Air conditioning unit control to reduce moisture varying operations

• US 20060100744A1
• Filed: 11/05/2004
• Published: 05/11/2006
• Est. Priority Date: 11/05/2004
• Status: Active Grant

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Bash, Cullen E., Sharma, Ratnesh K., Patel, Chandrakant D.
• Granted Patent: US 7,155,318 B2
• Time in Patent Office: Days
• US Class Current: 700/276
• CPC Class Codes: F24F 11/0008 for air-humidification F24F11/30 takes precedence
• CPC Class Codes: H05K 5/0212 Condensation eliminators
• CPC Class Codes: H05K 5/0213 Venting apertures; Constructional details thereof
• CPC Class Codes: H05K 7/20745 within rooms for removing heat from cabinets, e.g. by air conditioning device
• CPC Class Codes: H05K 7/20836 Thermal management, e.g. server temperature control
• CPC Class Codes: Y10S 165/90 Cooling towers

Abstract

In a method of operating an air conditioning unit to reduce moisture varying operations, psychrometric chart data is accessed. In addition, a constraint is set on the relationship between the temperature of air supplied by the air conditioning unit and the relative humidity of the air supplied based upon information contained in the psychrometric chart data. The air conditioning unit is controlled based upon the constraint to thereby reduce moisture varying operations of the air conditioning unit.

Claims

1. A method of operating an air conditioning unit to reduce moisture varying operations, said method comprising:

accessing psychrometric chart data;

setting a constraint on the relationship between the temperature of air supplied by the air conditioning unit and the relative humidity of the air supplied based upon information contained in the psychrometric chart data; and

operating the air conditioning unit based upon the constraint to thereby reduce moisture varying operations of the air conditioning unit.

2. The method according to claim 1, wherein the step of setting the constraint comprises setting a specific humidity level, and wherein the method further comprises:

detecting the temperature of air supplied by the air conditioning unit;

determining a relative humidity set point based upon a relationship between the temperature of the air and the specific humidity level from information contained in the psychrometric chart data; and

wherein the step of operating the air conditioning unit comprises operating the air conditioning unit substantially within the specific humidity level to thereby reduce moisture varying operations of the air conditioning unit.

3. The method according to claim 2, further comprising:

determining whether the relative humidity set point is outside of a predetermined range; and

setting the relative humidity set point in response to the relative humidity set point being inside of the predetermined range to substantially prevent the air conditioning unit from varying moisture content.

4. The method according to claim 3, wherein the predetermined range comprises a maximum relative humidity set point and a minimum relative humidity set point, said method further comprising:

decreasing the moisture content in the supplied air in response to the relative humidity set point exceeding the maximum relative humidity set point; and

increasing the moisture content in the supplied air in response to the relative humidity set point falling below the minimum relative humidity set point.

5. The method according to claim 3, wherein the predetermined range is between around 20% to 80% relative humidity.

6. The method according to claim 1, wherein the step of setting the constraint comprises defining relative humidity value bands for a plurality of supply air temperatures, said method further comprising:

detecting the temperature of air supplied by the air conditioning unit;

selecting the relative humidity band associated with the temperature of the air supplied;

detecting the relative humidity of the air supplied; and

determining whether the detected relative humidity is within the selected relative humidity band.

7. The method according to claim 6, further comprising:

determining whether the detected relative humidity exceeds a predetermined maximum allowable relative humidity in response to the detected relative humidity falling outside of the selected relative humidity band; and

wherein the predetermined maximum allowable relative humidity comprises an upper limit of the relative humidity band.

8. The method according to claim 7, further comprising:

decreasing the moisture content in the supplied air in response to the detected relative humidity exceeding the predetermined maximum allowable relative humidity; and

increasing the moisture content in the supplied air in response to the detected relative humidity falling below a predetermined minimum allowable relative humidity, wherein the predetermined minimum allowable relative humidity comprises a lower limit of the relative humidity band.

