Method and system for evaluating the efficiency of an air conditioning apparatus

• US 7,349,824 B2
• Filed: 07/18/2005
• Issued: 03/25/2008
• Est. Priority Date: 05/15/2001
• Status: Expired due to Fees

• Current Assignee: Chillergy Systems, LLC
• Original Assignee: Chillergy Systems, LLC
• Inventors: Seigel, Lawrence J.
• Primary Examiner(s): WACHSMAN, HAL D
• Application Number:
  US11/183,582
• Publication Number:
  US 20050251293A1
• Time in Patent Office: 981 Days
• Field of Search: 702/130, 702/182, 702/35, 702/36, 702/50, 702/51, 702/105, 702/113, 702/114, 702/136, 702/138, 702/140, 702/187, 702/188, 702183-185, 700/26, 700275-278, 700/299, 700/300, 700/83, 417/63, 417/32, 417/53, 622/281, 621/29, 621/32, 62125-127, 622/31, 236/34, 236/910, 236/16, 236/46.R
• US Class Current: 702/182
• CPC Class Codes: F24F 11/30 for purposes related to the operation of the system, e.g. for safety or monitoring
• CPC Class Codes: F24F 11/47 Responding to energy costs

Abstract

The applicant describes a system and methods of calculating the overall operating efficiency of an air conditioning chiller that evaluates efficiency of the component parts of the chiller and generates an overall efficiency based on these component efficiency values. If the overall chiller efficiency is less than the maximum attainable chiller efficiency, the cost of the inefficiency is calculated and presented to the user. Recommendations for corrective action to restore maximum chiller efficiency are identified and presented to the user. The system also adjusts the efficiency calculations as appropriate to account for actual compressor current load conditions.

Claims

1. A method for evaluating the performance of an air conditioning chiller having a compressor and a plurality of components including a condenser and an evaporator, comprising the steps of:

A. receiving performance data for the compressor and each of the plurality of components;

B. for each of the plurality of components, calculating a component loss value using at least one of a plurality of relationships correlating performance data with an efficiency loss;

C. calculating a chiller loss value based on at least one of the component loss values; and

D. determining for each of the plurality of components whether that component has a significant effect upon air conditioning chiller efficiency by comparing the component loss value for that component to a component loss threshold value associated with that component.

2. The method of claim 1, further comprising the step of:

E. identifying at least one of the plurality of components that is reducing the efficiency of the air conditioning chiller.

3. The method of claim 2, further comprising the step of:

F. identifying at least one potential cause of the reduction in the efficiency of the air conditioning chiller identified in step D.

4. The method of claim 3, further comprising the step of

G. identifying a potential solution to the at least one potential cause of the reduction in efficiency of the air conditioning chiller identified in step E.

5. The method of claim 1, further comprising the step of:

E. performing steps A-C for a second air conditioning chiller that along with the air conditioning chiller defines a group of two or more monitored chillers.

6. The method of claim 1, further comprising the step of:

E. calculating an energy cost based on the chiller loss value calculated in step C.

7. The method of claim 1, further comprising the step of:

E. receiving a full load current of the compressor and a running current of the compressor;

F. receiving information sufficient to define an expected condenser approach; and

in which the performance data for the condenser comprises;

i. a condenser refrigerant temperature,

ii. a condenser outlet temperature; and

in which step B further comprises, calculating the component loss value for the condenser by performing steps comprising;

i. calculating a fractional current by dividing the running current of the compressor by a full load current of the compressor,

ii calculating a full load condenser approach by subtracting the condenser outlet temperature from the condenser refrigerant temperature and dividing the result by the fractional current,

iii. if the full load condenser approach is greater than the expected condenser approach, calculating a condenser approach difference by subtracting the expected condenser approach from the full load condenser approach, and

iv. multiplying the condenser approach difference by a condenser approach loss factor to result in the component loss value for the condenser.

8. The method of claim 7, in which the expected condenser approach is selected from the group consisting:

of an estimated condenser approach based on when the chiller was made and an optimal condenser approach.

9. The method of claim 1, further comprising the step of:

E. receiving information sufficient to define an optimal condenser pressure and;

in which the performance data for the condenser comprises a condenser pressure; and

in which step B further comprises, calculating the component loss value for the condenser by subtracting the optimal condenser pressure from the condenser pressure and multiplying the result by a non-condensables constant based upon the type of refrigerant used in the air conditioning chiller and the units in which condenser pressure is received.

