The cooling air must be de-humidified to prevent moisture gain.  This can be
by cooling the gas below the dew point of the entering gas and then
reheating it about 5 degrees (to avoid carry over of droplets).  Since this
is a small volume of cooling gas, you may be able to use a desiccant bed to
remove moisture.  You will need tow beds, one to dry while the other
regenerates.