Abstract: A heat exchanger includes a plurality of flat, multi-channel heat exchange tubes extending between spaced headers. Each heat exchange tube has a plurality of flow channels extending longitudinally in parallel relationship from its inlet end to its outlet end. A plurality of connectors are positioned between the inlet header and the heat transfer tubes such that the connector inlet ends are in fluid flow communication with the header through a relatively small cross-sectional flow area openings and the connector outlet ends are adapted to receive the inlet end of a heat exchanger tube. The connector defines a fluid flow pathway from the relatively small cross-sectional flow area opening in the inlet end of the connector to an outlet opening in the outlet end of the connector that opens to the flow channels of the heat exchange tube received in the outlet end of the connector.

Abstract: A heat pump system operates in heating and cooling modes. The heat pump is provided with both a reheat function and economizer circuit. The economizer circuit provides augmented performance to the heat pump, while the reheat coil allows enhanced control over temperature and humidity of the air supplied to the conditioned space. A bypass line around an outdoor heat exchanger is also provided to achieve additional flexibility of control for a sensible heat ratio. Selective operation of the abovementioned components and subsystems allows precise control over system operation parameters and hence satisfaction of a wide spectrum of sensible and latent load demands and improved reliability.

Abstract: A scroll compressor is provided with a multiple-speed motor. A control selects a speed for operating the motor, along with selecting between several available options for the system capacity adjustment to meet external load demands in a most efficient and reliable manner. The disclosed embodiment includes an economizer circuit, an unloader function, and an optional suction modulation valve. By utilizing each of these features in combination with the multi-speed motor for the compressor, the present invention is better able to tailor provided capacity to desired capacity.

Abstract: A clip that utilizes a magnet to attach identification cards to clothing. The clip includes a clasp, a hinged metal bendable strap, and a magnetic connector which together allow identification cards to be displayed anywhere on a garment without penetrating, clamping or biting the fabric. The invention is connected to an identification card by passing the card attachment clasp through a slotted hole cut in the card and snapping it closed. The clasp is attached to a bendable strap that ties the card to the magnetic connector. The hinged metal bendable strap can bend and flex allowing the position of displayed card to adjust to the movement of the person wearing it. The magnetic connector consists of two parts. The first part is a ferrous metal plate which is fixed to the back of the bendable strap. The second part is an extra strong magnet which is placed behind clothing fabric when attaching the invention to a person's clothing.

Abstract: A refrigerant system is provided with a variable speed drive for at least one of its fluid-moving devices, wherein the variable speed drive is provided by an automated mechanical drive. In the disclosed embodiment, one of the pulleys for driving the fluid-moving device has a variable diameter to vary the speed at which the fluid-moving device is driven. The pulley may include two plates that are biased in one direction by a spring or permanent magnet force, and in an opposed direction by a hydraulic or electromagnetic force. A control adjusts the amount of hydraulic or electromagnetic force delivered to the plates to achieve a desired speed for the fluid-moving device.

Abstract: A fixed restriction is placed in a suction line leading to a compressor. The size of the restriction is selected to achieve a desired capacity reduction (correction) for the refrigerant system compressor. By selectively restricting the flow of refrigerant through the suction line, the capacity delivered by the compressor will be reduced. This allows a designer of a refrigerant system to utilize an available compressor of a specific size (displacement) to satisfy the desired system operating conditions and performance characteristics as well as application requirements. In embodiments, the refrigerant system may be provided with an economizer and unloader functions. The restriction may be placed in the compressor suction port, or in the suction line leading to the compressor. Further, a pair of parallel flow passages may communicate an evaporator to the compressor, with the restriction being placed in one and a solenoid valve placed in the other.

Abstract: A refrigerant system is provided with at least one variable frequency drive. In the past, the variable frequency drives were operable such that the voltage-to-frequency ratio remained constant regardless of operation. The present invention realizes that variations in the voltage-to-frequency ratio may be desirable, and the refrigerant system control drives the motors associated with relevant refrigerant system components to reach an optimum voltage-to-frequency ratios in order to achieve higher efficiency, provide operational safety and prevent nuisance shutdowns.

Abstract: A refrigerant system is provided with economizer vapor injection and liquid injection functions. As is known, the economizer function enhances performance of the refrigerant system. The liquid injection lowers the discharge temperature of the refrigerant to provide reliable compressor/system operation. The liquid injection and economizer vapor injection functions are selectively provided through distinct fluid passages leading to separate compression pockets. Single or dual pocket injection scheme could be utilized in conjunction with either function. The location of the liquid injection is preferably downstream in the compression process in relation to the economizer vapor injection. In this manner, a refrigerant system designer can select the optimal location of injection for each of the two refrigerant flows. The refrigerant system can consists of a single compressor or multiple compressors either connected in series or in parallel.

Abstract: A refrigerant system is provided with tandem compressors. As is known, tandem compressors operate in parallel to provide a refrigerant system designer with the ability to achieve a stepped capacity control of the refrigerant system. At least one of the tandem compressors is provided with a variable speed drive. Further, at least one of the tandem compressors may be provided with the economizer and/or unloader functions. System configurations with multiple compression stages and multiple injection ports are disclosed. In this manner, the stepless capacity control can be achieved.

