A refrigerating apparatus includes a high-temperature side circuit and a low-temperature side circuit connected to each other via a cascade condenser, a low-temperature side second flow control valve that turns a refrigerant, passing through a liquid pipe connecting between a cooling unit and other circuit parts in a low-temperature side circuit b, into a gas-liquid two-phase refrigerant, and an expansion tank connected to the suction side of a low-temperature circuit compressor via a tank electromagnetic valve.

A method for operating a compressor unit (2) comprising one or more compressors (8, 9, 10) is disclosed, the compressor unit (2) being arranged in a vapour compression system (1). Two or more options for distributing the available compressor capacity of the compressor unit (2) between being connected to a high pressure suction line (11) and to a medium pressure suction line (13) are defined. For each option, an expected impact on one or more operating parameters of the vapour compression system (1), resulting from distributing the available compressor capacity according to the option, is predicted. An option is selected, based on the predicted expected impact for the options, and based on current operating demands of the vapour compression system (1), and the available compressor capacity is distributed according to the selected option, e.g. by means of settings of one or more valve arrangements (14, 15).

The refrigeration cycle apparatus includes: liquid-side connection piping that extends from liquid-side refrigerant piping; gas-side connection piping that extends from gas-side refrigerant piping; a refrigerant storage tank that stores refrigerant, an intake side thereof being connected to the liquid-side connection piping, and a discharge side thereof being connected to the gas-side connection piping; an inlet-side electromagnetic valve that is disposed on the liquid-side connection piping, and that is opened when there is no passage of electric current; an inlet-side check valve that is disposed on the liquid-side connection piping, and that allows the refrigerant to flow only toward the refrigerant storage tank; and a valve apparatus that is disposed on the gas-side connection piping, that is opened during passage of electric current to the inlet-side electromagnetic valve, and that is delayed before being shut off after passage of electric current to the inlet-side electromagnetic valve is stopped.

A refrigeration cycle system includes a refrigeration cycle apparatus and a refrigerant storage portion. The refrigeration cycle apparatus includes an indoor unit, an outdoor unit, a gas-side connection pipe, and a liquid-side connection pipe. The refrigerant storage portion stores the refrigerant present inside a refrigerant circulation path. The refrigerant storage portion communicates with the refrigerant circulation path through a first storage portion pipe and a second storage portion pipe. The first storage portion pipe causes a first refrigerant pipe of an outdoor refrigerant flow path and the refrigerant storage portion to communicate with each other, or causes the gas-side connection pipe and the refrigerant storage portion to communicate with each other. The second storage portion pipe causes the second refrigerant pipe of the outdoor refrigerant flow path and the refrigerant storage portion to communicate with each other.

In a refrigeration cycle apparatus, a controller is configured to, when a defrost mode is started, control a first pressure reducing device is controlled to adjust a flow rate of refrigerant to bring a degree of superheat of the refrigerant at a suction side of a compressor close to a target value, control a flow path switching device to form a first flow path through which the refrigerant released from the compressor flows to a first heat exchanger; perform a refrigerant release operation of opening one of a second pressure reducing device and a valve and closing the other of the second pressure reducing device and the valve, and perform a refrigerant collection operation of opening the second pressure reducing device and the valve, with the flow path switching device retained to form the first flow path, after the refrigerant release operation.

An apparatus for optimizing an efficiency of a refrigeration system, comprising means for measuring a refrigeration efficiency of an operating refrigeration system; means for altering a process variable of the refrigeration system during efficiency measurement; and a processor for calculating a process variable level which achieves an optimum efficiency. The process variables may include refrigerant charge and refrigerant oil concentration in evaporator.

A receiver assembly for a heat pump system is provided including a first receiver volume and a second receiver volume. The first receiver volume is configured to accommodate an amount of refrigerant based on a difference between a refrigerant charge for cooling operations of the heat pump system and a refrigerant charge for heating operations of the heat pump system. The second receiver volume has a first fluid connection configured to receive a hot gas injection and a second fluid connection. An expander is disposed along the second fluid connection. The receiver assembly further includes a fluid line configured to connect the first receiver volume and the second receiver volume and a controllable valve configured to regulate flow between the first receiver volume and the second receiver volume disposed along the fluid line.

A condenser and evaporator system includes (i) a condenser system positioned to receive a gaseous refrigerant from a compressor system and configured to condense the gaseous refrigerant into a liquid refrigerant, (ii) a controlled pressure receiver (CPR) positioned to receive and store the liquid refrigerant, (iii) an evaporator system including a conduit, an expansion valve, and a fan, and (iv) a controller. The conduit is positioned to receive the liquid refrigerant from the CPR. The expansion valve is positioned between the CPR and the conduit, and configured to facilitate modulating an amount of the liquid refrigerant that flows into the conduit from the CPR. The fan is positioned to facilitate providing a cooling operation to an area associated with the evaporator system through evaporation of the liquid refrigerant flowing through the conduit. The controller is configured to control a stage of the condenser system and/or the evaporator system.

A heat exchanger, such as for example, a condenser coil constructed as a fin and microchannel tube is fluidly connected with a volume constructed and configured to store refrigerant in certain operations, such as for example during a pump down operation. The volume is fluidly connected to a fluid port of the heat exchanger, where the fluid port is an inlet (in the cooling mode) to the heat exchanger, such as the high side condensing section of the heat exchanger. The volume receives refrigerant exiting the heat exchanger from the fluid port in a mode other than a cooling mode, e.g., a pump down operation

A system for maximizing the measured efficiency of an HVAC&R system including two pressure sensors, two temperature sensors, a flow sensor, a power voltage sensor, a power current sensor, and a controller. Each pressure sensor may be adapted to measure different refrigerant pressures and generate respective pressure signals. Each temperature sensor may be adapted to measure different refrigerant temperatures and generate respective temperature signals. The flow sensor may be adapted to measure a refrigerant flow rate and to generate a flow signal. The power voltage sensor may be configured to measure an electrical voltage input and generate a power voltage signal. The power current sensor configured to measure an electrical current input and to generate a power current signal. The controller may be adapted to receive the signals, calculate a measured efficiency, and output a first voltage output signal having a value dependent upon the measured efficiency.