How do I decide between air-cooled and water-cooled Huber circulators?

Most Huber units are available in either air-cooled or water-cooled versions.

Water cooling and air cooling is referring to heat removed from the Huber unit itself (cooling of the condenser in its refrigeration system, after it has removed heat from your application).  It does not refer to how the Huber unit cools your application – e.g. a water-cooled Unistat would still circulate oil, not water, around a vessel’s jacket.

For relatively small (low to moderate cooling power) models, the air-cooled versions are recommended.  For some large units (very high cooling power), only water cooling is available.  If you are using a chiller to recirculate cooling water to minimise water consumption, you certainly should use an air-cooled rather than a water-cooled unit.

Air-cooled circulators
  • Use internal fans to pull cool air in for cooling.
  • Warm air is ejected into the lab.
  • This warm exhaust air must be able to rise without hindrance. Fresh air must also be able to enter the machine.  You must ensure there is sufficient space around the unit – more clearance is needed than for water-cooled units.
  • If grills get dusty or blocked, your efficiency will drop off and the system may cut out.
  • Large units can be noisy.
  • For high cooling power units where there is still a choice available between air-cooled and water-cooled, the air-cooled units can be larger (have bigger dimensions).
Water-cooled circulators
  • Water-cooled Hubers are denoted by a ‘w’ at the end of their model name, e.g. Unistat 405w.
  • Water circulates past the circulator’s condenser to remove the heat.
  • The water supply must be of a suitable pressure, temperature and purity.
  • The circulator must have access to a drain for waste hot water to be disposed of (unless you are using your own looped chilled water supply).
  • Water-cooled models are quieter than air-cooled.