Civil Engineering Reference
In-Depth Information
where
P
n
¼
P
P
i
is the total installed lighting power in the room or building power is
of all luminaires in the room or building, measured in watts.
Daylight time usage (t
D
) represent operating hours during the daylight time,
measured in hours.
Non-daylight time usage (t
N
) represent operating hours during the non-daylight
time, measured in hours. Default annual operating hours for t
N
is 250 h.
An estimate of the parasitic energy
required to provide charging energy for
emergency lighting and for standby energy for lighting controls in the building shall
be established using the equation:
ð
E
P
;
t
Þ
þ
P
f
P
pc
t
y
t
D
P
em
t
e
g
t
N
E
P
;
t
¼
ð
kWh
Þ
ð
42
Þ
1000
where
P
pc
total installed parasitic power of the controls in the room or building is the
input power of all control systems in luminaires in the room or zone, measured
in watts. This power is a sum of electrical power from the mains supply con-
sumed by the charging circuit of emergency lighting luminaires and the standby
power for automatic controls in the luminaire when lamps are not operating
ð
P
pc
¼
P
P
p
;
i
Þ
.
Standard year time (t
y
) is time taken for one standard year to pass, taken as 8
760 h.
P
em
total installed charging power of the emergency lighting luminaires in the
room or building is input charging power of all emergency lighting luminaires in
the room or building, measured in watts. This power is a sum of input power
(P
ei
) to the charging circuit of emergency luminaires.
Annual operating time (to) is annual number of operating hours of the lamps and
luminaires with the lamps on t
o
= t
D
+ t
N
(h). This number is determined
depending on the building use. Default annual operating hours for t
o
is 2,500 h.
t
e
emergency lighting charge time represent operating hours during which the
emergency lighting batteries are being charged.
Table
18
shows the standard values for the periods until the next recharging
(loading level < nominal value) and the possible times to provide electricity for
various sizes of the (acid) batteries based on average consumption.
European standard about energy requirements for lighting: EN 15193-2006
gives a methodology for a numeric indicator of energy performance of buildings. It
is Lighting Energy Numeric Indicator, (LENI) described by the equation:
m
2
year
LENI
¼
E
=
A kWh
=
ð
43
Þ
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