Granted Patent B2

US 11,187,425 · App. 16/565,464 · Granted Nov 30, 2021

Inventors: Robert J. Mowris (Olympic Valley, CA); John Walsh (Bozeman, MT)

F24F11/38F24F11/56F24F11/61F24F11/67F24F11/755F24F2140/40F24F2140/60

Abstract

Claims (50)

1. A method for controlling a Heating Ventilating Air Conditioning (HVAC) system fan with a thermostat, the method comprising:

at least one of:

cooling a conditioned space with an Air Conditioning (AC) compressor and the HVAC system fan until a drybulb temperature measurement of a Conditioned Space Temperature (CST) reaches a lower cooling differential used to end a thermostat call for cooling and providing a variable fan-off delay after the thermostat call for cooling has been satisfied to decrease the CST below the lower cooling differential, and

heating the conditioned space with a heater and the HVAC system fan until the CST reaches an upper heating differential used to end a heating on cycle and providing the variable fan-off delay after a heating on cycle to increase the CST above the upper heating differential; and

wherein the variable fan-off delay is ended based on comparing the CST to a CST variable fan-off delay threshold.

2. The method of claim 1 , wherein the CST variable fan-off delay threshold is a cooling fan-off delay differential offset from the lower cooling differential.

3. The method of claim 1 , wherein the CST variable fan-off delay threshold is a heating fan-off delay differential offset from the upper heating differential.

4. The method of claim 1 , wherein the CST variable fan-off delay threshold is a lower cooling differential, and the variable fan-off delay is ended when the drybulb temperature measurement of the CST during the variable fan-off delay crosses the lower cooling differential at least once after the thermostat call for cooling has been satisfied.

5. The method of claim 1 , wherein the CST variable fan-off delay threshold is an upper heating differential, and the variable fan-off delay is ended when the drybulb temperature measurement of the CST during the variable fan-off delay crosses the upper heating differential at least once after the end of the heating on cycle.

6. The method of claim 1 , further including at least one of:

the lower cooling differential used to turn off the AC compressor is less than or equal to a cooling setpoint; and

the upper heating differential used to turn off the heater is greater than or equal to a heating setpoint.

7. The method of claim 1 , wherein:

the lower cooling differential used to turn off the AC compressor is a lower variable cooling differential used to increase or decrease the duration of the thermostat call for cooling; and

the upper heating differential used to turn off the heater is an upper variable heating differential used to increase or decrease the heating on cycle.

8. A method for controlling a Heating Ventilating Air Conditioning (HVAC) system fan with a thermostat, the method comprising:

providing a variable fan-off delay after a cooling on cycle has ended or providing a variable fan-off delay after a heating on cycle has ended;

wherein the variable fan-off delay is ended based on comparing a drybulb temperature measurement of a Conditioned Space Temperature (CST) to a CST variable fan-off delay threshold;

wherein the CST variable fan-off delay threshold is based on a previous CST measurement monitored during the current variable fan-off delay; and

wherein the variable fan-off delay for cooling is ended when the CST increases above the previous CST measurement or the variable fan-off delay for heating is ended when the CST decreases below the previous CST measurement.

9. A method for controlling a Heating Ventilating Air Conditioning (HVAC) system fan with a thermostat, the method comprising:

providing a variable fan-off delay after a cooling on cycle has ended or providing a variable fan-off delay after a heating on cycle has ended;

wherein the variable fan-off delay is ended based on comparing a drybulb temperature measurement of a Conditioned Space Temperature (CST) to a CST variable fan-off delay threshold; and

wherein the CST variable fan-off delay threshold is an inflection point where the rate of change of the CST with respect to time (dT/dt) equals zero plus or minus a tolerance wherein the rate of change of the CST with respect to time is defined as a difference in temperature between at least two measurements of the CST divided by a difference in time between the at least two measurements of the CST.

