Total Annual Savings:
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 using the Honeywell Niagara BAS 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.
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:
• BAS Retrofit - Replace all zone controllers with BACnet controllers and integrate into Honeywell front end. Program with unoccupied setbacks, temperature and pressure reset voting and dual maximum control sequence. Having centralized digital insight and control of these terminal units will allow for:
‐ Better management of space conditions affecting staff
‐ Proactive maintenance of terminal units by removing aging infrastructure and allowing computer-based troubleshooting
‐ Ability for primary equipment to stage and react to the building load throughout the day and seasons, allowing for resets on static pressure, chilled water (CHW) temperature, and heating hot water (HHW) temperature
Note: A BAS retrofit is not required to complete all connected commissioning opportunities, but will greatly assist in identification, implementation, & resolution of issues.
• Heating & Cooling Setbacks - Establish and program standard unoccupied schedule heating and cooling zone setback setpoints , e.g. 60°F heating and 80°F cooling; ensure zones and equipment that do not need to operate with a setback are simply off when unoccupied.
• 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.
• 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.
• Equipment Schedules for Boilers - Boiler and hot water system currently runs 24/7. Program interlocks of boiler with the AHUs to prevent boiler run time when heating demand is non-existent.
• Boiler Lockout - Program boiler lockout when outside air temperature is above 80°F; ensure program includes wide hysteresis (10°F typ.) to prevent constant on/off cycling.
• Program Boiler System Heating Hot Water (HHW) Reset - Program outside air temperature reset of boiler supply temperature setpoint. For conventional boilers or boilers with 3-way valves, use 180-140°F when outside air temperature varies from 20-70°F. For condensing boilers, use 180-80°F when outside air temperature varies from 20-70°F. Alternatively, use voting or hot water value (HWV) rollup based trim and respond based resets.
• Heating Hot Water (HHW) Variable Speed Pumps & Loop Differential Pressure (DP) Reset - Install variable frequency drives (VFDs) & differential pressure sensors; program HHW loop differential pressure reset by modulating pump speed based on outside air temperature or difference in temperature between supply and return loop water (delta T) to reduce pumping demand.
• Program Air Handler/Rooftop Unit (AHU/RTU) Economizer Lockouts - AHU economizers lock out at 55°F; optimize control sequence 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.
• Program Dual Maximum Variable Air Volume (VAV) Control - Program dual maximum VAV control for VAV boxes with a single minimum CFM setpoint. Where minimum air flow setpoint requirements for heating are greater than the requirement for ventilation, minimum air flow setpoints can be reduced.
• Demand Response Sequence - Program sequences to allow non-critical loads such as common area lighting, fountains, displays, etc. to remain OFF during peak hours. Use any available load-shifting technology to delay energy use until after the peak period.
• Replace Broken Air Handler Unit (AHU) Economizers - Multiple issues identified with air handler economizer dampers. AC-1 and AC-2 both have sticking economizer dampers; lubricate or replace dampers to prevent operational issues. Other dampers found fully closed with air handler units running. Program minimum economizer position based on total air balance to provide adequate ventilation air to zones.
• Replace Broken Air Handler Unit (AHU) Sensors - Replace static pressure sensor on AC-1 (currently shows 0" w.c.); repair other known failed sensors as part of ongoing maintenance and use analytics-based connected commissioning to identify other faulty equipment.