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Civil Engineering and Urban Planning (CEUP 2016) 9in x 6in b2902-ch93
2. Parameters Optimization Model
2.1. Illuminance of road surface
When luminare has elevation angle, ξ, in Y direction (Figure 1), the horizontal
illuminance generated by the lamp at point b(x,y) is
2221.5
(,)
.
()
c
b
Ih
E
xyh
(1)
where, E
b
is the horizontal illuminance generated by one lamp at the point b(x,y)
of the road surface; h is the installation height of the lamp; γ is the intersection
angle of light ray Ab and optic axis AO
1
of the lamp,
arccos[(hcosξ+ysinξ)(x
2
+y
2
+h
2
)
-0.5
];
is the intersection angle between the
plane AOC and the plane AbO
1
; I
c
(
,
) is the luminous intensity of the lamp in
the direction of light ray Ab.
A
b
(
x
,
y
)
O
h
C
X
Y
O
1
Fig. 1. Lighting schematic diagram of one luminaire.
2.2. Luminous intensity of lamp
If photomatric data of lamp are available, the luminous intensity of the light-
direction deviating γ from the optic axis of the lamp is calculated as follows
1000 0
(,)
(,) .
1000
c
IM
I
(2)
where, I
1000
(γ,
) is the luminous intensity of the lamp from the photomatric data
corresponding to γ and
;
is light output rate of the lamp;
0
is utilization
factor of the lamp; M is maintenance factor of the lamp;
is the rated luminous
flux of the lamp,
=pq, where, p is the power of the lamp, q is luminous
efficiency of the lamp.
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