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A major part of the 97,000-square-foot Harrisburg, Pa., Giant Super Food Store’s energy savings and reduced carbon footprint comes from the cutting-edge refrigeration systems from Conyers, Ga.-based Hill PHOENIX.
“We’ve been building green technology into our stores for years because it not only makes sense financially, but it [also] reduces the environmental impact of our operations,” said Tharon Gilreath, manager of energy and mechanical design for Carlisle, Pa.-based Giant. “We expect the Hill PHOENIX Second Nature system to play an important role in enhancing our green technology package.”
The store, which opened last October, chose Second Nature to provide eco-friendly refrigeration for medium-temperature display cases and walk-in coolers. The systems, which were designed to keep refrigerated foods at optimum temperatures, replace R404A, a halogenated fluorocarbon (HFC) and contributor to greenhouse gases, with a 35 percent 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, Second Nature eliminates the circulation of high-pressure refrigerant throughout the store floor, enabling the system to achieve a 50 percent 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,” added Gilreath. “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 benefit of the 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, thus boosting 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,” explained Hill PHOENIX industrial systems engineer Tom Kilroy. “By eliminating excess cooling, this technology provides an energy savings of 40 percent over traditional pumping systems.”
Giant is excited 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 Second Nature, temperature control is more stable because the system employs the warm fluid side for defrost, shortening the defrost time and smoothing out big temperature swings — plus there’s 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.” Observed Gilreath. “This will result in improved product quality for customers due to shorter defrost periods and less temperature swings.”
Further, according to Clyde Miller, Giant’s director of construction, “The installation went very smooth, and the setup of the system and case temperatures were relatively simple.”
Since the medium-temperature secondary refrigerant isn’t under high pressure like primary refrigerant, Hill PHOENIX was able to use Georg Fischer-engineered ABS piping for construction of the Harrisburg store.
While copper mining and copper smelting are large producers of greenhouse gases in the production of copper piping materials, using engineered ABS pipe lowers a store’s environmental impact. Additionally, because it has a much lower thermal conductivity rate than copper and a larger wall thickness, ABS pipe is a superior insulator and provides energy efficiencies.
Among other benefits the technology will provide the Harrisburg store are:
—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 lower refrigerant charge and leak rate will result in 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 in a traditional direct-expansion refrigeration system, equaling a total savings of more than 7,300 pounds of installed copper tubing. This will lead to a further carbon footprint reduction of over 18,900 pounds of C02 emissions
Giant Food Stores, LLC operates stores in Pennsylvania, Virginia, Maryland and West Virginia under the Giant Food Stores, Martin’s Food Markets and Giant To Go banners.