Most people do not welcome houses that do not reflect light. This is exactly the reason why real estate agencies always emphasize the light-reflecting nature of the house they introduce to attract customers. Having enough light at home, in addition to its importance from the perspective of building engineering, also has physical and psychological benefits; Especially for a family with small children, this issue becomes more important.
Perhaps these are the factors that have prompted researchers, including Iranian researchers, to design an automatic solar lighting system or the so-called smart solar lighting system (Sunflower, Khurshid Shamal) for northern buildings that do not have enough light. Mansour Mansoori, the moderator of this In a conversation with us, the plan has provided more details about the automatic lightening system.
Where does the main problem in the lack of sufficient lighting in northern buildings come from?
At least 2 factors should be taken into consideration when examining the sun’s radiation to the earth. One is the direction of the sun and the other is the height of the sun. In other words, in the northern hemisphere, the sun rises in the morning from the east and reaches the middle of the sky in the south direction at noon and sets in the west, which is called the direction of the sun’s rays. On the other hand, the value of the angle that the sun has with the south line is called the height of the sun; The subject that the sun shines more vertically in summer and obliquely in winter.
The assumed axis of rotation of the earth is not perpendicular to the surface of its annual orbit around the sun and makes an angle of approximately 23.5 degrees, which has certain effects on the earth. The changes in the sun’s radiation angle in different geographical latitudes and in different seasons are due to changes in the angle of the earth’s axis, which changes during the year with the rotation of the earth around the sun in the range of positive and negative 23.5 degrees.
The sun rises and sets in its apparent motion in late March and early April parallel to the equator on the equatorial circle, or in other words, in the vernal equinox circle; Therefore, the ray of sunlight is perpendicular to the equator at this time, and the circle of light and darkness are equal to each other. As a result, the length of night and day is the same in this place, and since the equator is the starting point for calculating latitudes in the geographic coordinate system, the width of the earth along this circle is equal to zero. According to these conditions and the deviation angle of the earth’s axis and its change interval, the sun’s radiation angle is different in the northern and southern hemispheres.
All these things are different for each point of latitude and what is important in the topic of sunlight radiation for our plan is the angle of radiation and the direction of radiation of the sun to the earth in different seasons and geographical locations.
It is worth remembering this point to know that if the northern units do not have sun in the northern hemisphere, the same point in the southern hemisphere will not benefit from the sun. In other words, as stated, the direction of the sun’s rays in the northern hemisphere is from east to south and west, while in the southern hemisphere it is east to north and west, and in the same way at the equator in winter. The sun shines to the south of the buildings and in the summer season to the north of the buildings.
Why is the exposure system emphasized to solve this problem? What kind of system is this system?
The human need for natural light has always been emphasized. Color and lighting have positive mental and psychological effects on people, and from a medical point of view, it is emphasized that the work and living environment should be chosen in such a way that we can use natural light and sunlight.
As already known, the movement of the sun and the earth and the radiation angles are such that it is not possible to simultaneously benefit from the sun’s radiation from both the north and south sides. This issue is especially evident for residential complexes and construction conditions that have their own limitations.
In other words, the dimensions and specifications of the land for construction are such that for the northern hemisphere, only the south side of the buildings has sunlight, and the north side of the buildings, skylights, staircases, etc. are deprived of sunlight. It is necessary to explain that in this hemisphere and in the summer season, the northern side is exposed to sunlight in the early morning and late evening. Obviously, the lack of sunlight to the north side of the buildings is not only for residential complexes, but includes every construction, including warehouses, sheds, etc.
According to these conditions, the existence of a system that can sunshade the places that face a lack of light and lack of sunlight is felt. The necessity of such a need is felt for the benefits that can be obtained from this system; Benefits such as sunlight and increasing the luxury of light to the desired rooms and places, improving psychological effects due to sunlight and light to the residence and work, reducing electricity consumption due to sunlight entering the building, positive health and hygiene effects due to Sunlight, sunlight and sunlight to the northern units of the building (buildings next to the building), sunlight and sunlight to the skylights of the building anywhere in the building, especially for the buildings next to the yard, sunlight and sunlight to the stairwells which are located in the middle of the building, sunshine and sunlight to the corridors, alleys, warehouses and any place that needs to use the sun and sunlight and increasing the maneuverability of the architect in using the sun during the building design.
In this system, which is named after the sunflower, sunlight is irradiated to the entire height of the building and the desired location. In this system, which is named after the sunflower, the sunlight is radiated to the entire height of the building and the desired location How sunflowers work is that with the sun’s rays, sunflowers position
It adjusts itself with its radiation angle and shines the sun to the adjusted place. As the angle of the sun changes, the sunflower automatically detects the new position and adjusts itself to the angle of the sun. The sunflower system is designed in such a way that it shines the sun to the set place for about 8 hours in summer and almost from sunrise to sunset in winter. It should be noted that the design is such that it can be used for any type of building, regardless of the angle of the building’s position relative to the horizon line.
How does this system automatically help provide the required light in the building and automatically adjust its position to the sunlight?
As mentioned, the height of the sun and the direction of the sun’s radiation during a day from sunrise to sunset for a place, as well as in seasons and in different latitudes, are different. On the other hand, the places where sunflowers are supposed to be installed are not necessarily parallel to the horizon line and are built at different angles to this line; Therefore, the sun tracking system should be designed in such a way that it can intelligently adapt itself to the sun in all conditions.
For this purpose, we have used a set of electronic circuits along with optical sensors, which by reflecting the sun from the surface of the mirror to these sensors, the necessary commands are given to the motors so that the mirror moves in the right direction. It should be mentioned that for this purpose the surface of the mirror moves in 3 axes.
At what stage of the construction of a building can these systems be used?
Sunflower can be installed and used both on ready-made buildings that are in use, and for buildings under construction, its installation arrangements can be considered and used in advance.
How many percentages does its use increase the required light supply inside the building?
We use convex mirrors to shine the sun into buildings using this system. Obviously, the sun shines on a fixed cross section of the mirror system. We make our own design for each building according to the dimensions and height where exposure is to be done and other conditions explained before, because we shine the received light to the height that is needed. Of course, the intensity of its reflection is not as strong as that of direct sunlight, but it has enough light to illuminate the place.
In the investigations we conducted on the installed locations and measured the light intensity with a lux meter, for a skylight measuring 9.2 x 2.8 meters in a 6-story building, the light lux was 2 times compared to before. became.
Is its application in the buildings of the country capable of implementation and economic justification?
Our country is in a position where we see an average of 275 sunny days. On the other hand, the conditions of construction, especially in big cities, have been done in such a way that due to the high price of land and other factors, an attempt is made to make the most of the space. In this context, increasing useful infrastructure is the priority of architects. These conditions are the best opportunity, both economically and health-wise, to use a system that can make the most of natural light while minimizing unused spaces and also complying with building standards from the point of view of providing minimum light for the units. to be All these conditions are available in our country and this system can be used in buildings without any problems.
The text published in Jam Jam newspaper
The text published in Meg Iran