Farm Fresh is improving its energy efficiency and reducing its impact on the environment with the help of new technology. The supermarket chain, a division of Supervalu, has debuted an advanced two-stage, open-drive refrigeration system at its new store in Franklin, Va.
The main benefits of the system, from Hill Phoenix, Conyers, Ga., include a reduction in refrigerant leaks and refrigerant charge, improved energy efficiency, and overall system simplification, resulting in increased reliability and less maintenance.
“The Hill Phoenix technology we’ve selected offers benefits for the environment, our stores and our customers,” said Jon Perry, director of energy and maintenance, Farm Fresh, Virginia Beach, Va., which operates 46 locations.
Reducing leaks: A variety of system designs work to reduce the refrigerant and lower the potential for refrigerant leaks. The compressors are key. New technology incorporated into the open-drive compressor has eliminated many of the problems inherent in the past system. Laser alignment allows for a finer tolerance in lining up the compressors and motors, which translates into less vibration and energy consumption.
“And with less vibration you not only reduce refrigerant leak potential, but you can operate longer with less wear and tear on the equipment,” Perry said.
Another key to reducing refrigerant leak potential is the design of the compressor rooms. At the Farm Fresh store, the equipment operates in a completely contained compressor room in which conditioned air provides a controlled space.
“With the contained room design, we’re able to keep dirt out by using only conditioned air to cool the room,” Perry said. “If there is a refrigerant leak, it can be detected immediately at a higher concentration and at a lower leak rate, and addressed right away.”
The use of loop piping in the system helps lower leak potential due to the reduced amount of copper piping and fittings required. In the Farm Fresh application, only one liquid and three suction lines leave the main system in the machine room and branch out to the refrigerated cases, reducing the leak potential. In a more traditional supermarket refrigeration system, there can be up to 120 lines, making it much harder to identify the source of the leak.
The use of a roof-mounted vertical surge receiver offers reduced refrigerant charge because it requires less refrigerant than a horizontal receiver for proper operation. The roof mounting also provides natural sub-cooling, especially in the winter. All this translates into less refrigerant charge and higher energy efficiency for a store.
“In a typical 60,000-sq.-ft. store such as Franklin, we’ve been able to reduce refrigerant from 4,400 lbs. to 2,500 lbs.,” Perry said. “That’s a substantial reduction.”
Energy efficiency: One of the greatest advantages of the refrigeration system in place at Farm Fresh is energy efficiency. The overall system is 20% more energy-efficient than a standard DX store, according to Hill Phoenix. This is due in part to the use of high-efficiency motors that are 10% more efficient than standard compressor motors.
In addition, some of the efficiency gain comes from the two-stage low-temp compressors, which are more energy-efficient than single-stage ones. Another feature, hydronic heat reclaim, also impacts energy consumption by using the total store thermal heat of rejection (THR), including the air-conditioning THR, instead of just from one or two compressor systems in a typical store.
“By using more of the waste heat taken out of the display cases and air conditioning and reheating the air or water in the store, we’re able to greatly reduce energy consumption,” Perry explained.
To date, the new open-drive system has been installed in 10 Farm Fresh stores. The chain is committed to future installations, Perry said.