Source: https://insight.rpxcorp.com/pat/US9696735B2
Timestamp: 2019-12-09 05:50:55
Document Index: 191770849

Matched Legal Cases: ['art 800', 'art 800', 'art 800', 'art 800', 'art 800', 'art 800', 'art 800', 'art 800', 'art 900', 'art 900', 'art 800']

Patent US 9,696,735 B2
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
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.
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.
INDOOR AIR CONDITIONER AND OPERATION CONTROL METHOD THEREOF
US 20090158758A1
Thermostat and method for operating in either a normal or dehumidification mode
US 20060260334A1
Method and apparatus for adjusting the temperature set point based on humidity level for increased comfort
US 6,843,068 B1
US 20030181158A1
US 20130103204A1
US 20140230475A1
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:
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.
11. The thermostat of claim 1, wherein the first humidity threshold is higher than the third humidity threshold, and the first temperature threshold is higher than the second temperature threshold.
12. The thermostat of claim 1, wherein the 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 threshold amount is 15 minutes.
13. The thermostat of claim 2, wherein the thermostat is configured to wait for the first backoff interval when any of the following conditions are met(i) the temperature sensor measurements indicate that the temperature in the enclosure is lower the second threshold temperature;
and(ii) the first maximum time interval or the 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 the threshold amount has been exceeded.
14. The thermostat of claim 3, wherein the threshold number of dehumidification cycles to reduce the humidity level in the enclosure comprises 3 dehumidification cycles.
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;
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;
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;
7. The method of claim 6 further comprising waiting for a first backoff interval after any of the first set of conditions or any of the second set of conditions has been met before again activating the cooling function of the HVAC system to reduce the humidity level in the enclosure.
determining when a threshold number of dehumidification cycles to reduce the humidity level in the enclosure have occurred; and
waiting for a second backoff interval after the first/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.
9. The method of claim 8 wherein the second time interval is at least twice as long as the first time interval.
10. The method of claim 6 further comprising determining whether a dehumidifier is connected to the thermostat using a wire insertion sensing system, 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.
15. The method of claim 6, wherein the first humidity threshold is higher than the third humidity threshold, and the first temperature threshold is higher than the second temperature threshold.
16. The method of claim 6, wherein the first maximum time interval or the 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 threshold amount is 15 minutes.
17. The method of claim 7, wherein the thermostat is configured to wait for the first backoff interval when any of the following conditions are met:
(i) the temperature sensor measurements indicate that the temperature in the enclosure is lower the second threshold temperature; and
(ii) the first maximum time interval or the 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 the threshold amount has been exceeded.
18. The method of claim 8, wherein the threshold number of dehumidification cycles to reduce the humidity level in the enclosure comprises 3 dehumidification cycles.
Substantial effort and attention continue toward the development of newer and more sustainable energy supplies. The conservation of energy by increased energy efficiency remains crucial to the world'"'"'s energy future. According to an October 2010 report from the U.S. Department of Energy, heating and cooling account for 56% of the energy use in a typical U.S. home, making it the largest energy expense for most homes. Along with improvements in the physical plant associated with home heating and cooling (e.g., improved insulation, higher efficiency furnaces), substantial increases in energy efficiency can be achieved by better control and regulation of home heating and cooling equipment.
In another embodiment a method of dehumidifying an enclosure using a cooling function of an HVAC system may include 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. The method may also include processing humidity sensor measurements provided by a humidity sensor of the thermostat. In some embodiments, the thermostat may include 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 may be configured to be in operative communication with the one or more temperature sensors to receive the temperature sensor measurements. The processing system may be configured to be in operative communication with one or more input devices including the user interface for determining a setpoint temperature. The processing system may be configured to be 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. The method may additionally include operating, using a processing system of the thermostat, an occupancy-status-sensitive automated dehumidification feature. This feature may include (i) an occupied-state automated dehumidification algorithm designed to operate according to combined comfort-and-humidity criteria characterized in that when the humidity sensor measurements are above a first humidity threshold, and the temperature sensor measurements are below the setpoint temperature, a cooling function of the HVAC system may operate in order to reduce a humidity level in the enclosure until a first set of conditions are met; and (ii) an away-state automated dehumidification algorithm designed to operate according to away-humidity criteria characterized in that when the humidity sensor measurements are above a second humidity threshold, and the temperature sensor measurements are below the setpoint temperature, the cooling function of the HVAC system may operate in order to reduce the humidity level in the enclosure until a second set of conditions are met.
