Abstract: Systems and methods are provided for detecting performance degradation in a refrigeration system. Specifically, the present invention provides systems and methods for detecting, at a very early stage, a low refrigerant charge and degradation in condenser performance of a refrigeration system.

Abstract: An HVAC system and method for configuring a controller to control a compressor including a detection system provided to determine a type of compressor. The detection system includes a processor; and a load sensing circuit connected between the processor and a controller. The controller has a plurality of output connections connectable to a compressor. The load sensing circuit senses whether a load is present on each output connection of the plurality of output connections and provides a load signal to the processor indicating whether a load is present on each output connection. The load signals are processed with the processor to determine the type of compressor is present. The controller is configured to control the compressor in response to the determined type of compressor.

Abstract: A single medium voltage starter box is mounted on a chiller unit with the other components of the chiller system. The starter box can be positioned on the chiller system unit to permit the starter box to be close coupled to the motor, and specifically to the main motor lead exit hub without the need for any power conduit connections between the starter box and the motor. In addition, the starter box also does not require any control interface and receives controls from a control panel. A short conduit connection between the control panel and the starter box is used to provide the necessary connections between the control panel and the starter box.

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 single medium voltage starter box is mounted on a chiller unit with the other components of the chiller system. The starter box can be positioned on the chiller system unit to permit the starter box to be close coupled to the motor, and specifically to the main motor lead exit hub without the need for any power conduit connections between the starter box and the motor. In addition, the starter box also does not require any control interface and receives controls from a control panel. A short conduit connection between the control panel and the starter box is used to provide the necessary connections between the control panel and the starter box.

Abstract: An HVAC system having a main circuit and a subcooler circuit. The main circuit includes a main circuit evaporator, a main circuit expansion device, a main circuit condenser and a main circuit compressor connected in a closed refrigerant loop. The subcooler circuit includes a subcooler evaporator, a subcooler expansion device, a subcooler condenser and a subcooler compressor connected in a closed refrigerant loop. The subcooler evaporator is arranged and disposed to exchange heat between liquid refrigerant in the main circuit and the refrigerant in the subcooler circuit to cool the liquid refrigerant in the main circuit prior to entering the main circuit evaporator. The operation of the subcooler circuit provides an increased cooling capacity per unit of a mass flow of cooling fluid through the main circuit condenser and subcooler condenser for the HVAC system with a predetermined design efficiency.

Abstract: A control algorithm for controlling an economizer circuit in a chiller system is provided. The control algorithm opens and closes a port valve in the economizer circuit in response to predetermined criteria to engage and disengage the economizer circuit. The predetermined criteria can include an operating parameter of a compressor and a level of liquid refrigerant in a flash tank.

Abstract: A falling film evaporator is provided for use in a two-phase refrigeration system or process system. The evaporator includes a shell having an upper portion, a lower portion, and a tube bundle having tubes extending substantially horizontally in the shell. A hood is disposed over the tube bundle, the hood having an upper end adjacent the upper portion above the tube bundle, the upper end having opposed substantially parallel walls extending toward the lower portion, the walls terminating at an open end opposite the upper end. Once liquid refrigerant or liquid refrigerant and vapor refrigerant is deposited onto the tube bundle, the substantially parallel walls of the hood substantially prevent cross flow of refrigerant vapor or liquid and vapor between the tubes of the tube bundle.

Abstract: A method for configuring a controller for an HVAC system. The method comprises providing a closed loop refrigerant system and a control system to control the closed loop refrigerant system. The control system comprises a controller, an input device, and a processor including a signal sensing circuit. The input device is activated to provide one or more signals to the controller to control the components of the closed loop refrigerant system. One or more signals are sensed with the signal sensing circuit to determine whether signals are present between the input device and the controller. The signals are processed with the processor to determine what type of closed loop refrigerant system is present. The controller is then configured to control the type of system determined by the processor.

Abstract: An HVAC system including a compressor, a condenser and an evaporator arrangement connected in a closed refrigerant loop. The evaporator arrangement includes a plurality of refrigerant circuits. The evaporator arrangement also includes at least one distributor configured to distribute and deliver refrigerant to each circuit of the plurality of circuits. The plurality of circuits are arranged into a first and second set of circuits. The evaporator arrangement also includes a valve configured and disposed to isolate the first set of circuits from refrigerant flow from the condenser and provide flow of refrigerant from the compressor in a dehumidification operation of the HVAC system.

