Abstract: A tool for the analysis of heating, ventilation and air conditioning (HVAC) systems, methods for performing various analyses of an HVAC system with the tool, and a computer executable program used by the tool to perform the analyses are disclosed. The tool includes a processing machine, a database, a memory device having a software program executable by the processing machine, and a display device. The database stores information on each of a plurality of HVAC components and the software program is configured to identify and access information pertaining to at least one HVAC unit in an HVAC system from the database and is configured to generate a wiring diagram using the accessed information from the database that is displayed to the display device.

Abstract: In a chiller system, an electronic control transformer is powered by the DC link of a variable speed drive that drives a compressor motor. The electronic control transformer converts the DC voltage to a constant 120 VAC at 60 Hz, for providing power to auxiliary electrical devices associated with the chiller system. The electronic transformer includes four semiconductor switches to convert the DC voltage to AC. The energy stored in the compressor motor is transferred to the DC link of the VSD during an input voltage sag. The electronic control transformer maintains the control voltage and prevents the system auxiliary loads from dropping out during a voltage sag. The chiller system is able to ride through the input voltage sag or interruption. A boost converter may be provided at the input of the VSD to increase ride through capability.

Abstract: A startup control algorithm for a multiple compressor liquid chiller system is provided wherein the maximum number of compressors to be started to satisfy system load conditions is provided. The control algorithm designates all of the compressors of the multiple compressor system for starting and reduces the number to be started in response to the satisfaction of several predetermined criteria. The predetermined criteria are related to the leaving chilled liquid temperature, the shutdown time for the chiller system and the last operating time period for the chiller system.

Abstract: A startup control algorithm for a multiple compressor liquid chiller system is provided wherein the maximum number of compressors to be started to satisfy system load conditions is provided. The control algorithm designates all of the compressors of the multiple compressor system for starting and reduces the number to be started in response to the satisfaction of several predetermined criteria. The predetermined criteria are related to the leaving chilled liquid temperature, the shutdown time for the chiller system and the last operating time period for the chiller system.

Abstract: A heating arrangement is provided for use in an air handling unit. The heating arrangement includes at least one heating device to be disposed in the airflow of an air handling unit. A base is configured to support the at least one heating device and a first guide member to be mounted on a structural component inside the air handling unit. A second guide member is mounted on the base, the second guide member being configured to slidably engage the first guide member. Sliding engagement of the first guide member and the second guide member positions the at least one heating device to an installed position inside the air handling unit.

Abstract: A system and humidity control method is provided for a multi-stage cooling system having two or more refrigerant circuits that balances humidity control and cooling demand. Each refrigerant circuit includes a compressor, a condenser and an evaporator. A hot gas reheat circuit having a hot gas reheat coil is connected to one of the refrigerant circuits and is placed in fluid communication with the output airflow from the evaporator of that refrigerant circuit to provide additional dehumidification to the air when humidity control is requested. The hot gas reheat circuit bypasses the condenser of the refrigerant circuit during humidity control. Humidity control is performed during cooling operations and ventilation operations. During a first stage cooling operation using only one refrigerant circuit and having a low cooling demand, the request for humidity control activates the hot gas reheat circuit for dehumidification and activates a second refrigerant circuit to provide cooling capacity.

Abstract: A capacity control algorithm for a multiple compressor liquid chiller system is provided wherein the speed and number of compressors in operation are controlled in order to obtain a leaving liquid temperature setpoint. In response to an increase in the load in the chiller system, the algorithm determines if a compressor should be started and adjusts the operating speed of all operating compressors when an additional compressor is started. In response to a decrease in the load in the chiller system with multiple compressors operating, the algorithm determines if a compressor should be de-energized and adjusts the operating speed of all remaining operating compressors when a compressor is de-energized.

Abstract: A chiller system includes a switched reluctance motor for powering the compressor of the chiller system. A variable speed drive with a boost converter provides a boosted voltage to the switched reluctance motor. The switched reluctance motor and the compressor may be disposed within the same hermetic enclosure and driven by a common drive shaft. Cooling for both the variable speed drive and the switched reluctance motor is provided from condenser water in the condenser water circuit, or from an intermediate liquid cooled by water from the condenser circuit to increase system efficiency. Windage losses are reduced by barriers introduced within the motor, and by maintaining a reduced pressure in the switched reluctance motor.

Abstract: An evaporator including a shell having a first end and a second end. A plurality of tubes are disposed within the shell to circulate refrigerant through the shell. A plurality of shell inlets are in fluid communication with the shell to deliver a fluid to exchange heat in the plurality of tubes, preferably through a baffle arrangement. At least one of the shell inlets may be arranged to deliver fluid to the shell adjacent to the first end. In addition, at least one of the other shell inlets may be arranged to deliver fluid adjacent to the second end. A shell outlet is in fluid communication with the shell to discharge fluid from the shell. The shell outlet is arranged to receive the combined liquid delivered to the shell by the plurality of shell inlets.

Abstract: A variable speed drive with a boost converter is provided for a chiller system driven by a switched reluctance motor. The boost converter can be a diode or thyristor rectifier followed by a boost DC/DC converter or a three-phase pulse width modulated boost converter. The boost converter provides a boosted voltage to the DC link, which results in a boosted voltage being applied to the switched reluctance motor by the inverter of the variable speed drive.

