Recirculating chillers and immersion chillers are used in the laboratory to cool reactions and maintain samples at temperatures desirable for specific reactions. Some reactions are exothermic - they give off heat when the reaction occurs. This heat can be high enough to destroy the desired product of the reaction. A chiller will cool the reaction and maintain the optimum temperature for the reaction products. Most recirculating chillers have a bath for samples and an inlet and outlet for tubing which can send the chilled fluid to a jacketed reaction vessel. Recirculating chillers usually are supplied with a heater which increases the temperature range and enables finer temperature control.
For temperatures below 0°C a heat transfer fluid is necessary for the chiller. Chiller manufacturers will recommend the appropriate heat transfer fluid for a specific temperature range.
Polyscience, Julabo and Lauda are some of the manufacturers of laboratory chillers