We have to replace our refrigerated air dryer. Here is the original data plate information.

BRAND ZEKS-THERM H/S MODEL
MODEL 2H/S S/N 2H/S0979006 9/25/79
10 SCFM CAPACITY

Boy did we get our money worth out of that one !

Since we were starting over we know we can buy another refrigerated dryer but are considering all options. I was looking membrane type units. These seemed attractive at first glance in the fact that they use no electric... Our air supply system is used to operate a number of 3 way valves in the plant to control HVAC water temperatures in various heating and cooling units throughout our building. The system is supplied by a 20 gallon 1/2 hp single stage compressor.

I understand in principal how these work but am unsure if this is a good application for us. I am unfamiliar with the added requirements of the air compressor due to the air that is used to push the condensate out of the unit. I am told this is sometimes referred to as the "sweep flow"

I need to understand the difference in cost and maintenance in using a refrigerated air dryer vs. the cost of operating the air compressor a longer period of time to maintain the "sweep flow" of a membrane unit.
Currently the air compressor only runs 2 - 3 times a day.

Has anyone else gone down this path ?