Hi,
The whole issue here is really about saving energy and lowering "light
pollution". But regarding the mythbusters data - it may be true for
incandescent bulbs, but it is *not* true for many of the bulbs used in
street lamps (at least in the US). Low pressure sodium bulbs, or mercury
vapor lamps, metal halide bulbs, etc. are used for the street lights.
They use a ballast transformer and circuitry to either preheat the gas
in the tubes or generate a high voltage to ignite an arc. These bulbs
have a greater efficiency of light or lumens produced per watt consumed
- but cannot be continuously power cycled on/off. Typical on/off cycling
needs to be at least 5-10 minutes or more. Plus these types of lamps
typically have a slow start time, it may take up to a minute or more for
them to reach full brightness, which would render them not too useful
for this type of application. Now of course if a different type of bulb
technology is used (incandescent for example) then that's another story.
:-)
"On/off operation
It may seem simple, but on/off operation is an area where many designers
create an unworkable lighting scheme. For example, consider the
metal-halide lighting system in the /Photo/, on page 40. /Restrike
time/, which refers to the time it takes a lamp to begin giving off
light after being turned on, is crucial for this type of system. Once
metal-halides are shut off, they take several minutes to begin giving
off light again after being turned back on. If all of your lamps are
metal-halide and you shut them off at night, you'll wait 15 min for a
reasonable level of light when you turn them on the next day. By adding
other types of light, as well as dedicating certain fixtures to an
“always on” configuration, you can reduce the effect of the restrike
time. In planning the layout of your lighting controls, make it obvious
which lights should not be shut off, and pay special attention to exit
path lighting." (from EC & M ezine).
'mark
Carol Smith wrote:
Motion sensors might be set off by passing cars.
Regardless, it is always better to turn off a light rather than leave it on
- even for a few seconds.
Mythbusters proved that: http://mythbustersresults.com/episode69
Busted Myth: Temporarily leaving a light on is more energy efficient than
turning it off and back on.
"Through numerous tests, the MythBusters calculated that the power surge
from turning on a light would only consume as much power as leaving it on
for a fraction of a second (except for fluorescent tube lights; the startup
consumed about 23 seconds worth of power). Furthermore, the wear and tear of
turning the light on and off repeatedly did not reduce the bulb's total life
expectancy enough to offset the increased electricity usage. Therefore, it
is far more economical to turn a light off rather than leaving it on."
Happy New Year everyone!
Carol
On Sun, Dec 28, 2008 at 10:16 PM, Bengi Turgan <[email protected]>wrote:
well wouldn't motion sensors be a better solution? of course if there are
no
horses or cows running freely on the streets.
Bengi Turgan
Project Manager
Bilende LLC
On Mon, Dec 29, 2008 at 12:45 AM, Mark Young <[email protected]> wrote:
As I get older (and my night vision gets weaker) I think I will try
use a head lamp more often. I've started keeping one in my car.
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Posted from the new ixda.org
http://www.ixda.org/discuss?post=36621
________________________________________________________________
Welcome to the Interaction Design Association (IxDA)!
To post to this list ....... [email protected]
Unsubscribe ................ http://www.ixda.org/unsubscribe
List Guidelines ............ http://www.ixda.org/guidelines
List Help .................. http://www.ixda.org/help
________________________________________________________________
Welcome to the Interaction Design Association (IxDA)!
To post to this list ....... [email protected]
Unsubscribe ................ http://www.ixda.org/unsubscribe
List Guidelines ............ http://www.ixda.org/guidelines
List Help .................. http://www.ixda.org/help
________________________________________________________________
Welcome to the Interaction Design Association (IxDA)!
To post to this list ....... [email protected]
Unsubscribe ................ http://www.ixda.org/unsubscribe
List Guidelines ............ http://www.ixda.org/guidelines
List Help .................. http://www.ixda.org/help
________________________________________________________________
Welcome to the Interaction Design Association (IxDA)!
To post to this list ....... [email protected]
Unsubscribe ................ http://www.ixda.org/unsubscribe
List Guidelines ............ http://www.ixda.org/guidelines
List Help .................. http://www.ixda.org/help
