A high-efficiency air conditioning system for conditioning a plurality of zones within an interior of a building that includes: at least two independent ductwork systems within a building wherein each independent ductwork system directs heating and cooling to one zone within the building; a single outdoor unit a refrigerant flow pathway having a common refrigerant flow path portion, a first divergent flow path, and a second divergent flow path; at least one throttling device and at least a first indoor air handling unit providing cooling to a first independent ductwork system and a second indoor air handling unit providing cooling to a second indoor ductwork system. The compressor is incapable of simultaneously supplying both the first evaporator and the second evaporator at their full cooling capacity.

A carbon dioxide refrigerant vapor compression system and method of operating that system are provided. The refrigerant vapor compression system includes a compression device, a flash tank receiver disposed in the refrigerant circuit intermediate a refrigerant heat rejection heat exchanger and a refrigerant heat absorption heat exchanger, and a compressor unload circuit including a refrigerant line establishing refrigerant flow communication between an intermediate pressure stage of the compression device and the refrigerant circuit at a location downstream of the refrigerant heat absorption heat exchanger and upstream of a suction inlet to the compression device, and a unload circuit flow control device disposed in said unload circuit refrigerant line. In response to at least one system operating parameter sensed by at least one sensor, the controller selectively positions the unload flow control device to maintain the refrigerant vapor compression system operating below a preselected high pressure limit.

A method of operating a refrigeration system that receives power from an electrical grid includes selectively operating at least one component of the refrigeration system in a first state. The method includes selectively detecting a fault event of the electrical grid in response to a concurrent (i) increase in amount of current drawn by the component and (ii) decrease in voltage of power received by the component. The method includes, in response to detecting the fault event, switching the component from the first state to a second state. The component consumes less power in the second state than in the first state. The method includes determining a first delay period. The method includes identifying a conclusion of the fault event. The method includes, in response to the conclusion of the fault event, waiting for the first delay period before switching the component back to the first state.

A compressor includes a compressor housing, a fastening device arranged on the compressor housing, and a support device, connected to the fastening device, for a temperature sensor, the support device being designed to hold, by pressing, the temperature sensor against a wall of the compressor housing. The support device has, for multiple connection to the fastening device, at least two sections, located on different sides of the temperature sensor, wherein, when the compressor is used as intended, the temperature sensor is designed to brace against the compressor housing from below.

The air conditioner has a configuration such that, in an air-warming operation: the average refrigerant exit temperature, which is obtained by averaging the temperature of the refrigerant exits of indoor heat exchangers 7 in a plurality of indoor units 10, as detected by heat-exchanger-refrigerant-exit temperature probes 34 in the indoor units 10, is determined; the temperature difference between the average refrigerant exit temperature and the refrigerant exit temperatures of the indoor heat exchangers 7 of each of the indoor units 10 is determined; and the degree to which indoor expansion valves 9 of the indoor units 10 are open is controlled such that the determined temperature difference falls within a predetermined temperature difference range.

A cooling system includes a subcooling heat exchange assembly, which controls magnitude of subcooling of refrigerant circulated through the cooling system. The subcooling heat exchange assembly includes a first fluid line fluidly coupled to an output of a condenser to enable a first portion of the refrigerant output from the condenser to flow through the first fluid line; a second fluid line fluidly coupled to the output of the condenser to enable a second portion of the refrigerant output from the condenser to flow through the second fluid line; and an expansion valve disposed along the second fluid line, in which the expansion valve exerts a first pressure drop on the second portion of the refrigerant that facilitates extracting heat from the first portion of the refrigerant flowing through the first fluid line using the second portion of the refrigerant flowing through the second fluid line when valve position of the expansion valve is greater than a threshold position. Additionally the cooling system includes a plurality of capillary expansion tubes fluidly coupled in parallel to an output of the first fluid line and that to exert a second pressure drop on the refrigerant circulated through the cooling system.

A cooling system includes an expansion valve configured to exert a first pressure drop on refrigerant circulated through the cooling system. The cooling system also includes a plurality of capillary expansion tubes fluidly coupled in parallel to an output of the expansion valve and configured to exert a second pressure drop on the refrigerant circulated through the cooling system. The cooling system also includes a controller communicatively coupled to the expansion valve, wherein the controller is configured to control magnitude of the first pressure drop by instructing the expansion valve to adjust the valve position based at least in part on refrigerant mass flow expected to be supplied to the expansion valve to facilitate substantially uniformly distributing the refrigerant mass flow between each of the plurality capillary expansion tubes.

A compressor includes a housing defining a working chamber. The housing further includes a bore and an endplate disposed toward a discharge end. The compressor further includes a rotor having helical threads, the rotor being configured to be housed in the bore, a rotor clearance, a controllable bearing supporting the rotor, and a controller configured to control the controllable bearing such that the controllable bearing moves the rotor in a manner to reduce and/or enlarge the rotor clearance.

The invention relates to a method for controlling a refrigeration system by establishing a defrost period during an initial defrost period. One or more compressors of the refrigeration system are monitored to establish if the one or more compressors are running, and a parameter representative of the one or more compressors running is monitored. The monitoring establishes at least one parameter limit value representative of whether a defrost period or a non-defrost period is to be initiated. The invention also relates to a method for controlling a refrigeration system subsequent to an electrical power interruption. The invention also relates to control units for applying one or both of the methods according to the invention, and to a refrigeration system having one or more control units controlling the refrigeration system according to one or both of the methods.

A method for controlling a refrigeration system having a compressor, heat rejecting heat exchanger, expansion valve and heat absorbing heat exchanger circulating a refrigerant in series flow, the heat absorbing heat exchanger in thermal communication with working fluid, the method includes obtaining an expansion valve position set point; using a feedback control loop to generate a controlled expansion valve position; obtaining a rate of change of an operating parameter of the system; using the rate of change of the operating parameter to generate an adjustment; modifying the controlled expansion valve position using the adjustment; and controlling the expansion valve using the modified controlled expansion valve position.