This invention relates generally to the field of home automation, and more specifically to automated window coverings.
Home automation is a very popular field with a broad consumer market. Automated window covering systems have been developed that operate on a wide variety of inputs to achieve a desired outcome. Some systems seek to maximize the amount of light let in through a window. Others vary the amount of sunlight admitted based on a thermostat. Others seek to provide shade while still allowing natural light to enter. Some systems operate based on geographic locations, others based on photo sensors or time of day. Many problems have been addressed by the various systems existing in the prior art, however there are yet still problems that the state of the art have not solved.
It can often be uncomfortable to sit in a drafty room. One cause of air drafts is uneven heating of air in a room by sunlight through a window. While the current state of the art has addressed problems ranging from temperature control to brightness control, there is still a need to address the problem of preventing drafts near windows.
An automated window covering system is disclosed that overcomes or improves upon the limitations discussed above. In general, the automated window covering system includes a window covering that is adjusted by a microcontroller via a motor. The microcontroller instructs the moter to adjust the window covering based on temperature information received from two temperature sensors. When a temperature gradient is detected that results in convection in front of the window, the window covering is adjusted to reduce convection. Thus, the window covering is capable of resolving the draft-causing temperature gradient while still allowing natural light into the room.
In one embodiment, a system to reduce drafts in front of a window is described. The system includes a window covering and a motor and gearbox that adjust the window covering. The system also includes a first temperature sensor, a second temperature sensor, and a microcontroller networked to the motor and temperature sensors. The first temperature sensor is positioned above the window covering within a thermal convection zone of a window associated with the window covering, and the second temperature sensor is positioned below the window covering within the thermal convection zone. The microcontroller instructs the motor to adjust the window covering based on a temperature gradient from the first temperature sensor to the second temperature sensor.
In another embodiment, a method to reduce drafts in front of a window is also described. The method includes measuring a first temperature above a window covering within a thermal convection zone of a window associated with the window covering, measuring a second temperature below the window covering within the thermal convection zone, and calculating a temperature gradient based on the first and second temperatures. The method also includes adjusting the window covering based on the temperature gradient.
A more particular description of the invention briefly described above is made below by reference to specific embodiments. Several embodiments are depicted in drawings included with this application, in which:
A detailed description of the claimed invention is provided below by example, with reference to embodiments in the appended figures. Those of skill in the art will recognize that the components and steps of the invention as described by example in the figures below could be arranged and designed in a wide variety of different configurations without departing from the substance of the claimed invention. Thus, the detailed description of the embodiments in the figures is merely representative of embodiments of the invention, and is not intended to limit the scope of the invention as claimed.
The descriptions of the various embodiments include, in some cases, references to elements described with regard to other embodiments. Such references are provided for convenience to the reader, and are not intended to limit the described elements to only the features described with regard to the other embodiments. Rather, each embodiment is distinct from each other embodiment.
Throughout the detailed description, various elements are described as “off-the-shelf.” As used herein, “off-the-shelf” means “pre-manufactured” and/or “pre-assembled.”
In some instances, numerical values are used to describe features such as temperature gradients. Though precise numbers are used, one of skill in the art recognizes that small variations the precisely stated values do not substantially alter the function of the feature being described. In some cases, a variation of up to 50% of the stated value does not alter the function of the feature. Thus, unless otherwise stated, precisely stated values should be read as the stated number, plus or minus a standard variation common and acceptable in the art.
Window 107 is an exterior window between a room of a structure and an outside environment around the structure. Window 107 is generally made of glass or any of a variety of clear plastic composite materials. As such, window 107 allows sunlight from the outside environment, either direct from the sun or reflected off of other surfaces, to enter the room. Thermal convection zone 106 is on the room side of window 107. Zone 106 exists as a result of a temperature gradient caused by uneven heating of air by sunlight. Sunlight enters through window 107 and heats air in zone 106. The density of the air being heated decreases and a boyant force causes heated air 108 to rise. Heated air 108 displaces cool air 109 above window covering 101. Once the heated air has risen beyond exposure to the sunlight, the heated air begins to cool. As the air cools, it descends, eventually returning below window covering 101 where it is reheated by the sunlight and moved upward once again by the boyant force. The process repeats as heated air 108 rises and cool air 109 descends.
