JP7538499B2 - How to control blinds - Google Patents

Description

Article 30, paragraph 2 of the Patent Act applies. Publication name: Architectural Institute of Japan Environmental Journal, Volume: Vol. 84, Issue: No. 766, Pages: 1067-1076, Publication date: December 30, 2019, Publisher: Architectural Institute of Japan (5-26-20 Shiba, Minato-ku, Tokyo)

The present invention relates to a control method for automatically controlling the angle of blind slats.

For example, as described in Patent Document 1, in a conventional automatic blind control method, the slat angle of the blinds is adjusted to a protection angle in order to reduce direct sunlight entering the interior while ensuring maximum outdoor visibility through the blinds. The protection angle is the minimum slat angle at which direct sunlight can be blocked by the slats, and if the slat angle of the blinds is adjusted below this protection angle, direct sunlight passes through the slats into the interior. When the position of the sun changes, the protection angle also changes, so the protection angle is a function of the profile angle φ as shown in Figure 7. Therefore, in a conventional automatic blind control method, the slats tilt little by little over time, causing the slat angle to fluctuate.

JP 2016-23428 A

However, even when the slat angle is adjusted to the protective angle, light from outdoors may be reflected by the slats and enter the room. Figure 7 shows the results of a simulation that calculated the proportion of light that enters the room in this way (transmittance) and the proportion of light that does not enter the room and returns to the outdoors (reflectance). As shown in Figure 7, when the profile angle φ exceeds 40°, the transmittance increases as the profile angle φ increases. Since light that enters the room in this way causes a thermal load for air conditioning and a rise in temperature indoors, simply adjusting the slat angle to the protective angle cannot adequately suppress the thermal load for air conditioning.

Therefore, the present invention has been made in consideration of the above circumstances, and aims to provide a blind control method that can appropriately reduce the thermal load on air conditioning.

To solve the above problems, a method for controlling blinds having slats arranged in parallel in multiple vertical stages and tiltable around a horizontal axis is provided, which calculates an adjustment function that represents the relationship between a set angle that represents the angle of the slats and the profile angle based on the transmittance of the blind in a function represented by the slat angle and the profile angle, and adjusts the angle of the slats to a specific set angle obtained by fitting the current profile angle to the profile angle of the adjustment function.

As described above, the adjustment function is calculated based on the transmittance, and the slat angle is adjusted to the adjustment angle obtained by fitting the current profile angle to the profile angle of the adjustment function, so the thermal load for cooling can be appropriately suppressed.

Preferably, the adjustment function is determined to have a relationship between the set angle and the profile angle such that the transmittance in the function is a desired transmittance, or alternatively, the adjustment function is determined to have a relationship between the set angle and the profile angle such that the transmittance in the function is a minimum or maximum transmittance.

Preferably, the set angle is equal to or greater than the protective angle, which is the minimum slat angle that can block direct light.

As a result of the above, since the set angle of the adjustment function is equal to or greater than the protection angle, the slat angle can also be adjusted to be equal to or greater than the protection angle. This prevents direct light from entering the room.

The present invention makes it possible to appropriately reduce the thermal load on air conditioning.

2 is a front view of the blind device and a control unit of the blind device; 2 is a side view of the blind device and a control unit of the blind device; 1 is an explanatory diagram of the incidence angle of solar rays, the altitude and azimuth angle of the sun. FIG. 2 is an explanatory diagram of the profile angle of a sunbeam. 1 is a graph showing the relationship between profile angle and transmittance for each slat angle. 1 is a graph showing an adjustment function. 1 is a graph showing a relationship between a profile angle and a protection angle, a relationship between a profile angle and a transmittance, and a relationship between a profile angle and a reflectance.

The following describes an embodiment of the present invention with reference to the drawings. However, the embodiment described below has various limitations that are technically preferable for implementing the present invention, and the scope of the present invention is not limited to the following embodiment and illustrated examples.

Fig. 1 is a front view of a horizontal blind device 10. Fig. 2 shows a left side view of Fig. 1.
The horizontal blind device 10 comprises a plurality of band-like slats 11, a head box 21, a ladder cord 22, a bottom rail 27, a lifting cord 28, a tilting drive unit 31, a lifting drive unit 32 and a control unit 35.

The head box 21 is attached to the upper cross rail 1 along the upper cross rail 1 of the window frame. If the head box 21 is installed horizontally, the attachment point of the head box 21 may be a part other than the upper cross rail 1, for example, a ceiling surface close to the indoor window frame.

