Abstract: The present invention is directed to improvements in servicing the air filters in air conditioning units such as rooftop air conditioning units. More specifically, the invention is directed to an air filter channel and puller which facilitate the removal of rows of filters.

Abstract: A liquid refrigerant distributor for use within a heat exchanger having a body of heat exchange tubes. The distributor comprises a mesh screen and a liquid refrigerant sprayer. The liquid refrigerant sprayer is adapted to spray refrigerant on the mesh screen. The mesh screen being adapted to pass liquid and vaporous refrigerant but also to direct liquid refrigerant onto the heat exchange tubes.

Abstract: Compression refrigeration apparatus for removing heat from a heat load using a falling film evaporator, operated with an azeotropic refrigerant and utilizing a spray tree distribution system that distributes a refrigerant film on a heat exchange surface by spraying liquid refrigerant onto a surface and allowing the refrigerant to drip onto the primary heat exchange surface. The apparatus allows for efficient recovery of lubricant deposited in the evaporator without redistributing the lubricant within the evaporator. In an alternative embodiment, liquid refrigerant is sprayed onto a mesh screen where it drips onto the primary heat exchange surface.

Abstract: A method of controlling an expansion valve in a refrigeration system. The method comprises the steps of controlling the modulation of the expansion valve based upon a first feedback control criteria; and controlling the modulation of the expansion valve based upon a second feed forward control criteria.

Abstract: A high side co-rotational scroll compressor has lubricant sumps in both the discharge and suction pressure portions of its hermetic shell as well as a pressure biasing arrangement by which the scroll members are urged together in operation to minimize internal leakage. Lubrication of the bearing in which the driven scroll member rotates as well as to the bearing in which the idler scroll member rotates, both of which are located in the suction pressure portion of the shell, is provided for. Additionally, embodiments are taught by which the interface between the tips of the wraps of each scroll member and the end plate of the opposing scroll member are lubricated and by which the seal in the axial pressure biasing arrangement is lubricated and/or shielded from debris having the potential to damage it.

Abstract: A method of minimizing energy use in a chiller and cooling tower system is disclosed. The method comprises the steps of: determining a measure of chiller efficiency; determining a measure of cooling tower efficiency; determining a measure of the transfer rate of heat energy between the cooling tower and the chiller; calculating a near optimal water temperature as a function of the chiller work efficiency, the cooling tower efficiency and the transfer rate; and operating the cooling tower to provide a conditioned fluid at the temperatures to produce near optimal energy consumption.

Abstract: Compression refrigeration apparatus for removing heat from a heat load using a falling film evaporator, operated with an azeotropic refrigerant and utilizing a spray tree distribution system that distributes a refrigerant film on a heat exchange surface by spraying liquid refrigerant onto a surface and allowing the refrigerant to drip onto the primary heat exchange surface. The apparatus allows for efficient recovery of lubricant deposited in the evaporator without redistributing the lubricant within the evaporator. In an alternative embodiment, liquid refrigerant is sprayed onto a mesh screen where it drips onto the primary heat exchange surface.

Abstract: Liquid refrigerant interacts with the stream of gas flowing through in a centrifugal water chiller, downstream of the occurrence of the compression process in the compressor portion of the chiller but prior to the condensing of the gas in the chiller condenser, to reduce the acoustic energy of the gas. The noise emanating from the chiller which would otherwise result from the interaction of the discharge gas with the piping connecting the compressor portion of the chiller to the system condenser and/or with the components of the system condenser itself is thereby reduced without significantly affecting chiller performance or efficiency.

Abstract: A centrifugal fan includes a housing that defines an air inlet leading to an air chamber defined within the fan impeller and an air exit port coupled to an air passageway. The housing includes a shroud that defines a two zone air passageway in the housing. The first zone, commencing adjacent to the base of the exhaust port, is a conformal portion that is conformal to the exterior diameter of the centrifugal fan and spaced slightly apart therefrom. The second zone of the shroud is a scroll portion wherein the angle of expansion is capable of expanding between 10.degree. and 15.degree.. An air restrictor plate is supported inside the air chamber of the centrifugal fan. At the greatest width of the air restrictor plate, the air restrictor plate subtends an arc that is substantially coextensive with the arc subtended by the first conformal zone of the shroud. The restrictor prevents the flow of inlet air through the centrifugal fan in the region of the conformal shroud.

