instantaneous feedback to the NES controller, which then relays commands to increase or decrease motor speeds in proportion to CO readings.
Project Highlights
The Murphy Avenue Garage's energy bill is reduced from $47,800 a year (or $4,000 a month) to roughly $1,300 per year – or just $108 a month
The Results
Since commissioning the NES DCV system in December 2019, real-time data logging of kW consumption – a capability of NES controllers – shows it to be limiting the garage fan motors’ combined kWh consumption to less than 7,600 kWh/year. The cutback in consumption of 273,800-plus kWh a year represents a 97.3% savings. So too does peak kW demand being reduced by more than 31 kW/year – all while the garage’s sizeable ventilation system runs continuously.
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