York International Corporation

Johnson Controls Technology Company

Other

Johnson Controls Tyco IP Holdings LLP

Gregory Keith Beaverson

Harold Robert Schnetzka

John C Hansen

Steven Trent Sommer

Harold B Ginder

Andrew Michael Welch

Robert E Stabley

Sakin R Cakmakci

Steven J Estes

Dennis L Deitz, Jr

Craig N Shores

Timothy M Frank

Curtis Christian Crane

Ivan Jadric

William Fred McQuade

Florin Valcriu Iancu

Eric John Smyder

Ivan Jadri&cacute;

Wanda Jean Miller

John Trevino, Jr

Koman B Nambiar

Patrick Christian Marks

Rudy Chervil

Russell P Wueschinski

James Edwin Bender

Bart Andrew Smith

Russel P Wueschinski

Dennis L Deltz

A control system is provided that can identify the occurrence of a single surge cycle in centrifugal compressor using various methods and devices. Once the occurrence of a single surge cycle is identified, the control system can take remedial action to respond to the surge cycle, such as by adjusting the position of a variable geometry diffuser, and restore the centrifugal compressor to stable operation.

Control system for centrifugal compressor

A cooling system for a motor powering a compressor in a vapor compression system includes a housing and a cavity within the housing. A first fluid circuit has a first connection to receive a refrigerant into the cavity, and a second connection to deliver refrigerant from the cavity to a heat exchanger for a heat transfer relationship with a heat-generating component.

Motor cooling applications

A cooling system for a motor powering a compressor in a vapor compression system includes a housing enclosing the motor and a cavity located within the housing. A fluid circuit circulates a cooling fluid in the motor, and includes a first connection in the housing to receive cooling fluid and a second connection in the housing to remove cooling fluid. The fluid circuit includes a passageway for cooling fluid positioned in an internal chamber formed in a motor shaft.

A system and method is provided for detecting and controlling rotating stall in the diffuser region of a centrifugal compressor. The process begins with the detection or sensing of acoustic energy associated with the onset of rotating stall. A pressure transducer is placed in the gas flow path downstream of the impeller, preferably in the compressor discharge passage or the diffuser, to measure the sound or acoustic pressure phenomenon. Next, the signal from the pressure transducer is processed either using analog or digital techniques to determine the presence of rotating stall. Rotating stall is detected by comparing the detected energy amount, which detected energy amount is based on the measured acoustic pressure, with a predetermined threshold amount corresponding to the presence of rotating stall. Finally, an appropriate corrective action is taken to change the operation of the centrifugal compressor in response to the detection of rotating stall.

System and method for detecting rotating stall in a centrifugal compressor

Methods and systems consistent with this invention control a hot gas bypass valve in a refrigeration system including a centrifugal compressor, a condenser, an evaporator, and a hot gas bypass line between the compressor and the evaporator. Such methods and systems continuously sense for a surge condition during operation of the refrigeration system, indicate a surge condition when the refrigeration system is operating under surge conditions, and open at least partially the hot gas bypass valve in response to the sensed surge condition to return the refrigeration system to operating under non-surge conditions. Methods and systems consistent with this invention also sense a present head parameter representative of the present head of the compressor, sense a present load parameter representative of the present load, and control the hot gas bypass valve so as to avoid surging in the compressor in response to the present head parameter, the present load parameter, and stored head and load parameters.

Hot gas bypass control for centrifugal chillers

A pull-down 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 during a pull-down to maintain a desired pull-down rate. The desired pull-down rate is decreased proportionately as the temperature of the fluid being pulled down approaches a desired operating setpoint to avoid or minimize any overshoot of the operating setpoint. The desired pull-down rate is obtained by adjusting a rate sensitivity factor used in the control algorithm. When the temperature of the fluid being pulled down is above a predetermined value from the operating setpoint, the control algorithm uses a fuzzy logic methodology to determine a rate sensitivity that results in the desired pull-down rate that approaches the operating setpoint without overshoot.

