System and method for evaluating parameters for a refrigeration system with a variable speed compressor

• US 8,448,459 B2
• Filed: 10/07/2008
• Issued: 05/28/2013
• Est. Priority Date: 10/08/2007
• Status: Active Grant

• Current Assignee: Copeland Corporation LLC (Emerson Electric Company)
• Original Assignee: Emerson Climate Technologies Incorporated (Emerson Electric Company)
• Inventors: McSweeney, Daniel L., Seibel, Stephen M.
• Primary Examiner(s): Tyler, Cheryl J
• Assistant Examiner(s): Gonzalez, Paolo
• Application Number:
  US12/247,020
• Publication Number:
  US 20090094998A1
• Time in Patent Office: 1,694 Days
• Field of Search: 621/27, 621/29, 622/08, 622/09, 622/30, 417/42, 417/44.11, 702/99
• US Class Current: 62/127
• CPC Class Codes: F25B 2500/19 Calculation of parameters
• CPC Class Codes: F25B 2600/021 Inverters therefor
• CPC Class Codes: F25B 2700/151 of the compressor motor
• CPC Class Codes: F25B 2700/195 of the condenser
• CPC Class Codes: F25B 2700/197 of the evaporator
• CPC Class Codes: F25B 2700/21152 at the discharge side of the compressor
• CPC Class Codes: F25B 2700/2116 of a condenser
• CPC Class Codes: F25B 2700/2117 of an evaporator
• CPC Class Codes: F25B 49/005 of safety devices F25B49/02 and F25B49/04 take precedence
• CPC Class Codes: G01K 2201/00 Application of thermometers in air-conditioning systems
• CPC Class Codes: G01K 7/42 Circuits effecting compensation of thermal inertia; Circuits for predicting the stationary value of a temperature
• CPC Class Codes: G05B 9/02 electric
• CPC Class Codes: Y02B 30/70 Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Abstract

A system and method for evaluating parameters for a refrigeration system having a variable speed compressor is provided. A compressor is connected to a condenser and an evaporator. A condenser sensor and an evaporator sensor are provided. An inverter drive modulates a frequency of electric power delivered to the compressor to modulate a speed of the compressor. A monitor module receives compressor power data and compressor speed data from the inverter drive, determines a measured condenser temperature based on the condenser signal, determines a measured evaporator temperature based on the evaporator signal, calculates a first derived condenser temperature based on the compressor power data and the compressor speed data, calculates a second derived condenser temperature based on the measured evaporator temperature, the compressor power data and the compressor speed data, and compares the measured condenser temperature with the first and second derived condenser temperatures to determine whether any of the measured condenser temperature and the first and second derived condenser temperatures are inaccurate.

Claims

1. A system comprising:

a compressor connected to a condenser and an evaporator;

a condenser sensor that outputs a condenser signal corresponding to at least one of a condenser pressure and a condenser temperature;

an evaporator sensor that outputs an evaporator signal corresponding to at least one of an evaporator pressure and an evaporator temperature;

an inverter drive that modulates a frequency of electric power delivered to said compressor to modulate a speed of said compressor;

a control module that receives compressor power data and compressor speed data from said inverter drive, determines a measured condenser temperature based on said condenser signal, determines a measured evaporator temperature based on said evaporator signal, calculates a first derived condenser temperature based on said compressor power data and said compressor speed data, calculates a second derived condenser temperature based on said measured evaporator temperature, said compressor power data and said compressor speed data, and compares said measured condenser temperature with said first and second derived condenser temperatures to determine whether any of said measured condenser temperature and said first and second derived condenser temperatures are inaccurate.

2. The system of claim 1 wherein said control module determines whether each of the first and second derived condenser temperatures and the measured condenser temperature are within a predetermined temperature range.

3. The system of claim 2 wherein when one of said first and second derived condenser temperatures and said measured condenser temperature are outside of said predetermined temperature range, said control module disregards said one of said first and second derived condenser temperatures and said measured condenser temperature.

4. The system of claim 3 wherein said control module generates an alarm when one of said first and second derived condenser temperatures and said measured condenser temperature are outside of said predetermined temperature range.