Abstract: Refrigerant systems are provided with selectively operable components that allow variation in the capacity provided by the refrigerant system to achieve desired temperature and humidity levels. A reheat circuit is provided and an economizer circuit may also be added to the system. Typically, the reheat and economizer functions each provide a step change in the humidity control. A compressor having a variable speed drive is utilized.

Abstract: The shutdown of a compressor (10) installed in a refrigerant circuit (2) in air conditioning or refrigeration system is controlled so as to prevent unpowered reverse rotation of the compressor. Prior to terminating electric power to the compressor drive motor (24), the pressure within the system is relieved and substantially equalized across the compressor, thereby eliminating the possibility of unpowered reverse rotation of the compressor at shutdown. Pressure relief and equalization may be achieved by reducing the operating speed of the compressor to a low forward speed for a period of time prior to deenergizing the compressor drive motor. Pressure equalization may also be achieved by driving the compressor in reverse rotation prior to deenergizing the drive motor.

Abstract: A heat pump is provided with a method and control for eliminating compressor un-powered reverse rotation at shutdown. In particular, the position of the four-way reversing valve is changed and the heat pump is moved to the opposite mode of operation as compared to the one it had been operated before shutdown. The compressed refrigerant, that might otherwise re-expand through the compressor and cause the compressor to run in reverse, is now communicated to the suction line of the compressor, while the discharge port of the compressor communicates with a refrigerant at suction pressure. Thus the unpowered reverse rotation of the compressor is no longer possible.

Abstract: A control for an electric motor is utilized to avoid operation in or near the resonance frequencies for the electric motor and its associated system components. The resonance frequencies can be identified experimentally at the design stage, or during operation of a component and electric motor. During start-up, shutdown or frequency adjustment, the control drives the speed through the resonance frequency zones more rapidly, and also avoids operation in or near those resonance frequencies during steady state operation. In disclosed embodiments, the electric motors are associated with fans, pumps and compressors in a refrigerant system.

Abstract: A heat pump is provided with a method and control for eliminating flooded starts. In particular, the heat pump at start-up is operated for a short period of time in the opposite mode to that in which it had been operated before the previous shutdown. In this way, the compressor ingestion of liquid refrigerant is limited or completely eliminated. After a short period of time, the heat pump is moved back to the intended mode of operation. Additional features can be added to the control scheme to limit this type of operation at start-up only to certain ambient conditions or only to a prolonged period between shutdown and start-up.

Abstract: A refrigerant system is provided where the functions of an economizer heat exchanger and liquid-suction heat exchanger are combined. The two configurations are disclosed with a single common heat exchanger construction. In a first configuration, a series of valves selectively routes only one of two possible refrigerant flows through a common heat exchanger such that a control can selectively activate either an economizer heat exchanger circuit or a liquid-suction heat exchanger function. In a second configuration, both refrigerant flows are passed to the common heat exchanger through separate fluid lines and are selectively activated by the control. Variations of the second configuration are also disclosed.

Abstract: A refrigerant system is provided with a reheat function selectively utilizing the heat rejected by the variable speed drive controller and electronics that are often employed in known refrigerant cycles. By placing at least one of these variable speed drives in the path of air being delivered to an environment to be conditioned, the air is reheated to a desired temperature, after it has been overcooled in the evaporator to provide a desired humidity level. In this manner, the variable speed drive is cooled, and the reheat function is provided, without the requirement of any additional flow structure.

Abstract: In a parallel flow heat exchanger having an inlet manifold connected to a plurality of parallel channels, the degree of insertion depth of the parallel channels into the inlet manifold is variable so as to adjust the impedance to the refrigerant flow into the individual channels. The degree of insertion depth is progressively reduced toward a downstream end of the manifold for the individual channels or for the channel sections. The diameter of the inlet manifold is locally increased or its cross-section area altered in order to accommodate the flow of refrigerant around the tube insertions. Similar technique is applied to the outlet manifold as well to further balance hydraulic resistances.

Abstract: In a parallel flow evaporator, the inlet manifold construction consists of alternating expansion and contraction chambers to promote homogeneous conditions of the refrigerant, as it flows longitudinally through the inlet manifold, as a result of partial evaporation (throttling) and mixing and jetting effects (due to velocity augmentation). In a preferred embodiment, the parallel channels are fluidly connected to the expansion chambers so as to receive a homogeneous refrigerant mixture therefrom. In one embodiment, the expansion and contraction chambers are progressively smaller in size toward a downstream end, so as to accommodate the diminishing refrigerant flow as it progresses longitudinally along the inlet manifold. In another embodiment, the outlet manifold also consists of a repetitive pattern of alternating expansion and contraction chambers, so as to balance the impedances of the inlet manifold.

Abstract: In a shell-and-tube heat exchanger with the tubes disposed within the shell for conducting the flow of a fluid to be in heat transfer interaction with a refrigerant contained in the volume formed by the heat exchanger shell and the external surfaces of the tube bundle, the tubes are elongated in their cross-section, with the elongation axis being oriented in the vertical direction to thereby enhance the heat transfer process and potentially reduce the heat exchanger size or tube count. The design features can be applied to both flooded and falling film heat exchangers and are equally applicable to both evaporators and condensers.