Mike Eardley, PE, LEED AP, CCP Director of Commissioning CannonDesign Brian Berg, Jr., PE, LEED AP,...

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