Compressor control for increased efficiency
AssigneeTrane International Inc.
InventorsJay H. JOHNSON, Alberto SCALA
Life of this patent
Estimating the term…
Abstract
Control systems and methods for increasing efficiency of a compressor while the compressor capacity exceeds compressor load, by using a mechanical unloader such as a slide valve to reduce the internal volume ratio of the compressor and allow a more efficient speed to be maintained by a variable frequency drive (VFD) while reducing the compressor capacity based on the load. Control systems include the VFD, a controller for the VFD and the mechanical unloader, and temperature sensors. Compressor embodiments further include one or more compressors and mechanical unloaders operated by the control systems.
Claims20
A compressor system, comprising:
- a compressor, wherein the compressor includes one or more mechanical unloaders;
- a variable frequency drive, connected to the compressor and controlling the speed of the compressor;
- a mechanical unloader control connected to the one or more mechanical unloaders;
- at least one sensor measuring operational parameters;
- a memory configured to store a map of compressor efficiency based on compressor speed and mechanical unloading;
- and
- a processor that:
- receives the operational parameters;
- determines a desired compressor speed from the map of compressor efficiency, directs the variable frequency drive to operate the compressor at the desired compressor speed
- determines whether a compressor capacity exceeds a compressor load when operating the compressor at the desired compressor speed, and
- directs the mechanical unloader control to operate the one or more mechanical unloaders to reduce the capacity of the compressor if the compressor capacity exceeds the compressor load.
A method for controlling the capacity of a compressor, comprising:
- receiving operational parameters;
- based on the operational parameters, retrieving a map of compressor efficiency based on compressor speeds and mechanical unloading determining a desired compressor speed based on the map of compressor efficiency;
- commanding a variable frequency drive to operate the compressor at the desired compressor speed;
- comparing a compressor capacity to a compressor load when the compressor is operating at the desired compressor speed;
- and
- increasing the extent to which one or more mechanical unloaders reduce the capacity of the compressor if the compressor capacity exceeds the compressor load.
A control system for a compressor, comprising:
- a variable frequency drive;
- at least one sensor measuring operational parameters;
- an actuator connected to a mechanical unloader of the compressor
- a memory configured to store a map of compressor efficiency based on compressor speed and mechanical unloading;
- and
- a processor, connected to the variable frequency drive, the at least one sensor, the actuator, and the memory, wherein the processor:
- receives operational parameters,
- determines a desired compressor speed based on the map of compressor efficiency,
- provides the desired compressor speed to the variable frequency drive,
- determines whether a compressor capacity exceeds a compressor load, and
- commands the actuator to reduce the capacity of the compressor using the mechanical unloader if the compressor capacity exceeds the compressor load.
Dependencies are inferred from the claim text.