New technology reduces emissions for refrigerated transport


While there have been many improvements to marine and road transport refrigeration systems since they became popular modes of delivering fresh and frozen cargo more than 40 years ago, the basic concept of using man-made chemical refrigerants as the cooling agent has not changed.

However, recently technological advancements have been made in freight container refrigeration systems using the natural refrigerant CO2.

The new ‘Carrier Transicold NaturaLINE’ product made its debut at the Intermodal Europe Show. The debut comes exactly one year after the company announced it had developed and begun testing the technology. The science behind the new technology is that by using CO2 as a natural refrigerant in reefer boxes, the Carrier Transicold NaturaLINE design improves upon the company’s best in class performer PrimeLINE unit’s ability to reduce carbon dioxide emissions by a further 28% percent compared to previous units.

Its two stages of compression allow the NaturaLINE to improve efficiency, along with its cylinder unloading capability, which allows the compressor to save energy in light-load conditions, according to the release.

NaturaLINE uses two stages of compression, which improves the overall efficiency of the unit. Its unique cylinder unloading capability allows the compressor to save energy in light-load conditions. The variable-speed drive that controls the compressor is a first for a Carrier container refrigeration unit. The custom designed drive electronically adjusts the compressor’s speed to provide the precise amount of cooling capacity to meet demand, saving considerable energy compared to conventional units. The inbuilt technology replaces the condenser assembly found in conventional refrigeration units with a new heat exchanger called the gas cooler. The gas cooler coil wraps around the fan, maximizing heat-transfer surface area for greater efficiency in a design that is both compact and lightweight.

David Appel, president at Carrier Transicold said,

“Advancing Carrier’s leadership in environmental technologies for the marine container refrigeration market, the new design provides the global shipping industry with the most environmentally sound alternative for refrigerated transport. NaturaLINE stands apart as the only one to offer a natural refrigerant-based solution.”

Mike Griffin, Carrier Transicold’s new product development program manager commented:

“Addressing the special thermodynamic properties of CO2 necessitated the development of an innovative refrigerant management system, including a new purpose-built, multi-stage compressor with variable-speed drive, a ‘gas cooler’ with a wrap-around design and a flash tank. The patented reciprocating multi-stage compressor maximizes capacity and minimizes power consumption. The gas cooler makes the overall refrigeration system more versatile in responding to the thermodynamic properties of CO2, providing gas cooling after each compression stage for better efficiency.”

The flash tank, an entirely new component in a container refrigeration system, is designed to manage the flow and phase change of the refrigerant after leaving the gas cooler. For efficient cooling performance, the Carrier design, which has been patented, enables final separation of CO2 from its gas phase to the liquid state before entering the evaporator. The basic frame, the evaporator and evaporator fans, and the controller and control box are virtually identical to existing Carrier Transicold models. The easy-to-use control interface works the same as on other container refrigeration units.

In addition, serviceability will be similar to existing Carrier Transicold products, and will be supported by a new comprehensive training program.