Heat-pump-type vehicle air conditioning system and defrosting method thereof

Abstract

Provided is a heat-pump-type vehicle air conditioning system that flows hot gas to both an vehicle-cabin-exterior condenser and a vehicle-cabin-exterior vaporizer during a defrosting operation, and that, even during times of low outside air temperatures, can efficiently defrost in a short period of time and can use in a commoditized manner the cooling cycle of an existing system as-is. In the heat-pump-type vehicle air conditioning system (1): a vehicle-cabin-interior condenser (8) disposed downstream of a vehicle-cabin-interior vaporizer (7) within an HVAC unit (2) is connected, with a coolant switching means (16) therebetween, to a cycle (23) for cooling comprising an electric compressor (15), a vehicle-cabin-exterior condenser (17), a first decompression means (19) to which an on-off valve functionality is provided, the vehicle-cabin-interior vaporizer (7), and an accumulator (21); the vehicle-cabin-exterior vaporizer (27) disposed at the outside of the vehicle cabin is connected, with a second decompression means (26) to which an on-off valve functionality is provided therebetwen, to the exit-side liquid coolant tubing (22B) of the vehicle-cabin-exterior condenser (17); and furthermore a bypass circuit (32) having a third decompression means (30) to which an on-off functionality is provided is connected between the accumulator (21) and the exit exit-side liquid coolant tubing (22B) of the vehicle-cabin-exterior condenser (17).

Description

Technical field [0001] The present invention relates to a heat pump vehicle air-conditioning system suitable for air-conditioning devices such as electric vehicles and hybrid vehicles, and a defrosting method thereof. Background technique [0002] In vehicle air conditioning systems, electric vehicles (EVs) cannot use engine exhaust heat for heating. Even in hybrid vehicles (HEV, PHEV), people will try their best to control the engine to stop due to the fuel economy that people are promoting. Therefore, people have studied the use of heat pump heating systems using refrigerants or electric heating using refrigerants as a medium. Heating system composed of heaters. In particular, the power consumption of heating operation is large, so people hope to adopt a heat pump system that can realize high COP heating, where COP≤1 in the case of electric heaters. [0003] On the other hand, in the case of a heat pump system, when the car is driven with heating at a low outside temperature, f...

AI Technical Summary

Problems solved by technology

[0003] On the other hand, in the case of a heat pump system, when driving with the heater turned on at a low outside temperature, frost will form on the evaporator, which is the heat exchanger outside the vehicle, resulting in a decrease in heat absorption from the outside atmosphere. As a result, heating efficiency will be reduced

Therefore, it is necessary to defrost the evaporator, which is the heat exchanger outside the vehicle, and if the defrosting method applied to the heat pump air conditioner for buildings is used, the heating operation cannot be continued.

In the case of an air conditioner for a vehicle, there is a problem that if the heating operation is stopped, the windows will be fogged and driving safety cannot be ensured, so it is difficult to defrost while the vehicle is running.

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