FIG. 15A illustrates a user interface of a thermostat indicating that the cooling function is operating as part of the auto dehumidification feature.
FIG. 15B illustrates a user interface of a thermostat indicating that the cooling function may be operating as part of the auto dehumidification feature while the thermostat is in the away state.
The subject matter of this patent specification relates to the subject matter of the following commonly assigned applications, each of which is incorporated by reference herein: U.S. Ser. No. 13/864,929 filed Apr. 17, 2013 (Ref. No. NES0334-US); U.S. Ser. No. 13/632,070 filed Sep. 30, 2012 (Ref. No. NES0234-US); U.S. Ser. No. 13/624,881 filed Sep. 21, 2012 (Ref. No. NES0233-US); U.S. Ser. No. 13/624,811 filed Sep. 21, 2012 (Ref. No. NES0232-US); International Application No. PCT/US12/00007 filed Jan. 3, 2012 (Ref. No. NES0190-PCT); U.S. Ser. No. 13/466,815 filed May 8, 2012 (Ref. No. NES0179-US); U.S. Ser. No. 13/467,025 filed May 8, 2012 (Ref. No. NES0177-US); U.S. Ser. No. 13/351,688 filed Jan. 17, 2012, which issued as U.S. Pat. No. 8,195,313 on Jun. 5, 2012 (Ref. No. NES0175-US); U.S. Ser. No. 13/632,041 filed Sep. 30, 2012 (Ref. No. NES0162-US); U.S. Ser. No. 13/632,028 filed Sep. 30, 2012 (Ref. No. NES0124-US); and U.S. Ser. No. 13/632,093 filed Sep. 30, 2012 (Ref. No. NES0122-US). The above-referenced patent applications are collectively referenced herein as “the commonly-assigned incorporated applications.”
It will be understood by one having skill in the art that the various thermostat embodiments depicted and described in relation to FIGS. 1-5 are merely exemplary and not meant to be limiting. Many other hardware and/or software configurations may be used to implement a thermostat and the various functions described herein below, including those described in described in U.S. Ser. No. 13/624,881 (Ref. No. NES0233-US), supra, and U.S. Ser. No. 13/624,811 (Ref. No. NES0232-US), supra. These embodiments should be seen as an exemplary platform in which the following embodiments can be implemented to provide an enabling disclosure. Of course, the following methods, systems, and/or software program products could also be implemented using different types of thermostats, different hardware, and/or different software.
Auto Dehumidifier Using a Cooling Function
Out of concern for both occupant comfort and energy conservation, the auto dehumidifier feature may limit the amount that it will cool an enclosure below a setpoint temperature even if the humidity threshold has not yet been reached. For example, the auto dehumidifier feature may be deactivated when the temperature drops below the setpoint temperature by a threshold amount. The threshold amount may vary depending on whether the home is occupied (e.g. 3° below the setpoint temperature) or whether the home is unoccupied (e.g. 5° below the setpoint temperature). A floor temperature value may be used below which the auto dehumidifier feature should not operate (e.g. 75° F.). If users turn the thermostat “off” while they are away, the auto dehumidifier may use a predetermined setpoint temperature (e.g. 90° F.).
Because the cooling function of most HVAC systems is not specifically designed to dehumidify an enclosure, there are limits to how effective the auto dehumidifier feature can be. It has been determined that it may be most effective to operate the cooling function repeatedly at regular intervals rather than continuously for an extended period of time. It has been found that humidity is most effectively removed from an enclosure during the first portion of a cooling cycle. Therefore, limiting the length of cooling cycles while increasing the overall number of cooling cycles may reduce the humidity more than would a smaller number of extended cooling cycles. In one embodiment, the auto dehumidifier feature may turn off the cooling function after a first time interval where no significant decrease in the humidity of the enclosure is observed. For example, the auto dehumidifier feature may turn off the cooling function after 30 minutes of continuous cooling without a change in humidity. The auto dehumidifier function may then wait for a second time interval (e.g. 15 minutes) referred to as a backoff period before again attempting to lower the humidity of the enclosure using the cooling function of the HVAC system.
