Why is the operating time of the Peltier element limited to 10 minutes only? FAQ Report A Peltier element (electrical cooling) always has two sides – a cold and a warm side. The cold side is used to quickly freeze the specimens. The heat produced on the warm side has to be dissipated. The longer the Peltier element is activated, the more heat is produced and the warmer the cold side gets. To avoid “weakening” the freezing rate by a warming Peltier element, it is automatically switched off after 10 minutes of use.