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EER Analysis Results. Regional Technical Forum March 18, 2014. Energy Efficiency Ratio (EER) Definition. Given by ASHRAE as “…a ratio of the cooling capacity in Btu/h to the power input values in watts at any given set of Rating Conditions” Expressed in Btu/(W-h)
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EER Analysis Results Regional Technical Forum March 18, 2014
Energy Efficiency Ratio (EER) Definition • Given by ASHRAE as “…a ratio of the cooling capacity in Btu/h to the power input values in watts at any given set of Rating Conditions” • Expressed in Btu/(W-h) • Signifies the amount of power needed to remove heat from a space • Used as an interaction parameter in grocery UES measures that reduce case loads • Exception: Primary factor for direct refrigeration system reduction (i.e. Floating Head Pressure Control)
Energy Efficiency Ratio (EER) Use • EER is a single point estimate of efficiency • Usually given at AHRI standards: 80°F db/67°F wb • SEER looks at system efficiency over a given season • Site conditions are likely different than AHRI • DOE2.2R calculates an “annual average EER” value to arrive at seasonal efficiency • RTF uses this value in annual savings calcs for refrigeration measures
What do we reliably know about EER? • It is not easily measured in the field • Multiple variables exist among a population • Large sample likely needed to normalize results • Cost/site to obtain accurate measurements is large • Would results from field monitoring be more reliable than modeling? • Or more importantly, when does it matter?
What do we reliably know about the impact on UES measures? • Tasked PECI to perform a sensitivity analysis • Task 1 – Identify possible EER range • Task 2 – Perform sensitivity analysis on measures • Task 3 – Define a single EER value for LT and MT • Use EnergySmart Grocer (ESG) data to determine representative refrigeration systems • Determine which measures have savings which vary significantly with EER
Subcommittee Process • Grocery Subcommittee discussed all tasks and draft findings over email and webinar • General agreement on analysis approach and results
EER Sensitivity Analysis Results • Determine likely range of EER values • High/Low values represent AHRI range • Median values found in ESG (used as base EER)
EER Sensitivity Analysis Results • Results show minimal impact on savings for component reduction measures despite a wide range of possible EER values • Ex. LED lighting, Anti-Sweat Heater Controls • Large variation for system reduction measures • Ex. Autoclosers, Strip Curtains, Gaskets • Subcommittee agreed range presented was representative of field conditions • Wanted to define EER further for UES measures
EER Definition Work • PECI to use ESG audit data to develop representative LT & MT refrigeration systems • Representative systems from ESG mapped to eQuest to generate hourly reports • Grocery subcommittee reviewed mapping • No substantive changes requested • Hourly reports used to generate annual EER value for use in UES calculations
EER Definition Work – Draft Results * Weightings developed using grocery store audit data; 75% multiplex, 25% standalone
EER Definition Review Comments • Subcommittee agreed with general methodology used • Had a comment to use evaporator load to calculator EER instead of condenser load • Likely to results in about 15% lower EER value • Less of an impact on measure savings • Will require minor work to eQuest outputs • Not available in time for March RTF meeting • PECI to develop and present findings to group
EER Definition Proposal • Subcommittee recommends including results table and instructions for use in RTF Standard Information Workbook • Legacy measures • Use results to update • All small savers to use results of analysis • New measures • Use sensitivity analysis to determine EER impact • Values acceptable to use if interaction is +/-10%
Staff Recommendation • Reference the EER analysis in the SIW • Update final table with values from PECI • Grocery subcommittee will review results • Use to update legacy UES measures • Only where EER contributes minimally to savings or the measure is a small saver • Use table on applicable future measures after sensitivity analysis has been performed
Proposed Decision “I _______________ move that the RTF approve the EER analysis as presented and, following a diligent review by the Grocery Subcommittee, include the final EER results table in future updates of the Standard Information Workbook for use in UES measure assessments.”