Colruyt puts ammonia at heart of new factory

In deciding between a combined heat and power (CHP) plant or a heat pump to save energy at its new meat processing facility, leading Belgian retailer the Colruyt Group decided an ammonia heat pump was the most efficient option. Accelerate Europe reports.

Cross the bridge from the train station in the small town of Buizingen, just south of Belgian capital Brussels, and you cannot miss the row of wind turbines lining the canal alongside the Colruyt Fine Food factory.

The Colruyt Group’s official target is to reduce its relative CO ₂ emissions by 20% by 2020 compared to 2008 levels. To help achieve this, in 2014 the Group adopted the official target of using 100% natural refrigerants for all its cooling needs. Its own energy company, Eoly, operates wind turbines, solar panels and CHP plants.

Colruyt Fine Food’s new meat processing facility, located on the Buizingen site, opened in September 2016.

Having been cut down to size and cleaned elsewhere, pieces of meat arrive in the building for processing into sausages, bacon, smoked meat, meatballs in sauce and packaged sliced meat. The products are packaged on site and sent to a central fridge in nearby Halle for distribution to supermarkets.

“We had two ideas. One was a heat pump and the other was a combined heat and power (CHP) plant,” Project Engineer Kristof Lauwereys told Accelerate Europe.

The facility operates in two eight-hour shifts: from 6:00-14:00, and from 14:00 to 22:00. During the night, production shuts down for the plant to be cleaned with hot water at 55°C. Hot water is also required for the production process and air-handling units.

The site’s hot water consumption, together with the fact that most of its electricity demand is already satisfied by wind, ultimately led Lauwereys to opt for a heat pump over CHP.

“Our electricity production is more sustainable with a wind turbine than with CHP, because the CHP still needs to use gas,” Lauwereys explains.

“The heat pump that is installed here is 1 MW. During peak periods, we do use a small amount of gas, but not that much. During the day, the heat pump runs on three compressors with a frequency drive, making 200-250 kW. During the night, at its peak during the cleaning process, it peaks at a little over 1 MW,” he says.

From factory to shop

Upon arriving at the factory, the meat is briefly stored in fridges at 2°C before processing begins. “We have one freezer for peak moments, but usually we always produce fresh meat,” Lauwereys says.

At the end of the process, the meat is kept in fridges at -6°C to -10°C for 8-10 hours. “We leave it in there long enough to freeze a bit but not entirely, so that it can be easily sliced,” he explains.

To speed up the process during peak moments, the meat is placed in shocking cells for up to 20 minutes at -25°C to -30°C. “That’s why we need the subcritical CO₂ system. The rest of the time, the meat stays at an ambient temperature of -2°C to +2°C,” Lauwereys says.

Ammonia ticks all the boxes

Mayekawa (Mycom) provided the cooling system, the heat pump and the eight compressors. “There is 3,500 kg of ammonia in the cooling system and 850 kg of ammonia in the heat pump. For this big cooling capacity, ammonia is the best,” Lauwereys argues.

The ammonia heat pump satisfies most of the HVAC&R demand. “Ammonia produces most of the cooling. We have three little cooling productions with CO₂. In this factory, we need very low temperatures to shock the meat,” Lauwereys explains.

The ammonia heat pump is also used to upgrade low-temperature heat produced as a by-product of the cooling process to high-temperature heat that can be used in other processes.

“We don’t want to work with Freon. We don’t believe in it any more,” he declares.

Click here to read the full version of this story in the summer edition of Accelerate Europe.