VEHICLE AIR-CONDITIONING DEVICE AND VEHICLE AIR-CONDITIONING METHOD

An object of the invention is to provide a vehicle air-conditioning system and a vehicle air-conditioning method, which avoid occurrence of window fogging when heating is performed in air conditioning, thereby allowing a driver to put a vehicle in motion as soon as getting in the vehicle. A heating ventilation and air-conditioning unit (4) includes an intake door (3) which switches between an inside air introduction port (1) and an outside air introduction port (2), a blower fan (5), an interior heat exchanger (6), a heater core (10), and an air mix door (13). The air mix door (13) produces air at a target temperature by mixing cooled air and heated air. The air at the target temperature is blasted from ventilators (14). When there is a request for heating the inside of a vehicle cabin in preliminary air conditioning, an A/C controller (20) activates a PTC heater (12) and an electric water pump (11) to cause the heater core (10) to heat the air. At this time, by controlling the intake door (3), the A/C controller (20) alternately switches between an inside air recirculation mode for a first predetermined time period and an outside air introduction mode for a second predetermined time period.