Dryer Selection Calculator

Dryer selection is driven almost entirely by how dry your process needs the air to be. This calculator picks a technology from your required pressure dew point: 35°F and warmer routes to a refrigerated dryer with no purge air consumed; colder targets down to -40°F go to a membrane dryer if your flow is small (≤50 CFM) or otherwise a heatless desiccant dryer, both of which consume compressed air internally to regenerate their drying media (18% and 15% purge loss, respectively); and anything below -40°F calls for a heated desiccant dryer, which trades a lower purge loss (7%) for direct electrical heating. Once a type is chosen, the calculator applies two CAGI-style correction factors to the rated capacity: dryers are rated at a 100°F inlet, so hotter incoming air derates capacity by about 1.5% per degree above that baseline (and slightly uprates it below), and capacity is also corrected for operating pressure relative to a 100 psig baseline, since lower system pressure means the dryer must handle a larger actual air volume for the same mass flow.

The corrected capacity, minus whatever air the dryer consumes as purge, gives the net air actually delivered downstream. Power estimates differ sharply by type — a refrigerated dryer's own compressor draws roughly 0.2 kW per 100 CFM, while heatless and membrane dryers use minimal direct power but push their real cost onto the plant's air compressor, which has to generate the purge air; that indirect cost is folded into the "total system impact" figure using a rough 4.5 CFM-per-horsepower conversion. Because these are industry rule-of-thumb figures rather than a specific manufacturer's CAGI-certified data sheet, use the output to shortlist a dryer category and rough operating cost, then confirm against the vendor's actual performance curves.