EER Analysis Results

Regional Technical ForumMarch 18, 2014

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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)

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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

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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?

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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

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Subcommittee Process

• Grocery Subcommittee discussed all tasks and draft findings over email and webinar

• General agreement on analysis approach and results Attendees September 26 March 6

Bill Koran (Northwrite) xMichele Friedrich (SMUD) x xMike Baker (SBW) xJosh Rushton (RTF) x xJames Russell (PECI) xBen Wright (PECI) xChristopher Rogers (PECI) x xCharlie Grist (NWPCC) x xNick O'Neil (NWPCC) x xEric Mullendore (PECI) xJamie Anthony (BPA) xAndie Baker x

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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 Range for Grocery StoresSystem Temperature Base EER Low HighMedium Temperature 11 9.4 15Low Temperature 7.0 5.6 9.3

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Sensitivity Analysis Results - MT

Autoclosers

Strip Curtains

Gaskets

ECM Controller for Walk-ins

Reach-in Case LEDs

LED Motion Sensors

ECM for Walk-ins

ECM for Display Cases

LED for Open Cases - T8

LED for Open Cases - T12

Anti-Sweat Heater Control

-55% -45% -35% -25% -15% -5% 5% 15% 25% 35% 45% 55%

19%

19%

19%

5%

4%

4%

5%

4%

4%

2%

2%

-25%

-25%

-25%

-6%

-6%

-6%

-6%

-6%

-5%

-3%

-3%

High EERLow EER

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Sensitivity Analysis Results - LT

Autoclosers

Strip Curtains

Gaskets

ECM for Display Cases

ECM for Walk-ins

LED Motion Sensors

ECM Controller for Walk-ins

LED for Open Cases - T12

LED for Open Cases - T8

Anti-Sweat Heater Control

-55% -45% -35% -25% -15% -5% 5% 15% 25% 35% 45% 55%

25%

25%

25%

8%

8%

8%

8%

8%

8%

4%

-53%

-25%

-25%

-8%

-8%

-8%

-8%

-8%

-8%

-4%

High EERLow EER

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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

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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

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EER Definition Work – Draft Results

Grocery System Configurations

Annual Average EER Value (Btu/hr-

W)

Average EER of System

Configuration (Btu/hr-W)

Average EER of Temperature (Btu/hr-W)

Weighted Average EER

for Temperature *

(Btu/hr-W)

Medium Temperature Multiplex

15

14

13 14

141512

Medium Temperature Standalone

11

12121212

Low Temperature Multiplex

6.9

7.4

7.3 7.3

7.47.97.6

Low Temperature Standalone

6.5

7.16.77.97.1

* Weightings developed using grocery store audit data; 75% multiplex, 25% standalone

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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

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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%

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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

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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.”