Thermoelectric-cooled liquid bath chiller capable of unattended operation at -28 °C

Using thermoelectric elements, we have developed a simple liquid bath chiller that is inexpensive and easy to fabricate. Typically, small experimental apparatus can be cooled using a liquid cold bath. These cold baths require continuous addition of a coolant such as dry ice or liquid N₂ to maintain the desired temperature, which becomes tedious during long experiments. We demonstrate the capability of our liquid bath chiller to stably maintain a bath temperature of -28 °C for days at a time, without the need of continuous monitoring. We explore the effects of thermoelectric element capacity and configuration in addition to the temperature, composition, and flow rate of the liquid flowing through the liquid heat exchanger that transports heat away from the thermoelectric element.