Smart thermostat for ductless HVAC units
A system and method for intelligent operation and control of ductless HVAC devices in a manner similar to existing intelligent operation and control of central HVAC systems. In an embodiment, the system and method include using a smart thermostat to separately monitor the room temperature of a room in which a ductless HVAC device is installed, wherein the smart thermostat overrides the standard operation of the HVAC device by setting and re-setting the target temperature of the ductless HVAC device to force it to operate according to settings and algorithms of the smart thermostat which mimic the smart controls available on central HVAC systems.
1 . A smart thermostat for operation and control of a ductless heating, ventilation, and air conditioning (HVAC) device, the smart thermostat comprising a memory, a processor, a temperature sensor, an infrared emitter, and a first plurality of programming instructions stored in the memory which, when operating on the processor, causes the smart thermostat to:
monitor, using the temperature sensor, a room temperature of a room in which the smart thermostat is located;
when the room temperature rises above an upper threshold temperature of a temperature range, emit a first infrared control signal from the infrared emitter, the first infrared control signal comprising instructions for the ductless HVAC device to lower its target temperature to a first target temperature value; and
when the room temperature falls below a lower threshold temperature of the temperature range, emit a second infrared control signal from the infrared emitter, the second infrared control signal comprising instructions for the ductless HVAC device to raise its target temperature to a second target temperature value.
2 . The smart thermostat of claim 1 , wherein the smart thermostat is further programmed to:
after emission of the first infrared control signal:
determine a first rate of change in the room temperature in response to the emission; and
when the first rate of change indicates that the room temperature is decreasing, but below a first rate of change threshold, emit a third infrared control signal from the infrared emitter, the third infrared control signal comprising instructions for the ductless HVAC device to lower its target temperature further to a third target temperature value; and
after emission of the second infrared control signal:
determine the first rate of change in the room temperature in response to the emission; and
when the first rate of change indicates that the room temperature is increasing, but below a second rate of change threshold, emit a fourth infrared control signal from the infrared emitter, the fourth infrared control signal comprising instructions for the ductless HVAC device to raise its target temperature further to a fourth target temperature value.
3 . The smart thermostat of claim 2 , wherein the smart thermostat is further programmed to:
after emission of the third infrared control signal:
determine a second rate of change in the room temperature in response to the emission; and
when the second rate of change indicates that the room temperature is decreasing, but below a second rate of change threshold, emit a fifth infrared control signal from the infrared emitter, the fifth infrared control signal comprising instructions for the ductless HVAC device to lower its target temperature further to a fifth target temperature value; and
after emission of the fourth infrared control signal:
determine the second rate of change in the room temperature in response to the emission; and
when the second rate of change indicates that the room temperature is increasing, but below the second rate of change threshold, emit a sixth infrared control signal from the infrared emitter, the sixth infrared control signal comprising instructions for the ductless HVAC device to raise its target temperature to a sixth target temperature value.
4 . The smart thermostat of claim 1 , wherein the smart thermostat is further programmed to:
after emission of the first infrared control signal:
determine a third rate of change in the room temperature in response to the emission; and
when the room temperature approaches the lower threshold temperature of the temperature range, emit a seventh infrared control signal from the infrared emitter, the seventh infrared control signal comprising instructions for the ductless HVAC device to raise its target temperature to a seventh target temperature value to slow the third rate of change in the room temperature to a fourth rate of change; and
after emission of the second infrared control signal:
determine the third rate of change in the room temperature in response to the emission; and
when the room temperature approaches the upper threshold temperature of the temperature range, emit an eighth infrared control signal from the infrared emitter, the eighth infrared control signal comprising instructions for the ductless HVAC device to lower its target temperature to an eighth target temperature value to slow the third rate of change in the room temperature to the fourth rate of change.
5 . The smart thermostat of claim 4 , wherein the smart thermostat is further programmed to:
based on first target temperature value, the seventh target temperature value, the third rate of change, and the fourth rate of change, calculate subsequent target temperatures to force the ductless HVAC device to operate at a pre-defined duty cycle when cooling the room temperature.
6 . The smart thermostat of claim 4 , wherein the smart thermostat is further programmed to:
based on second target temperature value, the eighth target temperature value, the third rate of change, and the fourth rate of change, calculate subsequent target temperatures to force the ductless HVAC device to operate at a pre-defined duty cycle when heating the room temperature.
7 . The smart thermostat of claim 1 , wherein the smart thermostat is further programmed to:
after emission of either the first infrared control signal or the second infrared control signal, determine a change in the room temperature in response to the emission, and calculate a differential between the room temperature as indicated by the temperature sensor and a second temperature sensor of the ductless HVAC device.
