The Difference Between a Circulator and a Chiller

Definition

• A circulator -- or circulating bath or thermostat -- is a small, tabletop device intended for laboratory use. Circulators remove heat with a network of low pressure and low volume circulating pumps that stabilize the temperature of the liquid.
  A chiller -- or recirculating chiller -- is a large floor-model machine with greater heat removal capacity than a circulator. Chillers have higher volume and pressure pumps that provide more power for industrial use. Unlike circulators, chillers may be utilized for heating as well as cooling purposes.

Temperature Control and Stability

• Circulators provide more temperature control and stability than a chiller. The temperature control range of a circulator is minus 45 to 200 degrees Celsius with a stability factor of plus or minus .05 degrees Celsius. A chiller's temperature control range is minus 15 to 40 degrees Celsius with a stability factor of plus or minus .05 Celsius. When a chiller is used for heating purposes, the maximum temperature is 80 degrees Celsius.

Power and Design

• While circulators are more temperature sensitive, chillers offer more heat removal power. A circulator clears up to 750 Watts; a chiller removes 2,850 Watts for every one horsepower of energy. Circulators run on an open or closed loop system, while chillers use turbine, positive displacement or magnetic drive centrifugal technology. Both circulators and chillers have water reservoirs and pumping systems. However, the circulator's water reservoir creates a circulating bath, while a chiller's reservoir generates thermal mass.

Availability

• In the United States, chillers and circulators are available for both commercial or home use. Temperature control equipment manufacturers include PolyScience, Torrey Pines Scientific and Macro Scientific Works, which offer online product descriptions, price guides, knowledge centers and customer service information. Prices vary by model, manufacturer and capacity.