After heating which uses the most energy, lighting is the next largest energy user. Light has an important role for wakefulness and performance. Tremendous development is now taking place in the field of light sources.
At the same time, research is showing that daylight is of very great importance for people. Architects and town planners should make as much use as possible of daylight and only provide additional energy efficient lighting where conditiions for daylighting are quite impossible. Human environments are in this way created with a careful use of natural resources. Formas is supporting exciting research in the field of lighting.
Incandescent bulbs are being phased out and replaced by halogen lights, compact fluorescent lamps and, not least, by light emitting diodes (LED) which emit more light per installed load. Development of LED may result in a new phase in the history of lighting. Energy use can be reduced, and at the same time the quality of lighting increased and the quantity of generated light quadrupled.
In certain lighting installations, LED can soon reduce the need for electricity by up to eighty per cent. It is already possible to reduce the use of electrical energy for highly coloured illuminated signs by ninety-five per cent in comparison with those using the traditional low pressure fluorescent tube. Within five years, LED instead of the fluorescent lamps may replace incandescent bulbs in the home environment. LED are expected within thirty years to outcompete all other light sources. LED are now being tested in lifts, stairways, deep freeze cabinets and outdoor lighting.
Lighting must be not only energy efficient but must also promote human health. At an interdisciplinary centre for energy efficient lighting at Lund University, researchers from engineering, medicine, social sciences and the humanities are collaborating. The aim is to develop the right lighting for different situations.
Daylight is good, but sometimes it may be too much. Not only when the sun shines right in, but also on a cloudy day the light from the sky may be too strong. Controllable curtains of different kinds are therefore needed. Since computer screens arrived on most desks, people are looking right ahead instead of looking down at a paper. In the surrounding visual field there is often a window. The screen shines at a constant strength and should not be illuminated too much since the contrast may become too small and they can no longer be read.
Chemical compounds that are similar to natural signal substances disturb vital biological systems. Researchers have now discovered that UV light and also visible light form a biological signal substance (a new vitamin?) which may explain why dioxin is so toxic. Unique research in this field is being conducted at the Karolinska Institute KI and at Stockholm University. UV radiation can also be used to kill bacteria in sewage effluent. This is done in a project whose objective is to purify effluent from pharmaceutical residues and other hormone-disrupting substances. Researchers are now looking for the right methods and wavelengths.
Chickens are photophobic animals. The original breed, the junglefowl, tries to avoid open places and prefers the undergrowth where the light is filtered through leaves. Domesticated chickens may be sensitive and become stressed by strong light of the wrong character. With greater knowledge of avian vision, researchers are hoping to reduce stress among chickens. And perhaps also to prevent collisions between birds and planes.