Abstract: Adequate distribution of a two-phase refrigerant flowing through a plurality of heat transfer tubes in a generally parallel manner is ensured. Tapping a portion of predominantly vapor refrigerant from an upstream location and delivering it to a downstream location where separation of liquid and vapor refrigerant phases is likely to occur and a liquid refrigerant phase is likely to accumulate. Additional momentum from the predominantly vapor refrigerant creates homogeneous conditions for the vapor/liquid refrigerant mixture, promoting uniform distribution of the mixture In downstream heat transfer tubes. The vapor refrigerant may be tapped from various locations.

Abstract: A refrigerant system is provided with a suction pulse width modulation valve, and a pulse width modulation control for controlling this valve. System pressures, such as the pressure on the evaporator and the condenser are monitored. The measured system pressures are maintained within a band of acceptable lower and upper limits. As the pulse width modulation control cycles the valve, the refrigerant pressures in the evaporator and the condenser tend to fluctuate. The control ensures those fluctuations are within the limits by controlling the duty cycle of the valve.

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. By providing the reheat/economizer functions along with the variable speed compressor, continuously adjustable humidity control is achieved.

Abstract: A heat pump refrigerant system is provided with at least two sequential stages of compression. An intercooler is positioned intermediate the two stages. The refrigerant flowing through the intercooler. is cooled by a secondary fluid such as ambient air. The intercooler is positioned to be in a path of air flow passing over an outdoor heat exchanger, and preferably upstream of the outdoor heat exchanger, in relation to this air flow. Benefits with regard to efficiency and capacity are achieved due to proposed system configuration in both heating and cooling modes of operation, while no additional circuitry or components are required to provide the intercooler function for the heat pump refrigerant system. This invention is particularly important for the CO2 heat pump refrigerant systems operating in the transcritical cycle.

Abstract: A refrigerant system is provided that includes a compressor, a motor for driving the compressor, a refrigerant system component, and a controller. The refrigerant system component can operate in a pulse width modulated mode having a loaded phase and an unloaded phase. The compressor motor is loaded in the loaded phase but unloaded in the unloaded phase. The controller applies a first voltage to the compressor motor in the loaded phase and a second voltage to the compressor motor in the unloaded phase. Here, the second voltage is less than the first voltage.

Abstract: A refrigerant system is provided with at least two sequential stages of compression. An intercooler is positioned intermediate the two stages. The refrigerant flowing through the intercooler is cooled by a secondary fluid such as ambient air. A vapor/liquid injection function is also provided for the refrigerant system. The intercooler function and the vapor/liquid injection function are selectively activated on demand depending on environmental conditions and thermal load in a conditioned space. This invention is particularly important for the CO2 refrigerant systems operating in the transcritical cycle.

Abstract: A fuel cell is provided to furnish electrical power to an HVAC&R system, and the waste heat from the fuel cell is transferred to a secondary fluid directed to flow to the climate-controlled space of a building during periods of time in which heating is required. The heat rejected by the fuel cell may be a supplemental or primary source of heat as well used for precise temperature control within the climate-controlled space of the building. A channeling assembly is used to selectively direct the fuel cell heat either to and/or away from the climate-controlled space served by the HVAC&R system. Higher energy efficiencies of the HVAC&R equipment are achieved, and the “cold blow” phenomenon is reduced or eliminated.

Abstract: A refrigerant vapor compression system includes a compression device having at least a first compression stage and a second compression stage, a refrigerant heat rejection heat exchanger disposed downstream with respect to refrigerant flow of the second compression stage, and a refrigerant intercooler disposed intermediate the first compression stage and the second compression stage. The refrigerant intercooler is disposed downstream of the refrigerant heat rejection heat exchanger with respect to the flow of a secondary fluid. A second refrigerant heat rejection heat exchanger may be disposed downstream with respect to refrigerant flow of the aforesaid refrigerant heat rejection heat exchanger, and a second refrigerant intercooler may be disposed intermediate the first compression stage and the second compression stage and downstream with respect to refrigerant flow of the aforesaid refrigerant intercooler.

Abstract: To address the problem of lubricant entrainment within the refrigerant system components such as an evaporator and suction line, a control is provided to periodically, substantially and intermittently increase the refrigerant flow through these components to thereby carry the trapped lubricant back to the compressor. The increased flow of refrigerant can be accomplished by periodically throttling and then unthrottling either an expansion device or a suction modulation valve to cause instantaneous pressure buildup within a respective section of the vapor compression system and subsequent increase of the refrigerant flow through the above-referenced components such as an evaporator and suction line. Suggested time intervals of both the throttling and unthrottling states are provided, as well as the frequency of occurrence for subsequent oil return cycles.

Abstract: A refrigerant system incorporates an expander. At least a portion of refrigerant bypasses an evaporator and is injected into the compression process to cool main refrigerant vapor flow and compressor elements. In disclosed embodiments, the injected refrigerant may be partially expanded in the expander and routed either into the compressor suction or to an intermediate point in the compression process. A valve may control the amount of the injected refrigerant to achieve desired operational characteristics for the refrigerant system.

