Method and Apparatus for Equipment Health Monitoring

• US 20080027568A1
• Filed: 03/05/2007
• Published: 01/31/2008
• Est. Priority Date: 07/27/2006
• Status: Active Grant

• Current Assignee: Siemens Industry Incorporated (Siemens AG)
• Original Assignee: Siemens Industry Incorporated (Siemens AG)
• Inventors: Pearson, Scott Allan
• Granted Patent: US 7,536,276 B2
• Time in Patent Office: Days
• US Class Current: 700/80
• CPC Class Codes: G05B 23/0227 Qualitative history assessment, whereby the type of data acted upon, e.g. waveforms, images or patterns, is not relevant, e.g. rule based assessment; if-then decisions

Abstract

The present invention provides for monitoring the health of a system. In one embodiment, a method includes storing benchmark data in a memory, storing a second plurality of system data indicative of system conditions during system operations, determining from the second plurality of system data that the system was operating at a steady state capacity level during at least one sample window of the system operations, associating the steady state capacity level of the at least one sample window with the benchmark data, retrieving first health data for parameters associated with a first health condition from the first plurality of system data, retrieving second health data for parameters associated with the first health condition from the second plurality of system data that were obtained during the at least one sample window, comparing the health data and determining if the second health data is indicative of a health condition.

Claims

1. A method of monitoring the health of a system comprising:

storing a first plurality of system data associated with at least one steady state capacity level in a memory;

obtaining a second plurality of system data indicative of system conditions during system operations;

identifying from the second plurality of system data that the system was operating at a steady state capacity level during at least one sample window of the system operations;

associating the steady state capacity level of the at least one sample window with the at least one steady state capacity level;

retrieving first health data for parameters associated with a first health condition from the first plurality of system data;

retrieving second health data for parameters associated with the first health condition from the second plurality of system data that were obtained during the at least one sample window;

comparing the first health data with the second health data;

determining if the second health data is indicative of a health condition based upon the comparison; and

displaying the results of the determination.

2. The method of claim 1, wherein:

the at least one sample window comprises a plurality of sample windows; and

determining comprises;

determining, for one of the plurality of sample windows, the number of data of the second health data compared with first health data;

determining, for the one of the plurality of sample windows, the number of data of the second health data that indicate a health condition; and

determining that the second health data is indicative of a health condition for the one of the plurality of sample windows if the number of data of the second health data that were compared with first health data for the one of the plurality of sample windows is the same as the number of data of the second health data during the one of the plurality of sample windows that are indicative of a health condition.

3. The method of claim 1, wherein:

storing a first plurality of system data comprises storing, for each of a plurality of steady state capacity levels, an associated first plurality of system data;

identifying that the system was operating at a steady state capacity level during at least one sample window of the system operations comprises identifying that the system was operating at a steady state capacity level during a plurality of sample windows;

associating the steady state capacity level comprises associating the steady state capacity level of each of the plurality of sample windows with one of the plurality of steady state capacity levels;

retrieving first health data comprises retrieving first health data for parameters associated with a first health condition from the first plurality of system data for each of the associated one of the plurality of steady state capacity levels;

retrieving second health data comprises retrieving, for each of the plurality of sample windows, second health data for parameters associated with the first health condition from the second plurality of system data that were obtained during the respective one of the plurality of sample windows;

comparing comprises comparing, for each of the plurality of sample windows, the first health data with the second health data; and

determining comprises determining, for each of the plurality of sample windows, that the second health data is indicative of a health condition during a particular sample window of the plurality of sample windows if the number of data of the second health data that were compared with first health data for the particular sample window is the same as the number of data of the second health data during the particular sample window that are indicative of a health condition.

4. The method of claim 3, determining further comprising:

identifying the total number of the plurality of sample windows;

identifying the number of the plurality of sample windows indicative of a health condition; and

generating a percentage of the total number of the plurality of sample windows indicative of a health condition.

5. The method of claim 4, wherein generating a percentage comprises:

generating a percentage of the total number of the plurality of sample windows indicative of a health condition for each data interval of an analysis window.

6. The method of claim 5, wherein displaying comprises displaying the results of the determination in near real time.

7. The method of claim 5, further comprising:

providing an alert if the percentage exceeds an alert threshold; and

providing an alarm if the percentage exceeds an alarm threshold.

8. The method of claim 1, wherein storing a second plurality of system data indicative of system conditions during system operations comprises:

placing the system in a normal operating mode; and

storing the second plurality of system data indicative of system conditions during normal system operations.

9. The method of claim 1, further comprising:

obtaining the first plurality of system data associated with at least one steady state capacity level from design parameters for the system.

10. The method of claim 1, further comprising:

operating the system at the at least one steady state capacity level; and

obtaining the first plurality of system data while the system is operated at the at least one steady state capacity level.

11. The method of claim 1 wherein comparing comprises:

comparing, for each of the parameters associated with a first health condition, each of the second health data corresponding to the parameter with the first health data corresponding to the parameter.

