performance monitoring for efficiency · “the building performance tracking handbook,”...

THOMAS ANDERSON, CCPEMILY CROSS, MASc, PEng, CEM

Burlington, Vermontcx‐associates.com

tom@cx‐associates.comemily@cx‐associates.com

Performance Monitoring for Efficiency

Efficiency Vermont is a Registered Provider with The American Institute of Architects Continuing Education Systems (AIA/CES). Credit(s) earned on completion of this program will be reported to AIA/CES for AIA members. Certificates of Completion for both AIA members and non-AIA members are available upon request.

This program is registered with AIA/CES for continuing professional education. As such, it does not include content that may be deemed or construed to be an approval or endorsement by the AIA of any material of construction or any method or manner of handling, using, distributing, or dealing in any material or product.

Questions related to specific materials, methods, and services will be addressed at the conclusion of this presentation.

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Learning Objectives

Understand why performance monitoring is necessary

Learn how to apply real time performance monitoring economically and

effectively

Know which basic performance metrics to include on every project

Understand the best approaches to long term performance data archiving

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Course EvaluationsIn order to maintain high‐quality learning experiences, please access the

evaluation for this course by logging into CES Discovery and clicking on the Course Evaluation link on the left side of the page.

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Performance Monitoring

• Part of the ongoing commissioning process for buildings and building systems

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What is Commissioning?

• Comprehensive QA process for buildings and building systems

Soup to Nuts– Design Review– Equipment and Instrumentation Validation– Functional Performance Testing– Continuous Commissioning

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Soup to Nuts– Design Review– Equipment and Instrumentation Validation– Functional Performance Testing– Performance Monitoring

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Case Study: BIA CxBurlington International Airport

Chiller Plant Upgrade AHU/Boiler Upgrade

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Case Study: BIA Cx

Burlington International Airport

Chiller Plant Upgrade

Frictionless (Magnetic Bearing) Centrifugal ChillerTwo Fan Induced Draft Cross flow Cooling TowerBTU Meters with Insertion Turbine Flow Meters

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Case Study: BIA Cx

Burlington International Airport

HVAC Upgrade

Rooftop/VAVs (2)Condensing Boilers (2)Existing Ductwork

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Design ReviewChiller Plant

• The control diagram at this time lacks the capability for facility operators monitor how much power the pumps and the chiller consume…we suggest that pump and chiller KW values be imported into the DDC control system and displayed on the DDC graphics…display of chiller kW, tonnage, and a kW per Ton performance metrics.

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Design ReviewChiller Plant

• The piping diagram calls for glass “stick” type piping thermometers. These stick type piping thermometers are very difficult to read in the field. We suggest the use of round dial type piping thermometers. These are far easier to read in the field and will benefit facility operating staff.

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Design ReviewHVAC Systems

• Cross connects Cold/Hot duct cross connection: The new VAV boxes are shown connected to either the existing hot or cold duct mains…To mitigate main duct pressure losses, could the separate hot and cold duct mains be cross connected to equalize air flow?

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Equipment Checkout: Leaks• Air Leaks: loss of conditioned air

wasted fan energy– Existing ducts: seams, joints, corners, not sealed

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Equipment Checkout: Leaks• Air Leaks: loss of conditioned air

wasted fan energy– New equipment: damaged closure mechanisms and gaskets, as installed

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Equipment Checkout: Leaks

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Equipment Checkout: Pressure Drop • VAV box air inlet• 4 inch round duct runout installed• 6 inch round duct runout specified• 4 to 5 times inlet static pressure drop

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specified installed

C0 = 19 C0 = 89

Equipment Checkout: Pressure Drop

• Piping strainer inaccessible

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Top of duct

Roof

Strainer

Equipment Checkout: Retrofit• Known Issue

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Equipment Checkout: Retrofit• Opportunities for Communication

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Equipment Checkout: Per Drawings?

• Cogged vs. Standard fan V‐belts

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Equipment Checkout: Per Drawings?

• Counterflow piping

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Equipment Checkout: Air Quality• Standing water not permitted per ASHRAE 62.1• CHW pipe insulation remained to be installed, no drain

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Instrumentation: Gauges and Sensors

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Instrumentation: Gauges and Sensors• Pete’s plugs for validation of piping sensors and gauges• Round vs. Stick thermometers are easier to read

• Calibrate/compare against NIST certified test instruments• Location of thermostats and control system sensors

– Avoid interference from direct sun or equipment exhaust

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specified installed

Instrumentation: DDC Program Validation

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Instrumentation: DDC Program Validation

• Sensor scaling errors– 0 to 5 V or 0 to 10 V?– Chiller percent load displayed found to be one third of actual per BTU meters

• Physical checks– Outside air dampers found in a position other than commanded by the DDC system

– Too much outside air being brought in (expensive)

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Functional Performance Testing: Chiller

• Chilled water pump rate of flow change found to be too rapid

• Minimum chiller flow was not maintained

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Functional Performance Testing: HVAC

• Software programmed with an economizer mode lockout when the outdoor air temperature drops below 40F.

• Outside Air Control: configured for damper position rather than flow.

