Grossmont Medical Plaza



Estimated Start:

Total Annual Savings

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Capital Upgrade - Air Handler Unit (AHU) Replacement and Zone (Variable Air Volume) VAV Installation

Not Started

FY 2023




Numerous issues were identified with the 7 Trane AHUs that provide the primary HVAC for the building. These issues include running on a 24/7 schedule, limited monitoring & control capability from the Siemens BAS interface, constant speed fans, out-of-date AHU controllers with no visibility into setpoints, and units nearing end-of-life (EOL). Supply air temperatures between 51 - 53°F were observed at most AHUs with constant volume air to the zones, leading to an excessive amount of reheat at the terminal units. Zone-level terminal units that serve the spaces are all pneumatically controlled with no air flow turndown capability or visibility from the BAS. Economizer capability is underutilized due to control programming.

To solve all observed issues, complete the following measures:
1) Replace all 7 Trane AHUs with new, energy efficient units & fully integrate into the Siemens system;
2) Install variable air volume (VAV) boxes with DDC occupancy sensor thermostats to replace the current pneumatic thermostats with re-heat control only;
3) Implement new programming sequence with DDC upgrade to include supply air temperature resets, static pressure reset, economizer control, building pressure control, optimized zone-group level scheduling, dual maximum VAV heating control, boiler plant-based VAV heating mode lockout, occupancy sensing based setbacks, & condenser water (CDW) temperature setpoint reset on the condenser loop.

Note: This measure should be completed in concert with Grossmont Medical Plaza-1: Capital Upgrade - Install Dedicated Data Closet Split Systems & Schedule Air Handler Units (AHU) Completing these projects together will allow greater control & visibility to ensure estimated savings are realized.


See above Description.