When Giant Food Stores, Carlisle, PA, opened the doors to its new Harrisburg store last fall, the company gave customers a look at 97,000 sq.ft. of modern technology and convenience. Attention has been paid to every detail, including many aspects customers can’t actually see but that make the store a front-runner in green supermarkets.
A large part of the store’s energy savings and reduced carbon footprint comes from the state-of the-art refrigeration systems by Hill Phoenix, a leading designer and manufacturer of commercial refrigeration products.
“We’ve been building green technology into our stores for years because it not only makes sense financially, but it reduces the environmental impact of our operations,” says Tharon Gilreath, manager of energy and mechanical design for Giant Food Stores. “We expect the Hill PHOENIX Second Nature system to play an important role in enhancing our green technology package.”
The Giant Super Food Store management chose Hill PHOENIX Second Nature refrigeration systems to provide environmentally friendly refrigeration to the medium temperature display cases and walk-in coolers. Second Nature Medium Temperature systems – designed to keep refrigerated foods at optimum temperatures – replace R404A, a halogenated fluorocarbon (HFC) and contributor to greenhouse gases, with a 35% aqueous propylene glycol fluid and R407C, a non-halogenated refrigerant with less than half of the global warming potential of traditional HFC refrigerants. By using a low-pressure chilled water loop to circulate the refrigerant, the system eliminates the circulation of high-pressure refrigerant throughout the store floor, allowing the Second Nature system to achieve a 50% reduction in refrigerant charge.
“Hill Phoenix’s Second Nature technology lets us contain refrigerant charge within the machine room and condenser circuit where it’s exposed to substantially fewer pipe joints and potential leaks,” Gilreath explains. “Less piping, fewer valves and elimination of subsequent leaks that normally occur over time will reduce the refrigerant charge at the store. It will also lower costs with fewer maintenance calls.”
Another distinct advantage of the Second Nature Medium Temperature technology is the system’s Variable Speed Drives. By incorporating the drives on the compressor of each system, Hill Phoenix can provide precise capacity control throughout the operation and thereby improve energy efficiency.
“Using Variable Speed Drives with end-of-loop pressure controls on the glycol circulating system allows the system to optimize the flow rates at each display case and walk-in cooler,” adds Tom Kilroy, industrial systems engineer for Hill Phoenix. “By eliminating excess cooling, this technology provides an energy savings of 40 percent over traditional pumping systems.”
Management at Giant Food Stores is also optimistic about the use of the chilled glycol system and its ability to control product temperatures, especially as applied to medium-temperature applications such as meat, seafood and produce. With the Second Nature system, temperature control is more stable because the system uses the warm fluid side for defrost, making the defrost time shorter and eliminating large temperature swings -- plus there is reduced recovery time after defrost.
“With the warm fluid defrost, there is less shock to the product as compared to electric or hot gas defrost systems.” Gilreath notes. “This will result in improved product quality for customers due to shorter defrost periods and less temperature swings.” Additionally, according to Clyde Miller, Director of Construction for Giant Food Stores, “The installation went very smooth and the setup of the system and case temperatures were relatively simple.”
Georg Fisher Piping Reduces Greenhouse Gases
Because the medium temperature secondary refrigerant is not under high pressure like primary refrigerant, Hill Phoenix was able to use Georg Fischer-engineered ABS piping for construction of the Harrisburg store. Copper mining and copper smelting are large producers of “greenhouse gases” in the production of copper piping materials; however, using engineered ABS pipe lowers a store’s environmental impact. In addition, because it has a significantly lower thermal conductivity rate than copper and a larger wall thickness, it is a much better insulator and provides energy efficiencies.
A Reduced Environmental Footprint
According to Hill Phoenix, the Hill PHOENIX Second Nature Medium Temperature system at the Harrisburg Super Food Store is in keeping with Giant Food Stores’ green philosophy and will provide impressive benefits for the environment:
- The total annual carbon footprint will be reduced by 29,125,000 pounds of C02, which is equivalent to removing 242 passenger cars from the road annually for 10 years
- The reduced refrigerant charge and leak rate leads to a carbon emissions savings of more than 14,653 tons of C02 over a 10-year period
- The amount of installed copper piping is over 5,500 feet less than a traditional direct expansion refrigeration system, equating to a total savings of more than 7,300 pounds of installed copper tubing. This will result in a further carbon footprint reduction of more than 18,900 pounds of C02 emissions.
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