Abstract: A linear compressor that is operated at a frequency greater than the natural frequency of the spring-mass system of the compressor. Operating the compressor at such a frequency can increase the output of the compressor. In one embodiment, the linear compressor includes a cylinder block having a cylinder bore, a piston positioned within the cylinder bore, first and second springs for positioning the piston where the piston and the first and second springs comprise the spring-mass system, and an armature operably engaged with the piston to drive the piston at a frequency greater than the natural frequency of the spring-mass system. The linear compressor can also include a controller which monitors the instantaneous natural frequency of the spring-mass system and modulates the frequency of the current passing through the armature such that it exceeds the natural frequency of the spring-mass system.

Abstract: A method and apparatus for improving the rate of heat transfer between an evaporator of a refrigeration system and the environment surrounding the evaporator. In one embodiment, the evaporator is placed in thermal communication with the air of a data center where electronic equipment is operated therein. To improve the rate of heat transfer between the air and the evaporator, water is evaporated into the air before it flows over the evaporator coils. As a result, when the humidified air flows over the cold evaporator coils, a portion of the water vapor in the air condenses on the evaporator, thereby wetting the evaporator coils. The wetted surfaces of the evaporator coils improve the rate of heat transfer between the air and, ultimately, the refrigerant passing through the evaporator. In one embodiment, a humidifier having a water atomizer may be used for spraying and dispersing water into the air.

Abstract: A method of operating a vapor compression system, the vapor compression system defining a closed fluid circuit in which a refrigerant is circulated and having operably disposed therein, in serial order, a compressor, a high pressure heat exchanger, an expansion device and a low pressure heat exchanger. The method includes applying a variable thermal load on a first one of the heat exchangers, monitoring the thermal load placed on the first heat exchanger and controlling the operation of the system to limit the thermal load placed on the first heat exchanger when the thermal load exceeds a predetermined value. A heat exchange subsystem employed to limit the thermal load may include reducing the flow of a heat exchange medium over the heat exchanger or to recirculate the heat exchange medium in a manner which reduces the thermal load on the heat exchanger.

Abstract: A transcritical vapor compression system that includes a fluid circuit circulating a refrigerant in a closed loop. The fluid circuit has operably disposed therein, in serial order, a compressor, a first heat exchanger, a first capillary tube and a second heat exchanger. The compressor compresses the refrigerant from a low pressure to a supercritical pressure. The first heat exchanger is positioned in a high pressure side of the fluid circuit and the second heat exchanger is positioned in a low pressure side of the fluid circuit. The first capillary tube reduces the pressure of the refrigerant from a supercritical pressure to a relatively lower pressure. The refrigerant flows through the first capillary tube at its critical velocity and means for controlling the temperature of the refrigerant in the first capillary tube are provided.

Abstract: A rotary compressor comprising a rotor having a plurality of permanent magnets mounted thereon and a stator, where the rotor is aligned with respect to the stator via a magnetic attraction between the permanent magnets and the stator. The compressor includes a housing and is configured such that the rotor does not entirely bear against a top or bottom portion of the compressor housing. The permanent magnets of the rotor are sized and configured such that the magnetic attraction between the magnets and the stator, regardless of whether the stator is energized, positions, or suspends, the rotor substantially intermediate the top and bottom portions of the housing. As a result, less or, possibly, even no friction is experienced between the rotor and the compressor housing which reduces the potential for the rotor to seize or stall and allows the compressor to be operated with little or no oil.

Abstract: A method and apparatus for maintaining a relatively constant temperature of a working fluid in an evaporator of a refrigeration system by providing a constant volumetric displacement compressor and a heat exchanger for exchanging heat between the high pressure and low pressure portions of a refrigeration circuit to superheat, and hold substantially constant, the temperature of the refrigerant entering the compressor. In doing this, the pressure of the refrigerant in the low pressure portion of the circuit, including the evaporator, and the mass flow rate of the refrigerant remain substantially constant. As a result, the temperature of the saturated refrigerant in the evaporator remains substantially constant.

Abstract: A rotary compressor having a housing, a rotor positioned within the housing defining a compression chamber, the rotor rotatable about an axis of rotation, a discharge port in the rotor in fluid communication with the compression chamber, and a valve assembly mounted to the rotor to regulate the pressure of the fluid within the compression chamber. In one. embodiment, the valve assembly is canted or obliquely aligned with respect to the axis of rotation of the rotor and a radial axis perpendicular to and intersecting the axis of rotation. Aligning the valve assembly in this way allows the displacement of the valve head of the valve assembly to be substantially collinear with forces acting on the valve head.

