Energy Trust of Oregon Small Commercial HVAC Pilot Program

1. Energy Trust of OregonSmall Commercial HVAC Pilot Program Stellar Processes December 15, 2009

2. Small Commercial HVAC Pilot Program Goal: test feasibility of specifying a standard repair treatment that can be applied by contractors in a production mode in order to reduce deployment costs. • Install a new programmable thermostat. Set up proper scheduling and night setback. • Install drop-in economizers where appropriate. Ensure that economizers are connected with two-stage control wiring. Install the new sensors that permit better economizer operation. Properly set economizer changeover point. • Repair noticeable air leaks around roof curbs. • Clean coils. ETO Small Commercial RTU

3. Production Mode for Rooftop Units ETO Small Commercial RTU

4. Energy Signature Analysis Example ETO Small Commercial RTU

5. Short-term Monitoring Minimal metering. Short term measurements of (1) energy consumption by the HVAC unit and (2) temperature of the delivered air. Does not allow an explicit measurement of economizing or isolation of specific measures. Slope and intercept parameters from Energy Signature plot used to extrapolate savings. Are data sufficient? ETO Small Commercial RTU

6. Site Details Strip mall site containing a representative mix of small business types. Included are two sit-down restaurants, a fast food outlet, a retail store, an office and professional services (dentist, veterinarian, hair salon). Standard repair protocol on a row of essentially the same HVAC unit. ETO Small Commercial RTU

7. Field Treatment • Three of the HVAC units already had economizers. Only one was functional. The other two units did not have two-stage controls. • With one exception, outside ventilation was disabled on all the units. • None of the businesses had proper scheduling of HVAC operations. • All the units received a pressure wash of the coils. • Repair noticeable air leaks around roof curbs. ETO Small Commercial RTU

8. Implementation Challenges • Metering was still a challenging task. • True power to avoid any power factor issues. • Equipment problems on two HVAC units. However, both of these units had an identical twin serving the same space. • Data collected at one-minute intervals to bin consumption into heating or cooling events. This requires a database operation to merge all the data streams and align by time of day. ETO Small Commercial RTU

9. Analysis Challenges Sometimes the model fit is not clear and the regression must be forced through a zero point. In such cases, some judgment is necessary to estimate a fit to the observed data points. ETO Small Commercial RTU

10. Test of Extrapolation Method “Before” and “after” weather conditions lead to savings estimates that are similar but not exactly the same. Difference due to relative amount of change expected for compressor cooling (slope) versus the ventilation savings (flat part). ETO Small Commercial RTU

11. Test of Annual Extrapolation Method Average estimated savings on an annual basis agree closely with the average of short term results. ETO Small Commercial RTU

12. Local Microclimate versus Long-Term Weather Data Are the short term results representative of the 365-day weather data used for the annual extrapolation? This question is not resolved by the current study. ETO Small Commercial RTU

13. Summary of Electric Savings ETO Small Commercial RTU

14. Computed Space Heat Savings Observed instances of the warm-up length and balance temperature for seven cases. Assumed fixed percent outside air and airflow rate. Average for all units, 2.5 annual therms or 0.6% of space heat. ETO Small Commercial RTU

15. Program Cost Effectiveness Cases Average KWh Average Therm studied Savings Savings 13 Directly monitored 2,145 38% 2.4 0.6% 15 Including all units 2,074 37% 2.5 0.6% Unit cost $1,685 PV of electricity, per kWh $0.980 $0.702 PV of Gas, per therm $7.872 $6.078 PV of Benefits $2,052 $1,471 BCR 1.22 0.87 Discount Rate 5.2% 5.2% Lifetime 15 10 Levelized Cost, per kWh $0.078 $0.105 ETO Small Commercial RTU

16. Conclusions • In general, the energy signature methodology appears successful. A question remains regarding the use of long-term (TMY) data for extrapolation. • Savings averaged 2,074 annual kWh or 37% of VAC consumption. Estimates should still be validated with long-term billing simulation. • Energy Signature method provided reasonable extrapolations to annual savings. • Savings were due to a variety of treatment measures. Most important were proper scheduling and programming of night setback and the addition or repair of economizers. The verification methodology does not allow savings to be isolated to specific treatments. • For about one third of the cases, the tune-up repairs did not result in savings. This is a small amount of “dry holes” and it is probably not necessary to attempt to screen out such cases. • Before the repairs, most of the systems exhibited problems. • Computed small gas warm-up savings averaging 2.4 annual therms. The savings are due to lockout of outside air during morning warm-up and are accomplished by the new programmable controls. • Unit cost averaged $1,685 for labor and materials. The estimated Benefit Cost Ratio is 1.22 for 15-year life or 0.87 for 10-year life. ETO Small Commercial RTU