Energy FinAnswer Case Study: improved the efficiency of the entire store refrigeration system, saving energy in the compressor room (pictured above) as well as at the condensers and in the walk-ins and reach-in cases. There were good opportunities at each store we reviewed.we didn t walk away from a single store without identifying implementable measures. Jim Kelsey Principal kw Engineering at a glance Project: Refrigeration system and lighting upgrades at stores Energy FinAnswer is the best-run, best-delivered program we ve been involved with. Glenn Barrett Energy Management & Procurement Project overview: Number of stores............................. 36 Total energy (kwh/yr).......... 9,368,570 Total demand (kw/mo)................ 662 Average store energy (kwh/yr).... 260,238 Average store demand (kw/mo)......... 18 Percent of total energy : Refrigeration................................ 64% Lighting..................................... 36% Pacific Power As percent of project cost................... 37% Payback before s............... 5.0 years Payback after s................. 3.1 years Energy consultant: kw Engineering Inc. Contractors and suppliers: Refrigeration: Aztec Energy Partners Lighting: Various Acknowledgments:Thanks to Glenn Barrett and Jesse Dare of, and Jim Kelsey of kw Engineering for contributing to this case study.
Energy FinAnswer case study: Through its Energy FinAnswer program, Pacific Power and its partners worked collaboratively with to save energy and money at 36 stores. It has been a valuable partnership for the entire project team. Background According to Senior Manager, Energy Management and Engineering, Glenn Barrett, a typical grocery store uses 2.5 million kilowatt-hours of electricity per year. Cutting our energy use saves significant dollars, Barrett explains. took advantage of Pacific Power s Energy FinAnswer s to install energy-saving measures and multifunction controllers for continuous performance monitoring in 36 stores in Washington, Oregon and Utah.* The grocery store chain also completed refrigeration and lighting upgrades at its distribution center in North Salt Lake, Utah. Project There were good opportunities at the stores, and through the collaborative efforts of, Pacific Power, kw Engineering and Aztec Energy Partners, cost-effective energy-efficiency measures were identified. implemented a comprehensive set of refrigeration upgrades monitored through a master controller, improving the entire refrigeration system, including walk-ins and reach-in cases. The system was installed, commissioned and then baselined. If a component drops out of its parameters, the controller alerts that the system is not operating as it should and corrections can be made. This allows for continuous. Along with the refrigeration improvements, lighting retrofits and controls installed at many stores also improved efficiency. A complete description of energy-saving measures installed for can be found on the opposite page. Benefits Along with energy and cost, is also realizing additional benefits: Better temperature control on refrigeration system to keep products fresher Improved lighting color to enhance customer experience and employee work conditions Reduced maintenance and equipment downtime More features that help extend the life of equipment Savings trimmed its average store energy use by approximately 10 percent, representing a reduction of about one monthly electric bill each year. Energy FinAnswer s cut the average project payback from 5 years to 3.1 years. Including benefits in addition to energy cost, estimates the payback at 2.8 years. Because profit margins in the grocery industry are narrow, these go right to bottom line. * The Utah projects were completed through Pacific Power s sister company, Rocky Mountain Power. Along with energy and cost, also reaps other ongoing benefits, such as the new lighting color that enhances its customers shopping experience.
EEM Typical store efficiency measures Measure description Annual electricity (kwh) (kw) Actual installed cost the measures 1 Lighting retrofit 132,258 17.0 $18,767 2 Nighttime shutoff of rooftop units 2,687 0.0 $3,018 3 Case light controls 74,950 0.0 $12,103 4 Reduce defrost cycle 67,672 8.0 $23,867 5 Floating suction pressure 26,631 2.0 $13,967 6 Condenser fan control 6,974 3.0 $11,899 7 Nighttime shutoff for main air handlers 12,684 0.0 $3,270 8 Anti-sweat heater controls 74,393 5.0 $10,410 9 Variable-speed drive on main air handler 98,716 0.0 $4,637 10 Electronically commutated motors 19,867 2.0 $5,726 Total 516,832 37.0 $107,664 1. Lighting retrofit replaced existing T12 fluorescent lamps and ballasts with premium efficiency T8 fluorescent lamps and ballasts, resulting in energy, while maintaining or improving lighting levels. Premium T8 fluorescent lamps have a longer life and reduced maintenance costs. They also have better color rendition than T12s. 2. Nighttime shutoff of rooftop units Instead of running continuously, the 3-ton rooftop packaged units that serve bakeries, pharmacies and other areas, are turned off at night when the areas are not occupied. Automated controls more easily and accurately maintain comfort levels in the conditioned spaces. Reduced runtime also extends the lifetime of fan motors, belts and filters. 