There is disclosed herein a subsystem for a vapor-compression system having a compressor and a condenser. The subsystem includes a storage assembly fluidly communicable with a compressor inlet of the compressor for flow of refrigerant. The storage assembly is configured to receive and store refrigerant in a storing configuration, and release refrigerant stored therein to the compressor inlet of the compressor in a releasing configuration. The subsystem further includes a flow-directing assembly in fluid communication with the storage assembly for flow of refrigerant, and fluidly communicable with a condenser inlet of the condenser and a compressor outlet of the compressor for flow of refrigerant. The flow-directing assembly is configured to direct refrigerant from the compressor outlet to the storage assembly in a first flow configuration, and direct refrigerant from the compressor outlet to the condenser inlet in a second flow configuration.

A variable refrigerant charge refrigeration/air conditioner system is described that allows the refrigerant charge for the system to be altered based on operating or environmental factors. The system includes a main refrigerant loop holding a volume of refrigerant corresponding to a first level of refrigerant charge, a compressor in the main refrigerant loop, a condenser in the main refrigerant loop, and an evaporator in the main refrigerant loop. A branch refrigerant loop allows the alteration of the refrigerant charge using a control valve in the branch refrigerant loop and a receiver in the branch refrigerant loop. The receiver acts to hold a volume of refrigerant when the control valve is open, thereby removing the volume of refrigerant from the main refrigerant loop. A return path from the receiver to the main refrigerant loop allows refrigerant to flow back into the main loop from the receiver.

The refrigerant device includes a refrigerant circuit, an injection circuit, an inlet temperature sensor, an outlet temperature sensor, and a controller configured to control the operation of the refrigerant circuit. The controller includes an evaluation value calculation unit and a refrigerant amount detection unit. The evaluation value calculation unit calculates an evaluation value indicating a capability of a subcooling heat exchanger in accordance with an inlet temperature detected by the inlet temperature sensor and an outlet temperature detected by the outlet temperature sensor. The refrigerant amount detection unit determines whether there is a shortage of refrigerant in accordance with the evaluation value calculated by the evaluation value calculation unit.

A heating, ventilation, and air conditioning (HVAC) system includes an expansion device disposed between a condenser and an evaporator of a vapor compression system and a control panel communicatively coupled to the expansion device. The control panel is configured to: determine a liquid refrigerant level set point of the condenser based on parameters of the vapor compression system, provide a first control signal to increase an opening of the expansion device in response determining that the current liquid refrigerant level in the condenser is greater than a determined liquid refrigerant level set point of the condenser, and provide a second control signal to decrease the opening of the expansion device in response to determining that the current liquid refrigerant level in the condenser is less than the determined liquid refrigerant level set point of the condenser.

A variable refrigerant volume system includes: a compressor; a four-way valve; an indoor unit; a liquid tube, the first end thereof being connected to the indoor unit, the second end thereof being connected to the third valve port of the four-way valve, and a condenser being provided on the liquid tube; a low pressure air pipe, the first end thereof being connected to the indoor unit, and the second end thereof being connected to the fourth valve port of the four-way valve; a refrigerant adjustment tank, the first port thereof being connected to the liquid tube, the second port thereof being connected to the low pressure air pipe, and the third port thereof optionally communicating with the liquid tube or the low pressure air pipe.

A cooling device capable of preventing inflow of bubbles to a pump even in a zero-gravity space and a space structure including the cooling device are obtained. In a cooling device, a pump, a cooler, and a radiator are connected sequentially by a refrigerant flow path. An accumulator is connected to the refrigerant flow path connecting the pump and the radiator. The accumulator includes a container storing refrigerant, a cooling section cooling a base-end side of the container, and a heating section heating a front-end side of the container.

An HVAC system includes a first heat exchange coil with a plurality of coil circuits. For each coil circuit of the plurality of circuits, there is a manifold line fluidly coupling the coil circuit to a compressor of the HVAC system. A check valve is positioned in a first manifold line coupling a first coil circuit of the plurality of coil circuits to the compressor. The check valve is configured to allow flow of refrigerant from the compressor to the first coil circuit when the HVAC system is operating in a cooling mode and prevent flow of refrigerant from the first coil circuit to the compressor when the HVAC system is operating in a heating mode.

An HVAC system includes a first heat exchange coil with a plurality of coil circuits. For each coil circuit of the plurality of circuits, there is a manifold line fluidly coupling the coil circuit to a compressor. A first controllable valve is positioned in a first manifold line coupling a first coil circuit of the plurality of coil circuits to the compressor. A second controllable valve is located in a conduit fluidly coupling the first coil circuit to a second heat exchange coil. A controller is communicatively coupled to the first and second controllable valves and operates the valves to provide charge compensation in a heating and/or cooling mode.

An air conditioner and a control method of an air conditioner are provided. The air conditioner includes an outdoor unit, an indoor unit, a refrigerant circulation loop, and a controller. The controller is configured to determine whether the air conditioner is operating in a cooling mode; obtain a first target supercooling degree in a first standard condition if it determined that the air conditioner is operating stably in the cooling mode; convert a supercooling degree in a current condition into a supercooling degree in the first standard condition; obtain a first refrigerant amount difference according to the first target supercooling degree, the supercooling degree in the first standard condition, an outdoor unit internal volume in the first standard condition, and an outdoor unit internal volume in the current condition; and determine a refrigerant amount of the air conditioner according to the first refrigerant amount difference.

A microchannel heat exchanger has an upper portion connected in fluid communication with a header, a lower portion connected in fluid communication with the header at a location that is vertically lower on the header than the upper portion, and a sight glass on the header. The sight glass can be horizontally aligned with a top of the second portion. The sight glass can be served as a visual aid when charging the microchannel heat exchanger with a refrigerant at a predetermined level. When an indicator indicates that refrigerant is mixed vapor and liquid, refrigerant can be added into the microchannel heat exchanger. When the indicator indicates that the refrigerant is liquid, the charging process can be stopped.