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Draft Standard Protocol for Cooling and Fan Savings from RTUs

Draft Standard Protocol for Cooling and Fan Savings from RTUs. RTF March 1, 2011. RTF-RTUG Time Line. NEEA 2002-2004. RTF Phase I 2004. RTF Phase II 2006-2007. RTF Phase III 2009-2010. Test Protocol to Measure Savings Large BPA Field Test

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Draft Standard Protocol for Cooling and Fan Savings from RTUs

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  1. Draft Standard Protocol for Cooling and Fan Savings from RTUs RTF March 1, 2011

  2. RTF-RTUG Time Line NEEA 2002-2004 RTF Phase I 2004 RTF Phase II 2006-2007 RTF Phase III 2009-2010 • Test Protocol to Measure Savings • Large BPA Field Test • Goal: Deemed, Deemed Calculation or MV Protocol • Scope Phase IV • Pilot Field Work • Inconclusive Savings • Identified potential deadband issues • Not ripe for Market Transformation • Secondary Source Review • Frequency of Problems • Scope Next Phase • Lab Testing • Limited Field Test • Honeywell Sensor Redesign • Develop Protocol to Measure Savings • Scope Next Phase

  3. Rooftop Unit Working GroupTime Line RTF Phase IV 2011 RTF Phase V 2012 RTF Phase VI 2013 RTF Phase VII 2014 • Analyze annual data • Propose annual savings estimation methodology • Propose M&V protocol • Elements of a regional Strategic Plan/Roadmap • New/next generation technology • Recommendation to RTF for next steps • Expand West Coast collaboration • Deep RTU retrofit program • New gen evaporative • Adaptive controls • Implement Roadmap elements • Web-enabled T-stat approach verified with 2-yr data analysis • Premium Ventilation benefit established • Stronger regional/national collaboration • Identify deep retrofit options • Embedded RTU performance monitoring/FDD specification • Test deep retrofit options • Fix DOE2/eQUEST

  4. Rooftop Unit Working Group (End of) Time Line RTF Phase XXXIII 2046 • DxRTU’s illegal • Evaporative/hybrids, VRF and ground source heat pumps required by law • Self-replicating neural networks with self-diagnosing, self-regulating, & self correcting controls on all units • Bomb proof economizers/controls • 7-10 year maintenance intervals • HVAC OEM’s required to provide performance guarantee over product life • Cherniack Retires

  5. Today • Review Protocol & Calculator • Review issues raised & addressed at RTUG • Staff Recommendation • Resolve any RTF issues • Finalize protocol & calculator under proposed guidelines & template • Staff to scope task to finalize protocol, test calculator, compile documentation and conform to format

  6. Regional RTU Overview • Varied programs, participants, utilities and approaches across the region • Project Goal: Protocol for cooling & fan savings usable across programs, climates and building types • Collaborative research sponsored by • BPA, ETO, Avista, Idaho Power, RTF • Technical analysis by Cadmus, NBI, QuEST, Stellar Processes, Ecotope & others

  7. It took a village…

  8. The RTUG Process 2010 • 7 RTUG Subcommittee meetings • Prioritized research needed to develop protocol • Cadmus & NBI doing analytics • Feedback from RTUG Subcommittee • Lots of RTUG participation 20-30 people each • In- and out-of-region (CA/NE) participation • Other issues taken up too: DCV, Premium Ventilation, whole-building approach

  9. The Data PNW RTU 2008-09 Metered RTUs Avista = 2 pair side-by-side metered @ 12 months BPA RTU Pilot = 161 metered, 24 units @ 12 months Energy Trust of Oregon = 13 metered Idaho Power = 9 metered @ 12+ months (still going) >> The nation’s largest, most robust, publicly available measured RTU data set http://www.nwcouncil.org/energy/rtf/subcommittees/rtug/2009_rooftop/Default.aspx

  10. Current RTU Savings Research 2010-13/ Web-based T-Stats (Dreamwatts) BPA 2010 start: 44 RTUs on 3 buildings 24-36 months DA; Cadmus analysis on first 12 months only with report March 2011 RTF discussion on data analysis for trailing 12-24 months of BPA units Data available to upload to Regional RTU Database RTF 2011 start: 3 heat pumps @ 24 months w/analysis

  11. Results for 2010 • Substantial empirical & analytical basis to estimate savings attributable to RTU measures • Huge progress has been made! • Techniques are being used in impact evaluations • Developed protocol & associated calculator

  12. What Did We Find? Accurate measurements require understanding the distribution of daily temperatures and proper timing of metering Differences between hot east side metering and mild west side metering Measurements of average program savings at 90% confidence/10% precision can be achieved Buildings exhibit natural changes over a summer: ‘building squirm’ Methodology will pick up any spontaneous building operations (squirm) in between pre-post- measurement periods