After a number of cycles, the amount by which the humidity level in the enclosure drops with each cycle may begin to decrease. Therefore, some embodiments may include a longer rest interval after a threshold number of cooling cycles. For example, after three cooling cycles followed by rest intervals of approximately 15 minutes each, the auto dehumidifier function may activate a substantially longer rest interval of, for example, approximately 1 hour.
Some thermostats may be equipped with an “Airwave” feature that uses condensation from the condenser coils to further cool an enclosure after the cooling function has been deactivated by the thermostat. Even at low humidity levels, the Airwave feature may dramatically increase humidity levels. When the auto dehumidifier feature is enabled, the Airwave feature may be disabled to avoid introducing additional moisture into the enclosure atmosphere. The Airwave feature and the auto dehumidifier feature may rarely conflict in practice, as the Airwave feature is most effective in hot and dry climates, while the auto dehumidifier feature is most effective in hot and humid climates. The auto dehumidifier function may also be disabled when the thermostat automatically determines using wire insertion sensing that a separate dehumidifier is available as part of the HVAC system of the enclosure. The auto dehumidifier function may also be a disabled when the thermostat is in a heating mode.
Turning back to the HVAC space, similar algorithms to those discussed herein may be used to control an air purification feature combined with occupancy detection. A first algorithm may be performed when the house is occupied, while a second algorithm may be used when the house is unoccupied. Purification thresholds and runtimes could be reduced during unoccupied intervals. Additionally, higher quality HEPA filters could be used while the home is occupied and lower quality filters could be used when the home is unoccupied.
Turning back to embodiments implemented using a thermostat device, it has been determined through empirical data that use of a cooling function of an HVAC system can significantly lower the humidity level of an enclosure when no dedicated dehumidifier is available.
The thermostat may also include a processing system disposed within the housing 608. The processing system may be in operative communication with the one or more temperature sensors to receive the temperature sensor measurements. The processing system may also be in operative communication with one or more input devices that may include the user interface for determining a setpoint temperature. The processing system may also be in operative communication with the HVAC system of the enclosure. The processing system may be configured to control the HVAC system based at least in part on the setpoint temperature and the temperature sensor measurements.
As described above, the thermostat may include two modular sections referred to as a head unit and a backplate 604. In some embodiments, the humidity sensor 614 may be located in the backplate 604. In other embodiments (not shown), the humidity sensor 614 may be installed on a circuit board 606 located in the head unit. In some embodiments, the humidity sensor 614 may be combined with a temperature sensor. This additional temperature sensor may be used by ambient temperature determination algorithms in order to compensate for internal heating effects caused by the thermostat electronics and/or user interface, along with heating effects caused by exposure to direct sunlight for limited periods of time. In one implementation the humidity sensor 614 may be implemented using the SHT20 digital humidity sensor chip available from Sensirion®.
The results of the data displayed in graph 700 indicate a number of useful observations. First, the average maximum humidity level is significantly higher in unoccupied enclosures. For example, the average maximum humidity level for occupied enclosures is 57.0%, while the average maximum humidity level for unoccupied enclosures was 61.1%. Second, the distribution of graph 700 indicates that most of the daily maximum humidity levels were between approximately 50% and 60% in occupied enclosures. In contrast, a large percentage of the daily maximum humidity levels were centered between approximately 60% and 70% in the unoccupied enclosures. This indicates a large number of enclosures were subject to maximum humidity levels that far exceeded the EPA'"'"'s maximum humidity recommendation of between 55% and 60%.
Finally, because the homes under observation did not have a dedicated dehumidifier, graph 700 indicates that humidity levels may be significantly controlled using the intermittent operation of a cooling function primarily used to control temperature. In graph 700, unoccupied enclosures typically set their temperature setpoint higher while the home is unoccupied. Therefore, the cooling function did not operate as often, and as a result the maximum humidity levels rose dramatically inside the enclosure. However, when the enclosures were occupied, the temperature setpoint was typically set lower, causing the cooling function to operate more often. This in turn led to a more controlled level of maximum humidity inside the enclosure while the enclosure was occupied.
