A refrigeration system, comprising an evaporator, a condenser, a throttling device, a compressor, an economizer and an ejector, these devices together form a closed-loop refrigerant circulation loop, the ejector being connected to the economizer, and the ejector being provided on an exhaust side of the compressor. The structure enables the refrigeration system to realize the dual-stage boost, does not affect the stability of the compressor due to the instability of the airflow of the ejector, and does not affect the oil property of the compressor, thereby ensuring the operation safety of the compressor.

A heat pump system includes a first bypass pipe provided with a first bypass valve and connecting a liquid refrigerant pipe and a low-pressure refrigerant pipe, a refrigerant heat exchanger configured to cause a heat-exchange between refrigerant flowing in the liquid refrigerant pipe and refrigerant flowing in first bypass pipe, a second bypass pipe provided with a second bypass valve and connecting the liquid refrigerant pipe and the low-pressure refrigerant pipe, and a controller. The controller is configured to control opening degree of the first bypass valve based on detected superheated temperature of refrigerant flowing in the first bypass pipe, and detected discharge temperature of a compressor and control opening degree of the second bypass valve based on the detected discharge temperature.

A compressor includes a housing having a suction inlet, at least one economizer inlet, and an outlet. A first cylinder arranged within the housing includes a first suction valve arranged in fluid communication with the suction inlet and a first discharge valve fluidly connected to the outlet. At least one second cylinder is arranged within the housing. The at least one second cylinder has a second suction valve in fluid communication with the at least one economizer inlet and a second discharge valve fluidly connected to the outlet. A first piston is arranged within the first cylinder and a second piston is arranged within the at least one second cylinder.

A compressor includes a cylinder block having a first bore and a cylinder head overlapping the cylinder block. The cylinder head has a second bore aligned with the first bore. The second bore is separated into a plurality of distinct regions including a suction region and an economizer region. A plurality of valves includes a suction valve selectively operable to fluidly couple the suction region and the first bore, and an economizer valve selectively operable to fluidly couple the economizer region and the first bore.

A method for controlling a vapour compression system (1) including two or more evaporators (5, 12), each evaporator (5, 12) being arranged in thermal contact with a refrigerated volume, the refrigerated volumes storing goods of various types, and each evaporator (5, 12) receiving refrigerant via an expansion device (6, 13) is disclosed. In response to receipt of a load shedding command originating from a power grid (17), the vapour compression system (1) reduces a compressor capacity of the compressor unit. The refrigerated volumes are divided into at least two prioritized categories of refrigerated volumes, where a first category (18) includes refrigerated volumes storing goods of a temperature critical type, and a second category (19) includes refrigerated volumes storing goods of a temperature non-critical type. Refrigerant supply to the evaporator(s) (5, 12) being in thermal contact with the refrigerated volume(s) of the second category (19) is discontinued, and refrigerant supply to the evaporator(s) (5, 12) being in thermal contact with the refrigerated volume(s) of the first category (18) is continued. Thereby the vapour compression system (1) is capable of providing load shedding services for an extended period of time without compromising temperature critical storage.

A header includes a plurality of branch tubes and a header manifold. If refrigerant flowing into the header manifold forms a pattern of annular flow or churn flow, tips of the branch tubes inserted into the header manifold pass through a liquid-phase portion having a thickness δ [m] and reach a gas-phase portion. The thickness δ [m] of the liquid-phase portion is defined as δ=G×(1−x)×D/(4ρ.sub.L×U.sub.LS), where G is a flow speed [kg/(m.sup.2 s)] of the refrigerant, x is a quality of the refrigerant, D is an inside diameter [m] of the header manifold, ρ.sub.L is a liquid density [kg/m.sup.3] of the refrigerant, U.sub.LS is a reference apparent liquid speed [m/s] that is a maximum value within a range of variation in an apparent gas speed of the refrigerant flowing into a flow space of the header manifold. The reference apparent liquid speed U.sub.LS [m/s] is defined as G(1−x)/ρ.sub.L.

A vapor compression system includes a first conduit fluidly coupling a liquid collection portion of a condenser and an evaporator, where the first conduit is configured to direct a first flow of refrigerant from the condenser to a first inlet of the evaporator and a second conduit fluidly coupling the liquid collection portion of the condenser and the evaporator, where the second conduit is configured to direct a second flow of refrigerant from the condenser to a second inlet of the evaporator via gravitational force, and where the first inlet is disposed above the second inlet relative to a vertical dimension of the evaporator.

An integrated valve includes a connecting member including a first valve element and a second valve element. The first valve element is disposed in a pressure reducing chamber of a body of the integrated valve and forms a pressure reducing valve that reduces the pressure of the refrigerant discharged from a compressor. The second valve element is disposed in an on-off valve chamber of the body and forms an on-off valve for adjusting a flow rate of the refrigerant flowing into an intermediate-pressure port of the compressor. The on-off valve is in a fully opened state when the pressure reducing valve is in a throttling state, the on-off valve is in an opened state when the pressure reducing valve is in an opened state, and the on-off valve is in a closed state when the pressure reducing valve is in a fully opened state.

A refrigerant circuit includes a first compressor connected to a first suction pipe and a first discharge pipe and configured to compress a refrigerant, a second compressor connected to a second suction pipe and a second discharge pipe and configured to compress the refrigerant discharged from the first compressor, a radiator, and a high-pressure passage connecting the second discharge pipe and the radiator. A first oil drain passage guides an oil in the second compressor to one of the first suction pipe and an intermediate port of the first compressor, without via the high-pressure passage.

A subcooler is made up of a plate type heat exchanger. The accumulator is located between a compressor and the subcooler in a width direction of an outdoor unit in a planar view. The subcooler overlaps with the accumulator in the width direction in the planar view. As a result, a compact heat pump can be provided when the subcooler is a plate type heat exchanger.