10. A method for controlling a Heating Ventilating Air Conditioning (HVAC) system fan with a thermostat, the method comprising:

providing a variable fan-off delay after a cooling on cycle has ended or providing a variable fan-off delay after a heating on cycle has ended;

wherein the variable fan-off delay is ended based on comparing a drybulb temperature measurement of a Conditioned Space Temperature (CST) to a variable fan-off delay CST threshold;

wherein the variable fan-off delay duration is adjusted based on a duration of a cooling off cycle; and

wherein the variable fan-off delay duration is increased when the cooling off cycle duration is greater than a cooling on cycle duration or the variable fan-off delay duration is decreased when the cooling off cycle duration is less than the cooling on cycle duration.

11. A method for controlling a Heating Ventilating Air Conditioning (HVAC) system fan with a thermostat, the method comprising:

providing a variable fan-off delay after a cooling on cycle has ended or providing a variable fan-off delay after a heating on cycle has ended;

wherein the variable fan-off delay is ended based on comparing a drybulb temperature measurement of a Conditioned Space Temperature (CST) to a variable fan-off delay CST threshold; and

wherein the variable fan-off delay duration is decreased when the cooling off cycle duration is less than the cooling on cycle duration minus a tolerance based on a first coefficient times the cooling on cycle duration wherein the first coefficient varies as a function of the cooling on cycle duration.

12. A method for controlling a Heating Ventilating Air Conditioning (HVAC) system fan with a thermostat, the method comprising:

providing a variable fan-off delay after a cooling on cycle has ended or providing a variable fan-off delay after a heating on cycle has ended;

wherein the variable fan-off delay is ended based on comparing a drybulb temperature measurement of a Conditioned Space Temperature (CST) to a CST variable fan-off delay threshold;

wherein the variable fan-off delay duration is increased when the cooling off cycle duration is greater than the cooling on cycle duration plus a tolerance based on a second coefficient times the cooling on cycle duration wherein the second coefficient varies as a function of the cooling on cycle duration.

13. A method for controlling a Heating Ventilating Air Conditioning (HVAC) system fan with a thermostat, the method comprising:

providing a variable fan-off delay after a cooling on cycle has ended or providing a variable fan-off delay after a heating on cycle has ended;

wherein the variable fan-off delay is ended based on comparing a drybulb temperature measurement of a Conditioned Space Temperature (CST) to a CST variable fan-off delay threshold;

wherein the variable fan-off delay duration is adjusted based on a duration of a heating off cycle; and

wherein the variable fan-off delay duration is increased when the heating off cycle duration is greater than a heating on cycle duration or the variable fan-off delay duration is decreased when the heating off cycle duration is less than the heating on cycle duration.

14. A method for controlling a Heating Ventilating Air Conditioning (HVAC) system fan with a thermostat, the method comprising:

providing a variable fan-off delay after a cooling on cycle has ended or providing a variable fan-off delay after a heating on cycle has ended;

wherein the variable fan-off delay is ended based on comparing a drybulb temperature measurement of a Conditioned Space Temperature (CST) to a CST variable fan-off delay threshold; and

wherein the variable fan-off delay duration after the heating on cycle is decreased when the heating off cycle duration is less than the heating on cycle duration minus a tolerance based on a third coefficient times the heating on cycle duration wherein the third coefficient varies as a function of the heating on cycle duration.

15. A method for controlling a Heating Ventilating Air Conditioning (HVAC) system fan with a thermostat, the method comprising:

providing a variable fan-off delay after a cooling on cycle or providing a variable fan-off delay after a heating on cycle;

wherein the variable fan-off delay is ended based on comparing a drybulb temperature measurement of a Conditioned Space Temperature (CST) to a CST variable fan-off delay threshold; and

wherein the variable fan-off delay duration after the heating on cycle is increased when the previous heating off cycle duration is greater than the current heating on cycle duration plus a tolerance based on a fourth coefficient times the heating on cycle duration wherein the fourth coefficient varies as a function of the heating on cycle duration.

Assignments (1)

Continuity (13)