SYSTEM AND METHOD FOR MONITORING OVERHEAT OF A COMPRESSOR

• US 20090090117A1
• Filed: 10/07/2008
• Published: 04/09/2009
• 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.
• Granted Patent: US 8,539,786 B2
• Time in Patent Office: Days
• US Class Current: 62/204
• CPC Class Codes: F25B 2500/19 Calculation of parameters
• CPC Class Codes: F25B 2600/02 Compressor control
• CPC Class Codes: F25B 2600/2513 Expansion valves
• CPC Class Codes: F25B 2700/171 of the compressor
• CPC Class Codes: F25B 2700/21151 at the suction side of the compressor
• CPC Class Codes: F25B 2700/2117 of an evaporator
• CPC Class Codes: F25B 2700/21174 of the refrigerant at the inlet of the evaporator
• CPC Class Codes: F25B 2700/21175 of the refrigerant at the outlet of the evaporator
• CPC Class Codes: F25B 41/34 with the valve member being actuated by electric means, e.g. by piezoelectric actuators
• CPC Class Codes: F25B 49/005 of safety devices F25B49/02 and F25B49/04 take precedence
• 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 system and method for monitoring an overheat condition of a compressor is provided. A compressor connected to an evaporator. A suction sensor outputs a suction signal corresponding to a temperature of refrigerant entering the compressor. A control module is connected to the evaporator sensor and the suction sensor and determines an evaporator temperature, calculates a suction superheat temperature based on the evaporator temperature and the suction signal, and monitors an overheat condition of the compressor by comparing the suction superheat with a predetermined suction superheat threshold.

Claims

1. A system comprising:

a compressor connected to an evaporator;

a suction sensor that outputs a suction signal corresponding to a temperature of refrigerant entering said compressor;

a control module connected to said evaporator sensor and said suction sensor that determines an evaporator temperature, that calculates a suction superheat temperature based on said evaporator temperature and said suction signal, that monitors an overheat condition of said compressor by comparing said suction superheat with a predetermined suction superheat threshold, and that adjusts at least one of a speed of said compressor and an expansion valve associated with said compressor based on said monitoring.

2. The system of claim 1 wherein said control module stops said compressor when said suction superheat is greater than said predetermined suction superheat threshold.

3. The system of claim 1 wherein said predetermined suction superheat threshold is fifty degrees Fahrenheit.

4. The system of claim 1 wherein said control module determines whether said suction superheat is within a predetermined suction superheat range, an upper limit of said predetermined suction superheat range corresponding with said predetermined suction superheat threshold.

5. The system of claim 4 wherein said predetermined suction superheat range is between thirty degrees Fahrenheit and fifty degrees Fahrenheit and wherein said predetermined suction superheat threshold is fifty degrees Fahrenheit.

6. The system of claim 4 wherein said control module adjusts said speed of said compressor when said control module determines that said suction superheat is within said predetermined suction superheat range for a predetermined time period.

7. A method comprising:

determining an evaporator temperature of an evaporator connected to a compressor;

receiving a suction signal that corresponds to a temperature of refrigerant entering said compressor;

calculating a suction superheat temperature based on said evaporator temperature and said suction signal;

monitoring an overheat condition of said compressor by comparing said suction superheat with a predetermined suction superheat threshold.

adjusting at least one of a speed of said compressor and an expansion valve associated with said compressor based on said monitoring.

8. The method of claim 7 further comprising stopping said compressor when said suction superheat is greater than said predetermined suction superheat threshold.

9. The method of claim 7 wherein said predetermined suction superheat threshold is fifty degrees Fahrenheit.

10. The method of claim 7 further comprising determining whether said suction superheat is within a predetermined suction superheat range, an upper limit of said predetermined suction superheat range corresponding with said predetermined suction superheat threshold.

11. The method of claim 10 wherein said predetermined suction superheat range is between thirty degrees Fahrenheit and fifty degrees Fahrenheit and wherein said predetermined suction superheat threshold is fifty degrees Fahrenheit.

12. The method of claim 10 further comprising adjusting said speed of said compressor when said suction superheat is within said predetermined suction superheat range for a predetermined time period.