3. Case light controls Controls now turn off case lights when the store is minimally occupied. This reduces both lighting and refrigeration energy use. Reducing the amount of heat discharged into cases or walk-ins helps maintain case temperatures after stocking. 4. Reduce defrost cycle Instead of defrosting low-temperature cases and walk-ins using timers, controls were implemented to terminate defrost when the coils are clear. Temperature sensors were installed that measure case discharge temperatures at a typical fan coil in the case lineup. When the discharge temperature hits a threshold temperature, it indicates that the coils are clear and the defrost cycle is terminated. This saves defrost energy and also reduces the heat that the refrigeration system needs to remove. Reducing the defrost time will reduce the amount of heat discharged into the case or walk-in and helps maintain product temperatures. 5. Floating suction pressure Refrigeration systems were controlled using simple pressure switches to maintain design suction pressure at all times, regardless of the refrigeration load. By floating the suction pressure based on case load, the evaporator temperature can be increased by an average of 2 F to 5 F, resulting in energy. As part of the control strategy, discharge air temperature is measured in representative cases. The suction pressure can then be controlled to supply the maximum suction pressure that can still meet the discharge air temperature setpoints on all the circuits on the rack. Due to the reduction in the compressor operating pressure ratio, floating suction pressure greatly reduces wear and tear on compressor parts, extending the life of the compressor. 6. Condenser fan control Condenser fans were controlled using outside air temperature. They were staged so one fan operated continuously for each condenser and successive fans came on at higher air temperatures. Now fans are controlled to ensure that the condensing pressure is kept low, particularly when the weather is mild or cool. The strategy is to control the fans to maintain a fixed temperature difference ( T) across the condenser. For condensers serving low temperature systems, the target T is 8 F. For condensers serving medium temperature systems, the target T is 12 F. This strategy brings the condenser fans on longer and drives down the operating pressure of the system. Lower head pressure greatly improves the compressor efficiency while still providing a minimum pressure for reliable thermostatic expansion valve operation. Due to the reduction in the compressor operating pressure ratio, floating head pressure greatly reduces wear and tear on compressor parts. The measure helps extend the life of the compressor. 7. Nighttime shutoff for main air handlers The main air handling units typically ran continuously, even in stores that were closed at night. In the retrofit, the main air handling units were turned off from midnight to 6 a.m. Reduced runtime extends the lifetime of fan motors, belts and filters. 8. Anti-sweat heater controls Anti-sweat heaters typically run continuously to prevent fogging of frozen food case doors. In moderate and dry climates, the anti-sweat heaters do not need to run continuously to prevent fogging. Anti-sweat heater controls were installed at each site to limit the duty cycle of the heaters based on the humidity in the store. Reducing the amount of anti-sweat heat reduces the amount of heat discharged into the case and helps maintain product temperatures. 9. Variable-speed drive on main air handler Many of the sites had a main air handler with a constant-speed motor. This means that the fan ran at the same speed regardless of the cooling or heating load in the building. Installing a variable-speed drive on the fan motor enables the fan to slow down whenever the building load allows it, saving fan energy. The fan speed can be controlled to maintain store temperature, with a minimum flow set to make sure that adequate ventilation is maintained, evaporator coils do not ice, and furnace heat exchangers are protected. Reduced fan speed may help extend the life of fan motors and belts. 10. Electronically commutated motors Cooling coil fans in walk-in coolers and freezers typically use shadedpole fan motors. Shaded-pole motors are inexpensive and have been the standard for the supermarket industry for many years. However, shaded-pole motors are much less efficient than electronically commutated motors. Electronically commutated motors typically use about 70 percent less energy than shaded-pole motors in this application. In addition to reduced cooling coil fan motor power consumption, the new motors add less heat into the walk-in, resulting in refrigeration energy.
