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Technical And Financial Benefits Of Retro-Commissioning Initiatives Society of American Military Engineers Northern Virginia Post January 6, 2011 Presented By: Robert S. Bucey, PE, CEM, LEED AP
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What is Retro-Commissioning? Systematic investigation process for improving and optimizing the operation and maintenance of buildings Primarily focuses on energy-using equipment and low-cost improvements rather than expensive capital-intensive retrofit measures Involves detailed study of building system operation Faults in building systems are identified for resolution Control changes may be recommended that increase energy efficiency Economic analysis that calculates energy savings Follow-up required to verify that measures have been correctly implemented and have held up over time Can resolve problems that occurred during design or construction, or that have developed throughout the building’s life
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“Have you seen this?”
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Why Retro-Commission Now? Occupant comfort: Indoor air quality concerns Reduce employee absenteeism Reduce tenant turnover Improve employee productivity Improve thermal comfort Protect or enhance property condition: Protect against future liability Increased asset value of income-producing properties Fewer warranty claims
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Why Retro-Commission Now? Improved operation: Reduced maintenance calls Train building technicians on RCx process Create system-level benchmark to facilitate efficient monitoring of systems Provide single document resource for O&M staff Reduce operating cost / energy consumption: Problems never identified during initial building start-up Systematic problems in building operation Environmental problems Excessive equipment run times due to changes in occupancy or space use Malfunctioning equipment or sensors Control optimization issues Extend equipment life
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Why Retro-Commission Now? Cost avoidance !!!!!!
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Basic Steps In The RCx Process Document review Building walk through Organize utility data history Assess BAS and control system effectiveness Develop detailed work plan Establish current system performance Develop and implement functional performance test procedures Operator training program RCx manual, lessons learned and future RCx initiatives
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Retro-Commissioning Process Planning Select facility – prioritize groups of buildings Identify project objective (Performance/Energy/Both) Document performance requirements Perform initial site walk-through Establish energy benchmark Identify potential energy conservation measures Develop detailed work plan Assemble team & define responsibilities
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Retro-Commissioning Process
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Investigation Detailed review available documentation Diagnostic monitoring of building automation system Conduct functional performance testing Make “simple” modifications/repairs Document results Make recommendations for improvement Major repairs/modifications Update energy conservation measures
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Retro-Commissioning Process Fig. 1 Temperature data logger deployed Fig. 2 Power data logger deployed Fig. 3 Sample BAS Diaplay Fig. 4 Occupancy and photo sensor results for Operating Room
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Retro-Commissioning Process
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Turnover Develop scope of work documentation for improvements Provide operator training Compile retro-commissioning manual Share lessons learned Develop ongoing commissioning plan
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Where are the RCx Opportunities? (Examples) Simultaneous heating and cooling BAS programming vs. actual operation Correct and most efficient air damper sequencing Chilled water bypasses and leaks Corroded condenser coils Incorrect head pressure control and hot gas bypass connections Poor equipment access Equipment not responding to control system Temperature and humidity sensors out of calibration Control sequence not operating correctly Electric duct heaters with incorrect wiring Incorrect cooling load calculations
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Some RCx Lessons Learned Inadequate building documentation Access to building automation system data Systems “never ran right from day one” Zone level adjustments made but never tracked Changes made during construction “Improving Performance” may not always reduce energy consumption Set expectations up front Need buy in from all parties!
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Industry Results Our experience: 15% to 25% savings in energy alone GSA ARRA Program: Identified 2,794 energy conservation measures in 50 buildings Study of 643 buildings: over 10,000 energy-related problems, resulting in 16% median whole-building energy savings, with payback of 1.1 years
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Industry Results TargetLocationEnergy savingsProject cost ($/sf)Payback time (years) Local government buildings California14.3% source energy, 11% electricity, 34% gas 1.013.5 Class A officesConnecticut7.3% electricity0.621.37 Mixed commercialColorado7% electricity0.1851.51 University buildings California10% total source1.002.5 SupermarketsCentral California12.1% electricity0.140.25 Mixed commercialOregon10-15% electricity0.1751.24 Mixed commercial and educational California1.7-8.1% electricity0.403.0 Source: Evan Mills. 2009, 30-31. "Building Commissioning: A Golden Opportunity for Reducing Energy Costs and Greenhouse- gas Emissions"
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Industry Results Number of measures applied Type of deficiency solution Source: Evan Mills. 2009, 30-31. "Building Commissioning: A Golden Opportunity for Reducing Energy Costs and Greenhouse- gas Emissions"
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1 ROI Expectations Source: Evan Mills. 2009, 30-31. "Building Commissioning: A Golden Opportunity for Reducing Energy Costs and Greenhouse- gas Emissions"
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1 ROI Expectations Source: Evan Mills. 2009, 30-31. "Building Commissioning: A Golden Opportunity for Reducing Energy Costs and Greenhouse- gas Emissions"
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Options To Implement An RCx Program As an element of an overall energy plan Coordinate with predictive maintenance, facility condition assessments, capital R&R planning Combine with overall strategy to reduce deferred maintenance Seed program with annual funding to implement “low hanging fruit” initiatives; invest savings in further energy conservation measure implementation Canvas available rebates and invest in ECM implementation Energy services contract vehicle
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Questions Thank you for your attention
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