12. The method of claim 11, wherein the first health condition comprises one of the group of health conditions consisting of:

noncondensables in a chiller system;

low refrigerant;

oil in an evaporator;

fouled condenser tubes;

fouled evaporator tubes;

low condenser water flow rate;

low chilled water flow rate;

water bypassing condenser tubes; and

water bypassing evaporator tubes.

13. A method of monitoring the health of a device comprising:

identifying a plurality of parameters associated with a first condition of the device;

establishing a plurality of first steady state operating conditions for the device, each of the plurality of steady state operating conditions at a capacity level of the device different from the capacity level of each of the other of the plurality of steady state operating conditions;

obtaining first data corresponding to the plurality of parameters during each of the plurality of first steady state operating conditions;

storing the first data;

obtaining second data corresponding to the plurality of parameters during at least one sample window during a steady state condition during normal operations of the device;

identifying the system capacity level during the at least one sample window;

associating the at least one sample window with one of the plurality of first steady state operating conditions based upon the identification;

comparing, for each of the plurality of parameters, the second data from the at least one sample window with the first data obtained during the associated one of the plurality of first steady state operating conditions;

determining the health of the device based upon the comparison; and

displaying the results of the determination.

14. The method of claim 13, wherein identifying a plurality of parameters comprises at least one of:

identifying a plurality of parameters associated with noncondensables in a chiller system;

identifying a plurality of parameters associated with low refrigerant;

identifying a plurality of parameters associated with oil in an evaporator;

identifying a plurality of parameters associated with fouled condenser tubes;

identifying a plurality of parameters associated with fouled evaporator tubes;

identifying a plurality of parameters associated with low condenser water flow rate;

identifying a plurality of parameters associated with low chilled water flow rate;

identifying a plurality of parameters associated with water bypassing condenser tubes; and

identifying a plurality of parameters associated with water bypassing evaporator tubes.

15. The method of claim 14, wherein identifying a plurality of parameters comprises:

identifying a plurality of parameters associated with noncondensables in a chiller system;

identifying a plurality of parameters associated with low refrigerant;

identifying a plurality of parameters associated with oil in an evaporator;

identifying a plurality of parameters associated with fouled condenser tubes;

identifying a plurality of parameters associated with fouled evaporator tubes;

identifying a plurality of parameters associated with low condenser water flow rate;

identifying a plurality of parameters associated with low chilled water flow rate;

identifying a plurality of parameters associated with water bypassing condenser tubes; and

identifying a plurality of parameters associated with water bypassing evaporator tubes.

16. The method of claim 13, wherein each of the plurality of first steady state operating conditions is established at a capacity level of the device different from the capacity level of each of the other of the plurality of first steady state operating conditions by at least about ten percent.

17. The method of claim 13, wherein the at least one sample window comprises a plurality of sample windows, the method further comprising:

obtaining a plurality of second data corresponding to the plurality of parameters during the plurality of sample windows;

identifying the system capacity levels during the plurality of sample windows;

associating each of the plurality of sample windows with one of the plurality of first steady state operating conditions based upon the identification of system capacity levels;

comparing, for each of the plurality of sample windows, the plurality of second data corresponding to the plurality of parameters with the first data obtained during the associated one of the plurality of first steady state operating conditions;

identifying the total number of the plurality of sample windows wherein the plurality of second data was compared with the first data;

identifying the number of the plurality of sample windows wherein the plurality of second data is indicative of a health condition based upon the comparison; and

generating a percentage of the total number of the plurality of sample windows indicative of a health condition.

18. The method of claim 17, further comprising:

providing an alert if the percentage exceeds an alert threshold; and

providing an alarm if the percentage exceeds an alarm threshold.

19. A system for monitoring the health of a system comprising:

a plurality of sensors for obtaining a plurality of data associated with at least one health condition of the system;

a memory for storing the plurality of data and for storing commands in the memory to

store, for each of a plurality of system capacity levels, first steady state data for a plurality of parameters associated with the at least one health condition of the system,

obtain normal operations data corresponding to the plurality of parameters during a plurality of sample windows during steady state conditions of the system,

associate the normal operations data with the first steady state data based upon a sample window system capacity level for each of the plurality of sample windows,

compare, for each of the plurality of parameters, the normal operations data with the associated first steady state data, and

display the results of the comparison; and

a processor for executing the commands.

20. The system of claim 19, wherein the at least one health condition of the system comprises one or more of:

noncondensables in a chiller system;

low refrigerant;

oil in an evaporator;

fouled condenser tubes;

fouled evaporator tubes;

low condenser water flow rate;

low chilled water flow rate;

water bypassing condenser tubes; and

water bypassing evaporator tubes.

21. The system of claim 19, further comprising:

a network operably connecting the plurality of sensors and the processor for communicating the plurality of data associated with the at least one health condition of the system to the processor.

22. The system of claim 19, wherein:

the commands in the memory for comparing comprise commands to

identify each of the plurality of sample windows wherein the total number of parameters compared is the same as the total number of parameters indicative of the at least one health condition, and

determine the percentage of the plurality of sample windows identified for a plurality of selected intervals; and

the commands in the memory for displaying comprise commands to

display, for a selected timeframe, the percentage of the plurality of sample windows identified for each of the plurality of selected intervals.