Strip Curtains for Refrigerated Walk-in Boxes Michele Friedrich, PE – Sr. Engineer Eric Mullendore – Energy Analyst PECI 8/3/2010

Purpose Approval for new deemed measures for retrofitting strip curtains to walk-in coolers and freezers

Agenda Proposed Measures How do they save energy? CPUC EM&V Report Adapting savings for PNW Costs Effective Useful Life/Persistence Program Specifications Conclusions

Proposed Measures Measure Application Energy Savings (kWh/ ft2) EUL Measure Cost ($/ ft2) Benefit Cost Ratio Strip Curtains- Supermarket Freezer4434$ Strip Curtains- Supermarket Cooler1034$ Strip Curtains- Convenience Store Freezer304$ Strip Curtains- Convenience Store Cooler214$ Strip Curtains- Restaurant Freezer1344$ Strip Curtains- Restaurant Cooler254$ Strip Curtains- Rfg. Warehouse (MT)3504$

How do they save energy? ASHRAE Refrigeration Handbook, 2006.

CPUC/ADM EM&V Report Methodology 1.Measured the infiltration rates using tracer gas 2.Measured temperatures, relative humidities and door open times with loggers 3.Calculated annual kWh savings using data above as inputs into an hourly bin model Commercial Facilities Contract Group: Direct Impact Evaluation, Study ID: PUC ; Prepared by ADM Associates, Inc. et al. February 2010.

CPUC/ADM Report Results Average Evaluated Energy Savings (kWh/ft 2 ) Standard Deviation of Savings (kWh/ft 2 ) Relative Precision at 90% CI Supermarket Freezer % Supermarket Cooler % Convenience Freezer161844% Convenience Cooler142743% Restaurant Freezer % Restaurant Cooler181325% Refrig. Warehouse- MT %

Adapting Results for PNW Adjust for EER values found in PNW climate zones and system types* Adjust baseline barrier efficacy to reflect program design * EER and FLH values derived from DOE2.2R runs for various system types in PNW climate zones.

Energy Savings Assumptions Delta Efficacy (Proposed) EER (Proposed) Minutes Door Open/Day Delta Temp (ºF) Delta Efficacy (ADM) Nominal EER (ADM) Supermarket Freezer Supermarket Cooler Convenience Freezer Convenience Cooler Restaurant Freezer Restaurant Cooler Warehouse MT

Baseline Efficacy Adjustment Baseline Efficacy (ADM) Baseline Efficacy (Proposed) Post Efficacy (Both) Savings Using ADM ∆ Efficacy Savings Using Proposed ∆ Efficacy Supermarket Freezer Supermarket Cooler Convenience Freezer Convenience Cooler Restaurant Freezer Restaurant Cooler Warehouse Cooler

Energy Savings Calculations

where, I = refrigeration load from infiltration when door is open, Btu/hr D t = doorway open-time factor D f = doorway flow factor E = barrier efficacy

Comparison of Methodologies ADM Report (kWh/ft 2 ) ASHRAE Equation w/ Metered Values (kWh/ft 2 ) ASHRAE Equation w/ Proposed Values (kWh/ft 2 ) Supermarket Freezer Supermarket Cooler Convenience Freezer16 30 Convenience Cooler14 21 Restaurant Freezer Restaurant Cooler18 25 Refrigerated Warehouse

Costs Installed Cost: $9.77/ sq ft Average from 20 projects in the PNW Represents pricing of 7 trade allies Projects ranged from 1 to 8 walk-in doors

Effective Useful Life 4 years Value recommended by CALMAC* ODOE estimates 5 years ‡ Supported by program design * California Measurement Advisory Committee Public Workshops on PY 2001 Energy Efficiency Programs. September 2000, p. 60. ‡ SEED Guidelines, Appendix J.

Persistence Assured SDG&E Persistence Assured Strip Curtain Program Implemented by PECI ( ) Annual site inspection and maintenance Failure to persist resulted in rebate ‘clawback’

Persistence Results Initial 2 Year 4 Year Participation Persistence Persistence* Sites: % 75% Doors: % 82% *Not all sites have been reviewed for 4 year persistence. Values displayed in this column represent the 81% of the sites verified to date.

Program Specifications Must install Strip Curtains where no infiltration barriers are currently in use Claimed savings and rebate value will vary by site type Program will track and report persistence

Conclusion PECI seeks approval for the following deemed measures: Measure Application Energy Savings (kWh/ ft2) EUL Measure Cost ($/ ft2) Benefit Cost Ratio Strip Curtains- Supermarket Freezer4434$ Strip Curtains- Supermarket Cooler1034$ Strip Curtains- Convenience Store Freezer304$ Strip Curtains- Convenience Store Cooler214$ Strip Curtains- Restaurant Freezer1344$ Strip Curtains- Restaurant Cooler254$ Strip Curtains- Rfg. Warehouse (MT)3504$