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Grocery VSD Measure Deemed Savings Reid Hart, PE & Ken Anderson September 28, 2010. Acknowledgements. We would like to thank the following entities for their support: Avista Utilities Bonneville Power Administration Puget Sound Energy
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Grocery VSD MeasureDeemed SavingsReid Hart, PE & Ken AndersonSeptember 28, 2010
Acknowledgements • We would like to thank the following entities for their support: • Avista Utilities • Bonneville Power Administration • Puget Sound Energy We would also like to thank the RTF RTUG members for their valuable feedback
Purpose Approval for new deemed measures for VFD and controller installed on Grocery store sales floor HVAC supply fan.
Proposed Measures • Units are fan motor horsepower.
Agenda • Technology Overview • Energy Savings Calculation Methodology • Overview probability inputs for Expected Value Deemed Savings • Feedback on specific factors & probabilities • Cost • Measure Life • Program Specifications • Conclusions
Technology Overview: VSD Wiring a VSD on the electrical side saves substantial labor compared to replacing the motor and having to re-align the drive. VSDs come in a wide variety of sizes!
Basic premise: Existing fixed ventilation to remain set AS IS Lower fan speed will reduce ventilation below existing levels Relation to desired levels unknown Finding out doubles measure cost Ventilation Approach • CO2 control provided as an override for high occupancy • Fan speed will increase when CO2 concentration indicates high occupancy.
Measure Control Sequence of Operation • Standard Step Controls • Maintain set minimum speed for positive pressure (50% to 70%) • Discharge air temperature DAT maintenance; increase fan speed as necessary to: • Speed set to keep warmer than 55°F during cooling • Speed set to keep cooler than 160°F during heating • Ventilation override; increase speed to: • Maintain 1150 ppm CO2 concentration • Advanced controls include smart relay • Cooling impact; operate at full speed on: • Call for cooling & OSA below 70°F • Ventilation ramped rather than stepped with differential • Maintain temperature control & interface with DDC • Option for humidity control
Savings Methodology • Expected Value Deemed Savings • Consider baseline variation impact on savings • Typical & Hi/Lo values for influencing parameters • DOE 2 – eQUEST 3.64R • Evaluate parameter impacts on loads & fan sizing • Develop hourly loads for transfer to • Hourly spreadsheet • Pre- and post- occupied fan operation calculated • Sensitivity & Expected Value analysis
Refrigeration based model Typical grocery used in ES Grocer Focused on sales floor (80% of area) Parameters of interest Fan Control Hours Fan Operating Motor Selection Speed Turndown Ventilation % OSA “Typical” Grocery Analysis • Refrig. Space Load • Fan Affinity Coefficient • Climate • Light & Equip Density • Store Activity (People)
Fan Operating Hours Source: GrocerSmart Database
Remaining Parameter Sensitivity Motor Load Factor 0.73 1.08 30% 50% 5% 30% of supply 18. 3 45.6 kWh/sf-yr 2.0 2.7 Missoula Portland 1.1 / 0.8 2.1 / 1.3 W/sf 49% 100% (157 people)
Speed Turndown 50% speed probability reduced Ventilation % OSA Lower state (5%) added Refrigeration Space Load Clarified & calibrated; weighted to higher load Fan Affinity Coefficient Range increased from 1.8-2.4 to 2.0-2.7 Store Activity (People) Density reduced; High density lower probability Detailed parameter impact ranges, states, and probabilities are in posted detailed slides. Response to RTUG Feedback
Installed Costs Step Control$1000 + 225/HP Analog Control $1900 + $225/HP Prices from Manufacturers and invoices from like projects, includes labor
Measure Life VFD VFD on HVAC -CALMAC Protocol and Procedures 15 years CO2 Sensor NWPPC-Demand Control Ventilation 15 years
Program Specifications • Applicable to Main grocery sales floor RTU supply fans. • Units must have fixed ventilation damper (units with economizers will be able to use premium ventilation new measure). • Shut-off damper controls are allowed • Units must have continuous fan operation during occupied period. • Fans in “Auto” disqualified - poor IAQ and negative savings • Measure based on hours of operation of HVAC unit, not hours of operation of store. • Incentives paid based on HP of fan motor nameplate/nominal • CO2 sensor installed in return air duct or per local/state code
Conclusion PECI seeks approval for the following deemed measures: • Units are motor horsepower