An air-conditioning device includes a heater unit that heats the air to be lead to a vehicle cabin using the heat of the refrigerant compressed by a compressor, a liquid receiver arranged at the downstream side of an outside heat exchanger, a liquid receiver separating the refrigerant lead from the outside heat exchanger into a liquid-phase refrigerant and a gaseous-phase refrigerant and storing the liquid-phase refrigerant, and a restrictor mechanism provided between the heater unit and the outside heat exchanger, the restrictor mechanism decompressing and expanding the refrigerant. When there is a dehumidification request, the operation mode is temporarily switched from a dehumidifying cabin-heating mode which evaporates the refrigerant by an evaporating unit and radiates heat by the heater unit in the state in which the restrictor mechanism restricts the flow of the refrigerant, to the cabin-cooling mode which evaporates the refrigerant by the evaporating unit while promoting the storage of the liquid-phase refrigerant in the liquid receiver.

A system includes a turbine configured to exhaust an air stream. The system also includes a first coil configured to transfer thermal energy to the air stream when the air stream passes by or through the first coil, wherein the first coil is downstream of the turbine. The system also includes a second coil configured to transfer thermal energy to the air stream when the air stream passes by or through the second coil, wherein the second coil is downstream of the first coil. The system also includes a third coil configured to transfer thermal energy to the air stream when the air stream passes by or through the third coil, wherein the third coil is downstream of the second coil. The air stream is configured to cool one or more electronic components of a data center that is downstream of the third coil.

A system comprising a compressor, a first valve coupled to the compressor and to a first coil, a first expansion valve coupled to the first coil, and a second expansion valve. The second expansion valve coupled to a second coil. A second valve is coupled to the second coil and the compressor. A third valve is coupled to the compressor and a third coil. In response to receiving a heating demand that is below a threshold heating demand, a controller induces an artificial heating demand.

A system comprising a compressor, a first valve coupled to the compressor and to a first coil, a first expansion valve coupled to the first coil, and a second expansion valve. The second expansion valve coupled to a second coil. A second valve is coupled to the second coil and the compressor. A third valve is coupled to the compressor and a third coil. In response to receiving a heating demand that is below a threshold heating demand, a controller induces an artificial heating demand.

A system comprising a compressor, a first valve coupled to the compressor and coupled to a first coil, a first expansion valve coupled to the first coil, a second coil, and a second expansion valve. The second expansion valve coupled to a third coil, a second valve coupled to the compressor and the third coil. A controller operable to operate the first valve, the first expansion valve, the second expansion valve, and the second valve. The second coil is coupled to the compressor and the refrigerant flows from the second coil to the compressor.

A system comprising a compressor, a first valve coupled to the compressor and coupled to a first coil, a first expansion valve coupled to the first coil, a second coil, and a second expansion valve. The second expansion valve coupled to a third coil, a second valve coupled to the compressor and the third coil. A controller operable to operate the first valve, the first expansion valve, the second expansion valve, and the second valve. The second coil is coupled to the compressor and the refrigerant flows from the second coil to the compressor.

A dehumidification system includes a compressor, a primary evaporator, a primary condenser, a secondary evaporator, and a secondary condenser. The secondary evaporator receives an inlet airflow and outputs a first airflow to the primary evaporator. The primary evaporator receives the first airflow and outputs a second airflow to the secondary condenser. The secondary condenser receives the second airflow and outputs a third airflow to the primary condenser. The primary condenser receives the third airflow and outputs a dehumidified airflow. The compressor receives a flow of refrigerant from the primary evaporator and provides the flow of refrigerant to the primary condenser.

A dehumidification system includes a compressor, a primary evaporator, a primary condenser, a secondary evaporator, a secondary condenser, and a water pump. The secondary evaporator receives an inlet airflow and outputs a first airflow to the primary evaporator. The primary evaporator receives the first airflow and outputs a second airflow to the secondary condenser. The secondary condenser receives the second airflow and outputs a dehumidified airflow. The compressor receives a flow of refrigerant from the primary evaporator and provides the flow of refrigerant to the primary condenser. The primary condenser receives the flow of refrigerant and outputs the flow of refrigerant at a lower temperature through heat transfer with a flow of fluid. The flow of fluid is directed, by the water pump, to a heat exchanger or an external source, where heat is rejected from the flow of fluid.

Thermal management techniques include: transporting a refrigerant fluid from a receiver to an inlet of a flash tank that has a vapor-side outlet and liquid-side outlet such that a liquid phase of the refrigerant fluid moves to a bottom of the flash tank and outputs from the liquid-side outlet; forming a solid-vapor state from the liquid phase by expanding the liquid phase with an expansion valve to a first pressure that is less than a triple point pressure to form a solid-vapor mixture of the refrigerant fluid; extracting heat from a heat load with an evaporator that receives the solid-vapor mixture of the refrigerant fluid and sublimates the solid state of the solid-vapor mixture of the refrigerant fluid directly into a vapor phase of the refrigerant fluid; and discharging, from an exhaust line, the vapor phase to an ambient environment without returning the vapor phase to the receiver.

A volume ratio control system for a compressor includes a chamber formed within a housing of the compressor, a piston disposed within the chamber, where the piston is configured to separate the chamber into at least a first portion fluidly coupled to a low pressure side of the compressor and a second portion fluidly coupled to a high pressure side of the compressor, and a biasing device disposed within the chamber, where the biasing device is configured to adjust a position of the piston in response to a pressure differential between the low pressure side of the compressor and the high pressure side of the compressor falling below a threshold value.