As used herein, the term “cooling function” may be used to describe any operation of the HVAC system primarily configured to reduce a temperature within an enclosure. Most often, a cooling function will include an air conditioner that uses a fan, a compressor, and cooling coils to force cooled air into the enclosure. Additionally, a cooling function may include the operation of a fan without a compressor and cooling coils. Depending on the particular climate, season, and/or region, the cooling function of an HVAC system may further include other types of cooling systems that would be known to one having skill in the art.
FIG. 8 illustrates a flowchart 800 of a method for reducing a humidity level in an enclosure using a cooling function, according to some embodiments. Flowchart 800 may be considered a generic algorithm for which the various thresholds, time intervals, and operations may be varied according to an occupancy status of an enclosure. In some embodiments, flowchart 800 may describe what may be presented to a user as an “auto dehumidifier feature.” The user may be given the opportunity to choose to enable or disable the auto dehumidifier feature according to their own comfort level preference and energy-saving concerns. Therefore, in one embodiment, the algorithm may begin in a disabled state 802 until a command is received to enable the auto dehumidifier feature. The command may be received from a user through a user interface of the thermostat or through a remote interface on a portable computing device such as a laptop, tablet computer, and/or smart phone. The command may also be received from a central monitoring station that is communicatively coupled through a wireless connection to the thermostat. In other embodiments (not shown), the algorithm may begin in an enabled state by default instead of being specifically enabled through a command.
Once the auto dehumidifier feature is enabled, either through command or by default, the algorithm may enter state 804 and begin looking for a high level of humidity. As described above, the thermostat may include a humidity sensor that provides humidity sensor measurements to the processing system of the thermostat. The processing system may compare the humidity sensor measurements to one or more humidity thresholds. The humidity thresholds may vary according to various modes of operation. In one embodiment, the humidity thresholds may vary according to an occupancy status of the enclosure. Various occupancy statuses of the enclosure and their effects upon the algorithm flowchart 800 are described in greater detail below.
When the humidity level in the enclosure exceeds the humidity threshold, the algorithm may transition into state 806 to begin dehumidifying the enclosure using a cooling function, such as an air conditioner. In some cases, the cooling function may already be operating in order to reduce a temperature of the enclosure. In these cases, state 806 may simply continue allowing the cooling function to operate. If the temperature drops below the temperature setpoint that would normally cause the cooling function to stop operating, state 806 may cause the cooling function to continue operating in order to dehumidify the enclosure. In other cases, the temperature of the enclosure may already be at or below the setpoint temperature of the thermostat. In these cases, state 806 may cause the cooling function to operate in order to further dehumidify the enclosure. In other words, the auto dehumidification feature may cause the cooling function to operate at times when it normally would not, and to operate for longer time intervals than it normally would.
In order to transition out of state 806, one or more of a set of conditions may be met. As used herein, a “set of conditions” may include any parameters used to control the cooling function. The set of conditions may include information associated with temperature thresholds, humidity thresholds, time intervals, occupancy statuses, user preferences, energy usage, date and time, user profiles, and/or the like that can be used to control when the auto dehumidification features operates the cooling function of the HVAC system. The set of conditions may be dynamically adjusted using environmental measurements or communications received from a central monitoring facility or a user device.
In some embodiments, a target humidity threshold may be set to approximately 55% when the enclosure is unoccupied. In other embodiments, the target humidity threshold may be set to approximately 60%. In contrast, when the enclosure is occupied the target humidity threshold they be set significantly above 55%. For example, the target humidity threshold may be set to 65%, 70%, 75%, 80%, and/or the like.
In some embodiments, the set of conditions for exiting state 806 may also include temperature considerations. Even though the cooling function is operating primarily to dehumidify the enclosure rather than to lower the temperature, the temperature will still be lowered as the cooling function continues to operate. In order to balance user comfort and energy considerations with the benefits of dehumidification, it may be determined that excessive cooling should be avoided. Therefore, some embodiments may also compare the measured temperature during a dehumidification cycle to a minimum temperature and transition out of state 806 when the minimum temperature threshold is violated.
