7 Artificial Lighting 人人人人 The subject of this chapter is artificial lighting, and the following chapter deals with natural lighting. Although the principles of these two topics are treated separately it is important that they are considered together when designing a building.
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7 Artificial Lighting The subject of this chapter is artificial lighting, and the following chapter deals with natural lighting. Although the principles.
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7 Artificial Lighting
人工照明
The subject of this chapter is artificial lighting, and the following
chapter deals with natural lighting.
Although the principles of these two topics are treated
separately it is important that they are considered together
when designing a building.
The main functions of artificial lighting?
to provide enough light for people to
carry out a particular activity
to provide enough light for people to move about
with ease and safety
to display the features of the building in a manner
suitable for its character and purpose
To achieve these aims it is necessary to consider the pro
perties of lamps, of the lamp fittings 灯具 and of the roo
m surfaces that surround them.
7.1 Lamps 7.1 Lamps 灯灯
What is The oldest source of artificial light ?
the flame from fires, from candles and from oil lamps
(2) gas discharge sources(2) gas discharge sources 气体放电灯气体放电灯
produce light by passing an electric current through a gas or va
pour that has become ionised 电离 and hence able to conduct el
ectricity.
At low pressure, a luminous arc or discharge is formed betwee
n the electrodes and useful quantities of light are given off
7.1.1 how to evaluate the Properties of lamps7.1.1 how to evaluate the Properties of lamps
1) Luminous efficacy 1) Luminous efficacy 光效光效 which is given by the following formula.
inputpower Electrical
outputflux Luminousefficacy luminous
Unit: lumens /watt (lm/W)
2) Life 2) Life 寿命寿命
The luminous efficacy of a lamp decreases with time and for a
discharge lamp it may fall by as much as 50% before the lamp
fails.
The nominal life of a lamp is usually determined by the
manufacturer by considering the failure rate of a particular
model of lamp combined with its fall in light output.
In a large installation it is desirable that all the lamps are
replaced at the same time on a specified maintenance
schedule.
3) The correlated colour temperature (CCT) 3) The correlated colour temperature (CCT) 相关色温相关色温 is the absolute temperature of a perfect radiator when the colour
apperance of the radiator best matches that of the light source
Unit : kelvin (K)
•色温反映灯光本身的表观颜色•The CCT reflects the apparent color of light itself,
The lower values of colour temperature indicate light
with a higher red content.
Some examples of colour temperatures are given below
Compact fluorescent lamps give a light quality suitable
for domestic purpose and the use of such lamps are
important technique for low-energy lighting in homes.
How is the coulur quality of gas discharge lamps?
Apart from the well-known tubular fluorescent lamp,
gas discharge lamps usually have a poor colour rendering
So they have in the past been restricted to outdoor lighting, such as for roadways, where their generally poor colour qualities have not been imp
ortant.
Modern types of discharge lamp have a colour rendering
that is good enough for large-scale lighting inside buildin
g such as factories and warehouses 仓库 .
Continuing technical advances are producing more disch
arge lamps suitable for interior lighting
high efficiency of such lamps can give significant saving
s in the energy use of buildings.
Mercury discharge lamps Mercury discharge lamps 汞放电灯汞放电灯 An uncorrected mercury lamp emits sharp light at certain blue
and green wavelengths.
Some Modern types of discharge lampsSome Modern types of discharge lamps
In the mercury halide lamp
卤汞灯 , metallic halides are
added to the basic gas disc
harge in order to produce be
tter colour rendering and to r
aise the efficacy
A metal halide gas discharge lighting system provides illumination for a college baseball game at Olsen Field in College Station, Texas. Note the various colors of the lights as they warm up
Example of a Metal Halide lighting pole, at a baseball field
So the suggested layout is satisfactory provided that the distance between lamps is not greater than 4.5m
In a particular lighting system design ,the In a particular lighting system design ,the following factors need to be consideredfollowing factors need to be considered
Light quantity should reach the illuminance levels
Natural light 自然光
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Colour quality 光的颜色
Glare 眩光
Directional quality 方向性 Energy use 能耗 Costs 运行费 Physical properties 物理性能
That’s all for chapter 7, let’s do a summary together.
chapter 7 Artificial Lighting
7.1 Lamps 7.1 Lamps 灯灯7.1.1 how to evaluate the Properties of lamps7.1.1 how to evaluate the Properties of lamps
Luminous efficacy Luminous efficacy 光效光效
Life Life 寿命寿命
The correlated colour temperature (CCT) The correlated colour temperature (CCT) 相对色温相对色温