Method and apparatus for adjusting the temperature set point based on humidity level for increased comfort

• US 6,843,068 B1
• Filed: 07/25/2003
• Issued: 01/18/2005
• Est. Priority Date: 07/25/2003
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Wacker, Paul C.
• Primary Examiner(s): NORMAN, MARC E
• Application Number:
  US10/627,113
• Publication Number:
  US 20050017084A1
• Time in Patent Office: 543 Days
• Field of Search: 621/57, 621/761, 622/31, 165/222, 165/223, 165/237, 165/238, 165/239, 165/267, 236/44.C, 236/46.R
• US Class Current: 62/176.6
• 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 11/65 for selecting an operating mode
• CPC Class Codes: F24F 2110/20 Humidity

Abstract

Methods and apparatus for using humidity level to adjust the temperature set point of an HVAC system for increased occupant comfort. In one illustrative embodiment, the temperature set point for the inside space is moved downward when the humidity of the inside space rises above a predetermined humidity set point threshold value. In warm climates, this causes the air conditioner of the HVAC system to be activated, which lowers the temperature of the inside space to a new lower temperature set point. In some embodiments, the HVAC system retains the new lower temperature set point for a predetermined time period. The predetermined time period may be dependent on a number of factors, including whether the space is expected to occupied or unoccupied.

Claims

1. A method for controlling an air conditioner that is adapted to service an inside space, the method comprising the steps of:

identifying a temperature set point for the inside space;

identifying whether the inside space is expected to be occupied or unoccupied;

determining the humidity of the inside space;

determining if the humidity level of the inside space has risen above a predetermined upper humidity threshold level;

lowering the temperature set point for a first time period if the inside space is expected to be unoccupied;

lowering the temperature set point for a second time period if the inside space is expected to be occupied; and

wherein the first time period is shorter than the second time period.

2. The method of claim 1 wherein lowering of the temperature set point causes the humidity level of the inside space to drop.

3. The method of claim 2 further comprising the step of:

determining if the humidity level of the inside space has dropped below a predetermined lower humidity threshold level.

4. The method of claim 3 wherein, if the space is expected to be unoccupied, the first time period begins running when the humidity level of the inside space has dropped below the predetermined lower humidity threshold level.

5. The method of claim 4 wherein the first time period is approximately five minutes.

6. The method of claim 4 wherein, if the space is expected to be occupied, the second time period begins running when the humidity level of the inside space has dropped below the predetermined lower humidity threshold level.

7. The method of claim 6 wherein the second time period is approximately twenty minutes.

8. The method of claim 1 wherein, if the space is expected to be unoccupied, the first time period begins running when the humidity level of the inside space has risen above the predetermined upper humidity threshold level.

9. The method of claim 1 wherein, if the space is expected to be occupied, the second time period begins running when the humidity level of the inside space has risen above the predetermined upper humidity threshold level.

10. The method of claim 1 wherein the humidity level is a measure of relative humidity.

11. A system for controlling an air conditioner that is adapted to service an inside space, the system comprising:

means for storing a temperature set point for the inside space, an indication of whether the inside space is expected to be occupied or unoccupied, and a predetermined upper humidity threshold level;

one or more sensors for determining a humidity level in the inside space;

means for determining if the humidity level of the inside space has risen above the predetermined upper humidity threshold level; and

means for lowering the temperature set point for a first time period if the inside space is expected to be unoccupied, and for lowering the temperature set point for a second time period if the inside space is expected to be occupied, wherein the first time period is shorter than the second time period.

12. The system of claim 11 wherein the air conditioner causes the humidity level of the inside space to drop in response to lowering the temperature set point.

13. The system of claim 12 wherein said means for determining further determines if the humidity level of the inside space has dropped below a predetermined lower humidity threshold level.

14. The system of claim 13 wherein, if the space is expected to be unoccupied, the first time period begins running when the humidity level of the inside space has dropped below the predetermined lower humidity threshold level.

15. The system of claim 14 wherein the first time period is approximately five minutes.

16. The system of claim 14 wherein, if the space is expected to be occupied, the second time period begins ruling when the humidity level of the inside space has dropped below the predetermined lower humidity threshold level.

17. The system of claim 16 wherein the second time period is approximately twenty minutes.

18. The method of claim 11 wherein, if the space is expected to be unoccupied, the first time period begins running when the humidity level of the inside space has risen above the predetermined upper humidity threshold level.

19. The system of claim 11 wherein, if the space is expected to be occupied, the second time period begins running when the humidity level of the inside space has risen above the predetermined upper humidity threshold level.

20. The method of claim 11 wherein the humidity level is a measure of relative humidity.

21. A computer-readable medium having stored thereon a computer program for controlling an air conditioner that services an inside space which, when executed by a controller, is capable of performing the following steps reading a temperature set point for the inside space;

identifying whether the inside space is expected to be occupied or unoccupied;

reading a measure of the humidity of the inside space;

determining if the humidity level of the inside space has risen above a predetermined upper humidity threshold level;

lowering the temperature set point for a first time period if the inside space is expected to be unoccupied;

lowering the temperature set point for a second time period if the inside space is expected to be occupied; and

wherein the first time period is shorter than the second time period.