Abstract: A level control algorithm for an HVAC refrigeration system is provided. The control algorithm utilizes a fuzzy logic methodology to automatically adjust a flow of refrigerant in the system to maintain a desired liquid level in the condenser. The fuzzy logic methodology incorporates a plurality of fuzzy logic control algorithms each having different membership functions and other control parameters that can provide different degrees of level control in the condenser. A particular fuzzy logic control algorithm is selected based on the amount a measured liquid level in the condenser deviates from the desired liquid level in the condenser.

Abstract: A 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 only performed during cooling operations and ventilation operations.

Abstract: A noise control method is provided for a cooling system having at least one refrigerant circuit. The refrigerant circuit includes a compressor, a condenser, at least one condenser fan, and an evaporator. Noise control is only performed periodically in response to requirements for reduced operation at predetermined times. The request for reduced noise triggers the commencement of the noise control method. The noise control method involves reducing the operating speed of the compressor, as well as reducing the operating speed of at least one condenser fan, to within a predetermined range of allowable reduced operating speeds. The noise control method temporarily overrides the ability of the cooling system to fully respond to increased cooling or heating demands.

Abstract: A humidity control method is provided for a multi-stage cooling system having two or more refrigerant circuits. A hot gas re-heat circuit having a hot gas re-heat coil, an evaporator and a compressor, such as the evaporator and compressor utilized in one of the refrigerant circuits, is provided. The hot gas re-heat coil is placed in fluid communication with the output airflow from the evaporator of the re-heat circuit. 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 re-heat circuit for dehumidification and activates a second refrigerant circuit to provide cooling capacity. During a second stage cooling operation using multiple refrigerant circuits and having a high cooling demand, the request for humidity control is suspended until completion of the second stage cooling demand.

Abstract: A thermally-enhanced, insulated component for use with an HVAC system includes a component having an outer surface usable with an HVAC system, the component being substantially filled with an insulating material. A thin, dimensionally stable layer of thermal barrier material having opposed surfaces is disposed inside the component at a predetermined distance from the outer surface of the component. The thermal barrier layer is in contact with the insulating material on at least one surface of the opposed surfaces. When the outer surface of the component is subjected to an elevated temperature, the thermal barrier layer maintains a sufficient temperature differential between the surface of the opposed surfaces of the thermal barrier layer facing opposite the outer surface and the surface of the opposed surfaces of the thermal barrier layer facing the outer surface so that the insulating material produces a reduced rate of smoke.

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 level control algorithm for an HVAC refrigeration system is provided. The control algorithm utilizes a fuzzy logic methodology to automatically adjust a flow of refrigerant in the system to maintain a desired liquid level in the condenser. The fuzzy logic methodology incorporates a plurality of fuzzy logic control algorithms each having different membership functions and other control parameters that can provide different degrees of level control in the condenser. A particular fuzzy logic control algorithm is selected based on the amount a measured liquid level in the condenser deviates from the desired liquid level in the condenser.

Abstract: A method and system is provided for gathering and packetizing data from networked building automation equipment, and for transmitting data packets as instant messages to remotely located users. An instant messaging (IM) server-based system is provided to facilitate communication between networked building equipment and a remotely located service contractor. When a registered router is operated, the router establishes a continuous pass-through communication link with the IM server and with building equipment connected to the router. The router automatically polls connected building equipment for alarms, faults and system failures, and also receives, processes, and responds to user requests for specific data from particular items of building equipment. Data gathered by the router is packetized, and the packets are then encapsulated into an instant message that is transmitted to the IM server.

Abstract: A level control algorithm for an HVAC refrigeration system is provided. The control algorithm utilizes a fuzzy logic methodology to automatically adjust a flow of refrigerant in the system to maintain a desired liquid level in the condenser. The fuzzy logic methodology incorporates a plurality of fuzzy logic control algorithms each having different membership functions and other control parameters that can provide different degrees of level control in the condenser. A particular fuzzy logic control algorithm is selected based on the amount a measured liquid level in the condenser deviates from the desired liquid level in the condenser.

Abstract: A variable speed drive with a converter that is controllable to precharge a DC link is provided. The variable speed drive also includes an inverter. The converter converts a fixed line frequency, fixed line voltage AC power from an AC power source into DC power. The DC link filters the DC power from the converter. Finally, the inverter is connected in parallel with the DC link and converts the DC power from the DC link into a variable frequency, variable voltage AC power. The converter includes a plurality of pairs of power switches, wherein each pair of power switches includes a reverse blocking power switch arrangement connected in anti-parallel to another reverse blocking power switch arrangement. Alternatively, each pair of power switches includes a reverse blocking power switch connected in anti-parallel with a silicon carbide controlled rectifier.