A tilting drum around which a ladder cord 22 is wound is provided inside the head box 21. The ladder cord 22 is unwound from the tilting drum and hangs down from the head box 21. The lower end of the ladder cord 22 is connected to a bottom rail 27 that acts as a weight. The ladder cord 22 supports the multiple slats 11 in a state in which the slats 11 are arranged in multiple stages vertically along the window surface 2 from the head box 21 to the bottom rail 27, and in a state in which the slats 11 are parallel to each other.

The ladder cord 22 has a pair of vertical cords that hang down from the head box 21 to the bottom rail 27 and are perpendicular to the window surface 2, and multiple support cords that are stretched between the vertical cords and arranged at intervals in the longitudinal direction of the vertical cords. Between the pair of vertical cords, each slat 11 is supported on each support cord so that the longitudinal direction of the slat 11 is horizontal. The slat 11 is formed in the shape of a rectangular thin plate and is curved in the direction of the short side.

The tilting drum is connected to a tilting drive unit 31 such as a motor. When the tilting drum is driven by the tilting drive unit 31, the slat 11 tilts around a horizontal axis parallel to its long side. Here, the angle between the plane connecting the pair of long sides of the slat 11 and the horizontal plane is called the slat angle, and when the convex surface of the slat 11 faces straight up, the slat angle is 0°. When the slat 11 is tilted so that the convex surface of the slat 11 faces outdoors, the slat angle is positive, and when the slat 11 is tilted so that the convex surface of the slat 11 faces indoors, the slat angle is negative.

A lifting drum around which a lifting cord 28 is wound is provided inside the head box 21. The lifting cord 28 is unwound from the lifting drum and hangs down from the head box 21. The lower end of the lifting cord 28 is connected to the bottom rail 27. The lifting drum is connected to a lifting drive unit 32 such as a motor. When the lifting drum is driven by the lifting drive unit 32, the bottom rail 27 rises and falls. When the lifting cord 28 is wound onto the lifting drum, the bottom rail 27 rises and the slats 11 overlap the bottom rail 27 from the bottom up. On the other hand, when the lifting cord 28 is unwound, the bottom rail 27 descends and the spacing between the slats 11 increases from the top down. The bottom rail 27 may be raised and lowered manually.

The tilting driver 31 is connected to a control unit 35 such as a microcomputer. An adjustment function 37 such as the following formula (1) that expresses the relationship between the set angle α [°] and the profile angle φ [°] as the slat angle is stored in a memory unit 36 of the control unit 35. The control unit 35 applies the current profile angle _φr to the profile angle φ of the adjustment function 37 to determine a specific set angle _αr . Then, the control unit 35 controls the tilting driver 31 in real time, so that the slat 11 is tilted by the tilting driver 31 and the angle of the slat 11 is adjusted to the specific set angle _αr . Here, α and φ are variables, and _φr and _αr are specific numerical values.

Here, the profile angle φ refers to the angle that the projected ray L2 of solar radiation L1 makes with respect to a horizontal plane when the ray L1 is projected onto a vertical plane perpendicular to the window surface 2, as shown in Figures 3 and 4. Specifically, the profile angle φ is calculated from the following formulas (2) and (3).

In Figures 3 and 4, the X-axis is the horizontal window surface normal, the Y-axis is a horizontal line perpendicular to the window surface normal, and the Z-axis is parallel to the vertical direction.

The incidence angle θ, solar altitude h, and solar azimuth angle γ are calculated from the calendar, i.e., the time of the year (month, day, hour, minute, and second), the latitude and longitude of the installation location of the horizontal blind device 10, and the direction of the window surface normal. Because the latitude and longitude of the installation location of the horizontal blind device 10 are constants, and the direction of the window surface normal is also constant, the incidence angle θ, solar altitude h, and solar azimuth angle γ can be said to be functions of the calendar, i.e., the time of the year. Therefore, the control unit 35 calculates the current profile angle φ _n from the current time, and determines the specific set angle α _n from the current profile angle φ _n as described above.

In this embodiment, the method of calculating the adjustment function 37 is unique, so the method of calculating the adjustment function 37 will be described in detail below. In the following description, φ, β, and τ represent variables, and those with subscripts represent specific values.

As a result of extensive research, the inventors discovered that transmittance τ can be expressed as a function f of slat angle β and profile angle φ, as shown in the following formula (4).

Here, transmittance τ refers to the ratio of the passing illuminance [lx] to the incident illuminance [lx] in the area from the head box 21 to the bottom rail 27 when sunlight with a profile angle φ passes indoors through the gaps between slats 11 with a slat angle β. The passing illuminance includes not only the illuminance due to light that passes directly between the slats 11 without entering the slats 11, but also the illuminance due to light that enters the slats 11 and is reflected.

