How does induction save energy
How is it that an 200W induction lighting syetem can replace a 400W metal halide
lighting syetem and the performance is even much better.
The reason lies in what's pupil lumen:
How people see and are psychologically impacted by lighting has been
a subject of much study and discussion for years. Describing light as "lumen output"
and measuring it as "foot candles" on a work plane have been the traditional ways
of describing and defining how much light is required to perform a variety of tasks.
However, that is being re-examined based on results of studies on visual performance
and the psychological impacts of lighting. Additionally, the "color rendering index"
(CRI) and correlated color temperature (CCT) describe the quality of the light (relating
to how true colors appear compared to under a noon north sky on a clear day). As
lighting technology evolves into various types and colors, simply measuring the
lumens proves not to be fully adequate in predicting how well people can see In
bright light our pupils contract allowing more detail to be perceived, while depth
of field and perceived brightness also increase. In low light our eyes dilate to
allow more light in. Sam Berman—formerly with the Lighting Systems Research Group
at Lawrence Berkeley Laboratory and a major supporter of the importance of the P/S
ratio in lighting selection—developed a conversion factor that applies the P/S ratio
to lumen output of various light sources, and then expresses the effective lumens
the eye will perceive for vision based on the size of the pupil and the effect on
vision (see Table 1 below). Some lamps, like low-pressure sodium, lose most of their
output using this method, while others like high-quality induction lamps gain substantially.
|
Light source
|
Conventional lumens per watt
|
Correction factor (P/S ratio)
|
Pupil lumens per watt
|
|
Low-pressure sodium(SOX)
|
165
|
0.38
|
63
|
|
High-pressure sodium(35W)
|
55
|
0.57
|
31
|
|
High-pressure sodium(150W)
|
100
|
0.76
|
76
|
|
High-pressure mercury
|
40
|
0.86
|
34
|
|
Metal halide(at 2000hrs)
|
70
|
1.14
|
80
|
|
Clear metal halide(Na/Sc)
|
90
|
1.49
|
126
|
|
Standard incandescent
|
15
|
1.26
|
19
|
|
Tungsten halogen
|
22
|
1.32
|
29
|
|
5000K YML induction Lamp(200W)
|
85
|
1.96
|
167
|
|
6500K YML induction Lamp(200W)
|
85
|
2.25
|
191
|
Table calculations by Berkley Labs-actual selection of induction lamp wattage and
type will vary with installation and user requirement.
How to calculate visual effective lumens:
|
Note:The dates in green are the Conventional lumens per watt,the
dates in red are the (P/S)Ratio
|
|
Type
|
Initial Lumens
|
Lumens(2000hrs)
|
Lumens
(5000hrs)
|
Lumens
(10000hrs)
|
Lumens
(20000hrs)
|
Lumens
(100,000hrs)
|
|
400MH
|
400*85*1.49=50660
|
400*70*1.08=30240
|
27216
|
broken
|
2pcs MH already broken
|
10pcs MH already broken
|
|
200 Induction
|
200*85*1.96=33320
|
200*80*1.96=31360
|
29988
|
28322
|
26656
|
23324
|