Cheese Processor Reduces CO2 Emissions with Industrial Refrigeration Technologies

French cheese processor La Compagnie des Fromages, a subsidiary of the Bongrain Group, is pursuing a policy to reduce its energy usage and CO2 emissions. That’s why it invested in a facility designed by Cofely Axima, a France-based leader in industrial refrigeration, and relies on state-of-the-art refrigeration equipment from Emerson Group, Philadelphia, Pa.

"Because we serve as a consultant to our customers, we conducted an energy audit with la Compagnie des Fromages' plant in the town of Vire," says Jean-Yves Druillennec, sustainable development manager for Cofely Axima–GDF Suez.

The audit, which was based on a series of measurements, provided a snapshot of the Vire plant's consumption levels and suggested replacing its four piston compressors, which provided only cooling, with a thermo-refrigerating pump, a thermo-dynamic heat-transfer system that can cool and heat at the same time. The refrigeration system makes it possible to provide cooling capacity to the evaporator and heating capacity to the condenser. When 1000 kW of chilled water is produced at Vire, 1300 kW of energy is recovered at the same time and combined with just 100 kW of electricity to heat water to 62°C. All the energy produced and used is fully recovered. A 150 m³ buffer storage unit allows energy to be used to produce hot water as needed by the process (particularly cleaning operations). With the old system, this water was heated by gas, which has a much higher carbon footprint. In addition, the heat produced was rejected to the atmosphere by a cooling tower instead of being recovered and reused. The new system saves 9000 m3 of water a year and has reduced use of the cooling tower, which with its plumes of steam, always reflects negatively with local residents.

At the heart of the system are a 390 kW motor and a variable-speed drive. Both are made by Leroy-Somer, a unit of Emerson Industrial Automation, and power a Vilter single-screw compressor with 1000 kW of cooling capacity. The refrigerant circulated in the system is ammonia (NH3), a natural heat-transfer medium. Cooling and heating are simultaneously produced one-third of the time. To raise the water temperature from 15°C to 58°C (with a combined COP* of 7.67), the ammonia, after having removed heat from the cold side to produce chilled water, is compressed to achieve the right pressure and temperature. As this temperature is much higher than the usual temperature for a conventional cooling system, the ammonia condenses at 59°C. The water is heated by transferring the heat from the ammonia via the condenser and other heat exchangers located at various points in the system for heat-optimization purposes. During the remaining one-third of the time, chilled water is produced conventionally with a COP of 5.75. Ultimately, the system will recover all the heat extracted during the production of chilled water.

An 18-month return on investment
Chilled water at 1°C to 7°C and 200 m3 of hot water at 60°C are produced daily at the Vire plant. To do this, the old system consumed an average of 820 kW of energy per ton of production per year. With the new system, this level is now only 560 kW.