Heat pump system having a maximum percent demand re-calculation algorithm controller

• US 10,215,464 B2
• Filed: 08/10/2017
• Issued: 02/26/2019
• Est. Priority Date: 03/05/2014
• Status: Active Grant

• Current Assignee: Lennox Industries Incorporated (Lennox International Incorporated)
• Original Assignee: Lennox Industries Incorporated (Lennox International Incorporated)
• Inventors: Goel, Rakesh, Berg, Eric, Hrejsa, Pete
• Primary Examiner(s): Bradford, Jonathan
• Application Number:
  US15/673,839
• Publication Number:
  US 20170336117A1
• Time in Patent Office: 565 Days
• 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 11/46 Improving electric energy efficiency or saving
• CPC Class Codes: F24F 11/52 Indication arrangements, e.g. displays
• CPC Class Codes: F24F 11/58 using Internet communication
• CPC Class Codes: F24F 11/62 characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or estimation of values
• CPC Class Codes: F24F 11/63 Electronic processing
• CPC Class Codes: F24F 11/77 by controlling the speed of ventilators
• CPC Class Codes: F24F 11/86 by controlling compressors within refrigeration or heat pump circuits
• CPC Class Codes: F24F 11/871 by controlling outdoor fans
• CPC Class Codes: F24F 2110/10 Temperature
• CPC Class Codes: F24F 2140/00 Control inputs relating to system states
• CPC Class Codes: F24F 2140/12 Heat-exchange fluid pressure
• CPC Class Codes: F24F 2140/50 Load
• CPC Class Codes: F25B 13/00 Compression machines, plants or systems, with reversible cycle defrosting cycles F25B47/02
• CPC Class Codes: F25B 2313/029 Control issues
• CPC Class Codes: F25B 2500/02 Increasing the heating capacity of a reversible cycle during cold outdoor conditions
• CPC Class Codes: F25B 2700/1931 Discharge pressures
• CPC Class Codes: F25B 2700/195 of the condenser
• CPC Class Codes: F25B 49/005 of safety devices F25B49/02 and F25B49/04 take precedence
• CPC Class Codes: F25B 49/02 for compression type machines, plants or systems

Abstract

One aspect presents a controller that comprises a control board, a microprocessor located on and electrically coupled to the control board, and a memory coupled to the microprocessor and located on and electrically coupled to the control board. The controller is configured to receive an operating parameter signal and recalculate a first maximum heating % demand to a second maximum heating % demand that is greater than the first maximum heating % demand, when a value of the operating parameter signal exceeds a predetermined value, and operate the HP system based on the second maximum heating % demand.

Claims

1. A method of operating a heat pump (HP) system, the method comprising:

operating, by a controller, the HP system based on a first maximum heating % demand;

determining, by the controller, whether an operating parameter signal indicates that a current heating % demand exceeds the first maximum heating % demand;

responsive to a determination that the operating parameter signal indicates that the current heating % demand exceeds the first maximum heating % demand, setting the first maximum heating % demand to a second maximum heating % demand and operating the HP system based on the second maximum heating % demand;

wherein the controller sets the first maximum heating % demand as follows;

first maximum heating % demand/% indoor airflow rate=A+{B×

((ODT_ref+C)/(ODT+D))^N}, wherein;

first maximum heating % demand is an initial maximum limit heating % demand of the HP system, ODT ref is a reference outdoor temperature in degrees Fahrenheit adjusted for a given HP system, ODT is the outdoor temperature in degrees Fahrenheit, % indoor airflow rate=indoor airflow rate/indoor airflow rate @100% heating demand, where indoor airflow rate is airflow output of an indoor system, and where A, B, C, D, and N are real numbers; and

wherein the controller sets the second maximum heating % demand as follows;

second maximum heating % demand/% indoor airflow rate=A+{B×

((ODT_ref+C)/(ODT+D))^N}, wherein;

second maximum heating % demand is the maximum heating % demand after recalculation of the first maximum heating % demand of the HP system, ODT_ref is a reference outdoor temperature in degrees Fahrenheit adjusted for a given HP system, ODT is the outdoor temperature in degrees Fahrenheit, % indoor airflow rate=indoor airflow rate/indoor airflow rate @100% heating demand, where indoor airflow rate is airflow output of the indoor system, and where A, B, C, D, and N are real numbers.

2. The method of claim 1, wherein the second maximum heating % demand value is greater than the first maximum heating % demand.

3. The method of claim 1, wherein the controller comprises:

a control board;

a microprocessor located on and electrically coupled to the control board; and

a memory coupled to the microprocessor and located on and electrically coupled to the control board and having a controller couplable to an operating parameter sensor associated with the indoor system or an outdoor system of the HP system.

4. The method of claim 3, further comprising:

incrementing, by the controller, a heating % demand towards the second maximum heating % demand when a discharge air temperature of the indoor system is equal to or less than a discharge air temperature set point of the indoor system.