Additionally, minimum and/or maximum temperatures may also be used. In some cases, the users may turn off the cooling function or may set the setpoint temperature very high after they leave the house. For example, a homeowner may set the thermostat setpoint temperature to 95° and activate the auto dehumidification feature. In this case, the thermostat may use a maximum temperature of 90° in order to determine a threshold temperature for deactivating the auto dehumidification algorithm. Similarly, an absolute minimum may be used. For example, a minimum of 75° may be used by the algorithm as a threshold temperature below which the auto dehumidification feature should not cool. For example, if a user were to set the setpoint temperature very close to the minimum temperature, the auto dehumidification algorithm would cool until the minimum temperature was reached rather than the threshold temperature below the setpoint temperature that would otherwise be dictated by the algorithm under normal conditions.
Some embodiments may also include a time interval in the set of conditions for exiting state 806. For example, an absolute time interval may be used, such that the cooling function will only be operated for a maximum length of time, such as one hour. In other embodiments, humidity sensor measurements may be periodically monitored to determine when a predetermined time interval is exceeded wherein the measured humidity does not substantially change. For example, the algorithm may transition out of state 806 when, for example, 30 minutes have passed without any significant change in the humidity of the enclosure.
Note that according to flowchart 800, there are two ways to exit state 806. When the humidity level in the enclosure is the reason for leaving state 806, flowchart 800 may transition back into state 804 and again watch for the measured humidity to exceed the higher threshold. Alternatively, if the algorithm transitions out of state 806 due to conditions that are not generally related to the measured humidity, the algorithm may instead transition into decision block 808. These types of conditions may indicate that even though the desired humidity level has not yet been reached, there may be some benefit to stopping the cooling function periodically. These benefits may be related to user comfort, efficiency, and/or energy and cost savings.
For example, when operating the cooling function in order to dehumidify the enclosure, the temperature may decrease too far below the setpoint temperature. It may be necessary to allow the enclosure temperature to recover without significantly increasing the humidity. Additionally, when operating the cooling function for an extended period time, it may reach a point where it is no longer efficiently removing humidity from the enclosure. Continuously running the cooling function without removing significant humidity may not be cost effective. Therefore, it may be determined that the efficiency of the auto dehumidification feature may be increased by instituting backoff intervals where the cooling function is allowed to recover such that it may more effectively remove humidity during the next cooling cycle. The rationale and operation of the backup intervals will be described in greater detail below.
At decision block 808, the number of consecutive dehumidification cooling cycles may be compared to a threshold number. If the number of dehumidification cooling cycles exceeds the threshold number, a longer backoff interval may be used. The longer backoff interval may be substantially longer than the shorter backoff interval. In some embodiments, the longer backoff interval may be at least four times as long as the short backoff interval. For example, the short backoff interval may be approximately 15 minutes in some embodiments, while the long backoff interval may be approximately 1 hour. In one embodiment, the threshold number of consecutive dehumidification cooling cycles may be approximately three cycles. In other words, after three consecutive dehumidification cooling cycles separated by short backoff intervals, the third backoff interval may be implemented in order to reset the operation of the auto dehumidification feature, as will be described below. The lengths of the backoff intervals and the number of dehumidification cycles between backoff intervals may vary for each thermostat type and enclosure.
Again, it should be emphasized that the various humidity thresholds, temperature thresholds, backoff interval thresholds, backoff interval lengths, and/or the like, may be dependent upon user preferences as well as an occupancy status of the enclosure. These values may be determined dynamically according to received data from the sensors of the thermostat, and may be processed or assigned from a central processing location that is in wireless communication with the thermostat.
In some embodiments, flowchart 800 may be governed by two separate sets of conditions, namely a first set of conditions and a second set of conditions. These two sets of conditions include first and second humidity thresholds, respectively. These two sets of conditions may cause the auto dehumidification feature to operate as an “occupancy status sensitive automated dehumidification feature” that includes an occupied-state automated dehumidification algorithm and an away-state automated dehumidification algorithm. These two algorithms may both follow flowchart 800. In some cases these two algorithms may only differ in the values of the conditions used to govern transitions between states.
The occupied-state automated dehumidification algorithm may operate according to combined comfort-and-humidity criteria. These criteria may dictate values for the set of conditions, and may be characterized in that the cooling function is operated to reduce the humidity in the enclosure according to a first set of conditions that are tailored to balance user comfort with humidity reduction. In contrast, the away-state automated dehumidification algorithm may be designed to operate according to away-humidity criteria that may dictate values for another set of conditions, and may be tailored to balance humidity reduction with energy and efficiency concerns.
