If you are shopping for a refrigerated air dryer, it is a good idea to consult the Compressed Air & Gas Institute (CAGI) published data from the manufacturer before you buy.
If you buy a non-cycling air dryer, the unit will consume about the same power no matter what — even if the associated air compressor is not producing air. Consider the dryer data in Fig. 1; it will consume about 7.3 kW when running, which is about $6,400 per year in electrical costs if running full time. It doesn’t really matter how much air flows through this dryer because it doesn’t turn its power down much in response.
But the dryer in Fig. 2, produced by the same manufacturer, is a cycling style. It has a thermal mass installed within its enclosure that allows the refrigeration compressor to turn on and off — just like the refrigerator in your kitchen. Working at full flow, this dryer would consume about $3,900 per year in electrical costs, a savings of $2,500 per year. But if the load in the unit is lower than rated, say about 50%, the power will turn down saving even more electricity. The estimated additional savings would be $1,750 per year. Total savings for a lightly loaded cycling dryer at 50% load would be 66%.
It pays to consult the CAGI data sheets for dryers to see how each will compare to the others before you buy! Always ask for this information, it could save you a lot … on an ongoing basis.