Les Atokas Bieler, in collaboration with Carnot Refrigeration, opted for a CO2 transcritical technology to chill cranberries at its new refrigeration warehouse in Quebec, Canada.
As a special partner of the GUIDE to Natural Refrigerants in North America – State of the Industry 2015, Carnot Refrigeration provided a number of innovative case studies including Les Atokas’ warehouse in Saint-Louis-de-Blandford, which Carnot managed entirely from the design, manufacturing and installation.
Given the highly seasonal nature of processing cranberries, Les Atokas came to Carnot with very specific cooling requirements. The berries enter the warehouse only once a year – from late September to late October – directly from a flooded field to the cleaning room, without passing through a freezing tunnel.
This type of operation poses a particular challenge for system designers like Carnot, who were tasked with finding a catered solution to supply a very large charge for the concentrated period each year, while only maintaining temperatures for the rest of it. Another peculiarity of this project is that the berries are very humid, which requires special evaporators and a high-performance defrosting system.
About the system
- System capacity of 690 kW
- Divided into medium temperature section, that includes 9 semi-hermetic reciprocal compressors and two tanks; low temperature including 10 semi-hermetic reciprocal compressors and 2 tanks; and 2 gas coolers including 12 fans.
- Low pressure side contains 80 bar, 120 bar on the high pressure side
- All piping stainless steel
- Twelve evaporators stainless steel coils designed for 80 bar pressure
- Waste heat recovered from the system used for hot gas defrost and sub-slab heating
Since the installation both Carnot and Les Atokas have reported positive findings leading to a second-phase expansion of the same warehouse as well as interest from other cranberry growers. The effectiveness of the hot gas defrost system, combined with savings generated by heat recovery, especially for sub-slab heating, have been highlighted. Carnot continues to monitor the effectiveness of its sites and to refine its remote settings. This service is highly appreciated by many customers, starting with the client who can control the temperature of its room with a simple phone call. The technician in charge of maintaining the system can also obtain important information via this service, feeding Carnot will valuable information to help with future designs and installations.
About Carnot Refrigeration
Carnot is a Canadian company headquartered in Quebec and established in 2008 with the goal of addressing the HVAC&R industry’s failure to provide industrial and commercial clients with a thermodynamic option that would diminish environmental impact. Carnot makes a conscious effort to design refrigeration systems and heat pumps that cut down on the use of polluting refrigerants. Carnot specialises in meeting the needs of sports facilities (arenas), supermarkets, distribution centers and the agricultural food industry.