An air conditioner including a hot gas line for receiving a portion of refrigerant compressed in a compressor, an indoor heat exchanger, an outdoor expansion device for expanding the refrigerant having exchanged heat in the indoor heat exchanger, an outdoor heat exchanger functioning as a condenser in a cooling mode while functioning as an evaporator in a heating mode, and a 4-way valve for receiving a remaining portion of the compressed refrigerant, to guide the refrigerant emerging from the compressor to the outdoor heat exchanger in the cooling mode and to the indoor heat exchanger in the heating mode. The outdoor heat exchanger includes a main heat exchanger section functioning as a condenser in the cooling mode while functioning as an evaporator in the heating mode, and an auxiliary heat exchanger for receiving the refrigerant from the hot gas line in a frosting prevention mode.

A method for controlling operation of a refrigeration system (1), including one or more refrigeration entities (4), is disclosed. Each entity controller (7) obtains a measure for an error value between the measured value of a compressor control parameter and a setpoint value (8) for the compressor control parameter, and each entity controller (7) adjusts a refrigeration load of the corresponding refrigeration entity (4) to correspond to a cooling capacity of the compressor(s) (2), and in accordance with the obtained measure for an error value.

A refrigeration circuit comprises in the direction of flow of a refrigerant at least one compressor; at least one heat rejecting heat exchanger; at least one expansion device; and at least one evaporator. The refrigeration circuit further comprises at least one heat recovery heat exchanger having a refrigeration circuit side and heat recovery system side and being configured for transferring heat between the refrigeration circuit side and the heat recovery system side, wherein the refrigeration circuit side is fluidly connected in parallel to the at least one heat rejecting heat exchanger; and at least one regulation valve, configured for regulating the flow of refrigerant flowing through the refrigeration circuit side of the at least one heat recovery heat exchanger. The at least one regulation valve is switchable between an open position, a closed position, and at least one intermediate position.

A refrigeration system includes a valve and a controller. The valve is configured to control the flow of refrigerant into an evaporator, the refrigerant having an associated liquid setting comprising a temperature and a pressure at which the refrigerant flows through the valve. The controller is operable to adjust the liquid setting, the adjusted liquid setting comprising a temperature and a pressure selected to improve energy efficiency under conditions currently being experienced by the refrigeration system, wherein the controller is operable to adjust the temperature and the pressure simultaneously such that the adjustment does not interfere with operation of the valve.

An air conditioner and a method for controlling an air conditioner are provided. The air conditioner may include at least one indoor device, an electric heat pump (EHP) outdoor device connected to the at least one indoor device and having an EHP compressor driven using an applied current, and a gas heat pump (GHP) outdoor device connected to the at least one indoor device having an engine driven using a combustion of gas and a GHP compressor driven by receiving a driving force from the engine. The EHP compressor may include an inverter that controls a frequency of the current applied to the EHP compressor. The GHP compressor may include a first compressor that receives a driving force from the engine to compress a refrigerant; and a second compressor that is connected to the first compressor in parallel and receives the driving force from the engine to compress the refrigerant.

A method for controlling a vapour compression system (1) is disclosed, the vapour compression system (1) comprising an ejector (5). The method comprises controlling a compressor unit (2) in order to adjust a pressure inside a receiver (6), on the basis of a detected pressure of refrigerant leaving an evaporator (8). The portion of refrigerant leaving the evaporator (8) which is supplied to a secondary inlet (15) of the ejector is maximised and the portion of refrigerant supplied directly to the compressor unit (2) is minimised, while ensuring that the pressure of refrigerant leaving the evaporator (8) does not decrease below an acceptable level.

Disclosed is an integrated compressor system configured to be integrated with existing air conditioning systems. The integrated compressor system generally includes a mounting assembly, a first compressor and a valve. The mounting assembly can be mounted directly on a condenser of an existing air conditioning system. The first compressor and the valve are mounted directly on the mounting assembly. The valve has a first valve inlet, a second valve inlet and a valve outlet. When assembly and integrated with an existing AC system, the first valve inlet is fluidly coupled to a compressor outlet of the first compressor, the second valve inlet is fluidly coupled to a compressor outlet of the compressor of existing AC system, and a valve outlet is fluidly connected to a condenser inlet of the condenser.

A compressor controller includes: a control amount calculation unit configured to calculate at least two control amounts including a first control amount for controlling a first control object that relates to a gas amount for cooling a cryogenic apparatus, and a second control amount for controlling a second control object that relates to the refrigerant gas amount and that is different from the first control object, the second control amount being common with the first control amount; and a selection unit configured to select a control object to be controlled from at least two control objects including the first control object and the second control object on the basis of a comparison between the at least two common control amounts.

The present invention provides for a control system for operating a heating, ventilation, and air conditioning (HVAC) system. A controller operates compressors in tandem. In response to detection of a high pressure condition in refrigerant flowing through a high pressure side of the HVAC system, the controller operates the HVAC system with a first compressor on and a second compressor off.

An air conditioning system and a method for controlling the same are provided. The air conditioning system includes an enhanced vapor injection compressor, first and second direction switching assemblies, first and second heat exchangers and a flash evaporator. The enhanced vapor injection compressor has an air discharge port, an air supplement port, first and second air suction ports, and an air return port. Pressure in a sliding vane chamber of an air cylinder corresponding to the second air suction port is equal to a discharge pressure at the air discharge port. A first pipe port of the first direction switching assembly is connected with the second air suction port, a second pipe port thereof is connected with the air discharge port and a third pipe port thereof is connected with the liquid accumulator, and the first pipe port is communicated with one of the second and third pipe ports.