For some embodiments, the currently described methods may be used in conjunction with an intelligent, network-connected thermostat having one or more occupancy sensors and being configured and programmed to detect a plurality of occupancy statuses of the enclosure. These occupancy statuses may include (i) a “home” or “occupied” status in which it is determined likely that the home is occupied, (ii) an automated away status (or “auto-away” state) in which it is automatically determined based on occupancy sensor readings that the home is likely unoccupied, (iii) a manually invoked away status (or “manual” away) in which an affirmative user entry instructs the thermostat to function at “away” settings regardless of automated occupancy determinations, and (iv) a long-term away status (or “vacation” away state) in which it is determined that the house has likely been unoccupied for an extended time period and therefore is likely to continue to be so unoccupied for the near future. Examples of such intelligent, network-connected thermostats are described in one or more of the following commonly-assigned applications, each of which is incorporated by reference herein: U.S. Ser. No. 13/279,151 filed Oct. 21, 2011 (Ref. No. NES0103-US); and U.S. Ser. No. 13/632,070 filed Sep. 30, 2012 (Ref. No. NES0234-US).
FIG. 9 illustrates a flowchart 900 of a method for turning on the long-term away state, according to some embodiments. In these embodiments, the away-state automated dehumidification algorithm may be configured to operate with the thermostat in the long-term away status (the “away state”), while the occupied-state automated dehumidification algorithm may be configured to operate in the rest of the occupied statuses (the “occupied state”).
The algorithm may default to begin in the occupied state 902. The thermostat may then transition into an away status, such as the auto away status detected by the one or more occupancy sensors, or the manual away status as specified by a user. The algorithm may then use an internal clock or a date and time system available through a wireless network in order to count a number of days that have passed since the thermostat entered into the away status. At decision block 904, the thermostat may, for example, count the number of midnight crossings that have occurred since the thermostat went into one of the away statuses. After the Nth midnight crossing, the thermostat may transition into a long-term away status. This long-term away status may correspond to the away-state automated dehumidification algorithm. The algorithm may then move into the away state 908, and stay there until the thermostat receives either user inputs or sensor input indicating that a transition should be made back to the occupied state 902.
Note that the algorithm of flowchart 900 uses the long-term away status rather than the auto-away status or the manual-away status to transition to the away-state automated dehumidification algorithm. Alternatively, other embodiments (not shown) may simply transition to the away-state automated dehumidification algorithm when any of the away statuses are indicated by the thermostat. However, using the long-term away status may be more effective at balancing user comfort with energy/efficiency concerns. Many thermostats may enter the auto away state after the enclosure has been unoccupied for a few hours. The excess cooling that may occur using the away-state automated dehumidification algorithm may be uncomfortable for users who intend to return to the enclosure after a few hours.
As described above in relation to flowchart 800, it has been determined that some air conditioning units may have an optimal time interval during which humidity may be removed. First, the air conditioner should be allowed to operate for at least a minimum time interval in order to dehumidify the enclosure. Some air conditioner units may require a warming-up period before they begin removing moisture from the atmosphere. Other air-conditioning units may simply be most efficient during the first portion of an air-conditioning cycle. In either case, it may be most efficient to allow the cooling function to operate for at least the minimum amount of time.
Second, it has been discovered that many air conditioner units may become less effective at removing humidity from the atmosphere of an enclosure after a certain time interval. In other words, allowing the air conditioner to run for more than a maximum time interval may not be an efficient use of the air conditioner to remove humidity.
In order to overcome these problems, the backoff intervals described above may be implemented by various methods described herein to dehumidify an enclosure using the cooling function. FIG. 10 illustrates a graph 1000 of multiple dehumidification cycles using backoff intervals, according to some embodiments. In graph 1000, humidity level H1 and humidity level H2 may correspond to upper and lower humidity maintenance band thresholds that are determined by the occupancy status of the enclosure. When the humidity level reaches the upper threshold of H1, the cooling function may be activated at time t1. Curve 1002 illustrates how this particular air conditioner is most effective at removing humidity from the air during the first portion of the time interval. However, as time progresses the cooling function becomes less efficient at removing humidity, and curve 1002 begins to flatten. At time t2, the auto dehumidification algorithm may then turn off the cooling function. Note that the humidity has not reached the H2 humidity threshold, therefore the cooling function may have instead been deactivated because the temperature descended below the setpoint temperature by more than the threshold value, or because the maximum time interval was reached during which the flat portion of curve 1002 indicated that the humidity of an enclosure was not being significantly reduced.
