Sodium vapor lamps are apparently the most efficient light source
commercially available, which is why they're widely used in street
lighting. At 200 lumens/watt, they are about twice as efficient as
typical LED lamps, and have about half the service life. Their
construction uses borosilcate glass with a vacuum thermal insulation
envelope. Sound familiar? A discarded bulb might make a good core for a
Celani cell.
AlanG
ref: http://en.wikipedia.org/wiki/Sodium-vapor_lamp
On 2/15/2014 12:08 PM, Eric Walker wrote:
Another kind of light source I really have a hard time with is sodium
vapor. San Jose, which is just a 45 minute drive from where I live on
a good day, uses this for their street lamps.
