Examples of Commissioning Cost Savings

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Examples of Commissioning Cost Savings
Commissioning for Sustained Building
Performance September 29, 2011
Marriott Birmingham, AL
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What Are Trying to Avoid?
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Design Team or CxA?

• Chilled water valve is modulating to maintain AHU
  leaving air temperature at setpoint.
• Chilled water valve is modulating in a stable and
  uniform manner as required to maintain AHU
  leaving air temperature at setpoint without
  offset. Leaving air temperature setpoint is
  automatically adjusted as required to minimize
  reheat.

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Design Team or CxA?

• Water chillers are sequenced on and off as
  required to maintain chilled water supply
  temperature at setpoint.
• Water chillers are sequenced on and off in the
  most cost-effective manner possible as required
  to maintain chilled water supply temperature at
  setpoint and as required to ensure regular
  exercise of all equipment, automatic response in
  the event of an equipment failure, and regular
  exposure of all surfaces to water treatment
  chemicals.

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TAB or CxA?

• Laboratory space pressure is negative with
  respect to the corridor during occupied and
  unoccupied modes of operation.
• Laboratory space pressure is negative with
  respect to the corridor during occupied and
  unoccupied modes of operation and during
  transitions from occupied mode to unoccupied mode
  and from occupied mode to unoccupied mode.

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TAB or CxA?

• VAV terminal air flow modulates from minimum to
  maximum air flow settings as required to maintain
  space temperature at setpoint.
• VAV terminal air flow modulates from minimum to
  maximum air flow settings as required to maintain
  space temperature at setpoint. Minimum air flow
  setting is automatically reset during unoccupied
  periods to minimize reheat.

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Sample Findings
Hot water valve motion impeded by piping layout
EMC no date (a)
Exhaust fan hardwired in an always on position
Mittal and Hammond 2008
Rust indicates poor anti-condensation heating
control setpoints in supermarket refrigeration
cabinet Sellers and Zazzara 2004
Source Evan Mills, LBNL, 7/21/2009
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Sample Findings
Inadequate fan cooling and excessive fan power
due to poor fit between the light fixture and
ducting, causing significant duct leakage Martha
Hewett, MNCEE
Zone damper actuator arm broken (no temperature
control) Martha Hewett, MNCEE
Masonry unit balanced on conduit above door ASHE
Source Evan Mills, LBNL, 7/21/2009
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Sample Findings
Photosensor sees the electric lamps rather than
task-plane illumination Deringer 2008
Building envelope moisture entry Aldous 2008
Air leakage in an underfloor air-distribution
system Stum 2008
Photosensor (for daylight harvesting) shaded by
duct Deringer 2008
Failed window film applications
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Retro-Commissioning
Commissioning for Sustained Building
Performance September 29, 2011 Marriott Birmingham
, AL
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Source Evan Mills, LBNL, 7/21/2009
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Retro-Commissioning Process
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Process Frequency
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Energy Cost Reduction Opportunities

• Utility Rate Analysis
• Training and Education
• Unbundled Natural Gas Purchasing
• Power Factor Correction
• Lighting Controls and Retrofits
• Weekly Equipment Schedules
• Night Set-Back / Night Set-Up
• Supply Air Temperature Reset
• Minimum Airflow Settings
• Free Cooling

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Energy Cost Reduction Opportunities

• Building Pressure Control
• Variable Speed and Volume Control
• Pumping Modifications
• Air Terminal Settings
• Exhaust Fan Balancing
• Energy Management System (EMS) Tuning
• Review EMS Graphics

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Typical Commissioning Cost
Source Evan Mills, LBNL, 7/21/2009
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Operational Cost Savings
Source Evan Mills, LBNL, 7/21/2009
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Return on Investment
Source Evan Mills, LBNL, 7/21/2009
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Case Study A
Item Before After Savings () Remarks
Electricity Consumption (kWh) 10,175,200 8,884,600 12.7  
Average Peak Demand (kW) 1,499 1,403 6.4  
Electricity Consumption (kWh/SF/year) 49.9 43.6 12.7 Average is 32 kWh/SF/year
Electricity Load Factor () 77 72 6.7  
Average Peak Demand (watts/SF) 7.3 6.9 6.4  
Natural Gas Consumption (MMBtu) 35,507 28,283 20.3  
Natural Gas Consumption (Therms/SF/year) 1.7 1.4 20.3 Average is 1.23 therms/SF/year
Total Energy Consumption (MMBTU) 70,235 58,606 16.6  
Energy Utilization Index (kBTU per SF) 396 330 16.6 Average is 232 kBTU/SF/year
Total Energy Cost (/year) 1,121,614 801,141 28.6  
Energy Cost Index (/SF/year) 5.50 3.93 28.6 Average is 2.85/SF
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Case Study A Retro-Commissioning Economics

Retro-Commissioning Cost 55,000
ATC Retrofits 353,000
Infrastructure Upgrade 238,000
Total Cost () 646,000
Less Electrical Service (210,000)
Less Water Chiller And Tower (250,000)
Less Cath Lab AHU (90,000)
Less CEP Expansion (218,000)
Net Cost () (122,000)
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Case Study B
Item Before After Savings () Remarks
Electricity Consumption (kWh) 7,808,800 5,249,800 32.8  
Average Peak Demand (kW) 1,230 929 24.5  
Electricity Consumption (kWh/SF/year) 44.0 29.6 32.8 Average is 32 kWh/SF/year
Average Peak Demand (watts/SF) 6.93 5.23 24.5  
Natural Gas Consumption (MMBtu) 43,114 23,523 45.4  
Natural Gas Consumption (Therms/SF/year) 2.43 1.33 45.4 Average is 1.23 therms/SF/year
Total Energy Consumption (MMBTU) 70,137 41,457 40.9  
Energy Utilization Index (kBTU per SF) 393 233 40.6 Average is 232 kBTU/SF/year
Total Energy Cost (/year) 916,182 540,058 41.1  
Energy Cost Index (/SF/year) 5.16 3.04 41.1 Average is 2.85/SF
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Case Study B Retro-Commissioning Economics

Preliminary Energy Audit 8,350
Phase 1A and 1B 199,439
Total Cost () 207,789
Simple Payback 9 Months
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Questions
Michael W. Hardy, PE, LEED AP, CCP Phone
[phone] Email mikewhardy_at_eaton.com