Context adaptive cool-to-dry feature for HVAC controller

Patent metadata

Field	Value
Publication number	US-9696735-B2
Application number	US-201313871746-A
Country	US
Kind code	B2
Filing date	Apr 26, 2013
Priority date	Apr 26, 2013
Publication date	Jul 4, 2017
Grant date	Jul 4, 2017

Abstract

A thermostat and a method include using occupancy sensors, temperature sensors, and humidity sensors to control activation of a cooling function of an HVAC system to dehumidify an enclosure. During times when the enclosure is occupied, the cooling function is activated when the humidity exceeds a first threshold humidity, and continues until the humidity drops below a second threshold humidity or the temperature drops below a first threshold temperature. During times when the enclosure is unoccupied, the cooling function is activated when the humidity exceeds a third threshold humidity, and continues until the humidity drops below a fourth threshold humidity or the temperature drops below a second threshold temperature.

First claim

What is claimed is:

1. A thermostat, comprising:
a housing;
a user interface;
one or more temperature sensors, each of the one or more temperature sensors being configured to provide temperature sensor measurements;
a humidity sensor configured to provide humidity sensor measurements of humidity inside an enclosure in which the thermostat is installed;
an occupancy sensing system that characterizes an occupancy status of the enclosure in which the thermostat is installed from among a plurality of possible occupancy statuses including an occupied state and an away state; and
a processing system disposed within the housing, the processing system being configured to be in operative communication with the one or more temperature sensors to receive the temperature sensor measurements, in operative communication with one or more input devices including said user interface for determining a setpoint temperature, and in still further operative communication with a heating, ventilation, and air conditioning (HVAC) system to control the HVAC system based at least in part on the setpoint temperature and the temperature sensor measurements;
wherein said processing system is further configured to operate in conjunction with said occupancy sensing system to:
during a first time interval during which the occupancy sensing system characterizes the occupancy status of the enclosure as being in the occupied state:
determine that the humidity sensor measurements exceed a first threshold humidity; and
activate, in response to determining that the humidity sensor measurements exceed the first threshold humidity, a cooling function of the HVAC system to reduce the humidity level in the enclosure until any of a first set of conditions has been met, wherein the first set of conditions comprises:
(i) the humidity sensor measurements being less than a second threshold humidity;
(ii) the temperature sensor measurements indicating that a temperature in the enclosure is lower than a first threshold temperature; and
(iii) a first maximum time interval for the cooling function to be active to reduce the humidity level in the enclosure while the humidity sensor measurements change by less than a first predetermined threshold amount; and

during a second time interval during which the occupancy sensing system characterizes the occupancy status of the enclosure as being in the away state:
determine that the humidity sensor measurements exceed a third threshold humidity; and
activate, in response to determining that the humidity sensor measurements exceed the third threshold humidity, the cooling function of the HVAC system to reduce the humidity level in the enclosure until any of a second set of conditions has been met, wherein the second set of conditions comprises:
i) the humidity sensor measurements being less than a fourth threshold humidity;
ii) the temperature sensor measurements indicating that the temperature in the enclosure is lower than a second threshold temperature; and
iii) a second maximum time interval for the cooling function to be active to reduce the humidity level in the enclosure while the humidity sensor measurements change by less than a second predetermined threshold amount.

2. The thermostat of claim 1 wherein the processing system is further configured to wait for a first backoff interval after any of the first set of conditions or any of the second set of conditions are met before again activating the cooling function of the HVAC system to reduce the humidity level in the enclosure.

3. The thermostat of claim 2 wherein the processing system is further configured to:
determine when a threshold number of dehumidification cycles to reduce the humidity level in the enclosure have occurred; and
wait for a second backoff interval after the other of the first set of conditions or the second set of conditions are met before again activating the cooling function of the HVAC system in order to reduce the humidity level in the enclosure.

4. The thermostat of claim 3 wherein the second time interval is at least twice as long as the first time interval.

5. The thermostat of claim 1 further comprising a wire insertion sensing system that automatically detects when a dehumidifier is connected to the thermostat, wherein the processing system is configured to stop activating the cooling function of the HVAC to reduce humidity in the enclosure when the dehumidifier is detected.

6. A method of dehumidifying an enclosure using a cooling function of an HVAC system, the method comprising:
characterizing, using an occupancy sensing system of a thermostat, an occupancy status of the enclosure, the occupancy status being selected from among a plurality of possible occupancy statuses including an occupied state and an away state;
processing humidity sensor measurements of humidity inside the enclosure provided by a humidity sensor of the thermostat, wherein the thermostat comprises:
a housing;
a user interface;
one or more temperature sensors, each of the one or more temperature sensors being configured to provide temperature sensor measurements;
the humidity sensor;

The occupancy sensing system; and
A processing system disposed within the housing, the processing system being configured to be in operative communication with the one or more temperature sensors to receive the temperature sensor measurements, in operative communication with one or more input devices including said user interface for determining a setpoint temperature, and in still further operative communication with a heating, ventilation, and air conditioning (HVAC) system to control the HVAC system based at least in part on the setpoint temperature and the temperature sensor measurements; and
during a first time interval during which the occupancy sensing system characterizes the occupancy status of the enclosure as being in the occupied state:
determining that the humidity sensor measurements exceed a first threshold humidity; and
activating, in response to determining that the humidity sensor measurements exceed the first threshold humidity, a cooling function of the HVAC system to reduce the humidity level in the enclosure until any of a first set of conditions has been met wherein the first set of conditions comprises:
(i) the humidity sensor measurements being less than a second threshold humidity;
(ii) the temperature sensor measurements indicating that a temperature in the enclosure is lower than a first threshold temperature; and
(iii) a first maximum time interval for the cooling function to be active to reduce the humidity level in the enclosure while the humidity sensor measurements change by less than a first predetermined threshold amount; and

during a second time interval during which the occupancy sensing system characterizes the occupancy status of the enclosure as being in the away state:
determining that the humidity sensor measurements exceed a third threshold humidity; and
activating, in response to determining that the humidity sensor measurements exceed the third threshold humidity, the cooling function of the HVAC system to reduce the humidity level in the enclosure until any of a second set of conditions are met, wherein the second set of conditions comprises:
i) the humidity sensor measurements being less than a fourth threshold humidity;
ii) the temperature sensor measurements indicating that the temperature in the enclosure is lower than a second threshold temperature; and
iii) a second maximum time interval for the cooling function to be active to reduce the humidity level in the enclosure while the humidity sensor measurements change by less than a second predetermined threshold amount.

7. The method of claim 6 further comprising waiting for a first backo

Assignees

• Google Inc

Inventors

• Matsuoka Yoky
• Fisher Evan J

Classifications

• G05D23/1902

  characterised by the use of a variable reference value · CPC title

• G05D27/02 Primary

  characterised by the use of electric means · CPC title

• F24F3/1405

  in which the humidity of the air is exclusively affected by contact with the evaporator of a closed-circuit cooling system or heat pump circuit · CPC title

• G05D22/02

  characterised by the use of electric means · CPC title