Abstract: Compressor lubricant in a screw compressor-based refrigeration system is cooled by directing the lubricant from the system oil separator to an oil-cooling heat exchanger disposed in the lower portion of the system condenser where it is bathed in condensed system refrigerant. Parasitic capacity losses with respect to the compressor lubricant cooling process are thereby avoided.

Abstract: An apparatus for detecting faults in a starter circuit adapted to connect a multi-phase electrical motor to a power supply. The motor has at least one winding per phase, each of which terminates in at least one terminal. The starter circuit includes a plurality of contactors which are energizable to connect the motor windings to the power source. The fault detection apparatus comprises a current sensor for sensing the current flowing through the windings of each phase and responsively producing respective winding current signals. A diagnostic module controllably energizes the contactors, samples for the presence and absence of the winding current signals while different ones of the contactors are energized to detect faults in the contactors, and responsively produces fault signals.

Abstract: Compression refrigeration apparatus for removing heat from a heat load using a falling film evaporator, operated with an azeotropic refrigerant and utilizing a vapor-liquid separator, preferably inside the evaporator vessel. In one embodiment, two types of heat exchange surfaces are utilized--one for maximizing the axial distribution of refrigerant film on a heat exchange surface, the other for encouraging liquid refrigerant in contact with a heat exchange surface to boil and evaporate. The apparatus allows for efficient recovery of lubricant deposited in the evaporator without redistributing the lubricant within the evaporator.

Abstract: A method of controlling the operation of a centrifugal compressor in a water chiller system. The compressor's capacity is variable by modulating its speed of rotation or by modulating its inlet guide vane's position. The water chiller includes an evaporator having a leaving water temperature. The method comprises the steps of: monitoring the leaving water temperature; determining if the leaving water temperature is in a steady state; modulating the compressor capacity by modulating speed of rotation if the leaving water temperature is in a steady state; and modulating the compressor capacity by modulating inlet guide vane position if the leaving water temperature is not in a steady state.

Abstract: A system for transferring a refrigerant from a first refrigerant vessel having at least one refrigerant port to a second refrigerant vessel having at least one refrigerant port is disclosed. This system includes a condenser, a pump assembly having an inlet and an outlet, and conduits for operatively connecting the condenser and pump assembly to the first and second refrigerant vessel in several configurations. The pump assembly includes two pumps operated by one motor and interconnected to either provide series or parallel pumping. This system may also include a transfer tank interposed between the first and second refrigerant vessels. The transfer tank can be used to condense the vapor phase of the refrigerant removed from the first refrigerant vessel and collect the condensed refrigerant in one configuration, then to transfer the condensed refrigerant to the second refrigerant vessel in an alternate configuration.

Abstract: A method of controlling the operation of a centrifugal compressor in a water chiller system. The compressor's capacity is variable by modulating its speed of rotation or by modulating its inlet guide vane's position. The water chiller includes an evaporator having a leaving water temperature. The method comprises the steps of: monitoring the leaving water temperature; determining if the leaving water temperature is in a steady state; modulating the compressor capacity by modulating speed of rotation if the leaving water temperature is in a steady state; and modulating the compressor capacity by modulating inlet guide vane position if the leaving water temperature is not in a steady state.

Abstract: An average temperature sensor designed for use in an air conditioning unit, wherein the air conditioning unit has a high pressure region and a low pressure region and a method for making an average temperature measurement. The average temperature sensor senses the average temperature of air flowing in the high pressure region and comprises a device for conveying a flow of air that is in fluid communication with the high pressure region. A temperature sensor is disposed in a temperature sensing relationship to the device for conveying the flow or air. The high pressure in the high pressure region induces a flow of air in the device for conveying a flow of air. This flow of air flows from the high pressure region to the low pressure region and is at the average temperature of the air in the high pressure region.

Abstract: A system for transferring a refrigerant from a first refrigerant vessel having at least one refrigerant port to a second refrigerant vessel having at least one refrigerant port is disclosed. This system includes a condenser, a pump assembly having an inlet and an outlet, and conduits for operatively connecting the condenser and pump assembly to the first and second refrigerant vessel in several configurations. The pump assembly includes two pumps operated by one motor and interconnected to either provide series or parallel pumping. This system may also include a transfer tank interposed between the first and second refrigerant vessels. The transfer tank can be used to condense the vapor phase of the refrigerant removed from the first refrigerant vessel and collect the condensed refrigerant in one configuration, then to transfer the condensed refrigerant to the second refrigerant vessel in an alternate configuration.