Cycling Refrigerated Air Dryers, 300 to 1,250 SCFM

Cycling Refrigerated Air Dryers, 300 to 1,250 SCFM

Load-following dryers for 60 to 250 hp compressors and plants with idle hours

From 60 hp to 250 hp the compressor is a plant asset, and so is the electricity that dries its air: a non-cycling dryer at 600 SCFM absorbs about 4 kW every hour it is powered. This band is for the plant whose compressor unloads at night, stops at weekends or feeds a process that runs in batches, where a dryer that follows the load returns that power to the bill.

Four current series cover the band with three technologies. The thermal-mass and dry thermal-mass dryers store cold and stop their refrigeration compressor; the phase-change dryer does the same with a freezing medium around a brazed-plate exchanger; and from 600 SCFM the digital-scroll dryer modulates its compressor from zero to full capacity instead of stopping it, so the dew point never moves.

Thirty-two current models span 265 to 1,250 SCFM, nearly all on 460 V three phase, with 1-1/2 in to 3 in threaded connections and 3 in and 4 in flanges on the largest. Water-cooled versions of the phase-change and digital-scroll dryers are listed from 600 and 800 SCFM. The previous generation is in the table with its successor.

• Rated 300 to 1,250 SCFM at 100 psig, 100°F inlet and 100°F ambient
• Thermal-mass, phase-change and digital-scroll capacity control
• Air-cooled throughout, water-cooled options from 600 SCFM
• 1.4 to 9.5 kW at full load, 460/3/60 on all but the smallest sizes