8 . The smart thermostat of claim 7 , wherein the smart thermostat is further programmed to:
apply the differential between the room temperature as indicated by the temperature sensor and a second temperature sensor of the ductless HVAC device when making further changes to the target temperature.
9 . A method for operation and control of a ductless heating, ventilation, and air conditioning (HVAC) device by a smart thermostat, comprising:
using a smart thermostat comprising a memory, a processor, a temperature sensor, an infrared emitter, and a first plurality of programming instructions to:
monitor, using the temperature sensor, a room temperature of a room in which the smart thermostat is located;
based on the room temperature rising above an upper threshold temperature of a temperature range, emit a first infrared control signal from the infrared emitter, the first infrared control signal comprising instructions for the ductless HVAC device to lower its target temperature to a first target temperature value; and
based on the room temperature falling below a lower threshold temperature of the temperature range, emit a second infrared control signal from the infrared emitter, the second infrared control signal comprising instructions for the ductless HVAC device to raise its target temperature to a second target temperature value.
10 . The method of claim 9 , further comprising using the smart thermostat to:
after emission of the first infrared control signal:
determine a first rate of change in the room temperature in response to the emission; and
based on the first rate of change indicating that the room temperature is decreasing, but below a first rate of change threshold, emit a third infrared control signal from the infrared emitter, the third infrared control signal comprising instructions for the ductless HVAC device to lower its target temperature further to a third target temperature value; and
after emission of the second infrared control signal:
determine the first rate of change in the room temperature in response to the emission; and
based on the first rate of change indicating that the room temperature is increasing, but below a second rate of change threshold, emit a fourth infrared control signal from the infrared emitter, the fourth infrared control signal comprising instructions for the ductless HVAC device to raise its target temperature further to a fourth target temperature value.
11 . The method of claim 10 , further comprising of using the smart thermostat to:
after emission of the third infrared control signal:
determine a second rate of change in the room temperature in response to the emission; and
based on the second rate of change indicating that the room temperature is decreasing, but below a second rate of change threshold, emit a fifth infrared control signal from the infrared emitter, the fifth infrared control signal comprising instructions for the ductless HVAC device to lower its target temperature further to a fifth target temperature value; and
after emission of the fourth infrared control signal:
determine the second rate of change in the room temperature in response to the emission; and
based on the second rate of change indicating that the room temperature is increasing, but below the second rate of change threshold, emit a sixth infrared control signal from the infrared emitter, the sixth infrared control signal comprising instructions for the ductless HVAC device to raise its target temperature to a sixth target temperature value.
12 . The method of claim 9 , further comprising using the smart thermostat to:
after emission of the first infrared control signal:
determine a third rate of change in the room temperature in response to the emission; and
based on the room temperature approaching the lower threshold temperature of the temperature range, emit a seventh infrared control signal from the infrared emitter, the seventh infrared control signal comprising instructions for the ductless HVAC device to raise its target temperature to a seventh target temperature value to slow the third rate of change in the room temperature to a fourth rate of change; and
after emission of the second infrared control signal:
determine the third rate of change in the room temperature in response to the emission; and
based on the room temperature approaching the upper threshold temperature of the temperature range, emit an eighth infrared control signal from the infrared emitter, the eighth infrared control signal comprising instructions for the ductless HVAC device to lower its target temperature to an eighth target temperature value to slow the third rate of change in the room temperature to the fourth rate of change.
13 . The method of claim 12 , further comprising using the smart thermostat to:
based on the first target temperature value, the seventh target temperature value, the third rate of change, and the fourth rate of change, calculate subsequent target temperatures to force the ductless HVAC device to operate at a pre-defined duty cycle as the ductless HVAC device cools the room temperature.
14 . The method of claim 12 , further comprising using the smart thermostat to:
based on the second target temperature value, the eighth target temperature value, the third rate of change, and the fourth rate of change, calculate subsequent target temperatures to force the ductless HVAC device to operate at a pre-defined duty cycle the ductless HVAC device heats the room temperature.
15 . The method of claim 9 , further comprising using the smart thermostat to:
after emission of either the first infrared control signal or the second infrared control signal, determine a change in the room temperature in response to the emission, and calculate a differential between the room temperature as indicated by the temperature sensor and a second temperature sensor of the ductless HVAC device.
16 . The method of claim 15 , further comprising using the smart thermostat to:
apply the differential between the room temperature as indicated by the temperature sensor and a second temperature sensor of the ductless HVAC device based on further changes to the target temperature being made.