Low Flow Pre-Rinse Spray Valves Deemed Energy Savings for Seattle City Light and the Region Regional Technical Forum April 7, 2009

Goals Determine deemed value(s) for SCL’s program – Federal Minimum as baseline – Existing valve as baseline? Determine deemed value(s) for the Region – Federal minimum as baseline

Basic Energy Savings Variables Incoming water temperature – Assumed 58°F for Region, 55°F for Seattle Point of use water temperature Pre- and post-flow rate Pre- and post-hours of use per day Facility operation days per year – Assumed 350 days/year (360 for groceries)

Point of Use Water Temperature From Seattle City Light’s 2004 program Average = 98.6 deg F

Point of Use Water Temp (cont) “Pre-Rinse Spray Valve Programs: How Are They Really Doing?”, SBW Consulting and Koeller & Co. for AWWA, Jul 2006

Pre- and Post-Flow Rate “Pre-Rinse Spray Valve Programs: How Are They Really Doing?”, SBW Consulting and Koeller & Co. for AWWA, Jul 2006

Pre- and Post-Flow Rate (cont)

Average = 1.18gpm

Average = 1.68 gpm Gallons per minute Pre- and Post-Flow Rate (cont)

Pre- and Post-Hours of Use per Day

Note: CA Phase 1 data were unavailable

Pre- and Post-Hours of Use per Day (cont) Note: CA Phase 1 facility type breakdown was not available, so sample size and hrs/day by facility type for CA Phase 1 are based on the CA Phase 1 total values (18 and 1.27) and weighted based on the other four studies.

Pre- and Post-Hours of Use per Day (cont): Is there a reasonable way to disaggregate “restaurants”?

Deemed Savings Options & Issues Facility Type Option 1: Deem one average energy saving for all facility types – Issue: Need to predict mix of facility type Option 2: Deem average energy savings by facility type (Restaurant, Grocery, Institutional, Other) – Issue: More difficult program design, operation, & verification Option 3: Provide deemed savings for both options 1 and 2 – Issue: If ability to choose the higher value on a case-by-case basis is allowed, savings would be overstated; confusion about which to use Baseline Flow Rate, Measure Life Option A: Assume baseline is fed min standard, measure life is 4 years. – Issue: Not claiming entire savings where a PRSV was replaced early Option B: Assume baseline is existing valve, measure life is partly 4 years (fed min gpm to 0.65 gpm), and partly 2 years (existing valve gpm to fed min gpm) – Issue: Works only for early replacement type programs; we don’t know the measure life with any certainty; the baseline existing valve will change with time as valves are naturally replaced with fed min valves Option C: Provide deemed savings for options A and B – Issue: Confusion about which to use

Potential Solution to Option 1’s Issue “Pre-Rinse Spray Valve Programs: How Are They Really Doing?”, SBW Consulting and Koeller & Co. for AWWA, Jul 2006

Results - Regionwide Fed Min Baseline (Option 3A) Note: Water/Sewer kWh savings are not shown here, but are represented in B/C ratio

Results – Seattle City Light Fed Min Baseline (Option 3A) Note: Water/Sewer kWh savings are not shown here, but are represented in B/C ratio

Results – Seattle City Light Existing Baseline (Option 3B) Note: Water/Sewer kWh savings are not shown here, but are represented in B/C ratio; Analysis includes 1.68 to 1.18 gpm savings for years 1 and 2; and 1.18 to 0.65 gpm savings for years 1 through 4. Savings shown here are the average annual savings over the 4-year measure life.