Method and system for controlling a heating, ventilating, and air conditioning unit

• US 6,250,382 B1
• Filed: 05/04/1999
• Issued: 06/26/2001
• Est. Priority Date: 05/04/1999
• Status: Expired due to Fees

• Current Assignee: York International Corporation (Johnson Controls International plc)
• Original Assignee: York International Corporation (Johnson Controls International plc)
• Inventors: Rayburn, Ronald R., Hughes, Neil A.
• Primary Examiner(s): Lazarus, Ira S.
• Assistant Examiner(s): Ciric, Ljiljana V.
• Application Number:
  US09/304,640
• Time in Patent Office: 784 Days
• Field of Search: 165/209, 165/217, 165/248, 165/249, 165/250, 165/251, 236/49.3, 454/256
• US Class Current: 165/248
• 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 11/62 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 11/76 by means responsive to temperature, e.g. bimetal springs
• CPC Class Codes: F24F 11/81 by controlling the air supply to heat-exchangers or bypass channels
• CPC Class Codes: F24F 11/84 using valves
• CPC Class Codes: F24F 11/86 by controlling compressors within refrigeration or heat pump circuits
• CPC Class Codes: F24F 2110/10 Temperature
• CPC Class Codes: F24F 2110/12 of the outside air
• CPC Class Codes: F24F 3/044 Systems in which all treatment is given in the central station, i.e. all-air systems

Abstract

A method and system for controlling a heating, ventilating, and air conditioning unit is provided. The system includes a conditioning unit having a heating stage, a cooling stage, and a fan. The conditioning unit operates in an active mode where one of the heating stage and the cooling stage is activated to condition air in an enclosure. The conditioning unit also operates in a ventilation mode to provide supply air to the enclosure. A supply temperature sensor is provided to sense the temperature of the supply air. A central control operates to activate one of the heating stage and the cooling stage when the conditioning unit is operating in the ventilation mode and the temperature of the supply air is outside of a predetermined range.

Claims

1. A system for conditioning air within one or more zones, comprising:

a conditioning unit having a heating stage, a cooling stage, and a fan, the fan selectively operable to move air through at least one of the heating and cooling stages and to provide supply air to the one or more zones;

an economizer operable to selectively supply variable amounts of outdoor air to the conditioning unit;

a supply temperature sensor exposed to the supply air to sense the temperature of the supply air;

an indoor temperature sensor exposed to the air in at least one of the one or more zones to sense the temperature of the air within the one or more zones; and

a central control coupled with said sensors, conditioning unit, and economizer, the control selectively operating at least one of the heating stage, the cooling stage, and the economizer when the sensed temperature of the air in the one or more zones is outside of a first predetermined temperature range and further selectively operating at least one of the heating stage, the cooling stage, and the economizer when the sensed temperature of the air in the one or more zones is within the first predetermined temperature range and the sensed temperature of the supply air is outside of a second predetermined temperature range.

2. The system of claim 1, further comprising an outdoor temperature sensor exposed to the outdoor air to sense the temperature of the outdoor air, and wherein the central control controls at least one of the economizer, heating stage, and cooling stage based on the sensed outdoor and supply air temperatures.

3. The system of claim 2, wherein the central control modulates the economizer to adjust the volume of outdoor air entering the conditioning unit based on the temperature of the supply air and the temperature of the outdoor air.

4. The system of claim 1, further comprising a return air duct for conducting return air from the enclosure to the conditioning unit.

5. The system of claim 1, wherein the conditioning unit is a constant-volume roof-top heating, ventilating and air conditioning unit.

6. The system of claim 1, wherein the conditioning unit includes a plurality of heating stages.

7. The system of claim 1, wherein the conditioning unit includes a plurality of cooling stages.

8. The system of claim 1, wherein the heating stage includes a hot water coil having a control valve.

9. The system of claim 1, further comprising a thermostat coupled to the main control and operable to set the first predetermined temperature range to be maintained within the one or more zones.

10. The system of claim 1, wherein the second predetermined temperature range includes an upper setpoint and a lower setpoint.

11. The system of claim 10, wherein the conditioning unit includes a plurality of heating stages and the central control activates at least one of the heating stages when the sensed temperature of the air in the one or more zones is within the first predetermined temperature range and the sensed temperature of the supply air is below the lower setpoint.

12. The system of claim 10, further comprising an outdoor temperature sensor exposed to the outdoor air to sense the temperature of the outdoor air, the central control modulating the economizer to increase the amount of outdoor air supplied to the conditioning unit when the sensed temperature of the air in the one or more zones is within the first predetermined temperature range, the sensed temperature of the supply air is above the upper setpoint, and the temperature of the outdoor air is below the lower setpoint.

13. The system of claim 12, wherein the central control modulates the economizer to increase the amount of outdoor air supplied to the conditioning unit until the temperature of the supply air is between the upper and lower setpoints.

