Opera Plaza

San Francisco

Opera Plaza

The Property

Constructed in 1982 and offering a wide choice of residences, businesses and shops, Opera Plaza houses 450 residential units, more than 80,000 square feet of office and retail space and a subterranean garage providing 600 parking spaces.

The Savings Challenge

Our challenge was to: a) Demonstrate whether our innovative, demand-control ventilation (DCV) system could further reduce the baseline of energy consumed by a ventilation system already running its non-inverter duty, two-speed garage-fan motors 24/7 at low speed(s); and b) To remedy operational inefficiencies related to an old, dilapidated CO system bypassed 10-plus years ago . The annual energy draw totaled 118,000+ kWh at annual cost of $24,800.

Opera Plaza

Retrofit Prerequisites

Variable Frequency Drive (VFDs) are designed to sync with fan motors operating at 100% of capacity, i.e., their “high” speed. This required us to measure the power (kW) consumption of the motors at both their low and high speeds and then calculate the obtainable energy savings based on the difference between the energy consumed by the fan motors running in conjunction with VFDs at their high speeds (post installation) and the energy consumed by fan motors at their low speeds (pre retrofit).

Project Highlight

Minimum Cash Inflow (from energy savings) of $241,900 Throughout the 15-Year Lifespan of Our System

The Results

The NES retrofit included rewiring the respective garage exhaust motors to run at high speed to better “sync” with our system VFDs, as well as tying in “dV/dt” filter technology to each VFD. "dV/dt" filter technology reduces the risk of non-inverter-duty motor failure by 80%.

The energy savings achieved are noteworthy. Post-installation data logging showed our garage DCV system will reduce the garage fan motors’ combined kWh consumption by 100,953 kWh a year – an 85.5% savings.


How Can We Help?

Frank Nagle
(415) 378-5560

About Nagle Energy Solutions (NES)

Nagle Energy Solutions, LLC is a manufacturer, distributor and installer of an innovative demand-control ventilation (DCV) system for commercial garages that reduces energy consumption in the range of 95% – with quantifiable savings as high as 97% achieved – all while leaving your garage fan motors running.

Our sales and service capabilities extend nationally and internationally.

Nagle Energy