Abstract: A refrigeration system for use in cooling electronic equipment includes a closed vapor circuit having operably disposed therein, in serial order, a fluid pumping device, a first heat exchanger, a flow regulator and a second heat exchanger. A converter is operably couplable to a power supply and is operably coupled to at least one refrigeration system component. The at least one refrigeration system component is operably coupled to the closed vapor compression circuit. The converter supplies power to the at least one refrigeration system component. The converter further supplies DC power to the electronic equipment being cooled by the refrigeration system.

Abstract: A refrigeration system including a cabinet having an outer wall defining an insulated interior, an inner wall, and an insulative material disposed between the outer and inner walls. A cooling system is disposed in a space beneath the cabinet and cools the insulated interior. A convection channel is disposed between the outer and inner walls and extends and communicates air from an area outside an upper portion of the cabinet to the space beneath the cabinet. The channel is positioned within about 1.905 cm from the inner wall. The channel may have a plurality of different widths and may include a thermal bridge extending from the inner wall to the channel. The channel may include a primary branch extending from the upper portion of the cabinet to a junction point and a plurality of secondary branches extending from the junction point to a plurality of locations beneath the cabinet.

Abstract: A hydrocarbon cooling system including a housing having a substantially rectangular base defining a diagonal, a front wall defining a first air inlet, a back defining a first air outlet, and a pair of side walls. The cooling system includes a condenser mounted within the housing adjacent the first air inlet; a compressor; an evaporator; and a fan mounted within the housing and defining an axis. The fan is positioned such that a vertical plane aligned along the axis defines a first a non-perpendicular angle relative to a second vertical plane aligned perpendicular to the back of the housing. The fan creates a first horizontal airflow path, which enters the housing through the first air inlet and exits the housing through the first air outlet. The first horizontal airflow path induces a second horizontal airflow, which moves around the housing along a line substantially parallel to the diagonal.

Abstract: A vapor compression system including a circuit having operably coupled thereto, in serial order, a compressor, an interior heat exchanger, a second heat exchanger, an expansion device, an exterior heat exchanger, and an accumulator. A first bypass line extends from circuit between interior exchanger and second exchanger to between expansion device and third exchanger. A second bypass line extends from circuit between the exterior exchanger and accumulator to accumulator, and is operably coupled to second exchanger. A bypass expansion device is operably coupled to second bypass line. A first valve is coupled to first bypass line, and a second valve is coupled to second bypass line. During a defrost cycle first valve is in a first position wherein refrigerant flowing from interior exchanger flows to exterior exchanger through first bypass line, and second valve is in a second position wherein refrigerant flowing from exterior exchanger flows through second bypass line.

Abstract: A refrigeration system for use in cooling electronic equipment includes a closed vapor compression circuit having operably disposed therein a compressor, a condenser, a first expansion device, a second expansion device, and a two-part evaporator. A first part of the evaporator receives working fluid from the first expansion device at a first pressure, and a second part of the evaporator receives working fluid from the second expansion device at a second pressure that is different than the first pressure.

Abstract: A complete refrigeration system (CRS) including at least one heat exchanger which is designed to occupy an irregular volume to reduce the overall profile of the CRS. The heat exchanger may be a condenser or an evaporator, and includes a substantially solid body made of a thermally conductive metal, plastic, or other material. A plurality of fluid and refrigerant passageways are defined substantially within the solid body for conducing fluid and refrigerant, respectively, through the solid body and facilitating the transfer of heat between the fluid and refrigerant. Also disclosed is a method wherein the spatial orientation of each passageway is optimized with respect to all of the other passageways and the walls of the solid body by determining the relative distance of each passageway from all of the other passageways and the walls of the solid body at a plurality of points along each passageway, followed by adjusting the spatial orientation of the passageway accordingly.

