Examples of Commissioning Cost Savings Commissioning for Sustained Building Performance September...

Examples of Commissioning Examples of Commissioning Cost SavingsCost Savings

Commissioning for Sustained Building PerformanceSeptember 29, 2011

MarriottBirmingham, AL

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issioning for SustainedCom

missioning for Sustained

Building Performance


Birmingham, AL

Marriott9/29/11

What Are Trying to Avoid?

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Birmingham, AL

Marriott9/29/11

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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Birmingham, AL

Marriott9/29/11

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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Birmingham, AL

Marriott9/29/11

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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Birmingham, AL

Marriott9/29/11

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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Birmingham, AL

Marriott9/29/11

Exhaust fan hardwired in an “always on” position [Mittal and Hammond 2008]

Sample Findings

Hot water valve motion impeded by piping layout [EMC no date (a)]

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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Birmingham, AL

Marriott9/29/11

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]

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Birmingham, AL

Marriott9/29/11

Sample Findings

Failed window film applications

Building envelope moisture entry [Aldous 2008]

Photosensor “sees” the electric lamps rather than task-plane illumination [Deringer 2008]

Photosensor (for daylight harvesting) shaded by duct [Deringer 2008]

Air leakage in an underfloor air-distribution system [Stum 2008]

Retro-CommissioningRetro-Commissioning

Commissioning for Sustained Building PerformanceSeptember 29, 2011

MarriottBirmingham, AL

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Birmingham, AL

Marriott9/29/11


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Birmingham, AL

Marriott9/29/11

Retro-Commissioning Process

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Birmingham, AL

Marriott9/29/11

Process Frequency

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Birmingham, AL

Marriott9/29/11

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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Birmingham, AL

Marriott9/29/11

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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Birmingham, AL

Marriott9/29/11

Typical Commissioning Cost


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Birmingham, AL

Marriott9/29/11

Operational Cost Savings


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Birmingham, AL

Marriott9/29/11

Return on Investment


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Birmingham, AL

Marriott9/29/11

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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Birmingham, AL

Marriott9/29/11

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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Birmingham, AL

Marriott9/29/11

Case Study BItem 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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Birmingham, AL

Marriott9/29/11

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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Birmingham, AL

Marriott9/29/11

Questions

Michael W. Hardy, PE, LEED® AP, CCP Phone: (678) 254-1206Email: [email protected]

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