A heat pump device can discharge air in a heat medium circuit regardless of the height positions of two bodies of the heat pump device and prevents refrigerant outflow when the refrigerant enters the heat medium circuit in the liquid heat exchanger. A pump causes the liquid heat medium to flow in a predetermined circulatory direction in a heat medium pipe, and a liquid heat exchanger, a first air vent valve and a second air vent valve are arranged in this order along a circulatory direction.

An apparatus includes a flash tank, a medium temperature low side heat exchanger, a low temperature low side heat exchanger, a first compressor, a second compressor, and an ejector. The flash tank stores a refrigerant. The medium temperature low side heat exchanger uses the refrigerant from the flash tank to cool a space proximate the medium temperature low side heat exchanger to a first temperature. The low temperature low side heat exchanger uses the refrigerant from the flash tank to cool a space proximate the low temperature low side heat exchanger to a second temperature that is lower than the first temperature. The first compressor compresses the refrigerant from the low temperature low side heat exchanger. The second compressor compresses the refrigerant from the medium temperature low side heat exchanger. The ejector directs a mixture of the refrigerant from the first compressor and the refrigerant from the second compressor to the low temperature low side heat exchanger during a defrost cycle. The mixture defrosts the low temperature low side heat exchanger. The flash tank receives the mixture.

A heat pump unit and methods for operating the heat pump unit are provided. The heat pump unit includes a compressor (101), a throttling device (107), a first heat exchanger (104), a second heat exchanger (102), a third heat exchanger (103) and a mid-pressure tank (110). The heat pump unit operates in multiple run modes and switches between the run modes without shutdown. The first heat exchanger or the second heat exchanger is capable of acting as a condenser in the multiple run modes. When switching from a pre-switching run mode to a post-switching run mode, a control device determines whether to perform a pressure release operation to the first heat exchanger or the second heat exchanger.

A thermal management system includes a refrigerant system, which includes a compressor, a flow control device, a valve member, a first heat exchanger, a second heat exchanger, and a third heat exchanger. The flow control device includes a first throttle unit, a second throttle unit, and a valve assembly; the flow control device includes a first port, a second port, and a third port; a first connection port of the first heat exchanger is in communication with the second port, and a first connection port of the second heat exchanger is in communication with the third port, while a first connection port of the third heat exchanger is in communication with the first port. The thermal management system includes a first operating state and a second operating state.

An air conditioning system includes a bypass passage and a cooling-heating switching mechanism. The bypass passage is configured to be at least a part of a flow passage connecting a third port to a refrigerant inlet of a compressor. A linear expansion valve opens and closes the bypass passage. The cooling-heating switching mechanism includes check valves and four-way valves. The four-way valve causes a refrigerant outlet of the check valve to communicate with one of the refrigerant inlet and a refrigerant outlet of the compressor. The four-way valve causes a refrigerant inlet of the check valve to communicate with one of the refrigerant inlet and the refrigerant outlet of the compressor and causes a port to communicate with the other of the refrigerant inlet and the refrigerant outlet.

A cooling system of a vehicle, including a coolant circuit, which can be operated as a cooling circuit for an AC operation and as a heat pump circuit for a heating operation, an evaporator, a coolant compressor, a heat exchanger in the form of a coolant condenser or gas cooler for the coolant circuit or in the form of a heat pump evaporator for the heat pump circuit, a first expansion element which is paired with the evaporator, a second expansion element, the heat pump evaporator function of which is paired with the heat exchanger, and an inner heat exchanger with a high-pressure section and a low-pressure section. The low-pressure section is fluidically connected to the downstream coolant compressor. The high-pressure section of the inner heat exchanger is arranged in a coolant circuit section which connects the second expansion element to the heat exchanger.

An apparatus includes a flash tank, a medium temperature load, a low temperature load, a first compressor, a second compressor, and an ejector. The flash tank stores a refrigerant. The medium temperature load uses the refrigerant from the flash tank to cool a space proximate the medium temperature load to a first temperature. The low temperature load uses the refrigerant from the flash tank to cool a space proximate the low temperature load to a second temperature that is lower than the first temperature. The first compressor compresses the refrigerant from the low temperature load. The second compressor compresses the refrigerant from the medium temperature load. The ejector directs a mixture of the refrigerant from the first compressor and the refrigerant from the second compressor to the low temperature load during a defrost cycle. The mixture defrosts the low temperature load. The flash tank receives the mixture.

A reheating method for operating a refrigeration system for a motor vehicle. The refrigeration system includes a refrigerant compressor, connected to a primary line and a secondary line; an external heat exchanger; an evaporator; a heating register; at least one movable temperature flap; and at least one shutoff element, which is arranged downstream of the heating register in the secondary line. The reheating method includes following steps: setting the at least one shutoff element in a position in which the refrigerant flows into the evaporator downstream of the heating register while bypassing the external heat exchanger, and incorporating at least one further heat sink, which is fluidically arranged in parallel or in series to the evaporator, in particular a chiller operating as a water heat pump evaporator and/or the external heat exchanger operating as an air heat pump evaporator.

A reheating method for operating a refrigeration system for a motor vehicle is described, the refrigeration system includes a refrigerant compressor, which is connectable or connected to a primary line and a secondary line; an outer heat exchanger, which is arranged in the primary line; an evaporator, which is arranged in the primary line; a heating register, which is arranged in the secondary line; at least one movable temperature flap which is arranged upstream or downstream of the heating register in relation to a supply air flow direction; and at least one shut-off element, which is arranged downstream of the heating register in the secondary line. The reheating method includes adjusting the at least one shut-off element into a position in which refrigerant flows downstream of the heating register into the evaporator, while bypassing the external heat exchanger.

Provided is a heat pump device capable of discharging air in a heat medium circuit regardless of the height of the positions of two bodies, and capable of preventing a refrigerant from flowing out into a body not housing a liquid heat exchanger when the refrigerant enters the heat medium circuit in the liquid heat exchanger. To achieve this, the heat pump device includes: a refrigerant pipe connecting a compressor, a decompressor, an air heat exchanger, and a liquid heat exchanger circularly; a heat medium pipe connecting the liquid heat exchanger and a pump circularly; first and second air vent valves capable of discharging gas in the heat medium pipe to the outside; a first body housing the compressor, the decompressor, the air heat exchanger, the liquid heat exchanger, the refrigerant pipe, and the first air vent valve; and a second body housing the second air vent valve. The pump causes the liquid heat medium to flow in a predetermined circulatory direction in the heat medium pipe, and the liquid heat exchanger, the first air vent valve, and the second air vent valve are arranged in this order along the circulatory direction.