Patent Number: 
Section: claims

1. A computer implemented 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, wherein the memory is accessible by a building supervisory controller;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 normal operating level during at least one sample window of the system operations;associating the normal operating 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 by the building supervisory controller if the second health data is indicative of a health condition based upon the comparison; anddisplaying the results of the determination. 2. The method of claim 1, wherein: the at least one sample window comprises a plurality of sample windows; anddetermining 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; anddetermining 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 normal operating level comprises associating the normal operating 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; anddetermining 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; andgenerating 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; andproviding 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; andstoring 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; andobtaining 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.