Relative humidity (RH) levels as low as 50% are now attainable with Carrier Transicold’s PrimeLINE container refrigeration units, with no compromise in energy efficiency.
Low RH is important for shipping certain types of produce, such as ginger and other root crops, onions, garlic, and flower bulbs. A new control enhancement provides the lowest humidity level ever achieved by a Carrier Transicold container unit and expands the PrimeLINE unit’s dehumidification capabilities over a wider range of operating temperatures.
“Already best-in-class in so many ways, the PrimeLINE unit now offers this extended dehumidification range as a standard feature,” said James Taeckens, senior product manager. “In addition, this enhanced capability can be added to existing PrimeLINE models when users upgrade to the latest control software.”
Thanks to the PrimeLINE unit’s electronic expansion valve, the dehumidification enhancement was done entirely through software algorithms. No change to mechanical design was required.
“Carrier’s control software engineers were able to achieve exceptionally consistent humidity levels, even at 50% RH,” Taeckens said. “This was achieved without consuming any more energy than was needed to achieve the previous low-humidity threshold of 65%.”
To achieve low humidity levels, some competitive offerings with mechanical thermo-expansion valves or add-on heat exchangers require greater energy consumption without providing the same consistent humidity and temperature tolerances offered by PrimeLINE units. This was demonstrated in recent field tests conducted by two shipping lines. In one test, a competitive unit required 37% more energy to achieve 72% RH at 5° C. In other tests, the competitive units could not even reach specified humidity at setpoints of 50% RH at 5° C and 75% RH at 15° C, even though the PrimeLINE easily could. The upper dehumidification range of the PrimeLINE unit remains 95% RH.
The PrimeLINE unit was developed to help shipping lines conserve fuel and reduce emissions related to shipboard power generation. According to Carrier Transicold, PrimeLINE offers exceptional pull-down capability and the highest deep-frozen capacity of any unit using non-ozone-depleting R-134a.
Carrier Transicold is a unit of Carrier Corp, which is a business unit of United Technologies Corp (NYSE: UTX). Visit www.carrier.com for more information.