The NaturaLINE units have been performing at predicted levels during sea trials, proving the practicality of a natural refrigerant-based system for high-efficiency marine applications. To date, NaturaLINE sea trial units have logged hundreds of thousands of nautical miles and tens of thousands of service hours for customers, successfully delivering a wide spectrum of products, including Caribbean-grown bananas, Belgian beer, European wines, cookie dough, ice cream, meats and cheeses. The units have been operating over temperature set points ranging from -22 degrees Celsius to 13 degrees Celsius on Atlantic and Pacific routes ranging from four to 29 days. More sea trial units will be deployed over the next several months.

Using carbon dioxide (CO2) as its refrigerant, the NaturaLINE unit can help alleviate container shipping industry concerns about the use of conventional synthetic refrigerants, which have higher global warming potential (GWP). Combined with its outstanding energy efficiency, the NaturaLINE unit is proving itself to be the most environmentally sound alternative available for overseas shipping of frozen and refrigerated goods. It also has been validated by UL Environment as having a 95 percent recyclability rate, joining Carrier’s PrimeLINE® unit as the only container refrigeration units to achieve recyclability validation.

“Carrier’s natural leadership in refrigeration technologies provides marine and intermodal shipping operations with an unprecedented opportunity to further improve their environmental stewardship,” said David Appel, president, Carrier Transicold, at this year’s Intermodal Europe trade show, in Amsterdam. “Along with the PrimeLINE unit, the NaturaLINE unit leverages environmental technologies to consume less energy over its expected life compared to our previous equipment, reduce overall operating costs and increase the recyclability of its components when they reach the end of their useful life.”

The NaturaLINE unit’s CO2 refrigerant has a GWP equal to one, significantly less than the GWP of synthetic refrigerants used in other container refrigeration systems. Non-flammable, CO2 is cost-effective, available worldwide and requires no special disposal. Of further benefit to shipping line customers, there is no CO2 refrigerant tax, and no intermediate refrigerant step is required.

The NaturaLINE unit has been optimized to provide energy efficiencies over a range of performance conditions that equals Carrier’s most efficient unit, the PrimeLINE, while also providing rapid pull-down and high deep frozen capacities. By significantly reducing on-board power generation requirements, the NaturaLINE unit can help shipping lines save fuel used in the generation of electricity. This, in turn, helps hold down operating costs, with the added benefit of reducing emissions related to power generation.

When it comes to carbon emissions, the NaturaLINE unit excels. Its indirect CO2 equivalent (CO2e) emissions – those created through energy production to power the unit – match the indirect emissions of the PrimeLINE unit, which are 28 percent less than previous equipment. The NaturaLINE unit also eliminates concerns about direct emissions in the event of refrigerant leakage, since the CO2 is recycled from the atmosphere. Thus, over the life of the unit, NaturaLINE’s CO2e emissions are 5 percent less than PrimeLINE unit’s combined direct and indirect emissions, and 10 percent less than the closest competitive unit, according to published data.

"In a world of finite natural resources, the NaturaLINE unit stands with Carrier’s PrimeLINE unit as the leaders in energy-efficient marine container systems and the only systems certified for recyclability. This is how Carrier maximizes environmental technologies while lowering environmental impact," said John Mandyck, chief sustainability officer, UTC Climate, Controls & Security.

Addressing the unique thermodynamic properties of CO2, NaturaLINE units take advantage 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 optimized heat transfer surfaces, and a flash tank heat exchanger to maximize cooling performance.

While introducing many industry firsts, the NaturaLINE unit maintains consistency with other current Carrier Transicold models. The basic frame, evaporator motors and fans, and user interface are virtually identical to existing units, making operation of the NaturaLINE unit as easy as other Carrier units. Serviceability is also similar to Carrier’s existing line, supported by a comprehensive training program.