STANDARD PROTOCOL FOR MEASUREMENT OF FAN AND COOLING SAVINGS FROM COMMERCIAL-SECTOR PACKAGED ROOFTOP HVAC UNITS

Regional Technical Forum

March 13, 2012

Vast Contributions to Get to This Point

Started 2004 - Five Phases of RTF work Significant “Products” and “By-Products”

Much simplified measurement approach (standard protocol) Better understanding of RTU systems & opportunities Better understanding of measurement and sampling error RTU power measurement data library New Honeywell controller

Dozens of dedicated individuals

Issue: Highly Variable Savings by Site and by Program

From BPA 2009

4

Recent Steps to Get to Savings Methodology

Complete collecting & storing the 12-month data Set up a functioning data repository with open access Determine confidence in annual savings methodology Savings too variable for a UES – Need Protocol Understand the persistence of fan schedules Examine rooftop metered temperatures vs NOAA site Initial Calculator developed

Reliability of savings method analyzed & tested Data block analysis 10, 15, 21, 28 days Refined seasonal windows for pre & post measurements Calculator improved, streamlined, user-friendly & dependable Standard Protocol conformed to guidelines CT versus True Power tested and rejected (for now) Scope of applicability refined

2009-2011 Research Funded by BPA via Cadmus. Gets RTUG review & technical guidance.

2011-2012 Development by Coordinated RTF

RTU Subcommittee Involvement

RTUG Meetings– 2011: January, August, December– 2012: January, February, March

Protocol/Calculator Development Discussions (Contractors, RTF staff, subcommittee members)

– December 7, 2011– December 19– January 31, 2012– February 9– February 16

RTU Subcommittee Members

67 Members (Bold members participated in two or more protocol deliberations):

Alan Budman, Alan Mountjoy-Venning, Amy Patenaude, Anthony Hernandez, Bjorn Jensen, Bob Davis, Bruan Van Buskirk, Buck Taylor, Chris Helmers, Dale Gustavson, Dan Gaherty, Daniel Wilkinson, Danny Miller, Dave Baylon, Dave Robison, David Davis, Fred Gordon, Glenn Hensen, Graham Parker, Greta Zink, Jack Callahan, Jack Zeiger, Janice Peterson, Jeff Cole, Joe Schmutzler, John Palmer-Williams, Jon Linn, Jon Powell, Jonathan Wooley, Justin Sipe, Karen Des , Srinivas Katipamula, KC Spivey, Ken Keating, Kristin Heinmeier, Lauren Gage, Levi Westra, Marie McMahon, Mark Jerome, Marshall Hunt, Mike Kennedy, Mike Little, Mike Lubliner, Mira Vowles, Nick O'Neill, Paul Kyllo, Paul Needham, Peter Meyer, Jay Pilliod, Mark Rehley, Rob Penney, Erin Rowe, Sean Gouw, Shea Dibble, Sherry Hu, Stan Price, Judith Stasack, Danny Taasevigen, Tom Foley, Tom Leinhard, Will Miller, Will Price, Travis Reeder, Alan Fraser

Contractors: (NBI, NorthWrite, Cadmus, PECI, SBW) Mark Cherniack, Howdy Reichmuth, Bill Koran, Josh Rushton, Reid Hart, Mike BakerRTF Staff: Charles Grist, Mark Kendall

Standard Protocol Sections

PURPOSE

DEFINITION OF KEY TERMS

ELIGIBLE SYSTEMS AND MEASURES

– Rooftop package systems with constant speed supply fan + constant or variable speed compressors

– Split systems– Heat pumps in cooling/ventilation modes only –heating must

be turned off REQUIRED COMMISSIONING

SAMPLING PROCEDURE -NA

SUNSET CRITERIA

REQUIRED KNOWLEDGE AND SKILLS OF PRACTITIONER

Standard Protocol Sections-2

DATA COLLECTION REQUIREMENTS

PROVISIONAL DATA COLLECTION REQUIREMENTS- NA

SAVINGS ESTIMATION STEPS

ESTIMATE OF TYPICAL MEASUREMENT COST

RELATIONSHIP TO OTHER PROTOCOLS/GUIDELINES

USER’S GUIDE TO THE SAVINGS CALCULATOR

Final RTU Protocol Issues Raised & Addressed-1

Test on multiple sites to better understand confidence interval

– Annual use estimates typically plus/minus 5%

– Savings estimates plus/minus 20% WHEN savings >25% of annual use

Confidence intervals are wide at the individual unit level

Unit precision levels are low, but can have confidence in program wide savings

Limits of the protocol are stated with eligible measures identified and in field measurement timing

Calculator metrics for measurement error:

– R-squared and data range checks

RTU Protocol Confidence LimitsLimited Sites

• Confidence limits are normalized relative to annual energy• Confidence limits highest for metering periods starting in late June to

mid-July• Confidence limits of +- 5% are achieved with metering periods starting

in late May and early August

RTU Measure Savings Confidence

RTF Policy Considerations Guidelines call for 80% of cases to be +- 20%

RTU confidence in pre- and post- are 5% of the annual use

The effect of the 5% error on the savings is greater than 5% example: 5% error applied to savings of 50% of annual = 10% error relative to the savings

When savings between pre and post are small Guidelines standard may not be met

Need consideration for small savings measures

Final RTU Protocol Issues Raised & Addressed-2

Pre & Post measurement scheduling:

– Can we do Pre- in August and Post- in May?

o Yes, but additional effort required ~50% cost--need to fully document set points/schedules and either leave monitoring on all winter or take off/put on

– Can we do week-on/week-off testing?

o Yes, better way to test only for measures that can be turned on/off. Few measures: controls-related/economizer; added labor costs

Eligible system/measures included, but not specifically tested – split system– variable speed compressor– Demand Control Ventilation (depends on fan cycling/VSD)

Final RTU Protocol Issues Raised & Addressed-3

System & Measure Exclusions—potential for ‘Provisional’ Protocol

– VSD supply fan, variable refrigerant flow

– Heat pump heating is in development, not yet ready for Provisional Protocol, Savings Calculator cannot yet handle

Hone & specify Protocol measurements: See Protocol Section 8

Develop Savings Calculator steps: See Protocol Section 10

Cost to implement the protocol revised: See Protocol Section 11

Annualized Energy Use / SavingsCalculator

Working toward 3rd-party review of Protocol and Calculator by PNNL

Statistics package is of value—needs funding– Regression stats development– Annualization stats development– Stats in Calculator output– Charts of residuals/confidence intervals– Chart for annualization uncertainty

Other Issues of Note

Costs to implement the measurement protocol are not fixed, cost estimates based on mature program and lessons learned

Savings Calculator is for a single unit verification; not for program evaluation

When are savings too small to detect?

– Depends on measures applied to the RTU

– Alternate (lower cost) calculation options: changing fan schedule during non-cooling hours--don’t need the Savings Calculator to estimate savings, just multiply fan watts x time

Protocols and calculators need ongoing, variable RTF support

– Need to add to 2013 work plan & budget

– Savings Calculator statistics package development

Program Evaluation Metering Sample Size

Sample sizes to achieve an 80% confidence > 20% precision measurement for evaluating energy savings from similar programs on similar sites

Sample sizes are not directly related to the per unit savings protocol and Savings Calculator

RTUG Committee Recommendation

RTUG is being polled for support and any final comments on the proposed Standard Protocol

Will report results to RTF

Proposed RTF Motion

The RTF approves the Rooftop Unit Standard Protocol for active status

Provisional Protocol to be developed for future RTF consideration