Method of compressor staging for a multi-compressor refrigeration system

• US 5,123,256 A
• Filed: 05/07/1991
• Issued: 06/23/1992
• Est. Priority Date: 05/07/1991
• Status: Expired due to Term

• Current Assignee: Trane International Inc. (Trane Technologies plc)
• Original Assignee: American Standard Companies Incorporated (Ideal Standard International Topco SCA)
• Inventors: Oltman, Robert L.
• Primary Examiner(s): Wayner, William E.
• Application Number:
  US07/696,896
• Time in Patent Office: 413 Days
• Field of Search: 62/175, 62/228, 62/5, 236/1 EA, 417/5, 417/8, 307/39
• US Class Current: 62/175
• CPC Class Codes: F25B 2400/075 with parallel compressors
• CPC Class Codes: F25B 2500/26 characterised by the startup of the refrigeration cycle
• CPC Class Codes: F25B 2600/111 of condenser fans
• CPC Class Codes: F25B 2600/2513 Expansion valves
• CPC Class Codes: F25B 49/022 Compressor control arrangements
• CPC Class Codes: Y02B 30/70 Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Abstract

A method of staging a plurality of compressors in a refrigeration system. The method comprises the steps of: accumulating a first operative condition for each compressor; accumulating a second operative condition for each compressor; initiating operation of whichever compressor has the lowest accumulation of the first operative condition whenever a system controller calls for an increase in system capacity; and terminating operation of whichever compressor has the greatest accumulation of the second operative condition whenever the system controller calls for a reduction in system capacity.

Claims

1. A method of staging a plurality of compressors in a refrigeration system comprising the steps of:

accumulating a first operative condition for each compressor;

accumulating a second operative condition for each compressor where the second operative condition is distinct from the first operative condition;

initiating operation of whichever compressor has the lowest accumulation of the first operative condition whenever a system controller calls for an increase in system capacity; and

terminating operation of whichever compressor has the greatest accumulation of the second operative condition whenever the system controller calls for a reduction in system capacity.

2. The method of claim 1 wherein the first operative condition is the number of compressor starts and the second operative condition is the compressor run time.

3. The method of claim 1 wherein the first operative condition is compressor run time, and the second operative condition is compressor starts.

4. A method of staging a plurality of compressors in a refrigeration system comprising the steps of:

accumulating the number of starts for each compressor;

accumulating the run time for each compressor;

initiating operation of whichever compressor has the lowest accumulation of starts whenever a system controller calls for an increase in system capacity; and

terminating operation of whichever compressor has the greatest accumulation of run time whenever the system controller calls for a reduction in system capacity.

5. A refrigeration system comprising:

a plurality of compressors; and

a system controller operatively connected to each of said plurality of compressors, said controller including;

means for accumulating a first operative condition for each compressor;

means for accumulating a second operative condition for each compressor where the second operative condition is distinct from the first operative condition;

means for initiating operation of whichever compressor has the lowest accumulation of the first operative condition whenever the system controller calls for an increase in system capacity; and

means for terminating operation of whichever compressor has the greatest accumulation of the second operative condition whenever the system controller calls for a reduction in system capacity.

6. The system of claim 5 wherein the first operative condition is the number of compressor starts and the second operative condition is the compressor run time.