The present invention concerns a cooling or heating apparatus including at least a 5 compressor (1), a condenser (2), an expansion apparatus (7), a vaporizer (9) and a space for liquid accumulation (10). The invention is characterized essentially by a control system consisting of an electronic bubble detecting device (4) for detecting the occurrence of bubbles in the refrigerant condensate. The bubble detecting device (4) is attached in proximity to the condenser's (2) outlet or to its exit line, the bubble detecting device (4) is in electrical connection with an expansion apparatus (7) that is controlled electrically. The bubble detecting device (4) gives signals to the expansion apparatus (7). Gas bubbles in the condenser liquid affect the control system so that when the amount of gas bubbles registered/signal analyzed by the bubble detecting device (4) exceeds the set signal value for the presence of bubbles in the condensate there is a signal to the expansion apparatus' electric control unit (7) to shut off or alternatively to decrease the refrigerant flowthrough. When the gas bubble amount is absent or alternatively is less than the predetermined set signal value the expansion apparatus (7) is given a signal from the bubble detecting device (4) to the expansion apparatus' electric control unit (7) to increase the refrigerant flowthrough.