Air conditioning device for a heating installation, a ventilation installation and/or a air conditioning installation

The loop (12) has a compressor (14), a first heat exchanger (16) for heating an air flow distributed into a cab interior of a motor vehicle, a first expansion device (18) e.g. electronic expansion valve, an exterior heat exchanger (20) and a second heat exchanger (24), that are arranged according to a direction of closed circuit circulation of coolant in the loop. A thermal storage device (28) is connected to an outlet of the first heat exchanger and to an outlet of the exterior heat exchanger. A bypass arm (36) is arranged in parallel with the first expansion member. The coolant is chosen from a group comprising subcritical fluid, such as 1, 1, 1, 2-Tetrafluoroethane (R134A) or supercritical fluid such as R744 or carbon dioxide.