Ventilation controller

• US 20060117769A1
• Filed: 12/07/2004
• Published: 06/08/2006
• Est. Priority Date: 12/07/2004
• Status: Active Grant

• Current Assignee: Trane International Inc. (Trane Technologies plc)
• Original Assignee: American Standard Companies Incorporated (Ideal Standard International Topco SCA)
• Inventors: Crawford, Roy R., Helt, Robert W.
• Granted Patent: US 8,702,482 B2
• Time in Patent Office: Days
• US Class Current: 62/161
• CPC Class Codes: F24F 11/0001 for ventilation F24F11/30 takes precedence
• 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 11/75 for maintaining constant air flow rate or air velocity
• CPC Class Codes: F24F 11/77 by controlling the speed of ventilators
• CPC Class Codes: F24F 2011/0006 using low temperature external supply air to assist cooling
• CPC Class Codes: F24F 2110/50 Air quality properties
• CPC Class Codes: F24F 2120/10 Occupancy
• CPC Class Codes: F24F 7/007 with forced flow using ducting systems F24F7/06
• CPC Class Codes: Y02B 30/70 Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Abstract

A ventilation system for a building in some cases includes a main HVAC blower for moving temperature-conditioned air through the building plus a smaller ventilation blower for providing fresh air. A controller regulates the ventilation blower'"'"'s speed to provide a target ventilation flow rate regardless of changes in the pressure differential between the indoor and outdoor air. To ensure that the target rate is appropriate for a particular building, the target flow rate is determined based on a ventilation setting that reflects a specified number of bedrooms and a specified amount of floor space of the building.

Claims

1. An HVAC system for a building that defines an outdoor area and an indoor area, the building includes a specified number of rooms and a specified amount of floor space, the HVAC system comprising:

a main blower for moving temperature-conditioned air through the building;

a ventilation blower for moving ventilation air between the outdoor area and the indoor area; and

a control system having an electrical output and a manual input, wherein the electrical output is operatively coupled to the ventilation blower for urging the ventilation blower to move the ventilation air at a target ventilation flow rate, wherein the target ventilation flow rate is based on a setup signal that is communicated to the controller via the manual input, wherein the setup signal is based on the specified number of rooms and the specified amount of floor space.

2. The HVAC system of claim 1, wherein the manual input includes a touchpad.

3. The HVAC system of claim 1, wherein the manual input includes an electrical switch.

4. The HVAC system of claim 1, wherein the manual input includes dial.

5. The HVAC system of claim 1, wherein the ventilation blower is smaller than the main blower.

6. The HVAC system of claim 1, wherein the control system regulates a rotational speed of the ventilation blower.

7. The ventilation system of claim 1, wherein the control system cycles the ventilation blower on and off to achieve the target ventilation flow rate as averaged over a predetermined period.

8. The ventilation system of claim 1, wherein the ventilation blower operates substantially independently of the main blower.

9. The ventilation system of claim 1, further comprising a thermostat that helps control the main blower, wherein the controller is electrically coupled to the thermostat.

10. The ventilation system of claim 9, wherein the thermostat and the controller share a common enclosure.

11. The ventilation system of claim 1, wherein the main blower draws air from a return air duct, and the ventilation blower moves air between the return air duct and the outdoor area.

12. The ventilation system of claim 1, wherein the main blower discharges air into a supply air duct, and the ventilation blower moves air between the supply air duct and the outdoor area.

13. The ventilation system of claim 1, wherein the ventilation blower discharges air into the indoor area.

14. The ventilation system of claim 1, wherein the ventilation blower discharges air into the outdoor area.

15. A ventilation system for a building that defines an indoor area and an outdoor area and includes a specified number of bedrooms, a specified amount of floor space, and an HVAC system, wherein the HVAC system includes a main blower capable of moving air at a rated maximum flow rate, the ventilation system comprising:

a ventilation blower driven by an electrical power to move air between the indoor area and the outdoor area at a ventilation flow rate that is regulated to achieve a target ventilation flow rate, wherein the target ventilation flow rate is less than the rated maximum flow rate of the main blower;

a motor drive unit that provides the electrical power in response to a command signal; and

a controller operatively connected to receive a setup signal and a flow rate signal, wherein the controller provides the command signal such that the command signal is at least partially determined by the setup signal and the flow rate signal, wherein the flow rate signal helps determine a perceived air flow rate provided by the ventilation blower, and the setup signal is based on at least one of the specified number of bedrooms and the specified amount of floor space.

16. The ventilation system of claim 15, wherein the ventilation flow rate is regulated by regulating a rotational speed of the ventilation blower.

17. The ventilation system of claim 15, wherein the ventilation flow rate is regulated by a pulse width modulation method, whereby the ventilation blower is cycled on and off at a duty cycle that achieves the target ventilation flow rate when averaged over a predetermined period.

18. The ventilation system of claim 15, wherein the flow rate signal is at least partially based on an electrical current of the electrical power and a perceived rotational speed of the ventilation blower.

19. The ventilation system of claim 18, wherein the perceived rotational speed is at least partially determined based on a frequency of the electrical power.

20. The ventilation system of claim 18, wherein the perceived rotational speed is at least partially determined based on a voltage of the electrical power.

21. The ventilation system of claim 15, further comprising a pressure sensor in fluid communication with the ventilation blower, wherein the flow rate signal is at least partially determined based on a pressure sensed by the pressure sensor.

22. The ventilation system of claim 15, wherein the setup signal is at least partially based on the specified number of bedrooms and the specified amount of floor space.

23. The ventilation system of claim 15, wherein the ventilation blower operates substantially independently of the main blower.

