The supermarket chain Hy-Vee Inc.’s 64,000-square-foot store in Fairfield, Iowa, opened on April 12 as the company’s second Leadership in Energy and Environmental Design (LEED)-certified store. It is one of the few supermarkets in the country that has achieved U.S. EPA GreenChill Gold-Level certification.

Part of the reason for the dual recognitions relates to the refrigeration equipment. Working in partnership, Hy-Vee and Hill Phoenix mapped out a plan to incorporate refrigeration systems that would benefit the environment, reduce the store’s environmental footprint, and have a positive impact on products.

The store was outfitted with Second Nature® Technology systems (Figure 1, page 42) to keep refrigerated and frozen foods at optimum temperatures while using the latest technology to minimize environmental impact. (As an added benefit, the store is a working showcase for locally made products; many of the Hill Phoenix products in the store had been manufactured less than 30 miles away at the company’s Barker Specialty Division plant in Keosauqua.)

“Hy-Vee has a clear commitment to sustainability and to working on ways to be environmentally friendly,” said Mike Smith, director of real estate and sustainability for Hy-Vee. “Certainly what we’re doing at the Fairfield store is part of that effort.”

Medium-Temp Cases

Hy-Vee chose a medium-temperature glycol secondary system for its meat, seafood, and deli cases. The equipment manufacturer was able to replace a significant amount of HFC-404A refrigerant with food-grade propylene glycol and circulate this 35 percent aqueous fluid throughout the sales floor to refrigerate product displayed in the medium-temperature cases and coolers.

“A typical medium-temperature direct expansion system would use around 2,700 pounds of refrigerant for a store this size,” explains John Gallaher, director of business development for Hill Phoenix. “With the Second Nature glycol system, we’re using just a fraction of that amount and circulating the glycol to keep the cases cool.”

Because R-404A is used only to chill the glycol, the system uses 1,397 pounds of refrigerant charge along with 1,600 gallons of glycol, thus reducing the overall refrigerant charge on the medium-temperature side by 50 percent over a standard DX system.

This reduction in refrigerant is one of the features that attracted Hy-Vee to the system, according to Jon Scanlan, director of Refrigeration and Energy Management at Hy-Vee. “This system offers a significant reduction in refrigerant charge. It’s extremely important to us and it goes back to our objectives with the EPA GreenChill program, to reduce refrigerant charge and emissions.”

After a month in operation, Scanlan said the findings show that the refrigerant charge at the Fairfield supermarket is “less than half of what we find on our traditional DX systems; that bodes well for minimizing the charge and emissions at the store moving forward.”

Hy-Vee has also incorporated Coolgenix® case technology in its deli and seafood cases. These cases are said to control product temperature within one degree of the desired temperature. By controlling humidity and air temperature in the case, product temperatures remain constant throughout the case and on any shelves within it.

Because the glycol solution on the medium-temperature side can be delivered to the display cases and walk-ins via loop piping, the refrigerant is not under high pressure. This allows the use of Georg Fischer-engineered ABS piping for the store, and lowered the store’s environmental impact through better insulating properties that provide energy efficiencies, and the elimination of copper derived from the copper smelting process.

Low Temperature

For the first time, Second Nature low-temperature CO2 secondary system is being used by Hy-Vee for its cases and walk-in freezers. The system uses CO2 fluid as a secondary coolant in a loop piping system (Figure 2).

CO2 is supercooled into liquid form, then travels throughout the low-temperature food cases and walk-ins, where it absorbs heat. The heat is removed through condenser-evaporators in the machine room. Then the CO2 is supercooled again and returned through the cases in a continuing loop.

Gallaher said the system requires 303 pounds of HFC refrigerant, about one-fourth less than a typical DX system. The secondary side of the system uses a charge of 1,030 lbs of CO2, which is found naturally in the environment and is said to have excellent thermodynamic and transport properties, which help remove heat from the low-temp display cases and walk-in freezers.

The proprietary SmartValve superheat management system on the low-temp CO2 chillers “provides better control of the heat exchanger operation, which results in improved energy performance,” noted Gallaher.

Regarding maintenance and operations, Gallaher said, “With CO2 as the secondary coolant, we’re able to remove expansion valves from the display cases and replace them with solenoid valves. This allows for a much simpler set-up and operation of the system.”

What It Hinges On

The Fairfield Hy-Vee store is said to be the first supermarket to feature a proprietary walk-in cooler and freezer latch-and-hinge designs developed with both store associates and costs in mind.

There is a 3/4-in. lift on the hinge (vs. industry standard of ⅜-in.). The 3/4-in. lift was designed to increase the life cycle in service areas, increase energy savings, and reduce maintenance on door sweeps that no longer drag and become damaged on floors. In addition, improved latches provide ease of use while opening doors, and improve associate safety over traditional door latches.

Walk-in fastener-free jambs are said to be more durable than traditional jamb guards, save energy by focusing the door heat at the gasket for better performance, and eliminate the safety hazard of exposed edges and fasteners.

Sidebar: Gold Level

The Hy-Vee store in Fairfield, Iowa, was awarded GreenChill Gold-Level Certification from the GreenChill Advanced Refrigeration Partnership, a voluntary EPA partnership with food retailers to reduce refrigerant emissions and decrease their impact on the ozone layer and climate change. The certification program recognizes individual stores for using environmentally friendlier commercial refrigeration systems.

To achieve Gold-Level Certification, the new Fairfield Hy-Vee has met EPA GreenChill Gold-Level Certification requirements including using only non-ozone depleting refrigerants, using only refrigerants that have been found acceptable by EPA’s Significant New Alternatives Policy Program, achieving an average HFC charge of 1.25 pounds per MBtuh total evaporator heat load, and having a storewide annual refrigerant emissions rate of 15 percent or less.

Publication date: 09/19/2011