In order to provide a method for de-icing a heat exchanger of a motor vehicle, which prevents large amounts of melt water from a defrosting process running onto the floor or the road beneath the motor vehicle, freeze again and pose a risk of injury to pedestrians, in a method for defrosting a heat exchanger of a motor vehicle, in which, for a heat exchanger arranged in a motor vehicle, a defrosting process for removing a layer of frozen water or frost formed on a surface of the heat exchanger is carried out, the defrosting process comprising heating the surface, and melt water being produced, it is proposed that the amount of melt water discharged onto a local region of a floor beneath the motor vehicle is limited to a maximum value.

A method for operating a heat pump of a motor vehicle that includes a compressor, an expander, an ambient heat exchanger and a heating heat exchanger. In the method, a defrost mode for defrosting the ambient heat exchanger is initiated. In the defrost mode, a refrigerant is compressed to a high pressure by the compressor to transfer thermal energy to the ambient heat exchanger, the refrigerant is expanded to a low pressure by the expander, and the refrigerant absorbs thermal energy in the heating heat exchanger. Further, a defrosting process of the ambient heat exchanger triggered by the defrost mode is monitored. The monitoring of the defrosting process includes monitoring the pressure difference between the high pressure and the low pressure and/or monitoring the pressure gradient of the pressure difference between the high pressure and the low pressure and/or monitoring the high pressure.

This air conditioning device for a vehicle comprises: a refrigeration cycle having a compressor, a condenser, an expansion valve, and an evaporator through which refrigerant sequentially flows; a high-temperature heat medium circuit in which a high-temperature heat medium that has been heat-exchanged with the refrigerant in the condenser circulates; a low-temperature heat medium circuit in which a low-temperature heat medium that has been heat-exchanged with the refrigerant in the evaporator circulates; a connection line for connecting the high-temperature heat medium circuit and the low-temperature heat medium circuit; a plurality of heat exchangers outside the vehicle that allow introduction of the heat medium; and a switching unit capable of switching modes for each of the plurality of heat exchangers outside the vehicle, among a mode for connecting to the high-temperature heat medium circuit, a mode for connecting to the low-temperature heat medium circuit, and a mode for not connecting to either of the high-temperature heat medium circuit and the low-temperature heat medium circuit.

Heat flow management device for motor vehicles has a refrigerant circulation, a power train coolant circulation and a heating line heat carrier circulation. The refrigerant circulation includes a compressor, an indirect condenser, an expansion element, an ambient heat exchanger, an evaporator and a chiller. The power train coolant circulation includes a coolant pump, the chiller, an electric motor heat exchanger and a power train coolant radiator, wherein the heating line heat carrier circulation comprises a coolant pump, the indirect condenser and a heating heat exchanger, wherein the refrigerant circulation and the power train coolant circulation are directly thermally coupled with one another across the chiller. Refrigerant circulation and heating line heat carrier circulation are directly thermally coupled with one another across the indirect condenser. Power train coolant circulation and the heating line heat carrier circulation are only indirectly thermally coupled with one another across the refrigerant circulation.

There is provided a vehicle air-conditioning device capable of smoothly achieving pre-air-conditioning for preliminarily heating a vehicle interior without forming frost on an outdoor heat exchanger or while preventing frost formation thereon as much as possible. When the temperature of a battery 55 or a motor 65 for running is higher than or equal to a predetermined specified value upon executing the pre-air-conditioning for preliminarily heating the vehicle interior before boarding, a controller 32 operates a compressor 2 to let a refrigerant discharged from the compressor radiate heat in a radiator 4, decompress the refrigerant from which the heat is radiated, and then let the refrigerant absorb heat in a waste heat recovering heat exchanger 64 without using an outdoor heat exchanger 7.

In order to provide a method for initiating a defrosting process of a heat exchanger of a heat pump of a motor vehicle, which method is insensitive to external parameters influencing the air flow through the evaporator, and with which method unnecessary defrosting processes can be avoided, wherein a fan is assigned to the heat exchanger, wherein a power consumption and/or a speed of the fan is monitored, a defrosting process is initiated when the power consumption and/or the speed exceeds and/or falls below a threshold value, and the threshold value is determined as a function of a parameter, wherein the parameter is an indicator of a current relative air speed of the ambient air in relation to the motor vehicle.

In order to provide a method for initiating a defrosting process of a heat exchanger of a heat pump of a motor vehicle, which method is insensitive to external influences and can also be used in combination with other methods, wherein the heat exchanger and a coolant heat exchanger of a cooling circuit of the motor vehicle are arranged in a common air path, a coolant outlet temperature of a coolant from the coolant heat exchanger is determined, and a state of icing of the heat exchanger is determined using the coolant outlet temperature, and initiating a defrosting process of the heat exchanger if icing of the heat exchanger is determined.

A refrigeration cycle device includes a high-temperature side heat exchanger, an expansion valve for decompressing the refrigerant flowing out of the high-temperature side heat exchanger, a low-temperature side heat exchanger that exchanges heat between the refrigerant decompressed by the expansion valve and coolant, a high-temperature coolant circuit in which the coolant circulates to the high-temperature side heat exchanger, a low-temperature coolant circuit in which the coolant circulates to the low-temperature side heat exchanger, a battery and a low-temperature side radiator configured to exchange heat with the coolant in the low-temperature coolant circuit; and a heat transfer portion configured to transfer heat from the high-temperature coolant circuit to the low-temperature coolant circuit such that the coolant dissipates heat in the battery and the low-temperature side radiator.

In a refrigeration cycle device, a heat supply unit is disposed in parallel with a heat utilization unit in a flow of a heat medium. A branching part branches the heat medium flowing out of a heat radiator into a flow flowing toward the heat utilization unit and a flow flowing toward the heat supply unit. A merging part is configured to cause the heat medium having passed through the heat utilization unit and the heat medium having passed through the heat supply unit to merge together and to flow toward the heat radiator. A switching unit switches an operation state between a first state in which the heat medium circulates between the heat radiator and the heat utilization unit, and a second state in which the heat medium circulates between the heat radiator, the heat utilization unit and the heat supply unit.

An air-conditioning device includes: a compressor; an outdoor heat exchanger; an evaporating unit configured to evaporate refrigerant a heater unit configured to heat the air by using the heat of the refrigerant a liquid receiver arranged at the downstream side of the outdoor heat exchanger and a restrictor mechanism provided between the heater unit and the outdoor heat exchanger, wherein, in an operation state in which the flow of the refrigerant is restricted by the restrictor mechanism and heat is released in the heater unit, a first operation mode and a second operation mode are switched, the first operation mode being set such that the liquid-phase refrigerant is stored in the liquid receiver and the gaseous-phase refrigerant is guided to the compressor and the second operation mode being set such that the liquid-phase refrigerant stored in the liquid receiver is guided to the evaporating unit.