PRACTICAL -3
AIM:
TO STUDY OF ILLUMINATION AND ENERGY CONSERVATION.
OBJECTIVE:
Light
is an inevitable part of active human life. It effectively or adversely affects
the activity by its presence. In the absence of natural light, the light
produced through electrical phenomena has really provided its best suitable
alternate. But there are various phenomena and factors which accounts for
consumption of such electrical energy. And, if they are manipulated properly
with the advancement of new technology, it can result into the conservation of
energy, a big demand of 21st century. Because light application is a
significant part of total electrical energy produced.
THEORY:
In
technical terms, the light is defined as electromagnetic radiation in the form
of waves which produces a sensation of vision within the brain through eyes and
science dealing with it is termed as illumination engineering. There is certain
term, which is noted below for reference.
(1)
Luminous
flux
(2)
Luminous
intensity
(3)
Lumen
(4)
Lux
efficacy
(5)
Glare
(6)
Brightness
There
two basic purpose of light:
(1)
To identify the object
(2)
To identity (or render) the colors of
the object.
The use of light can be
divided into three categories:
(1)
Ambient
lighting: It provides security and safety.
(2)
Task
lighting: It is used to accomplish the task accurately. It is
also not necessary to cover the entire area,
(3)
Accent
lighting: It illuminates walls to blend more closely with
naturally bright areas like ceilings.
The science of light
i.e. illumination is governed by two laws:
(1) Inverse square laws
(2) Lambert’s cosine laws.
Ø The
candela power of light is derived using polar curves.
Ø Depending
up on reflecting or diffusing surfaces, there are various types of reflections
or shades used for illumination.
Ø Depending
up on the requirement there are three types of lighting schemes which are
arranged for illumination.
(1)
Direct lighting
(2)
Indirect lighting
(3)
Semi-direct lighting
For the effective
illumination purpose, following guiding factors are considered:
- Space height ratio: = The horizontal lamps/Total lumens radiated by lamps
- Utilization factor: = Total lumens utilized on working planes/ Total lumens radiated by lamp
- Depreciation factor: = Illumination under normal working conditions/ Illumination when everything is clean.
- Waste light factor: = It takes into the account the overlapping of light waves.
Ø With
proper combination of all such factors, the area of lighting is broadly
classified as under. :
1.
Household
lighting
2.
Commercial
lighting
3.
Factory
lighting
4.
Flood
lighting
Therefore,
if we wish to prepare optimum lighting design, it could be achieved by the
following means
- Choosing the proper light sources suited to the system such as color rendering, higher efficacy etc.
- Proper selection of luminaries to use the lamp output efficiently.
- Proper arrangement of luminaries considering the standards of lighting and structural limitations.
- Introducing control strategies based on variations in occupancy (location and time) and variation in the available day light.
- Combining local lighting and general lighting for intricate jobs requiring very high level of illumination.
Ø Ultimately,
it is the lamps which transfer the electrical energy in the form of light, so
its statistics in the form of efficacy, color rendering index and life are
considered in table-1.
Further, distribution
of energy after conversion in light is broadly classified as under as observation
table-1
SR NO.
|
LAMP
|
LIGHT
|
HEAT ENERGY
|
MAGNETIC ENERGY
|
1
|
incandescent
|
|||
2
|
Fluorescent
|
|||
3
|
Vapour
lamp
|
less
|
Thus, if we carefully
observe the table-1 and table-2 then, it is evident that efficacy (lumen/watt)
magnetic and heat energy generation are factors on which energy conservation
can be implemented. While lamp life and color rendering index are those factor
economical aspects.
Therefore, we need to concentrate on it and analyze it as
under:
v Incandescent lamp: try to reduce
the voltage fluctuation. Because as per data in developed country lamps
produces 90 lumens/watt while in India it gives 50/0 lumens/watt due to voltage
variation. Therefore, we need more Incandescent lamp
v Improvement in design:
this includes the aspect of reduction in heat losses and lamps developed
considering the same basis are:
- New fluorescent lamps
- Ballasted circular fluorescent lamps.
- Compact fluorescent lamps.
The typical power
rating changes from 60 watt to 16 watt same amount of light produced. Thus
about 75% saving over the incandescent lamp.
v Fluorescent lamps: The major
limiting factor in fluorescent lamp is magnetic losses. These are eliminated by
the use of electronic ballasts. It is a device which converts the low frequency
into high frequency for current limiting application then again converts it to
50 Hz frequency for tube light operation. Typical power consumption is 1 to 3
watts for such operation. Thus results into 85% of saving as compared to
magnetic ballast of 16 watt rating.
