ROXSTA G6 cools Carrefour E-Commerce-Center

16. December 2021 | All articles, Projects /

For Belgian consumers, e-commerce in groceries is not just a coronavirus-related trend, but has become a genuine habit. In response to this exponential growth, Carrefour Belgium announced in September 2020 that it had entered into an exclusive partnership with international company Food-X Technologies Inc. in order to benefit from their cutting-edge software. By 2026, Carrefour aims to advance its digital strategy and triple its sales in the e-commerce sector to 10 billion euros. 

Pic: Carrefour e-Commerce-Center Conveyor belt

In May 2021, the company announced a new milestone in the development of its e-commerce: a brand new distribution centre for online orders in Willebroek (Belgium). This new, semi-automatic warehouse with an area of 8,350 m2 has capacity for more than 5,000 orders with around 16,000 items per day. Customers can do their shopping online and have their goods delivered to their home or to one of the 230 drive-in collection points.

The distribution centre is not only characterized by its size, but also by its innovative character: the receivers that are used to pick the orders run automatically on a conveyor belt and are durable and reusable. The online orders via the web shop are picked into these boxes by the Carrefour staff. This is not done automatically by a robot system, but by hand and is divided into product areas in which the individual packing steps take place. Using one person to put the orders together would not be efficient. The goods are then collected on large loading ramps via the sender.


Pic: Adiabatic Gas Cooler & ROXSTA G6 in housing
Adiabatic Gas Cooler & ROXSTA G6 in housing

Refrigeration Technology Implementation

In April 2021, the commissioning of the refrigeration technology took place at our Belgian partner Sabcobel. The ROXSTA G6 – built into the housing – and the gas cooler with water sprinkler system are installed outside the building. 

The CO2 refrigeration unit cools three large normal cold rooms (total 1,072 m2) and a low temperature room (324 m2). Special features of the unit are heat recovery, integrated hot gas defrosting and a liquid separator in the LT suction line.


Hot Gas Defrosting

Pic: Control Valves LT Evaporator
Control Valves LT Evaporator

In this project, a special hot gas defrosting system is used, which is fed by the MT compressors. Here, the hot gas is first expanded to a lower pressure in order to maintain the engineering design pressures of the evaporator. The hot gas is then fed through the low temperature evaporator and the corresponding drip pan during the defrosting cycle, where it condenses at a constant +10 °C. The liquefied gas is returned to the medium-pressure tank via a constant pressure valve. The entire latent amount of heat in the refrigerant (CO2) can be used to melt the ice quickly and efficiently. The additional components are adapted in the form of another module on the side of the multi compressor system and are controlled in a demand-based manner by the main controller of the refrigeration unit.


LT Liquid Separator

In order to protect the low temperature compressor from any remaining liquid when the evaporator is switched on again following a defrost cycle, the suction line is also provided with a liquid separator. The liquid contained in the suction vapor is separated in the separator and can safely evaporate. 


Heat Recovery

The waste heat from normal cooling operation is fed into the cleaning unit of the picking boxes for use as process water. The heat recovery of the low temperature operation is used to heat the ventilated floor of the LT cell. This prevents the condensation of humidity below the cold room and protects the foundation.


Adiabatic Gas Cooler

The gas cooler with water sprinkling system increases the efficiency in transcritical operation during the summer. This regulates the flow of water in such a way that no more water is required than can be absorbed by the air. This reduces water consumption to an optimal minimum and exempts from further technical measures according to the Water Resources Act.


Description of the system technology

Pic: ROXSTA G6 in housing
ROXSTA G6 in soundproof housing

Numbers & Facts

  • Total surface area of the warehouse 8,350 m2
  • Capacity for 5,000 orders per day
  • 16,000 items per day

Cold Rooms

  • 3 MT rooms – total surface area 1,072 m2
    – Packaged goods 2-4 °C
    – Fruit & vegetables 12 °C
    – Fruit & vegetables 2-4 °C 
  • 1 Cold room -21 °C – surface area 324 m2

Refrigeration System ROXSTA G6

  • ROXSTA G6 in soundproof housing
  • Refrigerant R 744 (CO2)
  • Medium temperature cooling
    4x Bitzer Compressors (1st Compressor with FC / incl. Parallel Compressor)
    175 kW (t0 -8 °C / tGC out 42 °C)
  • Low temperature cooling
    3x Bitzer Compressors (1st Compressor with FC)
    40 kW (t0 -33 °C / tC -8 °C)

Technical Features

  • Heat recovery COOL2HEAT (MT/LT)
  • Hot Gas Defrosting
  • LT Liquid Separator
  • Parallel Compression
  • Lead Compressor frequency-controlled
  • Adiabatic Gas Cooler


About Carrefour Belgium

In Belgium, Carrefour has 786 stores with a total of 11,300 employees in various formats: Hypermarkets, supermarkets, express convenience stores and 230 pick-up points. 

In addition, Carrefour aims to lead the way in changing diets for everyone with its Act For Food program. The group is committed to taking concrete measures to protect the environment and ensure access to quality food for all.

In spring 2021 Carrefour Belgium signed the government’s 9th Green Deal – an initiative of associations dedicated to the reduction of fluorinated gases in supermarkets and grocery stores. Since sustainability is a central part of the company’s strategic decisions, it was only natural that Carrefour Belgium would get involved and sign the agreement.

>> Carrefour Belgium – Commitment regarding Climate Change <<


  Sarah Schröter

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