  13. Issue: Highly variable savings From BPA 2009 Probably not deemable UES Site-specific savings depend on as-found & program measures eg: ETO adding economizers to 3-4 ton RTUs

  14. Key Elements Addressed by Cadmus & NBI & RTUG -1 • Protocol issue raised: • Does a single signature accurately show annual energy use? • How issue was resolved: • Tested the signature prediction for 10+ months modeled data and 10+ months measured data How issue is expressed in the protocol: - The protocol is based on a single signature for annualization

  15. Basic Savings Algorithm Energy signature based on kWh/day and average daily temp • Horizontal line = fan energy • Sloped line = fan + compressor energy • Balance point = intersection of horizontal and sloped lines • Use with TMY3 data to annualize energy

  16. Key Elements Addressed by Cadmus & NBI & RTUG-2 • Protocol issue raised: • Does the duration of metering affect the accuracy of the prediction? • How issue was resolved: Data block analysis was done April – October in 1 week increments @ 10, 15, 21, 28 day intervals How issue is expressed in the protocol: - The protocol uses a 4 week measurement interval as most accurate; early/late summer intervals produce the same performance estimates within a few percent

  17. Key Elements Addressed by Cadmus & NBI & RTUG-3 • Protocol issue raised: - Does this method lead to biased predictions? • How issue was resolved: • Examined statistics from the data block analysis that showed hot mid-summer data can bias predictions especially on the East side How issue is expressed in the protocol: - The protocol recommends not using data from 1st week in July through 1st week in August

  18. Key Elements Addressed by Cadmus & NBI & RTUG-4 • Protocol issue raised: - Use of of site temperature data vs. recorded hourly data from local weather station data • How issue was resolved: • Use of local hourly data was successfully tested as source of the temp data for deriving the energy signature How issue is expressed in the protocol: - Protocol recommends use of data from local source within limits, otherwise use shielded site-based

  19. Key Elements Addressed by Cadmus & NBI & RTUG-5 • Protocol issue raised: • Sample size for M&V to achieve 90% confidence/10% precision • How issue was resolved: • Statistic were analyzed to determine sample sizes 1,000 RTUs: 137 500 RTUs: 129 100 RTUs:88 How issue is expressed in the protocol: - The protocol includes a table to guide sample size

  20. Key Elements Addressed by Cadmus & NBI & RTUG-6 • Protocol issue raised: • Can the annualized protocol be applied to VSD on compressor/fans or to VRF technology • How issue was resolved: • No specific work has been done yet, but the approach could and should be applied; need method to compare How issue is expressed in the protocol: - Not currently used in the protocol

  21. Key Elements Addressed by Cadmus & NBI & RTUG-7 • Protocol issue raised: • How can the field M&V be accomplished at lower cost? • How issue was resolved: • Used nearby weather station data in lieu of site temp data; used CT in lieu of true power measurement; How issue is expressed in the protocol: - Adjusted protocol to use these inputs

  22. Accurate Savings Estimate – West/East Sides Needs shortest possible measurement intervals to avoid building operation changes Need 4 week measurement during recommended metering window to capture sufficient weekend data Pre-measurement window 3rd wkMay through 1st week July Post-measurement window 2ndwkAug through 4thwk Sept Summer data usually shows no baseload in avg daily –needs to be calculated from minute data In practice: regressions based hot weather 1stwk July through 1stwk August can bias annualized predictions due to limited cool weather data (limited or no economizer use)

  23. Base Load Analysis 23 Examined for statistical differences in the base load calculation: calculated error did not affect sample size Found differences due to using more power in winter: heating fan energy

  24. Related Non-Protocol Issues Not Resolved Longevity of fan and t-stat settings Air flow issues: - How to treat negative savings from upgrade to minimum ventilation or ASHRAE 62.1? - Programmatic: in field measurement/reset options – use of DCV as a proxy? - Building code requirement - Program benefit-cost issue Measure life: 6th Plan = 5 years for O&M?

  25. Key Elements of Calculator • RTU power by minute; could be from single calibrated CT • RTU outside air temperature by hour from site minute data or hourly local weather station if acceptable • RTU supply air temperature by minute; not necessary for annual usage estimate, but useful for estimating minimum percent OSA • Annual histogram for normal average daily temperature at site from local TMY data

  26. Key Element: Normalized Annual Output

  27. Key Observations Protocol needs graphical data quality review Protocol performs annualization & normalization Signature will show economizer operation changes The data should be explicitly segregated by weekday and definable weekend Hourly load shape is available

  28. Summary • Protocol ready for finalization including • Resolving any remaining issues • Similar to the 7 protocols under development • Small team with contractor with conforming protocols • Cleaning up calculator • Add ProCost module • Finishing protocol template • Documentation of supporting data & protocol testing • Other conforming details • Bundle up for adoption & publishing • Staff to scope contract approach & budget

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