A device for filling vehicle air conditioning systems with refrigerant R744, wherein the device comprises at least one storage tank for liquid refrigerant R744, a pump station, a filling station, an adapter, an adapter support, a supply line, a line, a first line and a return line, wherein the storage tank is connected to the pump station via the line, the pump station is connected to the filling station via the supply line, and the filling station is connected to the adapter via the first line and to the storage tank via the return line, and wherein the refrigerant R744 can be fed into the vehicle air conditioning system via the adapter, characterized in that a temperature sensor and a valve circuit are arranged at the cross-over area between the supply line and the filling station, and the filling station includes a controller, wherein the controller controls the valve circuit in such a way that, depending on the respective operating situation, the refrigerant flow is controlled in such a way that, in the case of an interruption of the refrigerant flow, the refrigerant which is heated necessarily due to the interruption of the flow, is fed back and guided to the storage tank via the return line and cold refrigerant is fed back from the storage tank to the filling station, wherein the control of the valve circuit and, consequently, a recirculation and cooling of the refrigerant is initiated by the filling station and wherein the adapter support is designed in such a way that the adapter, in its resting position, can be held in a positive locking connection to a specific port, preferably a service port, in such a way that a feeding back and cooling of the refrigerant takes place via a return line (8; 9) assigned to the adapter support, wherein the controller of the filling system initiates the control of the adapter support and, consequently, any feeding back and cooling of the refrigerant is initiated by the filling station, and wherein the controller triggers a feeding back and cooling of the refrigerant by means of the valve circuit and the adapter support only at times when the application-specific operating behavior of the filling station is not impaired. a temperature sensor and a valve circuit are arranged at the cross-over area between the supply line and the filling station, and the filling station includes a controller, wherein the controller controls the valve circuit in such a way that, depending on the respective operating situation, the refrigerant flow is controlled in such a way that, in the case of an interruption of the refrigerant flow, the refrigerant which is heated necessarily due to the interruption of the flow, is fed back and guided to the storage tank via the return line and cold refrigerant is fed back from the storage tank to the filling station, wherein the control of the valve circuit and, consequently, a recirculation and cooling of the refrigerant is initiated by the filling station and wherein the adapter support is designed in such a way that the adapter, in its resting position, can be held in a positive locking connection to a specific port, preferably a service port, in such a way that a feeding back and cooling of the refrigerant takes place via a return line (8; 9) assigned to the adapter support, wherein the controller of the filling system initiates the control of the adapter support and, consequently, any feeding back and cooling of the refrigerant is initiated by the filling station, and wherein the controller triggers a feeding back and cooling of the refrigerant by means of the valve circuit and the adapter support only at times when the application-specific operating behavior of the filling station is not impaired.