Dynamic Pressure in the Bay: How Siemens DVO Optimized VAV Systems Across Oakland's Class-A Office Tower

The Problem: Excess Pressure in Legacy VAV Systems

1111 Broadway, a 24-story Class-A office building in Oakland City Center, faced a challenge common to many modern office towers: aging variable air volume (VAV) systems that were sized for peak occupancy but operated inefficiently under normal, part-load conditions.

Traditional VAV control relied on static pressure reset strategies—typically set to a fixed setpoint to ensure that the most demanding zone could be satisfied. In practice, this meant that on off-peak hours or during shoulder seasons, air handlers pushed significantly more pressure than necessary, wasting fan energy. The building's facilities team lacked real-time visibility into whether pressure setpoints were optimal or merely conservative.

For a 601,000-square-foot occupied property with significant tenant diversity and 24/7 operations, energy costs were material. Even a 10-15% reduction in VAV system energy would justify the investment in smarter controls.

Technology: Dynamic VAV Optimization (DVO)

Siemens deployed Dynamic VAV Optimization (DVO), an AI-driven control layer that operates within the building's existing air handling unit (AHU) control architecture. The system:

• Monitors real-time zone demand: Collects setpoint error signals from terminal VAV boxes across the building in real-time
• Optimizes static pressure dynamically: Continuously adjusts AHU discharge pressure setpoint to the minimum level required to satisfy the most demanding zone
• Coordinates supply temperature: Integrates pressure optimization with supply air temperature control to avoid energy penalties from simultaneous heating and cooling
• Operates across existing BMS: Requires no changes to VAV terminal controller logic or damper hardware—purely a supervisory control layer
• Responds to occupancy and season: Learns building occupancy patterns and thermal dynamics to anticipate pressure requirements

DVO operates in two modes at the user's preference: Green Mode prioritizes energy efficiency and comfort, while Defence Mode

Implementation & Commissioning Approach

The retrofit began with baseline M&V of existing VAV system performance. Siemens instrumented the building's five air handling units and monitored a representative set of terminal VAV boxes across multiple floors and zones. This 60-day baseline period established:

• Existing static pressure setpoints and their variability
• Fan speed profiles under typical operating conditions
• Zone demand patterns and peak pressure requirements by time of day
• Correlation between pressure setpoints and zone comfort (temperature tracking)

The DVO control algorithms were then tuned to the building's specific characteristics. The system was deployed in a staged approach: first on one AHU during off-peak hours, then expanded to all five units as operators gained confidence in the system's ability to maintain comfort while reducing pressure.

Results: Energy and Comfort Metrics

While detailed facility-level energy savings data from 1111 Broadway is proprietary, industry data on DVO deployments demonstrates expected performance ranges and the mechanisms driving those savings:

Building Context: LEED Gold Office Tower

1111 Broadway achieved LEED Gold certification (as of September 2019 recertification). The building occupies a premium position in Oakland City Center and attracts tenants prioritizing sustainability and operational transparency. The DVO retrofit enhanced this positioning by:

• Reducing operating carbon footprint without tenant disruption
• Maintaining strict thermal comfort standards for a multi-tenant environment
• Providing granular energy data for tenant billing and ESG reporting
• Supporting property owner goals for operational cost control

Operational Integration with Building Management

A critical success factor was the integration approach. DVO operates as a supervisory control layer above the existing BMS, meaning:

• No changes to terminal VAV logic or damper calibration
• Facilities staff could disable DVO and revert to manual setpoints if needed
• Existing preventive maintenance schedules remained unchanged
• Troubleshooting remained grounded in familiar VAV control concepts

This non-invasive approach reduced implementation risk and ensured buy-in from operations teams who are often skeptical of new control systems.

Lessons Learned

• Pressure optimization is low-hanging fruit: Many buildings operate with 20-40% pressure margin beyond the minimum needed to satisfy zones. DVO captures this through real-time zone demand monitoring.
• Existing VAV hardware is sufficient: No damper or sensor replacement is required. The control algorithm runs on the existing BMS infrastructure, making the retrofit capital-light.
• Multi-tenant comfort requires confidence: Transparent commissioning and staged rollout builds trust that optimization won't compromise individual zone comfort. Maintaining tight temperature control (±0.5°F) is essential.
• Cubic relationship drives ROI: The fan power law means small pressure reductions yield outsized energy savings. This is the primary mechanism driving 10-25% system energy reductions.
• Occupancy diversity is manageable: Different tenants, different hours of operation, different thermal loads—DVO's learning algorithms adapt to heterogeneous buildings better than fixed pressure setpoints.

Measurement & Verification Protocol

DVO energy savings were validated using:

• Pre-retrofit baseline: 60-day monitoring of static pressure, fan speed, zone temperatures, and humidity
• Post-retrofit measurement: Continuous monitoring of the same parameters under DVO control
• Normalization: Weather-normalized fan energy consumption (per IPMVP Deemed Savings or Option D)
• Comfort verification: Zone temperature tracking to confirm occupant satisfaction maintained