Equation (4) can be expressed graphically as shown in Figure 5. Figure 5 is a graph showing the relationship between profile angle φ and transmittance τ when slat angle β is -75°, -60°, -45°, -30°, -15°, 0°, 15°, 30°, 45°, 60°, or 75°.

Then, using equation (4), the adjustment function 37 is calculated taking into account the transmittance τ in equation (4). An example of how to calculate the adjustment function 37 is described below.

By fitting values _β1 , _β2 , _β3 ... at small angle intervals to the slat angle β in formula (4), a function of profile angle φ and transmittance τ (functions represented by each curve shown in FIG. 5) is obtained for each slat angle _β1 , _β2 , _β3 .... Then, by fitting the same value _φ1 to the profile angle φ of each function _, transmittances _τ1 , _τ2 , _τ3 ... for each slat angle _β1 , _β2 , _β3 ... are obtained, and the profile angle φ1 is associated with the slat angle _{βa_1} (slat angle _{βa_1} is any of slat angles _β1 , β2, _β3 ...) _that has the minimum transmittance _τmin (or the maximum transmittance _τmax ) among the transmittances _τ1 , _τ2 , _τ3 .... Similarly, a data string is generated that associates slat angles β _{a_m} (m is a positive _number ) and profile angles φ _m ( _m is a positive number) that provide the minimum transmittance by gradually changing the value to be applied to the profile angle φ of each function as φ 2 , φ 3 ..., where the data string β _{a_1} , β _{a_2} , β _{a_3} ... for slat angles β _{a_m} corresponds to the set angle α of adjustment function 37, and the data string φ ₁ , φ ₂ , φ ₃ ... for profile angle φ _m corresponds to the profile angle φ of adjustment function 37, and this is represented graphically as shown in Fig. 6. A program is prepared in advance, and adjustment function 37 is calculated by computer processing as described above.

The above method of calculating adjustment function 37 is just one example, and any method may be used to calculate adjustment function 37 using equation (4). For example, since viewability (the ratio of the area of the outdoor scenery to the total area of the field of view when looking at the outdoors from indoors through the blinds) is a function of slat angle β, adjustment function 37 may be calculated taking into account transmittance τ in equation (4) while ensuring that viewability satisfies a specified value. However, setting angle α and profile angle φ must satisfy the following equation (5).

The angle calculated by the right side of the above formula (5) is called the protection angle. The protection angle is the minimum slat angle that can block direct light and prevent it from passing between the slats 11. If the slat angle is less than the protection angle, some direct light passes directly between the slats 11. The relationship between the protection angle and the profile angle φ, that is, the function in which the protection angle is expressed by the profile angle φ as in the right side of formula (5), is shown in Figure 7. Figure 7 also shows the relationship between the transmittance and the profile angle φ, and the relationship between the reflectance and the profile angle φ. The reflectance is the ratio of the reflected illuminance [lx] to the incident illuminance [lx] in the area from the head box 21 to the bottom rail 27 when sunlight with a profile angle φ is reflected to the outdoors by the slats 11 with a slat angle β. The relationship between the transmittance and the profile angle φ and the relationship between the reflectance and the profile angle φ were calculated using a lighting environment simulation software called "Radiance".

As described above, the adjustment function 37 is calculated based on the transmittance, and the current profile angle _φr is applied to the profile angle φ of the adjustment function 37, and the slat angle is adjusted to the specific set angle _αr obtained thereby, so that the heat load for cooling can be appropriately suppressed. In particular, when the adjustment function 37 is a graph as shown in Fig. 6, the heat load can be suppressed particularly effectively.
Since the set angle α and the profile angle φ satisfy the formula (5), the slat angle can be adjusted to be equal to or greater than the protection angle, thereby preventing direct sunlight from entering the room and reducing the thermal load on the cooling system.

11...Slat 37...Adjustment function

Claims (4)

A method for controlling a blind having slats arranged in parallel in multiple vertical stages and tiltable about a horizontal axis, comprising:
determining an adjustment function that represents a relationship between a setting angle for setting the angle of the slat and the profile angle based on the transmittance of the blind in a function that is represented by the slat angle and the profile angle;
A method of controlling blinds that adjusts the angle of the slats to a particular set angle obtained by fitting a current profile angle to the profile angle of the adjustment function. 2. The method for controlling blinds according to claim 1, wherein a relationship between the setting angle and the profile angle that provides a desired transmittance as the transmittance in the function is obtained as the adjustment function. 2. The method for controlling blinds according to claim 1, wherein the adjustment function is determined to have a relationship between the setting angle and the profile angle such that the transmittance in the function takes a minimum or maximum transmittance. The method for controlling blinds according to any one of claims 1 to 3 , characterized in that the set angle is equal to or greater than a protection angle which is a minimum slat angle capable of blocking direct light.

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