ROXSTA G6 cools Carrefour e-commerce center
At Carrefour’s e-commerce logistics center in Willebroek, a ROXSTA G6 delivers sustainable CO₂ refrigeration with heat recovery, hot gas defrost, and an adiabatic gas cooler—ensuring maximum efficiency and reliability.
For Belgian consumers, online grocery shopping is not just a passing trend linked to the coronavirus, but a firmly established habit. In response to this rapid growth, Carrefour Belgium announced in September 2020 an exclusive partnership with international company Food-X Technologies Inc. to leverage its state-of-the-art software. By 2026, Carrefour aims to accelerate its digital strategy and triple its e-commerce revenue to 10 billion euros.
In May 2021, the company announced a new milestone in the expansion of its e-commerce operations: a brand-new distribution center for online orders in Willebroek, Belgium. This semi-automated 8,350 m² warehouse has the capacity to handle around 5,000 orders with approximately 16,000 items per day. Customers can shop online and have their groceries delivered either to their homes or to one of 230 Drive pick-up points.
What sets this distribution center apart is not only its size but also its innovative concept. The containers used for order picking move automatically along a conveyor system, are durable, and reusable. Orders placed via Carrefour’s web shop are picked by staff, not robots, organized by product groups to ensure efficient workflows. Large loading bays facilitate the smooth handover of goods to carriers for delivery.
In April 2021, our Belgian partner Sabcobel commissioned the refrigeration system. The ROXSTA G6, housed in an enclosure, along with the gas cooler featuring a water spray system, was installed outside the building.
The CO₂ system cools three large medium-temperature rooms (1,072 m²) and one freezer room (324 m²). Key features include heat recovery, integrated hot gas defrost, and a liquid separator in the LT suction line.
This project uses a special hot gas defrost system powered by the MT compressors. First, the hot gas is expanded to a lower pressure to comply with the design limits of the evaporators. During the defrost cycle, the hot gas is then directed through the freezer evaporator and its drip tray, where it condenses steadily at +10 °C. A pressure control valve returns the condensed gas to the medium-pressure receiver.
This process makes full use of the latent heat of the refrigerant (CO₂) to melt ice quickly and efficiently. The additional components are integrated as a separate module alongside the rack system and are controlled as needed by the main system controller.
LT liquid separator
To protect the low-temperature compressors when the evaporators restart after a defrost cycle, the suction line is equipped with an additional liquid separator. Here, any residual liquid in the suction vapor is separated and allowed to evaporate safely.
Heat recovery
Waste heat from the medium-temperature operation is used to supply hot water for cleaning the reusable picking crates. Heat recovery from the low-temperature operation is utilized to heat the ventilated floor beneath the freezer room. This prevents condensation under the cold store, protecting the foundation.
Adiabatic gas cooler
The gas cooler with water spray system boosts efficiency in transcritical operation during summer. The water supply is precisely regulated so that only as much water is used as the air can absorb. This minimizes water consumption and eliminates the need for further technical measures under the Water Resources Act.
Facts & figures
-
Total area: 8,350 m²
-
Capacity: 5,000 orders per day
-
16,000 items per day
Cold rooms
-
3 MT rooms – total area 1,072 m²
-
1 LT room –21 °C – area 324 m²
ROXSTA G6
- ROXSTA G6 in soundproof housing
-
Refrigerant: R744 (CO₂)
-
Medium temperature cooling
-
4 x Bitzer compressors (1 with frequency inverter / incl. parallel compressor)
-
175 kW (t₀ –8 °C / tGC out 42 °C)
-
-
Low temperature cooling
-
3 x Bitzer compressors (1 with frequency inverter)
-
40 kW (t₀ –33 °C / tC –8 °C)
-
Special features
-
Heat recovery COOL2HEAT (MT/LT)
-
Hot gas defrost
-
LT liquid separator
-
Parallel compression
-
Lead compressor with frequency control
-
Adiabatic gas cooler
In Belgium, Carrefour operates 786 stores with a total of 11,300 employees across different formats: hypermarkets, supermarkets, Express convenience stores, and Drive pick-up points.
Through its Act For Food program, Carrefour also aims to take a leading role in driving healthier eating habits. The group is committed to concrete actions that protect the environment while ensuring access to high-quality food.
In spring 2021, Carrefour Belgium signed the government’s 9th Green Deal—an initiative led by industry associations to reduce the use of fluorinated gases in supermarkets and food retail. Since sustainability is a cornerstone of the company’s strategic decisions, Carrefour’s active involvement and commitment to this agreement came as a natural step.