Self-tuning pull-down fuzzy logic temperature control for refrigeration systems

A heating, ventilation, and air-conditioning (HVAC) control system and method for controlling a device, a subsystem, and/or a process using a flash mini-card. Preferably, the present invention is directed to an HVAC control system and method for controlling a chiller and the devices and subsystems associated with the chiller using a flash mini-card. More preferably, the present invention obviates the need for the HVAC control system and method to use at least one of the following: a hard disk, a disk controller, a card reader, or a card controller. The method includes, for example, applying power to the HVAC control system, wherein the step of applying power initiates a boot-up of a processor associated with the HVAC control system; reading a default memory location, wherein the contents of the default memory location direct the processor to a Basic Input/Output System (BIOS) connected to the processor through a bus; configuring the processor associated with the HVAC control system by executing a set of BIOS instructions within the BIOS, wherein after the step of configuring, the processor reads a set of boot instructions that directs the processor to the flash mini-card containing a set of instructions; and performing at least one of the set of instructions contained within the flash mini-card to control the HVAC system using the HVAC control system.

System and method for controlling an HVAC system using a flash mini-card

Methods and systems consistent with this invention detect a failed short thyristor in a solid-state controller for delivering power to a load during reduced-voltage operation. Methods and systems consistent with this invention detect a voltage across the thyristor, and indicate a failed short thyristor when the absolute value of the voltage across the thyristor remains below a threshold value during a predetermined period of time. Methods and systems consistent with this invention detect a failed open thyristor in a solid-state controller during full-voltage operation. Methods and systems consistent with this invention detect a voltage across the thyristor, and indicate a failed open thyristor when the absolute value of the voltage across the thyristor exceeds a threshold value.

Method and apparatus detecting a failed thyristor

An adaptive control apparatus and a method for automatically controlling a refrigeration system as a function of cooling load and head. A control panel controls the operation of a hot gas bypass valve so as to avoid surging of the compressor in response to cooling load and head. The control apparatus and method also allow for automatic self calibration.

Adaptive hot gas bypass control for centrifugal chillers

A freeze point protection method and system is provided for water cooled chillers. The method prevents freezing of chilled water and damage to the chiller. The method allows the evaporator temperature to drop below a freezing temperature for a predetermined amount of time prior to shutting down the chiller. The temperature of the refrigerant in the water chiller is periodically sensed. The amount of time that the chiller is below a predetermined freezing temperature is periodically counted and compared with a determined maximum time that the chiller may operate at a sensed temperature below the predetermined freezing temperature without damaging the chiller. The method will shut down the water chiller if the counted time exceeds the determined maximum time. A system for shutting down a water cooled chiller to prevent freezing of chilled water is also provided.

Freeze point protection for water cooled chillers

A surge detection system for use in a fluid system having a load driven by a centrifugal compressor, the compressor being driven by an electric motor. The surge detection system comprises a means for sensing a differential pressure developed across the compressor and a means for sensing a current representing input power to the motor. The surge detection system further comprises a first computing means responsive to the differential pressure developed across the compressor for indicating when a valid surge is occurring in the compressor, and a second computing means responsive to the variable speed drive current for indicating when a valid surge is occurring in the compressor.

Methods and apparatuses for detecting surge in centrifugal compressors

Chiller operating efficiency is optimized by controlling the system to maintain the condenser liquid refrigerant level at a value which will minimize or prevent gas bypass to the evaporator. This is accomplished by sensing the level of liquid refrigerant in the condensor and incorporating fuzzy logic to properly position a multi-position valve which can variably restrict the flow of this liquid into the evaporator, according to this sensed parameter. The fuzzy logic utilizes as inputs both the level error from a set point level and the rate of change of the sensed level. Each of these inputs are combined by fuzzy logic techniques to provide the required output signal to control the opening and closing of the valve.

Fuzzy logic liquid level control

To capacity control a refrigeration system including a compressor, a condenser, and an evaporator all connected in a closed refrigeration circuit, the compressor having a plurality of adjustable inlet guide vanes and driven by an internal combustion engine, signals indicating the condenser pressure; the evaporator pressure; the inlet guide vanes position; the engine speed; the chilled water discharge temperature; and the engine intake manifold pressure are processed by a microprocessor to continuously calculate a surface speed and to equalize engine speed and calculated surface speed utilizing a fuzzy logic algorithm.

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York, PA, United States of America

Gregory Keith Beaverson