Defrost Control Using Fan Data

• US 20140150477A1
• Filed: 11/30/2012
• Published: 06/05/2014
• Est. Priority Date: 11/30/2012
• Status: Active Grant

• Current Assignee: Lennox Industries Incorporated (Lennox International Incorporated)
• Original Assignee: Lennox Industries Incorporated (Lennox International Incorporated)
• Inventors: Qu, Yi, Havard, H. Gene, Douglas, Jon, Mangum, Jeff
• Granted Patent: US 9,341,405 B2
• Time in Patent Office: Days
• US Class Current: 62/80
• 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 11/41 Defrosting; Preventing freezing
• CPC Class Codes: F24F 11/42 of outdoor units
• CPC Class Codes: F25B 13/00 Compression machines, plants or systems, with reversible cycle defrosting cycles F25B47/02
• CPC Class Codes: F25B 2313/0294 related to the outdoor fan, e.g. controlling speed
• CPC Class Codes: F25B 2700/11 Sensor to detect if defrost is necessary
• CPC Class Codes: F25B 2700/15 Power, e.g. by voltage or current
• CPC Class Codes: F25B 2700/173 of the evaporator fan
• CPC Class Codes: F25B 2700/19 Pressures
• CPC Class Codes: F25B 2700/21174 of the refrigerant at the inlet of the evaporator
• CPC Class Codes: F25B 47/02 Defrosting cycles
• CPC Class Codes: F25D 17/06 by forced circulation
• CPC Class Codes: F25D 21/002 Defroster control
• CPC Class Codes: F25D 21/006 with electronic control circuits
• CPC Class Codes: F25D 21/02 Detecting the presence of frost or condensate

Abstract

In various implementations, frost in a vapor compression system may be controlled. A property of a fan may be determined. A determination may be made whether a frost event and/or a nonfrost event has occurred based at least partially on the determined fan property.

Claims

1. A method comprising:

determining one or more fan properties of a vapor compression system; and

determining if a frost event has occurred based at least partially on at least one of the determined fan properties.

2. The method of claim 1 further comprising allowing the heat pump to operate in response to a request.

3. The method of claim 1 wherein one or more of the fan properties comprises at least one of fan speed, air flow rate, external static pressure, input power, change in fan speed, change in air flow rate, change in external static pressure, or change in input power.

4. The method of claim 1 further comprising allowing the vapor compression system to operate in a defrost mode, if the frost event has been determined to have occurred.

5. The method of claim 1 further comprising determining an evaporator inlet temperature of the vapor compression system;

and wherein determining if a frost event has occurred is further based at least partially on the evaporator inlet temperature.

6. The method of claim 1 further comprising determining if a nonfrost event has occurred based at least partially on at least one of the properties of the fan.

7. The method of claim 6 wherein the nonfrost event comprises soiling of the coil.

8. The method of claim 1 further comprising determining at least one of evaporator inlet temperature or time;

and wherein determining if a frost event has occurred is further based at least partially on at least one of the determined evaporator inlet temperature or determined time.

9. The method of claim 1 further comprising comparing at least one of the determined properties to a predetermined property value;

and wherein determining if a frost event has occurred is based at least partially on the comparison of at least one of the determined properties to the predetermined property value.

10. A vapor compression system comprising:

a fan;

a sensor that measures one or more fan properties; and

a management module that determines whether a frost event has occurred at least partially based on one or more of the measured fan properties.

11. The system of claim 10 wherein the fan comprises an outdoor fan of an air conditioner.

12. The system of claim 10 wherein the fan comprises a fan of a refrigeration unit.

13. The system of claim 10 wherein the one or more fan properties comprises at least one of fan speed, air flow rate, external static pressure, input power, change in fan speed, change in air flow rate, change in external static pressure, or change in input power.

14. The system of claim 10 further comprising a memory storing one or more predetermined property values.

15. The system of claim 10 wherein the management module further allows a defrost operation if the frost event has occurred.

16. The system of claim 10 wherein the management module further determines if a nonfrost event has occurred based at least partially on one or more of the measured fan properties.

17. The system of claim 10 further comprising an additional sensor to measure an evaporator inlet temperature.

18. An article comprising machine-readable medium storing instructions for managing a vapor compression system, the instructions operable to cause data processing apparatus to perform operations comprising:

determining one or more fan properties of a vapor compression system;

determining if a frost event has occurred based at least partially on at least one of the determined fan properties; and

transmitting a signal to allow one or more defrost operations to occur if a frost event has occurred, wherein a defrost operation is configured to reduce accumulation of frost on at least a portion of the vapor compression system.

19. The article of claim 18 wherein the instructions are further operable to cause data processing apparatus to perform operations comprising:

determining if a nonfrost event has occurred based at least partially on at least one of the determined fan properties.

20. The article of claim 18 wherein the instructions are further operable to cause data processing apparatus to perform operations comprising:

determining at least one of evaporator inlet temperature or time, and

wherein determining if the frost event has occurred is at least partially based on at least one of the determined evaporator inlet temperature or time.