Graph 1000 illustrates the fact that there is a time at which a single dehumidification cycle using the cooling function may become inefficient. Graph 1000 also illustrates the fact that repeated dehumidification cycles may also gradually become inefficient. Curve 1010 is significantly flatter than curve 1002. Therefore, repeatedly running dehumidification cycles may eventually limit the effectiveness of the cooling function at reducing enclosure humidity. One solution implemented by some embodiments is to simply increase the time of the backoff intervals between each cycle. However, as illustrated by curve 1004 and curve 1008, the humidity of the enclosure may begin to increase during the backoff intervals.
Alternatively, some embodiments may use a determined number of short backoff intervals followed by a longer backoff interval. The shorter backoff intervals may effectively reduce the humidity over a shorter period of time, while the longer backoff interval may allow the components of the cooling system to reset, condense, and return to a normal temperature. It has been determined that after allowing the air conditioner to “reset” using a longer backoff interval, the dehumidification cycles may restart using shorter backoff intervals at near the original efficiency.
FIG. 11 illustrates a graph 1100 of a determined number of dehumidification cycles followed by a longer backoff interval, according to some embodiments. The portion of the humidity curve prior to time t6 may be similar to the curve illustrated by graph 1000. At time t6, the thermostat may determine that the threshold number of dehumidification cycles has been reached, and instead of instituting a shorter backoff interval, the longer backoff interval may be used instead. During a longer backoff interval curve 1102 illustrates that the humidity may rise more than during the shorter backoff intervals. However, at time t7 the longer backoff interval may expire, and the dehumidification cycles may be restarted. Note that the humidity curve 1104 of the first new dehumidification cycle is similar in shape to the original curve 1002 of the first original dehumidification cycle. Thus, the longer backoff interval may be effective at restoring near the original efficiency of the cooling function at removing humidity from the enclosure.
FIG. 12A illustrates a user interface of a thermostat 1200a for enabling the auto dehumidification feature, according to some embodiments. Users may be allowed to turn the auto dehumidifier feature on or off depending upon their concerns for cost savings, energy efficiency, mold prevention, and/or the like. The user interface may provide a message describing the benefits of using the auto dehumidification feature, such as mold prevention. Additionally, the user interface may provide an indication that leaving the auto dehumidification feature off may be more efficient. For example, a leaf symbol 1202 may be displayed next to the “off” setting for the auto dehumidification feature in order to indicate that the disabling the feature may be more energy efficient.
The user interfaces described above may be presented to a user automatically when certain conditions are detected by the thermostat. In some embodiments, the thermostat may be equipped with a wire insertion sensing unit configured to detect when a dehumidifier is properly connected to the thermostat. The wire insertion sensing unit may use mechanical insertion sensors to physically detect when a wire is connected from an HVAC system dehumidifier to the thermostat. The wire insertion sensing unit may also use electronic tests in order to determine that a dehumidifier is properly connected. During a set up routine of the thermostat, if it is detected that a dehumidifier is not present, then the user interfaces described above may be presented to the user. If a dehumidifier is detected, then the user interfaces described above need not be presented automatically. However, users may be given the option to deactivate the dehumidifier and activate the auto dehumidification feature at their discretion through a menu interface of the thermostat.
Other operating modes and configurations associated with the thermostat may be adjusted when the auto dehumidifier feature is enabled. For example, when the user switches the auto dehumidification feature to the “on” state, an “Airwave” feature may be automatically deactivated. The Airwave feature may use condensation from the air conditioner coils to continue cooling the enclosure after the air conditioner compressor has been deactivated. The Airwave feature may also dramatically increase the humidity in the enclosure. Therefore, enabling the auto dehumidification feature may automatically deactivate the Airwave feature of the thermostat. In some embodiments, the thermostat may also determine whether the thermostat is in a heat mode rather than a cooling mode. The auto dehumidification feature can be automatically deactivated while the thermostat is in the heating mode and automatically reactivated when the thermostat is set to the cooling mode.
