A MOTOR-VEHICLE AUXILIARY AIR CONDITIONING SYSTEM

A motor-vehicle is equipped with an auxiliary refrigeration circuit (F') with an auxiliary electrically-operated compressor (C') of reduced size and power compared to the compressor (C) of the main refrigeration circuit (F). An air guide duct (2) which drives a flow of air towards the passenger compartment of the motor-vehicle includes an auxiliary inlet portion (201) arranged upstream of the main portion (200) which contains the auxiliary evaporator (E') of the auxiliary refrigeration circuit. An auxiliary circuit (H2) for the coolant of the internal combustion engine is provided through which the engine coolant can circulate through the auxiliary condenser (D') of the auxiliary refrigeration circuit (F') and then through a passenger compartment heater (H), and then return through said condenser (D'). A valve (T) controls the communication between the auxiliary circuit (H2) for the coolant and a main circuit (H1) for the coolant. In a first operating position of the valve (T), the auxiliary circuit (H2) for the coolant is insulated with respect to the main circuit (H1) for the coolant, so that if the auxiliary refrigeration circuit (F') is active, the coolant is able to draw heat from the auxiliary condenser (D') of the auxiliary refrigeration circuit and to deliver it by means of said passenger compartment heater (H) to an air flow directed towards the passenger compartment, even if the internal combustion engine is off. In a second operating position of the valve (T) the auxiliary circuit (H2) for the coolant is in communication with the main circuit (H1) for the coolant, so that during operation of the internal combustion engine, the passenger compartment heater (H) receives liquid that is heated by the engine.