9. The method according to claim 1, further comprising:

determining a supply air temperature set point;

determining a relative humidity set point;

detecting the temperature of the intake air of the air conditioning unit;

calculating the energy consumption required to achieve the supply air temperature set point and the relative humidity set point based upon the detected intake air temperature; and

determining whether the required energy consumption exceeds a predetermined threshold.

10. The method according to claim 9, further comprising:

determining whether a first number of iterations exceeds a first predetermined maximum number of iterations in response to the required energy consumption exceeding the predetermined threshold;

determining a comfort region around the relative humidity set point from the psychrometric chart data in response to the first number of iterations falling below the first predetermined maximum number of iterations;

recalculating the relative humidity set point such that the recalculated relative humidity set point is within the comfort region;

recalculating the energy consumption required to achieve the recalculated relative humidity set point; and

determining whether the recalculated required energy consumption exceeds the predetermined threshold.

11. The method according to claim 10, further comprising:

determining whether a second number of iterations exceeds a second predetermined maximum number of iterations in response to the first number of iterations exceeding the first predetermined maximum number of iterations;

activating an alarm in response to the second number of iterations falling below the second predetermined maximum number of iterations;

recalculating the supply air temperature set point;

recalculating the energy consumption required to achieve the recalculated supply air temperature set point; and

determining whether the recalculated required energy consumption exceeds the predetermined threshold.

12. The method according to claim 11, further comprising:

raising a threshold cooling load of the air conditioning unit in response to the second number of iterations exceeding the second predetermined number of iterations.

13. A system for operating an air conditioning unit, said system comprising:

a temperature sensor configured to detect temperature around the air conditioning unit;

a controller configured to control a device for varying moisture content in the air supplied by the air conditioning unit;

a memory accessible by the controller, said memory storing psychrometric chart data;

wherein the controller sets a constraint on the relationship between the temperature of air supplied by the air conditioning unit and the relative humidity of the air supplied based upon information contained in the psychrometric chart data; and

wherein the controller operates the moisture varying device based upon the constraint to substantially reduce operations of the moisture varying device.

14. The system according to claim 13, wherein the controller includes a supply air temperature control module and a relative humidity control module, wherein the relative humidity control module is configured to control the moisture varying device.

15. The system according to claim 13, wherein the controller comprises a computing device configured to control a plurality of air conditioning units.

16. The system according to claim 13, wherein the temperature sensor is positioned to detect the temperature of air supplied by the air conditioning unit, and wherein the controller is configured to define a specific humidity level and to determine a relative humidity set point based upon a relationship between the temperature of the air and the predefined specific humidity level from information contained in the psychrometric chart data.

17. The system according to claim 16, wherein the controller is configured to vary the relative humidity set point to substantially prevent the moisture varying device from operating when the relative humidity set point is within a predetermined range comprised of a minimum relative humidity set point and a maximum relative humidity set point.

18. The system according to claim 13, wherein the temperature sensor is positioned to detect the temperature of air supplied by the air conditioning unit, and wherein the controller is configured to define relative humidity value bands for a plurality of supply air temperatures and to select the relative humidity value band associated with the air supply temperature detected by the temperature sensor.

19. The system according to claim 18, further comprising:

a sensor for detecting relative humidity in the air supplied by the air conditioning unit; and

wherein the controller is configured to determine whether the detected relative humidity is within the selected relative humidity band, and wherein the controller is configured to operate the moisture varying device based upon the detected relative humidity falling outside of the selected relative humidity band.

20. The system according to claim 13, wherein the controller is configured to determine a supply air temperature set point and a relative humidity set point, wherein the temperature sensor is configured to detect the temperature of air taken into the air conditioning unit, and wherein the controller is configured to calculate the energy consumption required to achieve the supply air temperature set point and the relative humidity set point based upon the detected intake air temperature.

21. The system according to claim 20, wherein the controller is further configured to determine a comfort region around the relative humidity set point from the psychrometric chart data and to recalculate the relative humidity set point such that the recalculated relative humidity set point is within the comfort region in response to the required energy consumption exceeding the predetermined threshold, to recalculate the energy consumption required to achieve the recalculated relative humidity set point, and to determine whether the recalculated required energy consumption exceeds the predetermined threshold.