5. The system of claim 4 wherein said alarm indicates that at least one of said condenser sensor, said evaporator sensor, a discharge temperature sensor, a voltage sensor within said inverter drive, and a current sensor within said inverter drive are malfunctioning.

6. The system of claim 1 wherein said control module averages said first and second derived condenser temperatures and said measured condenser temperature.

7. A system comprising:

a compressor connected to a condenser and an evaporator;

a condenser sensor that outputs a condenser signal corresponding to at least one of a condenser pressure and a condenser temperature;

an evaporator sensor that outputs an evaporator signal corresponding to at least one of an evaporator pressure and an evaporator temperature;

a discharge temperature sensor that outputs a discharge temperature signal corresponding to a temperature of refrigerant exiting said compressor;

an inverter drive that modulates a frequency of electric power delivered to said compressor to modulate a speed of said compressor;

a control module that receives compressor power data and compressor speed data from said inverter drive, determines a measured condenser temperature based on said condenser signal, determines a measured evaporator temperature based on said evaporator signal, calculates a first derived evaporator temperature based on said compressor power data, said discharge temperature signal, and said compressor speed data, calculates a second derived evaporator temperature based on said measured condenser temperature, said compressor power data, said compressor speed data, and said discharge temperature signal, and compares said measured evaporator temperature with said first and second derived evaporator temperatures to determine whether any of said measured evaporator temperature and said first and second derived evaporator temperatures are inaccurate.

8. The system of claim 7 wherein said control module determines whether each of the first and second derived evaporator temperatures and the measured evaporator temperature are within a predetermined temperature range.

9. The system of claim 8 wherein when one of said first and second derived evaporator temperatures and said measured evaporator temperature are outside of said predetermined temperature range, said control module disregards said one of said first and second derived evaporator temperatures and said measured evaporator temperature.

10. The system of claim 9 wherein said control module generates an alarm when one of said first and second derived evaporator temperatures and said measured evaporator temperature are outside of said predetermined temperature range.

11. The system of claim 10 wherein said alarm indicates that at least one of said condenser sensor, said evaporator sensor, said discharge temperature sensor, a voltage sensor within said inverter drive, and a current sensor within said inverter drive are malfunctioning.

12. The system of claim 7 wherein said control module averages said first and second derived evaporator temperatures and said measured condenser temperature.

13. A method comprising;

receiving an evaporator signal corresponding to at least one of an evaporator pressure and an evaporator temperature corresponding to an evaporator connected to a condenser and a compressor;

receiving a condenser signal corresponding to at least one of a condenser pressure and a condenser temperature corresponding to said condenser;

receiving compressor power data and compressor speed data from an inverter drive that drives said compressor;

determining a measured condenser temperature based on said condenser signal;

determining a measured evaporator temperature based on said evaporator signal;

calculating a first derived condenser temperature based on said compressor data and said compressor speed data;

calculating a second derived condenser temperature based on said measured evaporator temperature, said compressor power data, and said compressor speed data;

comparing said measured condenser temperature with said first and second derived condenser temperatures to determine whether any of said measured condenser temperature and said first and second derived condenser temperatures are inaccurate.

14. The method of claim 13 determining whether each of the first and second derived condenser temperatures and the measured condenser temperature are within a predetermined temperature range.

15. The method of claim 13 further comprising, when one of said first and second derived condenser temperatures and said measured condenser temperature are outside of said predetermined temperature range, disregarding said one of said first and second derived condenser temperatures and said measured condenser temperature.

16. The method of claim 15 further comprising generating an alarm when one of said first and second derived condenser temperatures and said measured condenser temperature are outside of said predetermined temperature range.

17. The method of claim 16 wherein said alarm indicates that at least one of a condenser sensor, a evaporator sensor, a discharge temperature sensor, a voltage sensor within said inverter drive, and a current sensor within said inverter drive are malfunctioning.

18. The method of claim 13 further comprising averaging said first and second derived condenser temperatures and said measured condenser temperature.