20130174577 | Heating and Cooling Unit with Semiconductor Device and Heat Pipe - Aspects of the invention support the changing of a serving surface temperature in order to cool or heat the serving surface. Heat is transferred to or from the serving surface through at least one Peltier device, a heat pipe, and a heat sink. The mode of operation is determined by changing the electrical power polarity to the at least one Peltier device. A control device may activate the at least one Peltier device from a measured temperature and a temperature setting with a hysteresis. A plurality of Peltier devices may be partitioned into different subsets so that the control device may activate a selected subset during different time intervals. When the measured temperature is outside a temperature range, all of the Peltier devices may be activated, while only a selected subset may be activated when the measured temperature is within the temperature range and until a hysteresis temperature is reached. | 07-11-2013 |