24. The ventilation system of claim 15, wherein the setup signal is manually inputted into the controller.

25. The ventilation system of claim 24, wherein the setup signal is manually inputted by way of a switch.

26. The ventilation system of claim 24, wherein the setup signal is manually inputted by way of a touchpad.

27. The ventilation system of claim 24, wherein the setup signal is manually inputted by way of a dial.

28. The ventilation system of claim 15, further comprising a thermostat that helps control the main blower, wherein the controller is electrically coupled to the thermostat.

29. The ventilation system of claim 28, wherein the thermostat and the controller share a common enclosure.

30. The ventilation system of claim 15, wherein the main blower draws air from a return air duct, and the ventilation blower moves air between the return air duct and the outdoor area.

31. The ventilation system of claim 15, wherein the main blower discharges air into a supply air duct, and the ventilation blower moves air between the supply air duct and the outdoor area.

32. The ventilation system of claim 15, wherein the ventilation blower discharges air into the indoor area.

33. The ventilation system of claim 15, wherein the ventilation blower discharges air into the outdoor area.

34. A method for ventilating a building that defines an indoor area and an outdoor area and includes a specified number of bedrooms, a specified amount of floor space, a ventilation blower, and an HVAC system with a main blower, the method comprising:

using the main blower for moving temperature-conditioned air through the building;

using the ventilation blower for moving ventilation air between the indoor area and the outdoor area;

determining a ventilation setting based on the specified number of bedrooms and the specified amount of floor space; and

operating the ventilation blower in response to the ventilation setting.

35. The method of claim 34, further comprising controlling the ventilation blower substantially independently of the main blower.

36. The method of claim 34, further comprising regulating a rotational speed of the ventilation blower to achieve a target ventilation flow rate that is based on the ventilation setting.

37. The method of claim 34, further comprising:

sensing a current draw of the ventilation blower;

determining a rotational speed of the ventilation blower;

determining a perceived ventilation flow rate of the ventilation blower based on the current draw and the rotational speed; and

regulating a rotational speed of the ventilation blower in response to the ventilation setting and the perceived ventilation flow rate.

38. The method of claim 34, further comprising cycling the ventilation blower on and off to achieve a target average ventilation flow rate that is based on the ventilation setting.

39. A ventilation system for a building that defines an outdoor area and an indoor area, the building includes a specified number of rooms and a specified amount of floor space, the ventilation system comprising:

a ventilation blower for moving ventilation air between the outdoor area and the indoor area; and

a controller operatively coupled to the ventilation blower such that the ventilation blower moves the ventilation air at an average target airflow rate that is substantially constant regardless of a moderate change in a static pressure differential between the outdoor area and the indoor area.

40. The ventilation system of claim 39, wherein the average target airflow rate is based on the specified number of rooms and the specified amount of floor space.

41. The ventilation system of claim 39, wherein the average target airflow rate is based on a certain occupancy level of the building.

42. The ventilation system of claim 39, wherein the control system regulates a rotational speed of the ventilation blower to maintain the average target airflow rate.

43. The ventilation system of claim 39, wherein the control system cycles the ventilation blower on and off at a duty cycle that helps achieve the average target airflow rate.

44. The ventilation system of claim 39, wherein the control system selectively operates the ventilation blower at a normal mode and an alternate mode such that the average target airflow rate occurs during the normal mode, and an alternate airflow rate occurs during the alternate mode, wherein the alternate airflow rate is distinguishable from the average target airflow rate.

45. The ventilation system of claim 44, wherein the alternate airflow rate is greater than the average target airflow rate.

46. The ventilation system of claim 44, wherein the alternate airflow rate is less than the average target airflow rate.

47. The ventilation system of claim 44, wherein the alternate airflow rate is substantially equal to zero.

48. The HVAC system of claim 39, wherein the controller includes an input for receiving a setup signal that is based on at least one of the specified number of rooms and the specified amount of floor space.

49. The ventilation system of claim 39, wherein the ventilation blower discharges air into the indoor area.

50. The ventilation system of claim 39, wherein the ventilation blower discharges air into the outdoor area.

51. The ventilation system of claim 39, further comprising an alarm signal for indicating when the ventilation blower may be failing to achieve the target ventilation flow rate.

52. The ventilation system of claim 51, wherein the alarm signal is triggered by a rotational speed of the ventilation blower reaching a certain limit.

53. A ventilation system for a building that defines an outdoor area and an indoor area, the ventilation system comprising:

a ventilation blower for moving ventilation air between the outdoor area and the indoor area; and

a controller operatively coupled to the ventilation blower to render the ventilation blower selectively operable in a normal mode and an alternate mode, such that;

i. in the normal mode, the ventilation blower moves the ventilation air at an average target airflow rate that is substantially constant regardless of a moderate change in a static pressure differential between the outdoor area and the indoor area, and

ii. in the alternate mode, the ventilation blower moves the ventilation air at a high-volume airflow rate that is greater than the average target airflow rate, wherein the high-volume airflow rate and may change in response to the moderate change in the static pressure differential between the outdoor area and the indoor area.

54. A ventilation system for a building that defines an outdoor area and an indoor area, the building includes a specified number of rooms and a specified amount of floor space, the ventilation system comprising:

a ventilation blower for moving ventilation air between the outdoor area and the indoor area; and

a control system having an output and an input, wherein the output is operatively coupled to the ventilation blower for urging the ventilation blower to move the ventilation air at a target ventilation flow rate, wherein the target ventilation flow rate is based on a setup signal that is communicated to the controller via the input, wherein the setup signal is based on the specified number of rooms and the specified amount of floor space.