Window covering 101 is any of a variety of window shades or window blinds, including pleated shades, cellular shades, roller shades, sheer shades, horizontal blinds, and verticle blinds. Similarly, motor and gearbox 102 are any of a variety of off-the-shelf motors and gearboxes. In some embodiments, motor and gearbox 102 are battery-powered. In other embodiments, motor and gearbox 103 are solar-powered. In yet other embodiments, motor and gearbox 103 are powered by AC mains power, and include an AC to DC power converter.
Temperature sensors 103, 104 are any of a variety of thermocouples, thermistors, or resistance temperature detectors (RTD's). Temperature sensors 103, 104 are, in some embodiments, battery-powered. In other embodiments, temperature sensors 103, 104 are coupled to motor and gearbox 102 and powered via the same power source that powers motor and gearbox 102. In yet other embodiments, temperature sensors 103, 104 are solar-powered. And in other embodiments, temperature sensors 103, 104 are coupled separately to AC mains power, and include AC to DC power converters. Temperature sensors 103, 104 communicate with microcontroller 105 in a variety of ways. For example, in one embodiment, temperature sensors 103, 104 communicate with microcontroller 105 via a wired connection. In another embodiment, temperature sensors 103, 104 communicate with microcontroller 105 wirelessly via any of a variety of wireless protocols, such as Wifi, Bluetooth, Z-Wave, Zigebee, or SureFi (a proprietary, frequency-hopped wireless network on the 902-928 MHz ISM band).
Microcontroller 105 is any of a variety of off-the-shelf microcontrollers. Microcontroller 105 instructs motor 102 to adjust window covering 101 based on a temperature gradient from sensor 103 to sensor 104. Adjusting window covering 101 varies the amount and angle of sunlight that enters a room. By controlling the amount and angle of the sunlight, system 100 influences heating of the air in thermal convection zone 106. For example, in one embodiment, as depicted in
In one embodiment, window covering 101 is a set of vertical window blinds. Window covering 101 is tilted open, and because of the positioning of the sun, light passes through window 107 and heats the air below window covering 101. As in the embodiment described above, temperature sensors 103, 104 continuously measure the air temperatures above and below window covering 101, respectively, and transmit the temperatures to microcontroller 105. As the air below window covering 101 is heated, microcontroller 105 detects a temperature gradient between the air above and below window covering 101. Based on the temperature gradient, microcontroller 105 instructs motor and gearbox 102 to tilt window covering 101 closed, at least until a thermal equilibrium is reached between the air above and below window covering 101.
In another embodiment, window covering 101 is a set of roller shades. Window covering 101 is open, and because of the positioning of the sun, light passes through window 107 and heats the air below window covering 101. As with the other embodiments described above, a temperature gradient is detected, and microcontroller 105 instructs motor and gearbox 102 to tilt window covering 101 closed, at least until a thermal equilibrium is reached between the air above and below window covering 101.
A threshold temperature gradient sufficient to trigger microcontroller 105 to adjust window covering 101 is, in some embodiments, pre-programmed in microcontroller 105. The threshold gradient ranges, in various embodiments, from 0.25° F. to 5° F. In other embodiments, the threshold gradient ranges from 1° F. to 3° F. In one specific embodiment, the threshold gradient is 2° F. In yet other embodiments, the threshold gradient is programmable by a user. This embodiment is particularly beneficial because the magnitude and perceptibility of convection varies from room-to-room, structure-to-structure, and is also highly user-dependent. In some such embodiments where the threshold gradient is programmable, system 100 includes an airflow sensor to detect convection, and microcontroller 105 correlates an amount of convection with a temperature gradient. A user interface then conveys to the user a variety of levels of convection, and the user selects the threshold temperature gradient by selecting a desired level of convection.
