HVAC Systems

• US 20140158783A1
• Filed: 07/26/2012
• Published: 06/12/2014
• Est. Priority Date: 07/29/2011
• Status: Active Grant

• Current Assignee: Carrier Corporation (Carrier Global Corporation)
• Original Assignee: Carrier Corporation (Carrier Global Corporation)
• Inventors: Fan, Junqiang, Mijanovic, Stevo, Wang, Lishan
• Granted Patent: US 9,885,489 B2
• Time in Patent Office: Days
• US Class Current: 236/1.C
• CPC Class Codes: F24D 19/1039 the system uses a heat pump
• CPC Class Codes: F24D 19/1087 system using a heat pump
• 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 11/62 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 11/83 by controlling the supply of heat-exchange fluids to heat-exchangers
• CPC Class Codes: F24F 11/85 using variable-flow pumps
• CPC Class Codes: F24F 2110/10 Temperature
• CPC Class Codes: F24F 2140/00 Control inputs relating to system states
• CPC Class Codes: F25B 41/20 Disposition of valves, e.g. of on-off valves or flow control valves expansion valves F25B41/31
• CPC Class Codes: G05D 23/19 characterised by the use of electric means G05D23/1393 takes precedence

Abstract

A system includes a heat pump configured to match a working fluid'"'"'s temperature to a fluid temperature set-point, a fluid pump in fluid communication with the heat pump through the working fluid and configured to match the working fluid'"'"'s pressure/flow to a fluid pressure/flow set-point, at least one heat exchanger in fluid communication with the fluid pump, and a supervisory controller in signal communication with the at least one heat exchanger, the fluid pump, and the heat pump. The at least one heat exchanger includes a proportional valve and a return air temperature gauge configured to monitor return air temperature associated therewith. The supervisory controller is configured to vary the fluid temperature set-point and vary the fluid pressure/flow set-point based upon a position of the proportional valve and the return air temperature.

Claims

1. A system, comprising:

a heat pump, wherein the heat pump is configured to match a working fluid'"'"'s temperature to a fluid temperature set-point;

a fluid pump in fluid communication with the heat pump through the working fluid, wherein the fluid pump is configured to match the working fluid'"'"'s pressure to a fluid pressure set-point;

at least one heat exchanger in fluid communication with the fluid pump, wherein the at least one heat exchanger includes a proportional valve and a return air temperature gauge configured to monitor return air temperature associated therewith; and

a supervisory controller in signal communication with the at least one heat exchanger, the fluid pump, and the heat pump, wherein the supervisory controller is configured to vary the fluid temperature set-point and vary the fluid pressure set-point based upon a position of the proportional valve and the return air temperature.

2. The system of claim 1, wherein the fluid temperature set-point is a configurable default value varied by the supervisory controller.

3. The system of claim 1, wherein the fluid pressure set-point is a configurable default value varied by the supervisory controller.

4. The system of claim 1, wherein the at least one heat exchanger is a fan-coil unit.

5. The system of claim 1, further comprising a plurality of heat exchangers in communication with the fluid pump, wherein each heat exchanger of the plurality of heat exchangers includes a proportional valve and a return air temperature gauge configured to monitor return air temperature associated therewith.

6. The system of claim 5, wherein each heat exchanger of the plurality of heat exchangers is a fan-coil unit.

7. The system of claim 5, wherein the supervisory controller is configured to vary the fluid temperature set-point and vary the fluid pressure set-point based upon a weighted average value taken across all valve positions of each proportional valve of the plurality of heat exchangers and taken across all return air temperatures associated with the plurality of heat exchangers.

8. The system of claim 5, wherein the supervisory controller is a programmable processing apparatus configured to perform a method of HVAC system control, the method comprising:

monitoring valve positions of each proportional valve of the plurality of heat exchangers;

monitoring return air temperatures associated with each heat exchanger; and

calculating a weighted average value across the monitored positions and the monitored return air temperatures.

9. The system of claim 8, wherein the method further comprises determining a weighted valve position value for each proportional valve of the plurality of heat exchangers and determining a weighted temperature value for each return air temperature associated with the plurality of heat exchangers, wherein the weighted average value comprises an average of the weighted valve position values and the weighted temperature values.

10. The system of claim 9, wherein the method further comprises determining if the weighted average value is outside of a dead-band range associated with an average target valve position, and, if the weighted average value is outside of the dead-band range, determining a new fluid temperature set-point and a new fluid pressure set-point based upon the weighted average value.

11. A method of HVAC system control, the method comprising:

monitoring valve positions of proportional valves associated with individual heat exchangers of the HVAC system;

monitoring return air temperatures associated with the individual heat exchangers of the HVAC system;

determining a new fluid pressure set-point and a new fluid temperature pressure set-point for the HVAC system based upon the monitoring; and

providing the new fluid pressure set-point and the new fluid temperature set-point to the HVAC system.

12. The method of claim 11, further comprising:

calculating a weighted average value across the monitored positions and the monitored return air temperatures, wherein the new fluid pressure set-point and the new fluid temperature set-point are based upon the weighted average value.

13. The method of claim 11, further comprising:

determining a weight for each monitored valve position and each monitored return air temperature; and

calculating a weighted average value for the HVAC system across each determined weight, wherein the new fluid pressure set-point and the new fluid temperature set-point are based upon the weighted average value.

14. The method of claim 13, further comprising determining if the weighted average value is outside of a dead-band range associated with an average target valve position for the HVAC system, and providing the new fluid pressure set-point and the new fluid temperature set-point to the HVAC system if the weighted average value is outside of the dead-band range.

15. The method of claim 14, wherein the dead-band range is a range of average valve positions within a predefined acceptable set-point error range for the HVAC system.

16. The method of claim 15, wherein the predefined acceptable set-point error range is a range of variance between a desired return air temperature and actual return air temperature.

17. A system, comprising:

a heat pump, wherein the heat pump is configured to match a working fluid'"'"'s temperature to a fluid temperature set-point;

a fluid pump in fluid communication with the heat pump through the working fluid, wherein the fluid pump is configured to match the working fluid'"'"'s mass flow to a fluid mass flow set-point;

at least one heat exchanger arranged in a conditioned space and in fluid communication with the fluid pump, wherein the at least one heat exchanger includes a proportional valve and an air temperature gauge configured to monitor air temperature of the conditioned space; and

a supervisory controller in signal communication with the at least one heat exchanger, the fluid pump, and the heat pump, wherein the supervisory controller is configured to vary the fluid temperature set-point and vary the fluid mass flow set-point based upon a position of the proportional valve and the air temperature.