Zone system control

• US 5,829,674 A
• Filed: 09/15/1997
• Issued: 11/03/1998
• Est. Priority Date: 05/02/1997
• Status: Expired due to Term

• Current Assignee: Carrier Corporation (Carrier Global Corporation)
• Original Assignee: Carrier Corporation (Carrier Global Corporation)
• Inventors: Roher, Michael A., Vanostrand, William F., Werbowsky, Laurie L.
• Primary Examiner(s): WAYNER, WILLIAM E
• Application Number:
  US08/931,075
• Time in Patent Office: 414 Days
• Field of Search: 236/49.3, 236/51, 236/78 D, 165/217, 165/208, 165/209
• US Class Current: 236/49.3
• 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 11/64 using pre-stored data
• CPC Class Codes: F24F 11/65 for selecting an operating mode
• CPC Class Codes: F24F 11/74 for controlling air flow rate or air velocity
• CPC Class Codes: F24F 11/76 by means responsive to temperature, e.g. bimetal springs

Abstract

A device and method for controlling the conditioning of air in the zones of a forced air HVAC system. The device comprises thermostats located in at least two different zones, air ducts and dampers located therein to control the flow of air to the different zones. The microprocessor receives signals from the thermostats corresponding to perceived temperatures in the zones and compares the perceived temperatures to predetermined temperatures and determines a trajectory for each of the zones. The microprocessor in turn sends signals to the dampers corresponding to a positions between fully open and fully closed to control the amount of conditioned air through the ducts such that each of the zones follows the trajectory and reaches the predetermined temperatures at about the same time. The microprocessor further determines system demand and turns the HVAC system on and off in response to the system demand.

Claims

1. A control device for controlling an HVAC system, the HVAC system having an on cycle and an off cycle, at least two zones for conditioning the air in the least two enclosed spaces between a start temperature and a predetermined temperature, the control device comprising:

a control mechanism for each of the at least two zones operably connected to the HVAC system and capable of controlling the amount of conditioning to each zone between a fully open position and a fully closed position;

a temperature sensor capable of perceiving the temperature in the enclosed space of the at least two zones and capable of providing a signal corresponding to the perceived temperature;

a microprocessor operatively connected to receive the signals from the temperature sensors for comparing the perceived temperature to the predetermined temperature;

the microprocessor operative to determine a demand for each of the at least two zones and a trajectory between the start temperature and the predetermined temperature for each of the at least two zones; and

the microprocessor further operative to send a separate signal to each of the at least two control mechanisms corresponding to a position between fully opened and fully closed such that the temperature of each of the at least two zones follows the trajectory and such that each of the at least two zones reaches the predetermined temperature at about the same time.

2. A control device according to claim 1 wherein one of the at least two dampers is positioned in the fully open position.

3. A control device according to claim 1 wherein the sensors send a signal to the microprocessor at a predetermined time interval.

4. A control device according to claim 1 including a starting position for the dampers wherein the starting position is determined by a time weighted average of the position of the dampers during a previous on cycle of the HVAC system.

5. A control device according to claim 1 wherein the trajectory for each of the at least two zones is determined at a predetermined time interval by comparing the demands of each of the at least two zones with the demands of the at least two zones at the start temperature.

6. A control device for controlling an HVAC system, the HVAC system having an on cycle and an off cycle, a fan, at least two zones for conditioning the air in the least two enclosed spaces between a start temperature and a predetermined temperature, the at least two zones comprised of separate air ducts positioned to receive air from the fan and deliver to the enclosed spaces, the control device comprising:

a damper disposed within each of the at least two separate air ducts variably operable between a fully open position and a fully closed position;

a temperature sensor capable of perceiving the temperature in the enclosed space of the at least two zones and capable of providing a signal corresponding to the perceived temperature;

a microprocessor operatively connected to receive the signals from the temperature sensors for comparing the perceived temperature to the predetermined temperature;

the microprocessor operative to determine a demand for each of the at least two zones and a trajectory between the start temperature and the predetermined temperature for each of the at least two zones; and

the microprocessor further operative to send a separate signal to each of the at least two dampers corresponding to a position between fully opened and fully closed such that the temperature of each of the at least two zones follows the trajectory and such that each of the at least two zones reaches the predetermined temperature at about the same time.

7. A control device according to claim 6 wherein one of the at least two control mechanisms is positioned in the fully open position.

8. A control device according to claim 6 wherein the sensors send a signal to the microprocessor at a predetermined time interval.

9. A control device according to claim 6 including a starting position for the control mechanism wherein the starting position is determined by a time weighted average of the position of the dampers during a previous on cycle of the HVAC system.

10. A control device according to claim 6 wherein the trajectory for each of the at least two zones is determined at a predetermined time interval by comparing the demands of each of the at least two zones with the demands of the at least two zones at the start temperature.

11. A method of controlling an HVAC system, the HVAC system having a fan, at least two zones for conditioning the air of at least two enclosed spaces, the at least two zones comprised of separate air ducts positioned to receive air from the fan and deliver to the enclosed spaces, the method comprising the steps of:

setting the dampers at a predetermined start position;

sensing the temperature in the enclosed space;

comparing the sensed temperature with a desired temperature; and

controlling the positions of the dampers between fully open and fully closed to cause the temperature of the enclosed space of each of the at least two zones to reach the desired temperature at about the same time.

12. The method according to claim 11 wherein the setting step includes the step of determining the start position by a time weighted average of the position of the dampers during a previous on cycle of the HVAC system.

13. A method according to claim 11 the method further comprising:

the comparing step includes the step of calculating a trajectory for each of the at least two zones; and

the controlling step further includes the step of controlling the dampers to cause the temperature of the enclosed space to follow the trajectory.