SIAD, an Italian provider of gases, has for the first time publicly presented its COOOL FreeToGo refrigerated transport system, which uses liquid CO2 (R744) evaporation to generate cooling without the traditional vapor-compression cycle.

The system was showcased at REFRIGERA2021, held from November 3-5 in Bologna, Italy.

COOOL FreeToGo allows the “maintenance of the cold chain” inside a vehicle at a controlled temperature,” SIAD says on its website. It operates for both “mono and bi-temperature, for both fresh and frozen food.”

Unlike traditional refrigerated transport systems that employ vapor-compression systems or eutectic plates, SIAD’s system is compressor free and operates via the evaporation of CO2.

Notably, the system does not contribute any net CO2 emissions because the CO2 refrigerant it uses is obtained from the biogas released by organic matter and used to produce biomethane – an example of a virtuous cycle.

In the SIAD system, the CO2 gas does not enter the load space directly, eliminating the risk of under-oxygenation inside the vehicle, SIAD noted.

Because the system comprises few components, routine maintenance is reduced “to a minimum,” the company said. It also operates at “almost zero energy cost,” according to Italian refrigeration site Zerosottozero.

The system does not emit any noise during operation, said SIAD, which is an advantage during deliveries to residential areas.

Other features of the patent-pending system, according to SIAD, include the following:

  • Cooling speed is at least 10 times higher than a traditional system.
  • The operation of the system is independent from the vehicle traction, so it can operate with the engine off.
  • It does not emit any noise during operation.
  • It is adaptable to multiple vehicles and isothermal boxes.

Transcritical CO2 in transport refrigeration

Another refrigerated transport system using CO2 – though in a transcritical CO2 system – is Carrier Transicold’s NaturaLINE system, used in marine transport.

In 2018, the Mediterranean Shipping Company (MSC), based in Geneva, Switzerland, announced that it started to lease 2,000 containers chilled by Carrier Transicold’s NaturaLINE-based refrigeration system.

In 2016, Sainsbury, the U.K.-based supermarket chain, tested a truck-trailer prototype refrigeration unit running with a Carrier Transicold CO2 system designed for trucking.


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