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Functional Performance Testing: ControlsChiller MER exhaust fan stays on after alarm clears

MER temperature > 80FRefrigerant leak detection

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Up Next: Performance Monitoring

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Thomas Andersontom@cx‐associates.com

802.861.2715 x11

Why Performance Monitoring?

• How many miles per gallon is my building getting?

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Building Energy Tracking

• How does my building compare to peer building?

• Am I using what is expected?• Has anything changed?• Am I improving over time?

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System Energy Tracking

• Are systems behaving as they should?• How efficient are my systems?• Today’s performance vs. 3 years ago?

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• Building energy efficiency depreciates 2% to 3% a year

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Expectations for building operators:• Manage systems efficiently• But we do not provide efficiency feedback in our designs

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Energy Management

You cannot manage…

…What you cannot measure

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What To Measure

•Building Service‐ Electrical‐ Fuel

•Central Plants‐ Heating‐ Cooling‐ Refrigeration

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Other Sub Groups

•Key Lighting Circuits‐ Exterior Lighting‐ Key Lighting Zones

•Computer Rooms•Central Air Handlers•Central Pumps

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Devices

BTU Meters• Liquids:

‐ Heating Hot Water‐ Chilled Water‐ Domestic Hot Water

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Turbine Meters

•Closed Loop Fluids• Fairly Clean Water

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Turbine Meters

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Ultrasonic Meters

•Clamp‐on•Non‐Invasive•Good for Retrofits•Clean or Unclean Liquids

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Ultrasonic

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Electromagnetic Meter

• Critical water flow applications• Open loop• “Dirty Water”

‐ Gray Water‐ Sea Water‐ Process Liquids

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Electromagnetic Meter

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Power Monitoring

• Key Electrical Sub‐circuits‐ Exterior Lighting / Interior Lighting

• Key large equipment‐ Chillers‐ Large Compressors, etc…

• Primary Electrical Service – Possibly

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Power Monitoring

•Measure True kW•Also:

‐ Voltage‐ Power Factor

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Power Monitoring

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VFD Power Loss

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VFD Power Loss IO

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VFD Power Loss – Network Interface

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Performance Metrics

Building Annual Energy:• kBTU/Square Foot/Year

• EUI: Energy Use Index• “Miles per Gallon” for Buildings

• For Electrical and Fuels• Also: kWH/Square Foot/Year

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Unit Conversion

• Electrical:‐ kWH/YR x 3.41 kBTU/kWH

• Fossil Fuel:‐ Fuel Units/YR x BTU Per Unit/ 1,000

• Units Delivered to Building (not source Energy)

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Information Presentation

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Cooling Plant

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Cooling Plant

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Typical Pump

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Cx of Performance Monitoring

Commissioning:• BTU Meters: Water• Upstream/Downstream straight piping• T&B Accuracy Verification

‐ vs. Balance Valve‐ vs. Pump Curve‐ vs. Equipment Pressure Drop

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BTU Meters: Water

• Temperature‐ +/‐ 0.1°F Accuracy Goal‐ Insertion Temperature Probe‐ ≈ with +/‐ 0.1°F Accuracy ‐ ≈ RTD Type: Not Thermister‐ Must Have Insertion Test Ports!

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Power Meters

•Goal: +/‐ 0.1 kW (True kW)•3 Phase: Sum of 3 legs•Precision field meter required

‐ +/‐ $2,000 meter cost

• Stable operation required

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VFD Based Power

• +/‐ 0.1 kW Accuracy Goal• Compare VFD Display with building BMS• Check for 0.0 KW when off

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Data Acquisition

•Capture Related Data•Outside Air Temperature (All)•Cooling Plants

‐ OA Enthalpy‐ CHWS Temperature‐ Condenser Water Temperature

‐ To Chiller

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Correlate Related Data

• Heating: BTUH vs. Average Hourly OA Temp• Fans: kW/kCFM/HR vs. Average Hourly OA Temp

• Cooling Plant‐ kW/Ton vs. Average Hourly Enthalpy‐ kW/Ton vs. Average Hourly Condenser Temp

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Data Management

Central Plants• Data Frequency: Every Minute• Then 15 Minute Average• Then Hourly Average• Then Daily Average, etc...

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Data Management

• Too Much Data to Store•Develop Average Data

‐ For Permanent Storage

•Dump detailed data after +/‐ 90 days or so

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Further Resources

“The Building Performance Tracking Handbook,” California Commissioning Collaborative – cacx.org

ASHRAE Guideline 22‐2008 –“Instrumentation for Monitoring Central Chilled‐Water Plant Efficiency”

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Further Resources

CBECS – Commercial Building Energy Consumption Survey

Benchmarking Building Energy Performance Oak Ridge National Laboratory –

eber.ed.ornl

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Questions?

Thomas Andersontom@cx‐associates.com

802.861.2715 x11

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110 Main StreetStudio 1BBurlington, VT 05401802.861.2715

Emily Crossemily@cx‐associates.com

802.861.2715 x14Visit our blog at: http://buildingenergy.cx‐associates.com/

performance monitoring for efficiency · “the building performance tracking handbook,”...

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