Grossmont Hospital

Opportunity

Status

Estimated Start:

Total Annual Savings

Project Cost:

Project Payback:  

Description

Connected Commissioning of Airside Equipment

Not Started

FY 2020

$245,300

$660,000

2.7

Connected commissioning optimizes building performance, reduces operating and maintenance costs and extends equipment lifetimes. As a result of the energy audit, high priority lighting, automation/controls and heating, ventilation and air conditioning (HVAC)-related ECMs are recommended for implementation through a packaged connected commissioning project delivery. In most cases, the building automation system will be used to collect and analyze on-going performance data, identify new trends and ensure persistent savings from previously-implemented ECMs.

Perform connected commissioning of air handler units (AHUs) and zone level equipment with a focus on optimizing automated control sequences through programming and control device upgrades to achieve the following energy conservation measure outcomes. The connected commissioning process includes follow up investigation, controls upgrade specifications and sequences, coordination with installing contractor(s), and optimized control sequences validations. Control specifications and optimized sequences of operation will also be provided for all budgeted HVAC unit replacements.

Recommendation: 

The following measures were identified as specific opportunities to be completed as part of a connected commissioning process. These opportunities may be implemented independently or as part of a coordinated effort:

• Program Air Handler/Rooftop Unit (AHU/RTU) Economizer Lockouts - Optimize control sequence for AHUs with economizer control where the economizer shall be enabled when outside air temperature is 1) lower than 50°F and 2) when outside air temperature is lower than the return/zone air temperature by 2°F. Economizer control should be disabled when outside air temperature is 1) higher than 70°F or 2) when the outside air temperature is greater than return/zone air temperature. This measure includes all AHUs that have mechanical economizer capability, however it was observed that many units were not economizing properly due to manual overridden damper controls, conservative lockouts, or sensor/controls communication issues. This ECM applies to the following AHUs:
o Main Hospital AHU-401A, AHU-1A
o CT Suite AHU-1
o East Tower AHU-202, 203, 304, 205
o H&V AHU-21

• Program Air Handler/Rooftop Unit (AHU/RTU) Economizer Staging - Implement and commission adjustments to the supply air temperature control programming such that it is ensured that the economizer damper always opens fully prior to the CHW valve modulating open. This allows temperature control to take maximum advantage of outside air conditions prior to using chilled water for cooling. This ECM applies to the following AHUs:
o Main Hospital AHU-401A, AHU-1A
o CT Suite AHU-1
o East Tower AHU-202, 203, 304, 205
o H&V AHU-21

• Program Air Handler/Rooftop Unit (AHU/RTU) Static Pressure Reset- Static pressure setpoint resets are not configured for variable volume AHU systems. Program AHU supply air static pressure reset to modulate the supply air static pressure setpoint in order to maintain the maximum (critical) zone supply air damper position at an adjustable setpoint. For example, if static pressure setpoint is fixed at 1.5" water column (W.C.), reset between 0.2 - 1.75” W.C. based on VAV zone voting as referenced in ASHRAE Guideline 36. This ECM applies to the following AHUs:
o Main Hospital AHU-401A, AHU-1A
o CT Suite AHU-1
o East Tower AHU-202, 203, 304, 205
o H&V AHU-18, 19, 20, 21, 23, 25
o West Tower AHU-1, 2, 3, 4, 5, 6, 7

• Program Air Handler/Rooftop Unit (AHU/RTU) Supply Air Temperature Reset - Program air handler unit supply air temperature resets to modulate the supply air temperature setpoint (e.g. if supply air temperature setpoint is fixed at 55°F, reset between 55-63°F) in order to maintain total zone temperature cooling error at an adjustable setpoint. Use zone feedback to reset supply air temperature for both VAV zone and single zone units. This ECM applies to the following AHUs:
o Main Hospital AHU-401A, AHU-1A
o CT Suite AHU-1
o East Tower AHU-202, 203, 304, 205
o H&V AHU-18, 19, 20, 21, 23, 25
o West Tower AHU-1, 2, 3, 4

• Heating & Cooling Setpoints (Major Spaces) - Establish and program standard occupied schedule heating and cooling zone setpoints , e.g. 68°F heating and 74°F cooling. This should be done in conjunction with implementation of the AHU Supply Air Temperature Reset measure in order to maximize the ability of the reset. This ECM applies to the following AHUs:
o Main Hospital AHU-401A, AHU-1A
o CT Suite AHU-1
o East Tower AHU-202, 203, 304,205
o H&V AHU-18, 19, 20, 21, 23, 25
o West Tower AHU-1, 2, 3, 4

• Repair Slipped AHU Damper/Valve Actuators - Several air handler unit (AHU) valves and dampers were observed to be in override, which is typically due to slipped actuators that can no longer be relied on. Inspect valves & dampers for broken linkages and slipped actuators; repair known failed dampers as part of ongoing maintenance and use analytics-based connected commissioning to identify other faulty equipment.

• Replace Broken Air Handler Unit (AHU) Sensors - Multiple air handler units had temperature, pressure, and flow readings that were either not communicating, flatlined, or out of reasonable range leading to override of setpoints, valves, & dampers. Repair known failed sensors as part of ongoing maintenance and use analytics-based connected commissioning to identify other faulty equipment.