Keeping Cool
Ukrop’s Super Markets is committed to sustainability. To that end, the chain’s new 55,000-sq.-ft. store in Williamsburg, Va., utilizes an advanced refrigeration technology that replaces R404-A, a halogenated fluorocarbon greenhouse gas producer, with a nongreenhouse emissions-producing secondary fluid (a 35% aqueous propylene glycol fluid) as a primary refrigerant. This low-pressure “chilled water” loop eliminates the circulation of high-pressure refrigerant throughout the sales floor area.
The sustainability impact of the application is measurable in that by applying the new technology—Second Nature from Hill PHOENIX—the store has reduced the initial charge of R404-A by 40%, or approximately 1,500 lbs.
“Ukrop’s has always been proactive in seeking out innovations that not only improve the store’s efficiency, but also are good for the community and environment,” said Katie Chernau, director of construction and facilities, Ukrop’s Super Markets, Richmond, Va. “It only makes sense to operate this way.”
Ukrop’s anticipates the ongoing savings that will result from the elimination of refrigerant circulating between the display cases and the mechanical room, and the subsequent leaks that occur over time, will be significant.
“The typical supermarket has miles of piping through which refrigerant runs to cool the product in the cases,” explained Brad Roche, VP of marketing, Hill PHOENIX. “This system replaces the refrigerant in the pipes with a water-based solution and confines the refrigerant to the mechanical room. There is a direct reduction in the amount of refrigerant required to work the refrigeration system.”
HVAC/Refrigerant InitiativesUkrop’s Super Markets is environmentally proactive when it comes to its HVAC and refrigeration use. The chain made the switch three years ago from hydrochlorofluorocarbon (HCFC) refrigerants and has eliminated all chlorofluorocarbon (CFC) refrigerants for more than a decade (the two refrigerations contribute to ozone depletion). Its new stores only use hydrofluorocarbon (HFC) refrigerants.
The supermarket chain has used variable speed drives to control motors in its HVAC and refrigeration systems for some time now to reduce energy. Recently, it started using the technology to control unnecesssary exhaust and costly makeup air in the kitchen hood systems. Also, the waste heat from the refrigeration systems is being used to pre-heat the hot water for the store. It will supplement the space heating during the winter and dehumidification during the summer, reducing the use of natural gas.
Since the propylene glycol refrigerant is not under high pressure like primary refrigerant in a direct expansion system, the store uses an engineered plastic piping system. The system resulted in an overall linear footage reduction of installed copper piping of 60%. Using the plastic pipe in place of copper equates to a major reduction in overall environmental impact. It also has a significantly lower thermal conductivity rate than copper and a larger wall thickness. Both of these factors lead to lower energy loss.
Product quality: The store’s refrigerated display cases (also from Hill PHOENIX) are designed to work in concert with the Second Nature system. Because defrost time is equal to or less than other defrost methods and defrost temperatures are significantly lower, temperature control is more stable.
The result is reduced recovery time after defrost and less shock and moisture removal for better product quality which, in turn, yields longer shelf life.