Designers have come up with a simple, inexpensive switch that senses when sufficient daylight is available to take the place of electric light, and then responds by turning off the fixture. When daylight decreases, the device turns the light back on. Increase "day-lighting" architectural features, install the switches, and you have a achieved the "virtuous circle". Rensselaer Polytechnic Institute's Lighting Research Center engineers designed the switch for commercial and institutional buildings, estimating it could reduce lighting energy consumption by 30% in such settings. Because of its simple circuitry, this switch is inexpensive, and can work with all kinds of light fixtures. Projections are that capital cost can be recovered in one year. For a brochure on the design, download this pdf file .
There's a standup comedian who has a sketch where he mocks the light switches that go off as soon as you go out of the receptor's field of view: as in left in a darkened toilet stall and not able to find the TP. Even more vulnerable to criticism are the arbitrary timers on office lights that, once over ridden, stay on all night. This LRC innovation is so straightforward and common-sense, a smile and lower electric bills are all it should produce.
via: Roland Piquepaille's Technology Trends