22. The system according to claim 20, wherein the controller is configured to activate an alarm in response to the required energy consumption exceeding the predetermined threshold, to recalculate the supply air temperature set point, to recalculate the energy consumption required to achieve the recalculated supply air temperature, and to determine whether the recalculated energy consumption exceeds the predetermined threshold.

23. The system according to claim 22, wherein the controller is configured to raise a threshold cooling load of the air conditioning unit in response to the recalculated energy consumption exceeding the predetermined threshold.

24. An air conditioning unit configured to supply air, said air conditioning unit comprising:

a device for varying moisture content in the supplied air;

a memory storing psychrometric chart data;

a controller configured to set a constrain on the relationship between the temperature of the supplied air and the relative humidity of the supplied air based upon information contained in the psychrometric chart data; and

wherein the controller operates the moisture varying device based upon the constraint to substantially reduce energy consumption of the air conditioning unit in operating the device for varying moisture content.

25. The air conditioning unit according to claim 24, wherein the controller is configured to vary the relative humidity set point to substantially prevent the moisture varying device from operating when the relative humidity set point is within a predetermined range comprised of a minimum relative humidity set point and a maximum relative humidity set point.

26. The air conditioning unit according to claim 24, wherein the controller is configured to define relative humidity value bands for a plurality of supply air temperatures and to select the relative humidity value band associated with the air supply temperature detected by a temperature sensor, wherein the controller is further configured to determine whether a detected relative humidity is within the selected relative humidity band, and wherein the controller is configured to operate the moisture varying device based upon the detected relative humidity falling outside of the selected relative humidity band.

27. The air conditioning unit according to claim 24, wherein the controller is further configured to determine a supply air temperature set point and a relative humidity set point, wherein the controller is configured to calculate the energy consumption required to achieve the supply air temperature set point and the relative humidity set point based upon a detected intake air temperature, wherein the controller is further configured to determine a comfort region around the relative humidity set point from the psychrometric chart data and to recalculate the relative humidity set point such that the recalculated relative humidity set point is within the comfort region in response to the required energy consumption exceeding the predetermined threshold, to recalculate the energy consumption required to achieve the recalculated relative humidity set point, and to determine whether the recalculated required energy consumption exceeds the predetermined threshold.

28. A system for operating an air conditioning unit, said system comprising:

means for detecting temperature;

means for varying moisture content in air supplied by the air conditioning unit;

means for controlling the means for varying, wherein the means for controlling sets a constraint on the relationship between the temperature of air supplied by the air conditioning unit and the relative humidity of the air supplied based upon information contained in a psychrometric chart data, and wherein the means for controlling operates the means for varying based upon the constraint.

29. The system according to claim 28, wherein the means for controlling comprises:

means for controlling relative humidity in the supplied air; and

means for controlling temperature of the supplied air.

30. A computer readable storage medium on which is embedded one or more computer programs, said one or more computer programs implementing a method of operating an air conditioning unit to substantially reduce moisture varying operations, said one or more computer programs comprising a set of instructions for:

accessing psychrometric chart data;

setting a constraint on the relationship between the temperature of air supplied by the air conditioning unit and the relative humidity of the supplied air based upon information contained in the psychrometric chart data; and

operating the air conditioning unit based upon the constraint to thereby substantially reduce moisture varying operations of the air conditioning unit.

31. The computer readable storage medium according to claim 30, said one or more computer programs further comprising a set of instructions for:

detecting the temperature of air supplied by the air conditioning unit;

determining a relative humidity set point based upon the relationship between the temperature of the air and a specific humidity level from information contained in the psychrometric chart data; and

wherein the step of operating the air conditioning unit comprises operating the air conditioning unit substantially within the specific humidity level to thereby reduce moisture varying operations of the air conditioning unit.

32. The computer readable storage medium according to claim 31, said one or more computer programs further comprising a set of instructions for:

decreasing the moisture content in the supplied air in response to the relative humidity set point exceeding a maximum relative humidity set point; and

increasing the moisture content in the supplied air in response to the relative humidity set point falling below a minimum relative humidity set point.