What is the best light source of all?
- Daylight, sunlight is best of all!
Image Credit: MS Office ClipArt: Homes, Houses, Mirrors
2011 @ wobuilt.com
Mirror, mirror on the wall, what is the best light source of all? - Daylight / sunlight is best of all.
Wouldn't be great to have a magic mirror that can give a definitive answer all the time? Life would be so easy. But this was an easy question as the answer is undisputed. Generally, we humans love daylight and sunlight, it makes us feel more secure, safe, our productivity is up and our health improves. So it is absolutely important to include daylight/sunlight into our designs.
Now the question how to do this would stretch even the best magical mirror, since there are so many different things to consider:
Let's look at some of the components:
- Is it used for lighting or heating?
- Are the windows used for views or sunlight penetration?
- Do you need even lighting or can there be highlights?
- What are the spaces used for?
- And many more...
Daylight as a light source
Daylight is diffused light, that has less extreme brightness contrasts and thermal impacts, than direct sunlight. For working environments daylight is preferred, as it has excellent colour rendering, high even light levels that make tasks easier to perform, creates a visual comfort and allows energy savings. However, there is no drama in daylight and it provides little visual stimulation.
So a good daylight design will take natural visual variations into consideration. Maybe sunlight is reflected via light shelves to an area that is not necessary for tasks performance such as a ceiling or an end wall. Or the windows provide a view to the outside world. The challenge is to avoid glare, so that a comfortable working environment can be achieved.
Sunlight as a thermal source
However direct sunlight is perfect for passive solar design where a thermal mass such as a floor or a wall is heated up by the sun and acts as a heat sink. The heat, if designed properly, will be released during the cooler periods to heat the environment.
The two components are often in conflict with each other and a balance will have to be struck, even in a residential setting. Lighting and thermal design is not only for offices, malls, commercial and public buildings, but also has to be considered for a person's home. For example, glare in a kitchen would not do considering that sharp knives are used and glare could lead to accidents. Overheating in summer would be very uncomfortable. And view windows in a bathroom might not be appropriate.
Daylight will have to be introduced in a sensitive and effective method via skylights or utilizing external shading devices such as overhangs and trees. Trees, especially trees that loose their leaves in winter are very good sources of sunlight control as they provide shade in summer and let through light and heat in winter.
Daylight can also be introduced by using light tubes, which are coated on the inside with highly reflective material, which allows the light to travel longer to an area. Light tubes can bring light into basements from the roof, making the spaces more pleasant.
Daylight / sunlight is a renewable energy, it is available in abundance and if designed correctly will enhance spaces and make them more comfortable while saving energy.
Wo-Built Inc. - Innovative Design and Build
wobuilt.com/blog: Illuminating with Presents from the IESNA
IESNA - Illuminating Engineering Society of North America
wobuilt.com/blog: Light – the Music of Architecture
bchydro.com: Make The Most Of Natural Light
Daylight is by far the best light source. It's free, sustainable and can give a sense of energy and well being. Some housing is not well designed to catch sunlight, but by making the most of the light that is available, you are likely to achieve some energy savings and create a more comfortable and healthy living space.
www.gia.uk.com: Natural Light Works
creativeapplications.net: DaylightCal visualises the duration, angle and quality of sunlight wherever you are.
Using weather forecast data, DaylightCal calculates the distribution of daylight for any location and date worldwide. Find out how much daylight you’ve got left today and how much to expect tomorrow.
omeonet.info: Light medicine of the future: Let there be light
freelanceswitch.com: 10 Things You Can Do to Improve Your Home Office Cheaply
9. Improve the lighting
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useefficiency.eu: Educational issue: “Rule of thumb“ for students in architecture
"To include energy optimized building design from the beginning of a draft there are some simple rules architectural students can follow to avoid problems with the daylight, the ventilation and the protection against overheating."
Escrito por Sonja Schelbach, HCU-Hamburg