System and method for controlling a system that includes fixed speed and variable speed compressors
AssigneeTrane International Inc.
InventorsJohn Qianghua Zhou, Roger Joseph Voorhis, Caleb Ryan Joiner, Benjamin Hayes, James Philip Crolius, William Hansen
Life of this patent
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Abstract
A system and method for controlling a system that includes fixed speed and variable speed compressors are described. The method generally allows the system, for example, a heating, ventilating, and air condition (HVAC) system that includes fixed speed and variable speed compressors, to maximize unit modulating capability. The method allows the use of a variable speed compressor that is relatively smaller, which can lead to cost savings, easier installation, manufacturing, etc.
Claims19
A system for controlling the operation of a variable speed compressor and a fixed speed compressor,
- wherein the system comprises
- a fixed speed compressor;
- a variable speed compressor, and
- a control unit that includes a PI controller and is configured to:
- (a) determine a first parameter value;
- (b) determine a first PI capacity value based on the first parameter value determined in (a) and a set point using the PI controller;
- (c) determine a first operating mode based on the first PI capacity value determined in (b);
- (d) operate the fixed speed and variable speed compressors based on the determination made in (c);
- (e) determine a second operating mode after (d);
- (f) determine an operational state of the fixed speed compressor;
- (g) operate the fixed speed compressor based on the determination made in (f);
- (h) determine a speed of the variable speed compressor using the PI controller;
- and
- (i) operate the variable speed compressor according to an operational state based on the determination made in (h).
A method of controlling the operation of a variable speed compressor and a fixed speed compressor in a refrigeration or a heating, ventilating and air conditioning system, the method comprising:
- (a) determining a discharge air temperature (DAT);
- (b) determining a PI capacity value based on the DAT determined in (a) and a set point using a PI controller;
- (c) determining a first operating mode based on the PI capacity value determined in (b);
- (d) operating the fixed speed compressors and the variable speed compressor based on the determination made in (c);
- (e) determining a second operating mode after (d);
- (f) determining the operational state of the fixed speed compressor;
- (g) operating the fixed speed compressor based on the determination made in (f);
- (h) determining a speed of the variable speed compressor using the PI controller;
- and
- (i) operating the variable speed compressor according to an operational state based on the determination made in (h).
Dependencies are inferred from the claim text.