VEHICLE AIR CONDITIONING SYSTEM AND VEHICLE AIR CONDITIONING METHOD

The present invention provides a vehicle air conditioning system and a vehicle air conditioning method that increase heating performance while recovering exhaust heat from onboard equipment. The vehicle air conditioning system comprises: a refrigerant circuit; a heat medium circuit including a high-temperature medium circuit and a low-temperature medium circuit; an interior heat exchanger that exchanges heat between a heat medium and air; an exterior heat exchanger that exchanges heat between the heat medium and outside air; an exhaust heat recovery circuit; and a switching part. The following are provided as operating modes; an exhaust heat-recovery heating mode in which the heat medium in the high-temperature medium circuit is supplied to the interior heat exchanger and exhaust heat from onboard equipment is recovered by the heat medium in the low-temperature medium circuit, while the heat medium that has recovered and transferred exhaust heat to the refrigerant is supplied to the exterior heat exchanger; and an exhaust-heat-as-main-heat-source heating mode in which the heat medium in the high-temperature medium circuit is supplied to the interior heat exchanger and exhaust heat from onboard equipment is recovered by the heat medium in the low-temperature medium circuit, while the heat medium that has recovered and transferred exhaust heat to the refrigerant is caused to bypasses the exterior heat exchanger.