Total power vs. outside air temperature Total power (kw) 130.0 120.0 110.0 100.0 90.0 80.0 70.0 60.0 50.0 40.0 30 40 50 60 70 80 90 100 Dry bulb temperature ( F) Pre-install Post-install Pilot study: evaporative pre-cooler is always looking for new technologies and approaches that will help it operate more reliably and cost-effectively. Pacific Power helped conduct a North Salt Lake distribution center also completed significant refrigeration system and lighting upgrades at its distribution center in North Salt Lake, Utah, with the help of Pacific Power s energy efficiency programs. The process is easy and helpful we learned a lot about saving energy. And when you can save that much money, why wouldn t you do it? Jesse Dare Facilities Maintenance Manager About Pacific Power s energy efficiency programs Pacific Power has helped commercial and industrial customers save money and improve energy efficiency for more than a decade. In Washington, our Energy FinAnswer helps eligible businesses build energy efficiency into new construction and more comprehensive system retrofits. Energy FinAnswer includes investment-grade energy engineering assistance and financial s. We also offer other energy efficiency programs for businesses. pilot study of one such technology for its grocery store refrigeration system an evaporative pre-cooler for aircooled condensers.this pilot showed promising in dry climates. Water is sprayed over specially treated cellulose pads in the pre-cooler, and as air is drawn through the pads it is humidified and cooled. The inlet air temperature for the condenser is reduced, increasing the capacity and efficiency of the condenser. This results in lower head pressure in the system and reduced refrigeration compressor energy use. Detailed monitoring at the pilot site in Utah showed a total refrigeration system energy of 58,000 kilowatthours per year a 5 percent reduction and 20 kilowatts. With an Energy FinAnswer of more than $8,000, the project payback was three years. distribution center upgrades Energy efficiency measure (EEM) Energy (kwh/yr) (kw/mo) Incentive as percent of EEM cost Simple payback before Simple payback after Efficient condensing 770,915 53 50% 5.7 2.8 Efficient compressor operation 785,967 54 50% 5.0 2.5 Efficient evaporators 1,123,535 64 50% 5.0 2.5 High-speed doors 318,213 29 27% 11.2 8.2 High-pressure sodium to T5 lighting 1,979,213 187 34% 4.8 3.2 T12 to T5 lighting 309,298 28 35% 2.4 1.5 T12 to T8 lighting 481,218 75 33% 3.6 2.4 Lighting controls 92,789 0 11% 7.4 6.6 Total 5,861,148 490 40% 5.1 3.1 Energy consultant: Cascade Energy Engineering Contractors and suppliers: Refrigeration: Louis A. Roser Company Lighting: Lighting Maintenance & Service Inc. Do the bright thing For more information on how we can help your facility save energy and money: Call our Energy Services Hotline toll free at 1-800-222-4335. E-mail energy.expert@pacificorp.com. Visit our Web site at www.pacificpower.net and click on Business and Save Energy & Money. Because we have some requirements to qualify for an, it is important to call us before you start your project. 2007 Pacific Power 2/07
The multifunction controller provides continuous performance monitoring, helping maintain and improve its energy over time. stores Store location State Total energy (kwh/yr) (kw/mo) Incentive as percent of project cost Payback before (years) Payback after (years) Yakima WA 178,359 7 31% 7.7 5.3 Yakima WA 191,041 18 30% 8.4 5.9 Bend OR 216,547 11 35% 7.3 4.7 Bend OR 291,568 12 44% 4.8 2.7 Corvallis OR 252,232 13 39% 6.1 3.7 Grants Pass OR 224,580 16 36% 6.7 4.3 Medford OR 297,313 24 48% 4.6 2.4 Medford OR 237,148 21 41% 6.6 3.9 Medford OR 422,608 34 47% 3.8 2.0 Pendleton OR 188,983 15 36% 8.1 5.2 Redmond OR 166,742 12 30% 8.7 6.1 American Fork UT 250,140 27 48% 3.6 1.9 Cedar City UT 409,953 36 28% 4.8 3.5 Centerville UT 258,048 15 40% 4.3 2.6 Clinton UT 307,126 19 42% 3.9 2.2 Draper UT 262,821 17 43% 4.6 2.6 Draper UT 300,430 26 24% 4.8 3.7 Layton UT 152,372 9 36% 5.8 3.7 Magna UT 249,749 14 39% 5.4 3.3 Ogden UT 288,452 27 31% 5.4 3.7 Orem UT 192,357 11 37% 6.7 4.2 Park City UT 515,154 22 45% 2.6 1.4 Riverton UT 348,835 36 42% 4.7 2.7 Salt Lake City UT 169,215 11 33% 6.7 4.5 Salt Lake City UT 220,323 12 37% 5.8 3.6 Salt Lake City UT 257,499 12 47% 1.7 0.9 Salt Lake City UT 260,875 18 31% 6.1 4.2 Sandy UT 214,104 10 30% 5.6 4.0 Sandy UT 258,219 16 41% 5.0 3.0 South Ogden UT 192,595 12 38% 6.2 3.8 Taylorsville UT 57,825 8 46% 4.0 2.1 Tooele UT 698,518 47 48% 1.8 0.9 West Jordan UT 217,950 13 32% 6.0 4.1 West Jordan UT 317,176 27 25% 6.4 4.8 West Valley City UT 134,003 18 58% 1.9 0.8 West Valley City UT 167,708 16 36% 6.7 4.3 Total for 36 stores 9,368,570 662 37% 5.0 3.1 Average 260,238 18 37% 5.0 3.1