The new “smart” buildings we have been seeing more and more often in recent years stand out not only for their architectural innovations but also for the significant energy savings they achieve, chiefly through the use of natural light.
With the price of electricity climbing relentlessly, designers are looking for ways to make use of natural light, which is abundant in Greece, in order to cut operating costs and avoid burdening the environment with energy-hungry light sources.
Natural lighting: what is it and how is it applied?
A natural lighting system can be defined as the combination of:
1) Glazing or another light-transmitting element
2) A frame
3) A shading device (either a structural element or something else)
The main categories of natural lighting systems are as follows:
1) Openings in vertical walls (e.g. windows, glazed facades).
2) Roof openings (e.g. skylights).
3) Atriums
4) Light wells.
5) Special glazing
6) Prismatic light-transmitting materials
7) Light shelves, reflectors, louvres
8) Shading devices
9) Transparent insulating materials.
How do you create a good natural lighting design?
For a natural lighting design to be considered successful, the right systems and techniques must achieve what is known as visual comfort. In other words, the building’s interior functional spaces must have an adequate lighting level and an even distribution of light, so that there are no sharp variations that cause glare.
The adequacy and distribution of natural light vary from space to space and depend on:
the geometry of the space and its openings (e.g. how large or small the windows are, what angles there are in the room, etc.)
• the photometric characteristics of the opaque surfaces (e.g. the colour of the walls and whether that colour absorbs or reflects natural light, etc.)
• the photometric characteristics of the glazing (e.g. the light transmittance or reflectance of a building’s glass, etc.)
Natural light versus eye strain
Studies have shown that natural light reduces or eliminates eye strain, a modern complaint that has afflicted more and more workers in recent years. Eye strain is a temporary condition that affects the eyes of people who work mainly in front of a computer. Its symptom is blurred vision, which fortunately does not last long as long as the sufferer focuses on a point other than the screen.
Dr. James Lamott and his colleagues at the Northern California College of Optometry in the USA studied the effect of fluorescent light on 49 employees of the University of California. These employees worked in the university’s personnel records department, and their work required many hours of computer use.
First, the researchers asked the employees to fill in a questionnaire about the symptoms their eyes experienced after many hours of strenuous work. They then replaced the traditional filters in front of the fluorescent lamps with acrylic ones, which give off a more natural light.
After two weeks, the employees reported that the symptoms of eye fatigue had dropped significantly. The same was true of sensitivity to light. However, no differences were observed in symptoms such as burning, itching or headaches.
Unsurprisingly, 75% of the employees said they preferred the acrylic filters, which give off more natural light. The researchers also advised anyone wishing to reduce the symptoms of eye strain to fit special filters in front of the computer screen, which absorb a significant part of the radiation it emits.