With regard to the embodiments discussed above in
Air flow detector 407 is any of a variety of off-the-shelf sensors capable of detecting airflow, such as an anemometer, a velocimeter, a mass flow sensor, and/or an interferometer. For example, in one specific embodiment, air flow detector 407 is a blade-style anemometer.
Air flow detector 407 is useful in counteracting the convection effects of air flowing from air vent 406. In some embodiments, cold air blows through vent 406 into the room. In many cases, the cold air is colder than a desired temperature of the room to speed cooling of the room. As the cold air flows into the room, it sinks, displacing warmer air beneath it. Because air flowing from air vent 406 has a higher speed than the air directly beneath the flow, a pressure gradient results that forces warmer air beneath the stream up. Together, these forces cause convection in front of window 401, which in some cases is uncomfortable for a person near window 401. In such embodiments, air flow detector 407 monitors the air flow and sends air flow information to microcontroller 403. Microcontroller 403 compares air flow to temperatures sensed by sensors 404, 405 and adjusts window covering 402 to minimize convection. For example, in one embodiment, window covering 402 is closed, and a temperature gradient between temperature sensors 404, 405 is less than a required threshold to adjust window covering 402. Air flow detector 407 detects air flow from air vent 406, and temperature sensor 404 measures that the air flow is a lower temperature than a room temperature. Microcontroller 403 instructs the motor to adjust window covering 402 so that sunlight is reflected towards the air flow to heat the air flow and reduce convection. The instructions to adjust window covering 402 based on the air flow override the instructions to adjust window covering 402 based on the temperature gradient.
In some embodiments, the air flow is warmer than the room temperature. For example, in one embodiment, microcontroller 403 instructs the motor to open window covering 402 to heat air in front of the window to the same temperature as air flowing through air vent 406. Microcontroller 403 then detects a temperature gradient that exceeds the threshold gradient, indicating that convection is or will be occurring. Microcontroller 403 instructs the motor to close window covering 402. The instructions to adjust window covering 402 based on the temperature gradient override the instructions to adjust window covering 402 based on the air flow.
In some embodiments, the first temperature is measured by measuring an air temperature in a zone adjacent to a vertical wall above a window associated with the window covering. In the same or other embodiments, the second temperature is measured by measuring an air temperature in a zone adjacent to a vertical wall below a window associated with the window covering. In other embodiments, the second temperature is measured by measuring an air temperature in a zone adjacent to a bottom portion of the window covering.
Method 500 is accomplished, in some embodiments, by the systems depicted in
In the depicted embodiment, airflow detector 806 is positioned outside air vent 805. However, in some embodiments, airflow detector 806 is within air vent 805 behind air vent slats.
Window 801, window covering 802, motor and gearbox 803, microcontroller 804, air vent 805, airflow detector 806, and temperature sensors 808, 809 are similar to corresponding components described above with regard to
As described above with regard to
In the depicted embodiment, air vent 1001 is positioned above window 1003. However, in other embodiments, air vent 1001 is positioned in a ceiling above window 1003, on a vertical wall below window 1003, or in a floor below window 1003.
As depicted in
In
Number | Name | Date | Kind |
---|---|---|---|
4950871 | Pollak | Aug 1990 | A |
6369935 | Cardinal | Apr 2002 | B1 |
9569955 | Hall | Feb 2017 | B2 |
9834983 | Hall | Dec 2017 | B1 |
20030146289 | Sekhar | Aug 2003 | A1 |
20110270446 | Scharf | Nov 2011 | A1 |
20120107085 | McCowan | May 2012 | A1 |
20130233496 | Ogden, Jr. | Sep 2013 | A1 |
20150086383 | Toy | Mar 2015 | A1 |
20150160626 | Cregg | Jun 2015 | A1 |
20150234369 | Wen | Aug 2015 | A1 |
20160168906 | Mullet | Jun 2016 | A1 |
20170350187 | Hall | Dec 2017 | A1 |
Number | Date | Country |
---|---|---|
WO 2016011040 | Jan 2016 | WO |
Number | Date | Country | |
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20180016840 A1 | Jan 2018 | US |