5. The method of claim 1, further comprising:

testing, by the controller, operating parameters of the HP system at a set time interval and resetting operating parameters to operational settings of the HP system based on the first maximum heating % demand.

6. The method of claim 1, further comprising:

resetting the HP system to operational settings based on the first maximum heating % demand when an outdoor temperature reaches a predetermined value.

7. The method of claim 1, wherein the HP system, when operating based on the second maximum heating % demand, is configured to receive a refrigerant high pressure trip signal from a refrigerant high pressure trip sensor and recalculate the second maximum heating % demand to a third maximum heating % demand based on a current heating % demand existing when the controller receives the refrigerant high pressure trip signal and operate the HP system based on the third maximum heating % demand.

8. The method of claim 7, further comprising:

recalculating, by the controller, the third maximum heating % demand, wherein the recalculating is performed as follows;

Third maximum heating % demand=B×

current heating % demand at trip signal, wherein;

B is a real number having a value between zero and 1.

9. The method of claim 3, wherein the indoor system comprises an indoor heat exchanger equipped with an indoor blower.

10. The method of claim 9, wherein the outdoor system comprises an outdoor heat exchanger equipped with an outdoor fan.

11. The method of claim 10, wherein the indoor system and the outdoor system are fluidly coupled by a refrigerant tubing that forms a refrigerant system.

12. A heat pump (HP) system comprising:

a controller, wherein, prior to receiving a refrigerant high pressure trip signal from a refrigerant high pressure trip sensor, the controller is configured to;

operate the HP system based on a first maximum heating % demand;

determine whether an operating parameter signal indicates that a current heating % demand exceeds the first maximum heating % demand;

responsive to a determination that the operating parameter signal indicates that the current heating % demand exceeds the first maximum heating % demand, set the first maximum heating % demand to a second maximum heating % demand that is greater than the first maximum heating % demand and operate the HP system based on the second maximum heating % demand;

wherein the controller sets the first maximum heating % demand as follows;

first maximum heating % demand/% indoor airflow rate=A+{B×

((ODT_ref+C)/(ODT+D))^N}, wherein;

first maximum heating % demand is an initial maximum limit heating % demand of the HP system, ODT_ref is a reference outdoor temperature in degrees Fahrenheit adjusted for a given HP system, ODT is the outdoor temperature in degrees Fahrenheit, % indoor airflow rate=indoor airflow rate/indoor airflow rate @100% heating demand, where indoor airflow rate is airflow output of an indoor system, and where A, B, C, D, and N are real numbers; and

wherein the controller sets the second maximum heating % demand as follows;

second maximum heating % demand/% indoor airflow rate=A+{B×

((ODT_ref+C)/(ODT+D))^N}, wherein;

second maximum heating % demand is the maximum heating % demand after recalculation of the first maximum heating % demand of the HP system, ODT_ref is a reference outdoor temperature in degrees Fahrenheit adjusted for a given HP system, ODT is the outdoor temperature in degrees Fahrenheit, % indoor airflow rate=indoor airflow rate/indoor airflow rate @100% heating demand, where indoor airflow rate is airflow output of the indoor system, and where A, B, C, D, and N are real numbers selected such that the second maximum heating % demand value is greater than the first maximum heating % demand.

13. The HP system of claim 12, further comprising:

the indoor system comprising an indoor heat exchanger equipped with an indoor blower;

an outdoor system comprising an outdoor heat exchanger equipped with an outdoor fan, wherein the indoor system and the outdoor system are fluidly coupled by a refrigerant tubing that forms a refrigerant system;

an operating parameter sensor associated with at least one of the indoor system and the outdoor system; and

wherein the operating parameter sensor is configured to provide an operating parameter signal of at least one of the indoor system and the outdoor system.

14. The HP system of claim 13, wherein the controller is further configured to increment a heating % demand towards the second maximum heating % demand when a discharge air temperature of the indoor system is equal to or less than a discharge air temperature set point of the indoor system.

15. The HP system of claim 12, wherein the controller is configured to test operating parameters of the HP system at a set time interval and reset operating parameters of the HP system to operational settings based on the first maximum heating % demand.

16. The HP system of claim 12, wherein the controller is configured to reset the HP system to operational settings based on the first maximum heating % demand when an outdoor temperature reaches a predetermined value.

17. The HP system of claim 12, wherein the HP system, when operating based on the second maximum heating % demand, is further configured to receive the refrigerant high pressure trip signal from a refrigerant high pressure trip sensor and recalculate the second maximum heating % demand to a third maximum heating % demand based on a current heating % demand existing when the controller receives the refrigerant high pressure trip signal and operate the HP system based on the third maximum heating % demand.

18. The HP system of claim 17, wherein the controller recalculates the third maximum heating % demand, as follows:

Third maximum heating % demand=B×

current heating % demand at trip signal, wherein;

B is a real number having a value between zero and 1.