Abstract: A vapor compression system including a closed fluid circuit having operably coupled thereto, in serial order, a compressor, a first heat exchanger, an expansion device, a second heat exchanger and a fluid vessel. The refrigerant is compressed in the compressor and circulated through the fluid circuit. Thermal energy is removed from the refrigerant in the first heat exchanger. The pressure of the refrigerant is reduced in the expansion device, and thermal energy is added to the refrigerant in the second heat exchanger. Upon ceasing operation of the system, refrigerant present in the vessel defines a lower temperature than the refrigerant present in the second heat exchanger. A thermal energy storage medium is operably coupled to the vessel and provides the vessel with thermal inertia wherein the temperature of the refrigerant in the vessel remains cooler than the temperature of the refrigerant in the second heat exchanger.

Abstract: A transcritical vapor compression system includes a fluid circuit circulating a refrigerant in a closed loop. The fluid circuit has operably disposed therein, in serial order, a first compressor, an intercooler, a second compressor with a variable capacity, a first heat exchanger, an expansion device and a second heat exchanger. The first compressor compresses the refrigerant from a low pressure to an intermediate pressure. The second compressor compresses the refrigerant from the intermediate pressure to a supercritical pressure. The first heat exchanger is positioned in a high pressure side of the fluid circuit. The second heat exchanger is positioned in a low pressure side of the fluid circuit. The expansion device reduces the pressure of the refrigerant from a supercritical pressure to a relatively lower pressure. Cooling means cools the refrigerant within one of the compressors.

Abstract: A refrigeration system includes a fluid circuit circulating a refrigerant in a closed loop. The fluid circuit has operably disposed therein, in serial order, a compressor, a first heat exchanger, an expansion device and a second heat exchanger. The compressor is pivotable about an axis. The compressor has a first part and a second part slidably coupled to the first part. A linkage includes a cyclically movable element. A linking element is attached to the second part of the compressor and is pivotably coupled to the cyclically movable element such that the linking element follows movement of the cyclically movable element to thereby slide the second part of the compressor relative to the first part of the compressor and pivot the compressor about the axis.

Abstract: A vapor compression system having a multi-stage compressor with a minimal number of ports located in the hermetically sealed compressor housing. A working fluid at suction pressure enters the compressor housing through a first port and is compressed to an intermediate pressure. The intermediate pressure refrigerant flows from the first stage compressor mechanism to the second stage compressor mechanism where it is compressed to a discharge pressure and discharged through a second port. The intermediate pressure refrigerant is in thermal communication with a heat exchange medium which is introduced into the compressor housing through a third port in the housing.

Abstract: In a given design of a refrigeration system, the present invention provides a method for reducing the charge of the refrigerant flowing through the refrigeration system. The refrigeration system includes a fluid conduit through which a flammable refrigerant circulates. The fluid conduit couples, in serial order, a compressor, a first heat exchanger, an expansion device, and a second heat exchanger. The conduit defines an interior diameter, an interior surface, and a given friction factor range. The method includes the steps of reducing the interior diameter of the conduit to thereby reduce the system design refrigerant charge, and coating the interior surface of the reduced diameter conduit with a coating composition to thereby reduce the surface roughness of the interior surface and provide a friction factor for the reduced diameter conduit that is substantially within the given friction factor range.

Abstract: A method of operating a vapor compression system, the vapor compression system defining a closed fluid circuit in which a refrigerant is circulated and having operably disposed therein, in serial order, a compressor, a high pressure heat exchanger, an expansion device and a low pressure heat exchanger. The method includes applying a variable thermal load on a first one of the heat exchangers, monitoring the thermal load placed on the first heat exchanger and controlling the operation of the system to limit the thermal load placed on the first heat exchanger when the thermal load exceeds a predetermined value. A heat exchange subsystem employed to limit the thermal load may include reducing the flow of a heat exchange medium over the heat exchanger or to recirculate the heat exchange medium in a manner which reduces the thermal load on the heat exchanger.

Abstract: A transcritical vapor compression system that includes a fluid circuit circulating a refrigerant in a closed loop. The fluid circuit has operably disposed therein, in serial order, a compressor, a first heat exchanger, a first capillary tube and a second heat exchanger. The compressor compresses the refrigerant from a low pressure to a supercritical pressure. The first heat exchanger is positioned in a high pressure side of the fluid circuit and the second heat exchanger is positioned in a low pressure side of the fluid circuit. The first capillary tube reduces the pressure of the refrigerant from a supercritical pressure to a relatively lower pressure. The refrigerant flows through the first capillary tube at its critical velocity and means for controlling the temperature of the refrigerant in the first capillary tube are provided.