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
What is Retro-Commissioning?
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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
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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
“Have you seen this?”
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
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:
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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
Why Retro-Commission Now?
Cost avoidance !!!!!!
Basic Steps In The RCx Process
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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
Retro-Commissioning Process
 Planning
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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
Retro-Commissioning Process
Project Site and Comparison Building Energy Consumption
100.0
88.7
80.0
Annual Energy Consumption (kBTU/SF)
80.0
65.1
64.7
62.8
62.1
61.4
60.7
60.0
56.2
46.3
40.0
20.0
0.0
Building #1
Building #2
Building #3
Building #4
Building #4
Building #5
Building #6
Project Site
Building #7
Building #8
Retro-Commissioning Process
Financial Impact
Project Description
1
Winter Free
Cooling
Install plate and frame heat exchangers, piping, and
necessary controls that would allow complete chiller
shut down during periods when outdoor conditions
allow. This alternate also includes the addition of a
VFD on one of the existing chillers and additional
controls. NOTE: This project can be completed in
phases - the initial phases to maximize ROI
2
Enable
occupancy
control where
currently
programmed
into system
ECM #
Energy
Conservation
Measure
Project
Cost
Estimated
Annual
Operating
Savings
ROI
$350,000
$120,000
34%
This initiative would be to enable the Occupancy
Control feature that is currently programmed into the
2nd floor clinic spaces (fan coil units).
$31,500
$25,200
80%
3
Implement
The goal of this measure would be to implement
occupancy cycle occupancy cycle control strategy to areas/zones that
control for
would reset space temperature setpoints as well as
general spaces airflow requirements.
$99,000
$49,500
50%
4
The goal of this measure would be to implement
occupancy cycle control strategy to clinical
Implement
occupancy cycle areas/zones (patient rooms, exam rooms, diagnostic
control for
imaging spaces, etc.) that would reset space
clinical spaces temperature setpoints as well as airflow
requirements.
$117,000
$66,857
57%
$30,000
$17,143
57%
$175,000
$58,333
33%
5
6
The goal of this measure would be to implement
occupancy cycle control strategy to the OR Suite
that would reset space temperature setpoints as
Implement
occupancy cycle well as airflow requirements. Space pressure
control for OR relationships would be maintained during the
Suite
unoccupied cycle (e.g., OR's would remain under
positive pressure with respect to the adjacent
spaces).
This initiative is to install variable frequency drives
(VFD's) on air handling units and exhaust fan
systems that do not currently have them. There will
be subsequent cost savings realized through
Variable
reductions in energy consumption and reduced
Frequency
maintenance requirements by being able to control
Drives
fan speed and vary flow when conditions allow.
Another option here would be to install VFD's on the
heating hot water systems - this would involve
verification of HW control valve operation.
Retro-Commissioning Process
 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
Retro-Commissioning Process
Fig. 1 Temperature data logger
deployed
Fig. 2 Power data logger deployed
Fig. 4 Occupancy and photo sensor
results for Operating Room
Fig. 3 Sample BAS Diaplay
Retro-Commissioning Process
ID
Equipment
/ System ID
Finding
Recommendation
Measurement
Category¹
Priority²
Status³
Mechanical
AHU-1
Supply VFD will not start
or stop by BAS and runs
continuously at 100% do
to being place in
bypass.
Bring in VFD factory
technician to
troubleshoot problem
with drive and
determine possible
solutions.
2
1
F
M-2
AHU-1
Return Fan VFD needs
to be replaced. It is
being used for spare
parts.
Replace return fan drive
and tie back in to DDC.
2
1
F
M-3
AHU-1
Damper actuators are
not responding to BAS.
Troubleshoot modules
and replace if
necessary.
2
1
F
M-4
AHU-1
All dampers need
adjusting and lubricated.
Adjust and lubricate all
dampers and tighten all
setscrews.
1
2
F
M-5
AHU-1
All Filters need
changing.
Place filters on more
frequent schedule.
1
2
P
AHU-2
Supply VFD will not start
by BAS and runs
continuously at 100% do
to being place in
bypass.
2
1
F
M-7
AHU-2
Return Fan is in bypass
and runs at 100% do to
safety circuit being
open.
1
1
F
M-8
AHU-2
All dampers need
adjusting and lubricated.
1
2
F
M-1
M-6
Bring in VFD factory
technician to
troubleshoot problem
with drive and
determine possible
solutions.
Bring in VFD factory
technician to
troubleshoot problem
with drive and
determine possible
solutions.
Adjust and lubricate all
dampers and tighten all
setscrews.
Date
Started
Date Complete
Retro-Commissioning Process
 Turnover
 Develop scope of work documentation for improvements
 Provide operator training
 Compile retro-commissioning manual
 Share lessons learned
 Develop ongoing commissioning plan
Where are the RCx Opportunities? (Examples)
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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
Some RCx Lessons Learned
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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!
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
Industry Results
Target
Location
Energy savings
Project cost ($/sf)
Payback time
(years)
Local government
buildings
California
14.3% source
energy, 11%
electricity, 34% gas
1.01
3.5
Class A offices
Connecticut
7.3% electricity
0.62
1.37
Mixed commercial
Colorado
7% electricity
0.185
1.51
University
buildings
California
10% total source
1.00
2.5
Supermarkets
Central California
12.1% electricity
0.14
0.25
Mixed commercial
Oregon
10-15% electricity
0.175
1.24
Mixed commercial
and educational
California
1.7-8.1% electricity
0.40
3.0
Source: Evan Mills. 2009, 30-31. "Building Commissioning: A Golden Opportunity for Reducing Energy Costs and Greenhousegas Emissions"
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Industry Results
700
600
500
400
300
200
100
Type of deficiency solution
Source: Evan Mills. 2009, 30-31. "Building Commissioning: A Golden Opportunity for Reducing Energy Costs and Greenhousegas Emissions"
1
ROI Expectations
Source: Evan Mills. 2009, 30-31. "Building Commissioning: A Golden Opportunity for Reducing Energy Costs and Greenhousegas Emissions"
1
ROI Expectations
Source: Evan Mills. 2009, 30-31. "Building Commissioning: A Golden Opportunity for Reducing Energy Costs and Greenhousegas Emissions"
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
Questions
Thank you for your attention