10. The method of claim 1, further comprising the step of:

E. receiving information sufficient to define an optimal condenser pressure drop and;

in which the performance data for the condenser comprises;

i. an condenser inlet water pressure,

ii an condenser outlet water pressure,

iii. an condenser inlet water temperature,

iv. an condenser outlet water temperature, and

in which step B further comprises, calculating the component loss value for the condenser by;

i. subtracting condenser outlet water pressure from the condenser inlet water pressure to define an actual condenser water pressure difference,

ii. taking the square root of the ratio of the actual condenser water pressure difference to the optimal condenser water pressure drop to define a delta variance.

iii. subtracting the condenser inlet water temperature from the condenser outlet water temperature to define a condenser water temperature difference.

iv. subtracting delta variance from one and multiplying the result by the condenser water temperature difference to define a final variance.

v. multiplying the final variance by a condenser flow loss factor to result in the component loss value for the condenser.

11. The method of claim 1, further comprising the step of:

E. receiving a full load current of the compressor, a running current of the compressor, and an optimal evaporator approach; and

in which the performance data for the evaporator comprises;

i. an evaporator refrigerant temperature,

ii. a chill water outlet temperature,

in which step B further comprises, calculating the component loss value for the evaporator by performing steps comprising;

i. calculating a fractional current by dividing the running current of the compressor by a full load current of the compressor,

ii. calculating a full load evaporator approach by subtracting the chill water outlet temperature from the evaporator refrigerant temperature and dividing the result by the fractional current,

iii. if the full load evaporator approach is greater than the optimal evaporator approach, calculating a evaporator approach difference by subtracting the optimal evaporator approach from the full load evaporator approach, and

iv. multiplying the evaporator approach difference by a evaporator approach loss factor to result in the component loss value for the evaporator.

12. The method of claim 1, further comprising the step of reading instruments measuring condenser parameters and in which:

the receiving step comprises receiving the performance data for the condenser based upon the condenser parameters; and

steps B and C are performed by a computing device.

13. The method of claim 1, further comprising the step of reading instruments measuring condenser parameters and

in which the receiving step comprises receiving by a portable handheld device the performance data for the condenser based upon the condenser parameters, and further comprising the step of:

E. sending the performance data for the condenser to a computing device that performs steps B and C.

14. The method of claim 1, further comprising the steps of:

E. reading with a portable handheld device the performance data for the condenser from a plurality of sensors that measure at least one condenser parameter, and

F. sending the performance data for the condenser to a computing device and in which steps B and C are performed by the computing device.

15. The method of claim 1, and further comprising the step of storing the calculated chiller loss value.

16. The method of claim 1, and further comprising the step of outputting the calculated chiller loss value.

17. The method of claim 16, wherein the outputting step comprises outputting the calculated chiller loss value to a display device.

18. The method of claim 1, and further comprising the step of generating an output signal comprising a signal representative of the calculated chiller loss value.

19. A method of evaluating the performance of a condenser of an air conditioning chiller having a compressor, comprising the steps of:

A. receiving chiller data, comprising;

i. an expected condenser approach,

ii. a compressor running current,

iii. a full load compressor current,

iv. a condenser refrigerant temperature, and

v. a condenser outlet water temperature;

B. determining a condenser loss value by calculating;

i. a fractional current by dividing the compressor running current by a full load compressor current,

ii. a full load condenser approach by subtracting the condenser outlet water temperature from the condenser refrigerant temperature and dividing the result by the fractional current,

iii. a condenser approach difference if the full load condenser approach is greater than the expected condenser approach by subtracting the expected condenser approach from the full load condenser approach, and

iv. multiplying the condenser approach difference by a condenser approach loss factor to result in the condenser loss value.

20. The method of claim 19, in which the expected condenser approach is selected from the group consisting of an estimated condenser approach based on when the chiller was made and an optimal condenser approach.

21. The method of claim 19, further comprising the step of:

C. determining whether the condenser loss value represents a significant reduction in the efficiency of the air conditioning chiller by comparing the condenser loss value to a condenser loss threshold value.

22. The method of claim 19, further comprising the step of:

C. calculating an energy cost based on the condenser loss value determined in step B.

23. The method of claim 19, and further comprising the step of storing the determined condenser loss value.

24. The method of claim 19, and further comprising the step of outputting the determined condenser loss value.

25. The method of claim 24, wherein the outputting step comprises outputting the calculated condenser loss value to a display device.

26. The method of claim 19, and further comprising the step of generating an output signal comprising a signal representative of the condenser chiller loss value.

27. One or more computer readable media containing instructions that when executed by a computer perform the method of claim 19.

28. A system for evaluating the performance of an air conditioning chiller having a compressor and a plurality of components including a condenser and an evaporator, comprising:

A. means for receiving performance data for the compressor and each of the plurality of components;

B. means for calculating for each of the plurality of components a component loss value using at least one of a plurality of relationships correlating performance data with an efficiency loss;

C. means for calculating a chiller loss value based on at least one of the component loss values;

D. means for determining for each of the plurality of components whether the has significant effect air conditioning efficiency by comparing the component loss value for the component to a component loss threshold value associated with the component; and

E. means for identifying at least one of the plurality of components that is reducing the efficiency of the air conditioning chiller.