FIG. 13 illustrates a user interface 1300 of a user device for activating the auto dehumidification feature, according to some embodiments. This user interface may be displayed on a smart phone, a tablet computer, a laptop computer, a PDA, a portable music player, a desktop computer, and/or the like. The user device may communicate through the Internet, a local area network, a wide-area network, a private network, or using a dedicated wireless connection with the thermostat. The user interface may provide similar indications as described in relation to FIG. 12A and FIG. 12B that described the costs and benefits associated with the auto dehumidifier feature. The user interface 1300 may also provide indications that easily allow users to choose the most energy-efficient setting, such as the “leaf” icon.
User interface 1300 may be used to activate or deactivate the auto dehumidification feature while away from the enclosure. This may be particularly beneficial to owners of vacation homes. For example, vacation homes in humid areas such as Florida may experience seasonal heat and/or humidity. Owners may be away from vacation homes for extended periods of time. An owner may decide to leave the auto dehumidification feature off during the winter and activate the auto dehumidification feature during the summer without needing to physically visit the vacation home.
FIG. 14 illustrates a user interface 1400 of a user device for assessing the efficiency of an auto dehumidification feature, according to some embodiments. User interface 1400 may display various indications that describe how efficiently an HVAC system was used during an extended time interval, such as during one week, during one month, or during a particular season. User interface 1400 may also include an indication that the auto dehumidification feature caused the energy usage in a particular time interval to be above what would normally be expected. User interface 1400 may be beneficial to users to explain outlying energy usage and help users associate a cost that can be balanced with a benefit provided by the auto dehumidifier can feature. Although not shown explicitly, a similar interface may be displayed on the thermostat as well as the user device.
FIG. 15A illustrates a user interface of a thermostat 1500a indicating that the cooling function is operating as part of the auto dehumidification feature. In this embodiment, a current temperature may be displayed without showing time-to-temperature ticks along the dial of the interface. Alternatively, a current humidity may be displayed instead of a current temperature. FIG. 15B illustrates a user interface of a thermostat 1500b indicating that the cooling function may be operating as part of the auto dehumidification feature while the thermostat is in the away state. FIG. 15C illustrates a user interface of a thermostat 1500c indicating that the cooling function may be operating as part of the auto dehumidification feature while the thermostat is in the auto-away state. Finally, FIG. 15D illustrates a user interface of a thermostat 1500d indicating that the cooling function may be operating as a part of the auto dehumidification feature while the thermostat is in the long-term away state. Each of these indications may be changed by manually interacting with the thermostat by way of the user interface, or by providing commands to the thermostat from a user device or from a central monitoring station.
Whereas many alterations and modifications of the present invention will no doubt become apparent to a person of ordinary skill in the art after having read the foregoing description, it is to be understood that the particular embodiments shown and described by way of illustration are in no way intended to be considered limiting. By way of example, while one or more of the above embodiments is applied in the context of a “cool-to-dry” feature, the principles of the present teachings are not necessarily limited to such scenarios. Thus, by way of example, in view of the present teachings one skilled in the art may adapt the present teachings to an equivalent but converse case of “do-not-heat-to-too-dry.” For example, operating a heater may reduce the humidity of an enclosure, and depending on the particular context, air that is too dry may be undesirable for one or more reasons (for example, causing dry skin, damage to wood furniture or instruments, or endangering certain pet or plant life). Thus, in one alternative embodiment, the algorithms described herein may be applied in a converse context such that the heating function is limited in order to reduce the dryness that can result. For example, when the home is occupied, the heating function may perform as normal until the humidity drops to a specified threshold humidity level. When the home is unoccupied, the heating function may be limited in order to avoid too much of a reduction in humidity, but not limited so much as to allow pipes to freeze or to cause the enclosure to be too cold when the occupants return. Therefore, reference to the details of the preferred embodiments is not intended to limit their scope.
Matsuoka, Yoky, Fisher, Evan J.
US 20140319231A1
Context Adaptive Cool To Dry Feature For Hvac Controller