Abstract: A refrigeration device including a thermally-insulated housing enclosing an inner chamber to be cooled and an evaporator for cooling the chamber. The evaporator is arranged in an air passage communicating with the chamber through openings in a wall separating the evaporator from the chamber. A control device controls a heating device to heating the evaporator to defrost the evaporator. The air flow through the air passage is measured by a measuring device arranged in the air passage or opening to provide a signal representative of the air flow. When the measured air flow falls below a threshold value, the control device operates the heating device to defrost the evaporator.

Abstract: A refrigeration device including a method and apparatus for defroster heating. The defroster heating, such as supplied by an integrated defroster heater, includes a recording circuit for recording a voltage value of the supply voltage to the defroster heater. The recording circuit also generates a keyed control signal with a repetition rate dependent upon the recorded voltage value. The keyed control signal operates an interrupter for the supply power of the defroster heater. The repetition rate is set with relation to the recorded voltage value to limit power variations of the defroster heater caused by supply voltage variations.

Abstract: A refrigeration device with a thermally-insulating housing enclosing a cooling chamber and an evaporator separated form the cooling chamber. Two temperature sensors are placed in the vicinity of the evaporator to sense the layer of ice, which can form during operation. The temperature sensors are placed such that only one is embedded in the ice layer for a given thickness of the ice layer. A monitoring circuit is coupled to the temperature sensors to measure the temperature difference sensed by the temperature sensors. The monitoring circuit determines from the temperature difference if a defrosting of the evaporator is necessary. The monitoring circuit provides a signal for the determination, which can be used in an automatic defrosting process.