Energy Trust of Oregon Small Commercial HVAC Pilot Program Stellar Processes December 15, 2009

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. 12/15/20092ETO Small Commercial RTU

Production Mode for Rooftop Units 12/15/20093ETO Small Commercial RTU

Energy Signature Analysis Example 12/15/20094ETO Small Commercial RTU

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? 12/15/20095ETO Small Commercial RTU

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. 12/15/2009ETO Small Commercial RTU6

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. 12/15/2009ETO Small Commercial RTU7

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. 12/15/2009ETO Small Commercial RTU8

Analysis Challenges 12/15/2009ETO Small Commercial RTU9 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.

Test of Extrapolation Method 12/15/2009ETO Small Commercial RTU10 “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).

Test of Annual Extrapolation Method 12/15/2009ETO Small Commercial RTU11 Average estimated savings on an annual basis agree closely with the average of short term results.

Local Microclimate versus Long-Term Weather Data 12/15/2009ETO Small Commercial RTU12 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.

Summary of Electric Savings Case Pre- retrofit kWh Post- retrofit kWh KWh Saved% SavedTreatment Dentist Back5,8261,6454,18172%New economizer, new thermostat, implemented setback Dentist Front7,8272,7165,11265%New economizer, new thermostat, implemented setback Pizza Kitchen3,1921,1592,03364%New economizer, new thermostat, implemented setback Sandwich Shop15,1316,4328,69957%New economizer, new thermostat, implemented setback Shipping Store2,9491,2551,69457%New economizer, new thermostat, implemented setback Pub5,7163,3812,33441% Restored non-functioning economizer, set changeover to 63 deg, new thermostat, implemented setback Office4,6583, %New economizer, existing thermostat, implemented setback Pizza Front12,94110,6322,30918%No economizer, new thermostat, implemented setback Vet Front3,5613, % Restored non-functioning economizer, set changeover to 63 deg, new thermostat, implemented setback Hair Salon4,0263, % New economizer, new thermostat, implemented setback, increased ventilation Retail Front2,4212,371492% Existing economizer was functional, set changeover to 63 deg, new thermostat, implemented setback Vet Back4,2314,169621%New economizer, new thermostat but no setback Retail Back %Cleaning but no other treatment, unit is seldom in use Average 5,6003,4552,14538% All units (15 cases) 2,07437% 12/15/2009ETO Small Commercial RTU13

Computed Space Heat Savings 12/15/2009ETO Small Commercial RTU14 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.

Program Cost Effectiveness Cases Average KWh Average Therm studied Savings Savings 13 Directly monitored2,14538%2.40.6% 15 Including all units2,07437%2.50.6% 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 Discount Rate5.2%5.2% Lifetime1510 Levelized Cost, per kWh$0.078$ /15/2009ETO Small Commercial RTU15

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. 12/15/2009ETO Small Commercial RTU16