Abstract: A refrigerant system is provided with at least two stages of compression connected in series. An intercooler is positioned intermediate the two stages and is cooled by an indoor air stream. The intercooler is positioned to be in a path of air flow passing over an indoor heat exchanger, and preferably downstream of the indoor heat exchanger, in relation to this airflow. The intercooler cools the refrigerant flowing between the two compression stages as well as provides the reheat function. Benefits with regard to system performance (efficiency, capacity and reliability) are achieved with no additional circuitry or components required to provide the intercooler and reheat functions. This invention is particularly important for the CO2 refrigerant systems operating in the transcritical cycle. Methods of control are presented for both the intercooler and reheat functions.

Abstract: Various control methods are disclosed for removing moisture from the external surfaces of an evaporator in a refrigerant system to avoid moisture entering a conditioned space. In one embodiment, the evaporator fan is driven in a reverse direction, and the air is guided to the outdoor environment. In other embodiments, a supplemental exhaust fan is utilized in conjunction with the evaporator fan. Also, a reheat circuit, hot gas bypass circuit, or specific features of a heat pump unit may be utilized to more efficiently perform the moisture removal.

Abstract: A compressor assembly includes at least two tandem compressors. Tandem compressors have at least one common suction manifold, communicating a source of working fluid to be compressed by each of at least two compressors, and at least one common discharge manifold communicating a compressed fluid downstream for further use. A common intermediate pressure manifold communicates with intermediate pressure ports in at least two compressors. The intermediate manifold may communicate fluid to or out of the at least two compressors. There is normally no direct communication between suction and discharge manifolds.

Abstract: A parallel flow heat exchanger is disclosed having heat transfer tubes with a plurality of relatively small channels, which are aligned in a parallel manner, and wherein the heat transfer tubes are in fluid communication with at least one manifold structure, are received in manifold wall openings and are attached to the manifold structure by brazing process The manifold walls and/or the tubes are modified to minimize the likelihood of brazing material plugging or at least partially blocking any of the plurality of channels In one feature, the openings in the manifold structure are formed by deforming the material of the manifold structure outwardly In another feature, the edges of the heat transfer tubes may be formed such that the outermost end channels within each heat transfer tube extend farther inwardly than do the central channels Various design configurations are disclosed.

Abstract: A refrigerant system is configured to alternatingly run in an economized mode and a standard mode. A control system shifts the refrigerant system between the economized mode and standard mode responsive to a determined efficiency reflecting a combination of at least two of: compressor isentropic efficiency; condenser efficiency; evaporator efficiency; efficiency of hardware mechanically powering the compressor; and a mode-associated cycling efficiency. In a bypass mode, a bypass refrigerant flow from an intermediate port may return to the suction port. Shifting into the bypass mode may be similarly controlled based upon the determined efficiency.

Abstract: A system has a compressor. A heat rejection heat exchanger is coupled to the compressor to receive refrigerant compressed by the compressor. An ejector has a primary inlet coupled with heat rejection heat exchanger to receive refrigerant, a secondary inlet, and an outlet. The system has a heat absorption heat exchanger. The system includes means for providing at least of a 1-10% quality refrigerant to the heat absorption heat exchanger and an 85-99% quality refrigerant to at least one of the compressor and, if present, a suction line heat exchanger.

Abstract: A heat exchange tube includes a tubular member having a flattened cross-section and extending along a longitudinal axis, and a longitudinally extending condensate drain channel formed in an upper wall of the flattened tubular member. A heat exchanger includes a first and a second spaced apart and generally vertical longitudinally extending headers, a plurality of heat exchange tubes disposed in parallel, spaced relationship in a generally vertical array and extending longitudinally between the first header and the second header, and a condensate drain extending longitudinally along, the upper wall of at least one of the plurality of flattened heat exchange tubes. The condensate drain may comprise a longitudinally extending condensate drain channel formed in an upper wall of said flattened tubular member, and/or a series of condensate drain portals formed in the heat transfer fins in a base portion bounding to the upper external surface of at least one heat exchange tube.

Abstract: A system for monitoring a mobile refrigerant system including one or more system components is provided. The system includes a global positioning system, a performance monitor, and a processor. The global positioning system includes a receiver that provides a locator signal. The performance monitor provides a monitor signal indicative of operational performance of at least one of the system components of the refrigerant system. The processor is adapted to receive and combine the locator signal and the monitor signal, and produce a combined locator and monitor signal output.

Abstract: In a method of operating a compressor at startup, the compressor is rotated in reverse for a brief period of time. The compressor is of a type that does not compress liquid when rotated in reverse. The purpose is to boil off the liquid refrigerant from the oil by heating and agitating the mixture of oil and refrigerant in the oil sump. This results in a much more benign forward start as less refrigerant is drawn into the compressor pump and the amount of oil pumped out of the compressor on start up is minimized. Also, the viscosity of oil is increased and lubrication of the bearings is improved. After a short period of time reverse rotation is stopped and the compressor can start rotating in the forward direction. The short period of time of reverse rotation is varied based upon system conditions. In one embodiment, the variation can occur by reducing the reverse run time as ambient temperature increases.

Abstract: A compressor (20) has a case (22) and a crankshaft (38). The case has at least one cylinder (30 32). For each of the cylinders, the compressor includes a piston (34) mounted for reciprocal movement at least partially within the cylinder. A connecting rod (36) couples each piston to the crankshaft. The case has a wall through which the crankshaft extends. The case bears a lip seal as a primary seal (97). The lip seal engages an adjacent portion (86) of the crankshaft. The adjacent portion bears a coating (140).