14. The system of claim 10, wherein the conditioning unit includes a plurality of cooling stages and the central control activates at least one of the cooling stages when the sensed temperature of the air in the one or more zones is within the first predetermined temperature range and the sensed temperature of the supply air is above the lower setpoint.

15. The system of claim 10, further comprising an outdoor temperature sensor exposed to the outdoor air to sense the temperature of the outdoor air, the central control modulating the economizer to increase the amount of outdoor air supplied to the conditioning unit when the sensed temperature of the air in the one or more zones is within the first predetermined temperature range, the sensed temperature of the supply air is below the lower setpoint, and the temperature of the outdoor air is above the upper setpoint.

16. The system of claim 15, wherein the central control modulates the economizer to increase the amount of outdoor air supplied to the conditioning unit until the temperature of the supply air is between the upper and lower setpoints.

17. A system for conditioning air within one or more zones, comprising:

a conditioning unit having a heating stage and a fan, the fan selectively operable to move air through the heating stage to provide supply air to the one or more zones;

an economizer operable to selectively supply variable amounts of outdoor air to the conditioning unit;

a supply temperature sensor exposed to the supply air to sense the temperature of the supply air;

an indoor temperature sensor exposed to the air in at least one of the one or more zones to sense the temperature of the air within the one or more zones; and

a central control coupled with said sensors, conditioning unit, and economizer, the control selectively operating at least one of the heating stage and the economizer when the sensed temperature of the air in the one or more zones is outside a first predetermined temperature range and further selectively operating at least one of the heating stage and the economizer when the sensed temperature of the air in the one or more zones is within the first predetermined temperature range and the sensed temperature of the supply air is outside of a second predetermined temperature range.

18. The system of claim 17, further comprising a thermostat coupled to the main control and operable to set the first predetermined temperature range to be maintained within the one or more zones.

19. The system of claim 17, wherein the second predetermined temperature range includes an upper setpoint and a lower setpoint.

20. The system of claim 19, wherein the conditioning unit includes a plurality of heating stages and the central control activates at least one of the heating stages when the sensed temperature of the air in the one or more zones is within the first predetermined temperature range and the sensed temperature of the supply air is below the lower setpoint.

21. The system of claim 19, further comprising an outdoor temperature sensor exposed to the outdoor air to sense the temperature of the outdoor air, the central control modulating the economizer to increase the amount of outdoor air supplied to the conditioning unit when the sensed temperature of the air in the one or more zones is within the first predetermined temperature range, the sensed temperature of the supply air is above the upper setpoint, and the temperature of the outdoor air is below the lower setpoint.

22. The system of claim 21, wherein the central control modulates the economizer to increase the amount of outdoor air supplied to the conditioning unit until the temperature of the supply air is between the upper and lower setpoints.

23. The system of claim 19, wherein the heating stage includes a hot water coil.

24. A system for conditioning air within one or more zones, comprising:

a conditioning unit having a cooling stage and a fan, the fan selectively operable to move air through the cooling stage to provide supply air to the one or more zones;

an economizer operable to selectively supply variable amounts of outdoor air to the conditioning unit;

a supply temperature sensor exposed to the supply air to sense the temperature of the supply air;

an indoor temperature sensor exposed to the air in at least one of the one or more zones to sense the temperature of the air within the one or more zones; and

a central control coupled with said sensors, conditioning unit, and economizer, the control selectively operating at least one of the cooling stage and the economizer when the sensed temperature of the air in the one or more zones is outside a first predetermined temperature range and further selectively operating at least one of the cooling stage and the economizer when the sensed temperature of the air in the one or more zones is within the first predetermined temperature range and the sensed temperature of the supply air is outside of a second predetermined temperature range.

25. The system of claim 24, further comprising a thermostat coupled to the main control and operable to set the first predetermined temperature range to be maintained within the one or more zones.

26. The system of claim 24, wherein the second predetermined temperature range includes an upper setpoint and a lower setpoint.

27. The system of claim 26, wherein the conditioning unit includes a plurality of cooling stages and the central control activates at least one of the cooling stages when the sensed temperature of the air in the one or more zones is within the first predetermined temperature range and the sensed temperature of the supply air is above the lower setpoint.

28. The system of claim 26, further comprising an outdoor temperature sensor exposed to the outdoor air to sense the temperature of the outdoor air, the central control modulating the economizer to increase the amount of outdoor air supplied to the conditioning unit when the sensed temperature of the air in the one or more zones is within the first predetermined temperature range, the sensed temperature of the supply air is below the lower setpoint, and the temperature of the outdoor air is above the upper setpoint.

29. The system of claim 28, wherein the central control modulates the economizer to crease the amount of outdoor air supplied to the conditioning unit until the temperature of the supply air is between the upper and lower setpoints.