The PrimeLINE container unit’s latest enhancement may be a “dry subject,” but it’s anything but dull.
A new control enhancement now provides the lowest relative humidity (RH) level ever achieved by a Carrier Transicold container unit – 50 percent. Better yet, this was accomplished with no compromise in the PrimeLINE unit’s industry-leading energy efficiency.
Low RH is important for shipping certain types of produce, such as ginger and other root crops, onions, garlic and flower bulbs. Too much moisture, and bulbs can sprout prematurely. Keeping things dry can also be helpful when shipping paper products, artwork, pharmaceuticals, electronics and even certain metals that may be subject to surface staining.
The new control enhancement also 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,” says Jim Taeckens, senior product manager. “This enhancement can be made to existing PrimeLINE models when users upgrade to the latest control software.”
Dehumidification functionality also requires a humidity sensor, an option that can be factory installed or added in the field.
A Software-Based Solution
Thanks to the PrimeLINE unit’s electronic expansion valve, the dehumidification enhancement was done entirely through sophisticated software algorithms. No change to the mechanical design was required, and the upper end of the dehumidification range remains 95 percent RH.
“Carrier’s control software engineers were able to achieve exceptionally consistent humidity levels, even at 50 percent RH,” Taeckens adds. “This was achieved without consuming any more energy than was needed to achieve the previous low-humidity threshold of 65 percent.”
That is a stark contrast to the approach taken by some competitive units to achieve low humidity levels. Competitive offerings with 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 percent more energy to achieve 72 percent RH at 5oC (41ºF) than a PrimeLINE unit with enhanced dehumidification control. In other tests, competitive units could not even reach specified humidity at setpoints of 50 percent RH at 5ºC (41ºF) and 75 percent RH at 15ºC (59ºF), even though the PrimeLINE unit easily could.
“Relative humidity is a challenge to control because so many variables affect it,” explains Taeckens.
Now, the PrimeLINE unit handily tackles the greatest dehumidification challenges without breaking a sweat.back to top