technical and financial benefits of retro-commissioning initiatives society of american military...

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?

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

“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: 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

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 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


Project Site and Comparison Building Energy Consumption

80.0

64.7

46.3

60.761.4

65.1

56.2

62.8 62.1

88.7

0.0

20.0

40.0

60.0

80.0

100.0

Building #1 Building #2 Building #3 Building #4 Building #4 Building #5 Building #6 Project Site Building #7 Building #8

Ann

ual E

nerg

y C

onsu

mpt

ion

(kB

TU/S

F)

Retro-Commissioning ProcessFinancial Impact

EC

M #

Energy Conservation

Measure Project Description

Project Cost Estimated

Annual Operating Savings

ROI

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

$350,000 $120,000 34%

2

Enable occupancy

control where currently

programmed into system

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 occupancy cycle

control for general spaces

The goal of this measure would be to implement occupancy cycle control strategy to areas/zones that would reset space temperature setpoints as well as airflow requirements.

$99,000 $49,500 50%

4


control for clinical spaces

The goal of this measure would be to implement occupancy cycle control strategy to clinical areas/zones (patient rooms, exam rooms, diagnostic imaging spaces, etc.) that would reset space temperature setpoints as well as airflow requirements.

$117,000 $66,857 57%

5


control for OR Suite

The goal of this measure would be to implement occupancy cycle control strategy to the OR Suite that would reset space temperature setpoints as well as airflow requirements. Space pressure relationships would be maintained during the unoccupied cycle (e.g., OR's would remain under positive pressure with respect to the adjacent spaces).

$30,000 $17,143 57%

6 Variable

Frequency Drives

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 reductions in energy consumption and reduced maintenance requirements by being able to control 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.

$175,000 $58,333 33%


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


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

Retro-Commissioning ProcessID Equipment

/ System ID Finding Recommendation Measurement

Category¹ Priority² Status³ Date

Started Date Complete

Mechanical

M-1 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

M-6 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-9 AHU-2 All Filters need changing.

Place filters on more frequent schedule.

1 2 P

M-10 AHU-3

Supply VFD will not start or stop by BAS and runs continuously at 100% do to being place in bypass.


2 1 F

M-11 AHU-3 Dampers need adjusting and lubricated.


1 2 F


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)

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

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 ResultsTarget 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 Greenhouse-gas Emissions"

Industry Results

0

100

200

300

400

500

600

700

Num

ber

of m

easu

res

appl

ied

Type of deficiency solution


1

ROI Expectations


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

technical and financial benefits of retro-commissioning initiatives society of american military...

Documents

equipment life slide

buildings life slide

leed ap slide

building systems

energy benchmark

current system performance

financial benefits of

energy savings followup