Mike Eardley, PE, LEED AP, CCPDirector of CommissioningCannonDesign

Brian Berg, Jr., PE, LEED AP, CSIPrincipalBerg Engineering Consultants, Ltd.

April, 2014

The Power of Retro-Commissioning

Illinois Healthy & HighPerforming Schools Symposium

•Commissioning (Cx) Definition•Cx Process•Cx Applied to Existing Buildings•Retro-Commissioning Examples•Human Factor in Buildings•Hot/Cold and Energy Concerns•Q&A

Agenda

High Performance Buildings

Characteristics• Functionality• Energy Efficiency• Indoor Environmental Quality• Comfort• Sustainability (ability to perform its function in a long term)

Building Systems Commissioning

• Buildings function as intended • Realize high system performance

• Promotes integration of systems• Document facility requirements

•Commissioning (Cx) is a comprehensive and systematic process to verify and document that new or renovated facility systems function completely as designed to meet the owner’s requirements

•Retro-Commissioning (RCx) is the commissioning of a building that has never been commissioned.

• Energy goals and low/no-cost measures often a focus

Commissioning Definition

Without Commissioning

• Placement and calibration of Sensors• Simultaneous Heating and Cooling• Incorrect function of air-side Economizer and other efficiency measures• Operating Schedule is not what is necessary, or assumed by energy model• Cycling daylighting and other systems

Energy Impacts

- Large effort in sustainable and energy efficient design- Will not be realized if design or intended use is:

misunderstoodignored

- Or if building systems are:operating incorrectlynot thoroughly tested

Purpose of Functional Testing

- Verification of an operational systemnot a trouble shooting exercise (in theory)

- Reduces adjustment and tuning during occupancy- Impacts

energycomfortmaintenancefunctionality

Types of Functional Testing

- Building Automation System- False load- Seasonal testing- Trend analysis

•Commissioning: Process applied to new construction or major building renovation

•Re-commissioning: Facility has previously been commissioned and is in need of a “tune-up”

•Retro-commissioning: Performed on facilities that have been in service and never commissioned

•Ongoing commissioning: Ongoing program of structured commissioning throughout the lifetime of a building

New and Existing Buildings

•Definition: Commissioning a building that never has been

• In practice: re-tuning systems

•Or, identify low-cost / no-cost measures to implement

• Site survey, owner interview, trending

•Drawings study, engineering calculation

Retro-Commissioning Process

• Energy measure identification

• Implementation

•Measurement & Verification

• Persistence

• SEDAC Retro-Commissioning Program

•ComEd Retro-Commissioning Program

Retro-Commissioning Process

Trending

- Functional testing before occupancy is a snapshot- Trending shows operation over time- Methods of trending

building automation systemportable data loggers

- Analyze trendsspreadsheet calculationssoftware tools

Ongoing Commissioning

- GoodCx process with

functional testing- Better

Re-Cx program- Best

Ongoing Cx- Combination of software,

engineering support, action

•Document current operation

• Identify opportunities for improvement

• Evaluate payback, consider measures

• Implement measures

• Verify measures

LEED for Existing Buildings

Typical Air Handling Unit

Typical Air Handling Unit – Components

economizervariable air

volume

hot water heating

chilled water cooling

Moving Parts

Common Problems – Air-side Economizer

- Damper is stuck / broken / non-functional- Control algorithms fighting

heating during economizermechanical cooling when free

cooling available- Outside sensor calibration or location

static pressure reset

supply air temperature reset

hot water reset

chilled water reset

demand control ventilation

zone level CO2 control

Controls

morning warm-up

occupied / unoccupied

Scheduling