Abstract: A transition fitting interconnects a furnace combustion air chamber to an air duct supplying combustion air to the furnace. The fitting includes a housing portion having opposed first opening and second openings, the first opening being disposed adjacent a furnace combustion air chamber upon installation and three tubular portions connected to the housing portion and disposed adjacent to the second opening. Each of the three tubular portions define a central axis and have a first opening into the housing portion and a second opening configured to receive an inlet air duct. One tubular portion is disposed at an angle to the central axes of the other two tubular portions. A peripheral flange portion sealably attaches the housing portion to a frame portion of a furnace. A removably attachable cap is configured to selectively close a tubular portion not connected to an external air duct.

Abstract: A motor disconnect arrangement is provided for a variable speed drive having a plurality of inverters electrically connected in parallel to a DC link to power a plurality of motors. The disconnect arrangement includes a contactor or other disconnect device connected in series between each inverter output of the variable speed drive and its corresponding motor. The contactor operates to disconnect, isolate or remove the motor from the variable speed drive in the event of a failure of the motor. By removing a failed motor from the variable speed drive, the other motors connected to the variable speed drive can continue to operate normally.

Abstract: Apparatus and methods are provided for cooling motors used to drive gas and air compressors. In particular, the cooling of hermetic and semi-hermetic motors is accomplished by a gas sweep using a gas source located in the low-pressure side of a gas compression circuit. The gas sweep is provided by the creation of a pressure reduction at the compressor inlet sufficient to draw uncompressed gas through a motor housing, across the motor, and out of the housing for return to the suction assembly. The pressure reduction is created by means provided in the suction assembly, such as a nozzle and gap assembly, or alternatively a venturi, located upstream of the compressor inlet. Additional motor cooling can be provided by circulating liquid or another cooling fluid through a cooling jacket in the motor housing portion adjacent the motor.

Abstract: A high efficiency, low-noise fan ring for use with a heat exchanger having an annular fan ring body attached to a coaxial mounting ring. The fan ring body extends in a substantially perpendicular direction from an inner periphery of the mounting ring. The annular body has a circumferential periphery profile defined by a plane coincident the center axis and an inner surface of the fan ring body. The periphery profile includes a transition portion and a curved portion. The transition portion extends in a substantially perpendicular direction from the mounting ring and attaches to an end of the curved portion. In order to reduce noise and increase uniformity of airflow, the length of the curved portion of the periphery profile is sufficient long to reduce recirculation of air entering the fan ring body.

Abstract: An air-conveying device for use in an HVAC system having an interior surface and an exterior surface. An air-moving device is arranged and disposed to move air through the air-conveying device adjacent to the interior surface of the air-conveying device. The air-conveying device conveys air having passed through an HVAC heat exchanger. The air-conveying device includes one or more openings disposed and arranged to provide a pressure differential sufficient to cause passage of air through the openings from an area adjacent to the interior surface to an area adjacent to the exterior surface in order to decrease aerodynamic drag.

Abstract: A photocatalytic coating composition and method of coating articles, the composition containing solvents for rapid evaporation at room temperature, polyalkylphenylsiloxane, xylene, nano densified hydrophilic fumed silica, nanostructured composite photocatalyst powder and nano inorganic anti-bacteria powder. The coating may be applied by conventional coating methods to organic or inorganic structured surfaces where photocatalytic activity is desired, such as in a forced air-circulating environment. Once applied, the coating quickly dries to leave an adherent, flexible, durable, and long-lasting photocatalytic coating having a large surface area and exhibiting high surface activity against pathogens and pollutants such as bacteria, viruses, mold, fungi, and volatile organic compounds.

Abstract: A method and system for controlling refrigerant pressure in an HVAC system. The method includes providing a compressor, a condenser and an evaporator connected in a closed refrigerant loop. The condenser has a header arrangement capable of distributing refrigerant to a plurality of refrigerant circuits within the condenser. The header arrangement also is capable of selectively isolating at least one of the circuits from refrigerant flow. Refrigerant pressure is sensed at a predetermined location in the refrigeration system. At least one of the circuits is isolated when the refrigerant pressure is less than or equal to a predetermined pressure.

Abstract: A method for dehumidification and controlling system pressure in a refrigeration system includes providing a refrigeration system having a compressor, a condenser and an evaporator connected in a closed refrigerant loop. Each of the condenser and evaporator have a plurality of refrigerant circuits. A first heat transfer fluid is flowed over the condenser and a second heat transfer fluid is flowed over the evaporator. At least one of the refrigerant circuits of the condenser is isolated to provide a decreased amount of heat transfer area within the condenser and to increase the refrigerant pressure within the refrigeration system when the refrigerant pressure within the refrigeration system is at or below a predetermined pressure. At least one of the refrigerant circuits of the evaporator is isolated to dehumidify and maintain the temperature of the second heat transfer fluid at or above a predetermined temperature when dehumidification is required.

Abstract: A panel provided for use in an air handling unit includes a skin and a fixture, the fixture and the skin composed of a metal material. The fixture has a base, with an opening formed in the base. The base includes at least one riser extending substantially perpendicular to the base, the at least one riser being secured to the skin to form an enclosed chamber between the skin and the fixture. A perforated sheet is disposed over the opening, a layer of film disposed on a surface of the perforated sheet facing the skin. A first insulating material is disposed on a surface of the film layer opposite the perforated sheet. A second insulating material is disposed in the enclosed chamber between the first insulating material and the skin.

Abstract: A viewport including substantially aligned openings disposed in inner and outer panels for a door or wall is provided. A pane assembly configured to permit viewing therethrough is provided, the pane assembly being secured into position between the inner and outer panels in alignment with the openings. An injected insulating material is disposed between the inner and outer panels and around the pane assembly to substantially fill an open space between the inner and outer panels, the insulating material being configured and disposed to maintain the secured position of the pane assembly.