1. Determine the basic strategy of window opening
In order to overcome the negative factors such as uneven illuminance, direct glare, excessive brightness ratio and excessive heat in summer when ordinary windows are used for natural lighting, designers should follow the following principles when designing windows:
(1) Increase the installation height of windows, and make them widely distributed and appropriate in area. The effective distance of natural light is limited to an area about 1.5 times the height of the top of the window. The amount of natural light entering the interior increases as the windows are raised. Whenever possible, the height of the ceiling should be increased in order to raise the height of the windows (see Figure 1).
(2) Open windows on more than two walls as much as possible. One-way lighting is prone to glare. In order to distribute light evenly and reduce glare, two-way lighting should be used as much as possible (that is, windows on both walls). Windows on each wall illuminate adjacent walls, thus reducing the contrast between each window and its surrounding walls.
(3) Open a window near the other side of the wall. A wall adjacent to a window can act as a low-light reflector to reduce the too strong directivity of natural lighting. Because of the light emitted from the side walls, the brightness ratio between the window and the wall on which the window is located can be reduced.
(4) Natural light filtering. Use trees or devices such as shades and horizontal blinds. Trees filter and soften sunlight, while devices such as shading panels and horizontal louvers block direct sunlight while allowing some diffuse sunlight into the windows.
(5) Avoid the windows being exposed to excessive light in summer. Due to seasonal demands for indoor comfort, it is ideal to let in a small amount of sunlight through the windows in the summer and as much sunlight in the winter as possible. Overhangs on south-facing windows provide ideal, seasonal control of light, while also eliminating shadows, reducing glare, and even reducing illuminance gradients.
(6) Use a removable shading device. A dynamic environment requires a dynamic response, and the dynamic changes in natural lighting are especially pronounced for east- and west-facing windows. East-west windows have direct light half the day and diffuse light the other half. Movable shades or curtains are able to respond to these particular changes. If installed indoors, in order to reduce heat, shading devices or curtains with high reflectivity should be used.
2. Strategies for skylights
A skylight is a horizontal or slightly inclined, glazed opening on the roof. Because the skylight is located at the top or top side of the building, it allows light to pass through with very high levels of illumination. However, direct sunlight is not suitable for visual work objects, so incoming sunlight must be diffused in some way. Unlike ordinary windows, it is more suitable to install translucent glass on skylights, which can eliminate a lot of direct glare.
The main problem with all skylights is that they face the sun more in summer than in winter. They get much more visible light and heat in summer than in winter. Therefore, whenever possible, high side windows should be used instead of skylights.
Here is a common strategy for opening skylights:
(1) In order to obtain uniform lighting, a certain interval should be maintained when opening the skylight. If there are no side windows, the skylight spacing should be equal to the floor height; the skylight to side wall distance should be 1/2 of the height. If there are side windows, the skylight spacing should be equal to the floor height; the distance from the skylight to the side wall should be 2 times the height.
(2) The skylight should be located in a higher space. Skylights installed high above the space become diffused light before the light reaches the interior floor. This can greatly avoid the glare caused by direct exposure.
(3) Open the skylight close to the wall. Any wall, especially north-facing walls, can act as a diffuse reflector for the skylight. Bright walls will make the space appear larger and brighter. The reflection of the north wall can balance the light coming in from the south window and eliminate the sun's light and shadow cast on the foot of the wall.
(4) Use an indoor reflector to diffuse sunlight. If a reflector is hung on the lower part of the skylight to reflect the light onto the ceiling, the large window will bring a very uniform diffused light.
(5) Use outdoor sunshades and reflectors to improve the balance of light in summer/winter. Block strong sunlight in summer, and use reflectors to increase the amount of skylight collected in winter.
(6) Use skylights with steeper slopes to balance summer/winter light. Because horizontal skylights get more light and heat in summer than in winter, using skylights that are steeper in slope and face south or north can provide more even light throughout the year. As the slope increases, the sunroof eventually becomes a high side window.
(7) Use sunlight to achieve dramatic effect. In halls, lounges, and other places where no particularly important visual work objects need to be seen clearly, use sunlight and sun shadows to create a lighthearted atmosphere. A patch of sunlight moving slowly across an object's surface can create some dramatic effect and can suggest the passage of time. To minimize excessive temperatures in summer, open skylights smaller, or install heat-reflecting glass on larger skylights, coat the glass with corrugations, or install photovoltaic cells to block excessive sunlight.