Thermostat device with improved energy optimization
A device such as a smart thermostat is provided for controlling heating and cooling systems. The device is operable to execute an energy control program to control the heating and a cooling systems based upon different control strategies: a first control strategy that compares the at least one temperature setpoint in the programming schedule to the current measured dry bulb temperature to determine whether to engage or disengage the heating and a cooling systems, and a second control strategy that compares the at least one temperature setpoint in the programming schedule to a normalized humidex temperature to determine whether to engage or disengage the heating and a cooling systems, the normalized humidex temperature being the current measured dry bulb temperature modified by historical humidity values to provide an indicator of thermal comfort within the premise.
1. A device for controlling at least one of a heating system and a cooling system within a premise, the device comprising:
a housing;
at least one relay within the housing, the at least one relay connected to the at least one of a heating system and a cooling system;
at least one environmental sensor within the housing, operable to measure the temperature and humidity within the premise;
memory, operable to store a programming schedule having at least one temperature setpoint and further operable to store current and historical temperature and humidity values provided by the at least one environmental sensor; and
a processor, connected to the at least one relay, the at least one environmental sensor and the memory, the processor being operable to execute an energy control program;
wherein the energy control program is operable to control the at least one of a heating system and a cooling system based upon one of the following control strategies:
a first control strategy that compares the at least one temperature setpoint in the programming schedule to the current measured dry bulb temperature to determine whether to engage or disengage the at least one of a heating system and a cooling system, and
a second control strategy that compares the at least one temperature setpoint in the programming schedule to a normalized humidex temperature to determine whether to engage or disengage the at least one of a heating system and a cooling system, the normalized humidex temperature being the current measured dry bulb temperature modified by historical humidity values to provide an indicator of thermal comfort within the premise and
wherein the energy control program uses the second control strategy when the memory contains historical humidity values covering a time period exceeding a time threshold, and uses the first control strategy when the memory contains historical humidity values covering a time period smaller than the time threshold.
2. The device of claim 1 , wherein the energy control program is automatically able to select between the first control strategy and the second control strategy based upon a user preference setting stored in the memory.
3. The device of claim 1 , wherein the energy control program is automatically able to select between the first control strategy and the second control strategy based upon a user preference setting stored in the memory, the user preference setting indicating whether the energy control program should optimize for energy savings or for user comfort.
4. The device of claim 1 , wherein the energy control program is operable to receive current measured temperature values from at least one remote sensor located elsewhere in the premise and calculate a modified measured temperature value using the current measured temperature value form the at least one environmental sensor and the at least one remote sensor.
5. The device of claim 1 , further comprising a display, and wherein the energy control program presents the current measured dry bulb temperature on the display when using the first control strategy and presents the normalized humidex temperature on the display when using the second control strategy.
6. The device of claim 1 , wherein the energy control program is operable to automatically select the first control strategy when the current measured humidity is below a threshold and the second control strategy when the current measured humidity is above the threshold.
7. The device of claim 1 , wherein the energy control program is operable to automatically select the first control strategy when the current measured humidity is above a threshold and the second control strategy when the current measured humidity is below the threshold.
8. The device of claim 1 , wherein the energy control program is operable to modify the difference between the normalized humidex temperature and the current measured dry bulb temperature based upon a user preference setting stored in the memory.
9. The device of claim 1 , wherein the energy control program is operable to automatically adapt and modify the difference between the normalized humidex temperature and the current measured dry bulb temperature based upon user overrides of the temperature setpoint stored in the programming schedule.
10. The device of claim 1 , further including an occupancy sensor, the occupancy sensor being operable to provide an occupancy value, and wherein the energy control program is operable to automatically switch between the first control strategy and the second control strategy based upon the occupancy value.
11. The device of claim 1 , the device being operable to receive an occupancy value from at least one remote sensor, and wherein the energy control program is operable to automatically switch between the first control strategy and the second control strategy based upon the occupancy value.
12. The device of claim 1 , the device further being operable to receive a geofence signal from a remote device located within the premise, the geofence signal being operable to provide an occupancy value, and wherein the energy control program is operable to automatically switch between the first control strategy and the second control strategy based upon the occupancy value.
13. The device of claim 1 , wherein the energy control program includes a user preference for a savings setting that when the savings setting is activated, the energy control program engages the at least one of the heating system and the cooling system only when both of the first control strategy and the second control strategy indicate that the at least one of the heating system and the cooling system should be engaged.
14. The device of claim 1 , wherein the second control strategy for cooling the premise comprises: calculating a humidex temperature, the humidex temperature being the current
measured dry bulb temperature modified by the current humidity values, calculating a humidex setpoint temperature, the humidex setpoint temperature being the current setpoint from the programming schedule modified by the historical humidity value, and engaging the at least one of the heating system and the cooling system when the humidex temperature is greater than the humidex setpoint temperature.
15. The device of claim 1 , wherein the second control strategy for cooling the premise comprises: calculating a humidex temperature, the humidex temperature being the current measured dry bulb temperature modified by the current humidity values, calculating a humidex setpoint temperature, the humidex setpoint temperature being the current setpoint from the programming schedule modified by the historical humidity value, and engaging the at least one of the heating system and the cooling system when the humidex temperature is greater than the humidex setpoint temperature plus a humidex differential.