Dryer dew point explained
The number on the datasheet is a pressure dew point. Compare it with your plant, not with the weather report.
Dew point is the temperature at which the water vapour in your air starts to condense. Compressed-air datasheets quote the pressure dew point (PDP): the dew point at line pressure. Let the air expand to atmosphere and a PDP of +3 °C becomes roughly −23 °C. Don’t compare a PDP with an ambient humidity reading.
A refrigerated dryer cools air to about +3 °C, condenses the water, drains it, and reheats the air so pipes do not sweat. It is right for most machine shops, textile mills and packaging lines, where the air never runs through a pipe colder than 3 °C.
A desiccant dryer (−20 to −40 °C PDP) is for air that goes outdoors in winter, into paint booths, or into instruments. It costs three to four times as much to run, because it dumps 10–15% of your air to regenerate. Don’t buy one because the number looks better.
Whichever dryer you fit, put a separator, a filter and an auto-drain before it. A dryer fed with liquid water is working on the wrong problem.