Grocery VSD MeasureDeemed 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

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.

Measure Name

Minimum Fan Motor Size HP

Energy Savings (kWh/yr-

HP)

Measure Life

(years)

Measure Cost

($/ HP)Benefit

Cost RatioGrocery HVAC

VFD- 12 hrs 1.0 (~5 ton) 1,295 15$1225-$3250 1.3-4.9

Grocery HVAC VFD- 16 hrs 1.0 (~5 ton) 1,724 15

$1225-$3250 1.7-6.5

Grocery HVAC VFD- 24 hrs 1.0 (~5 ton) 2,551 15

$1225-$3250 2.6-9.6

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: VSDWiring 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!

Ventilation Approach• 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 Response

50%60%70%80%90%

100%110%

400 600 800 1000 1200

PPM CO2

Fan

Spe

ed

• 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

Calculations &Variable Assumptions

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

Grocery Fan VSD Sensitivity Tornado Diagram

1000 1200 1400 1600 1800 2000 2200 2400

Hours Open

Refrigeration % Open

Motor Selection

Speed Turndown

Ventilation

Fan Affinity Coefficient

Climate

Store Activity (People)

Duct Static

Light & Equip Density

Fan/Drive/Motor Eff

Annual Savings kWh/Nom Fan HP

“Typical” Grocery 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

– Refrig. Space Load – Fan Affinity

Coefficient– Climate– Light & Equip Density– Store Activity (People)

Impact on Savings of all Considered Parameters

Fan Operating Hours

Source: GrocerSmart Database

Occupied Schedule Distribution n=4230

0%

2%

4%

6%

8%

10%

12%

14%

16%

18%

5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Average Occupied Hours per Day

Bin mean occupied Hours: 11.0 15.4 22.8Modeled as fan hours: 12 16 24Up to 1.2 hours of fan operation added to occupied time (2 hours typical)

Bins Occupied: 0-12; 13-18; 19-24Fan Operation: 0-13; 14-19; 20-24

Remaining Parameter Sensitivity

Grocery Fan VSD Sensitivity Tornado Diagram

1400 1500 1600 1700 1800 1900 2000 2100

Motor Selection

Speed Turndown

Ventilation

Refrigeration Load

Fan Affinity Coefficient

Climate

Light & Equip Density

Store Activity (People)

Annual Savings kWh/Nominal Fan HP

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)

0.73 Motor Load Factor

Response to RTUG Feedback

• 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.

Expected Value Savings

Bin Fan Opr Hrs/day Opr EV Save kWh/nom HP

0-13 12 1295

14-19 16 1724

20-24 24 2551

Step Control$1000 + 225/HP

Prices from Manufacturers and invoices from like projects, includes labor

InstalledCosts

Analog Control $1900 + $225/HP

Measure Life

VFDVFD on HVAC -CALMAC Protocol and Procedures 15 years

CO2 SensorNWPPC-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

Measure Name

Minimum Fan Motor Size HP

Energy Savings (kWh/yr-

HP)

Measure Life

(years)

Measure Cost

($/ HP)Benefit

Cost RatioGrocery HVAC

VFD- 12 hrs 1.0 (~5 ton) 1,295 15$1225-$3250 1.3-4.9

Grocery HVAC VFD- 16 hrs 1.0 (~5 ton) 1,724 15

$1225-$3250 1.7-6.5

Grocery HVAC VFD- 24 hrs 1.0 (~5 ton) 2,551 15

$1225-$3250 2.6-9.6

• Units are motor horsepower

PECI seeks approval for the following deemed measures:

Category Store Hours Fan Motor HPSite Savings

(kWh) Capital Cost ($) TRC B/C Ratio

Analog 24 1.0 2,551 $ 2,125 1.5

Analog 24 1.5 3,827 $ 2,238 2.1

Analog 24 2.0 5,102 $ 2,350 2.7

Analog 24 3.0 7,653 $ 2,575 3.6

Analog 24 4.0 10,204 $ 2,800 4.5

Analog 24 5.0 12,755 $ 3,025 5.2

Analog 24 7.5 19,133 $ 3,588 6.5

Analog 24 10.0 25,510 $ 4,150 7.5

Step 24 1.0 2,551 $ 1,225 2.6

Step 24 1.5 3,827 $ 1,338 3.5

Step 24 2.0 5,102 $ 1,450 4.3

Step 24 3.0 7,653 $ 1,675 5.6

Step 24 4.0 10,204 $ 1,900 6.6

Step 24 5.0 12,755 $ 2,125 7.4

Step 24 7.5 19,133 $ 2,688 8.7

Step 24 10.0 25,510 $ 3,250 9.6

VSD on HVAC Fan: TRC Benefit Cost Ratio – 24-Hour Grocery

Category Store Hours Fan Motor HPSite Savings

(kWh) Capital Cost ($) TRC B/C Ratio

Analog 16 1.0 1,724 $ 2,125 1.0

Analog 16 1.5 2,586 $ 2,238 1.4

Analog 16 2.0 3,448 $ 2,350 1.8

Analog 16 3.0 5,172 $ 2,575 2.5

Analog 16 4.0 6,896 $ 2,800 3.0

Analog 16 5.0 8,620 $ 3,025 3.5

Analog 16 7.5 12,930 $ 3,588 4.4

Analog 16 10.0 17,240 $ 4,150 5.1

Step 16 1.0 1,724 $ 1,225 1.7

Step 16 1.5 2,586 $ 1,338 2.4

Step 16 2.0 3,448 $ 1,450 2.9

Step 16 3.0 5,172 $ 1,675 3.8

Step 16 4.0 6,896 $ 1,900 4.5

Step 16 5.0 8,620 $ 2,125 5.0

Step 16 7.5 12,930 $ 2,688 5.9

Step 16 10.0 17,240 $ 3,250 6.5

VSD on HVAC Fan: TRC Benefit Cost Ratio – 16-Hour Grocery

Category Store Hours Fan Motor HPSite Savings

(kWh) Capital Cost ($) TRC B/C Ratio

Analog 12 1.0 1,295 $ 2,125 0.7

Analog 12 1.5 1,943 $ 2,238 1.1

Analog 12 2.0 2,590 $ 2,350 1.4

Analog 12 3.0 3,885 $ 2,575 1.9

Analog 12 4.0 5,180 $ 2,800 2.3

Analog 12 5.0 6,475 $ 3,025 2.6

Analog 12 7.5 9,713 $ 3,588 3.3

Analog 12 10.0 12,950 $ 4,150 3.8

Step 12 1.0 1,295 $ 1,225 1.3

Step 12 1.5 1,943 $ 1,338 1.8

Step 12 2.0 2,590 $ 1,450 2.2

Step 12 3.0 3,885 $ 1,675 2.8

Step 12 4.0 5,180 $ 1,900 3.3

Step 12 5.0 6,475 $ 2,125 3.7

Step 12 7.5 9,713 $ 2,688 4.4

Step 12 10.0 12,950 $ 3,250 4.9

VSD on HVAC Fan: TRC Benefit Cost Ratio – 12-Hour Grocery