Energy conservation

1. Energy Audit and Management
Prof. C. S. Solanki
Department of Energy Science and Engineering

2. It is a systematic research of energy conservation
opportunities as well as a systematic approach to
measure energy level of plant. It is an effective tool
in defining comprehensive energy management
program.
Definition of Energy Audit
In general Energy Audit is the translation of
conservation ideas into realities, by blending technically
feasible solutions with economic and other
organizational consideration within a specified time
frame.

3.  Identify all the energy streams in a facility and to
quantify energy use
 Indicates where the major potential for improvement
 Identifies the cost of energy and where and how it is
used.
 It provides a base from which results can be
measured and from which programmer can be further
developed.
NEED FOR ENERGY AUDIT (EA)

4. • Assessment and reduction of electricity bill
• Identifying potential areas of electrical energy
economy
• Assessing present pattern of energy consumption
and optimizing energy consumption level
• Highlighting wastages in major areas
• Recommending energy saving measures with
minimum possible investment and realization of
savings.
OBJECTIVES OF ENERGY AUDIT

5. Comply with government regulations:
• The Energy Conservation Act 2003 (India), has identified 14
industry sectors and commercial buildings as designated
consumers. A comprehensive Energy Audit helps these
industries comply with major provisions of the act like:
•
~ Maintaining energy consumption within standard norms
~ Maintaining and reporting accurate energy usage patterns
~ Training of Energy Managers responsible for energy
efficiency of the plant
•
• The Energy conservation techniques can be understood by
studying the Energy conservation Act, 2003 (INDIA).

6.  Industries in specific sectors, with connected load of 5 MW and
above and/or consuming 20 MT of oil equivalent per hour on an
average are notified as designated consumers. All commercial
buildings with connected load of more than 500KW are also notified
as designated consumers.
 Designated consumers will comply with energy consumption
standards and norms. Different standards and norms are prescribed
for different designated consumers.
 The Central Government, in consultation with BEE, can direct
designated consumers to conduct Energy Audits by an accredited
Energy Auditor based on a certain periodicity
Major Provisions of the Energy Conservation Act, 2003
(India):

7. Industries notified under the Energy
Conservation Act, 2001 (India):
1. Aluminum
2. Fertilizer
3. Iron and Steel
4. Cement
5. Pulp and Paper
6. Chlor Alkali
7. Sugar
8. Textile
9. Chemical
10. Railway

8. Conservation of energy through Auditing
• Removal of discrepancies between the operating and the design
figures of energy consumptions
• Improvement in process technology
• Improvement in system design; change in temperature approach in
heat exchangers
• Improvement in automations and controls for optimal utilization of
energy
• Units/Systems integration: provision of a facility of one equipment for
the other
• Incorporation of measures to improve efficiency such as cascading
of energy
• Recovery of waste and low level heat, minimizing of losses, etc
• Detailed study of measure energy consuming equipments for
possible energy savings by improving operations, improvement in
hardware design and replacement with more efficient hardware.

9. The type of EA to be performed depends on
•Function and type of Industry
•Depth to which final audit is needed
•Potential and magnitude of cost reduction desired
There can be two types of EA
•Preliminary Energy Audit ( PEA )
•Detailed Energy Audit ( DEA )
TYPES OF ENERGY AUDIT

10. PEA DEA
Objective Set priorities for optimizing
energy consumptions
a) Quantify Energy consumption and
utilization
b) Evolve detailed engineering for
options to reduce energy cost
Scope Highlight energy cost and
wastages in major equipment
/problems
Formulate detailed plan on the basis of
quantitative evaluation
Duration 2-10 days 1 – 10 weeks
Audit a) No pre audit visit required
b) Detailed questionnaire to
be completed before audit
a) One / two pre audit visits are required
b) In addition
- Advance notice to HOD’s
- Arranging office and secretarial
support
- Advance tentative schedule
- Audit kit planning

11. SCOPE OF EA
• The scope of an energy audit varies according to the
facilities being audited.
• At the extreme is a light manufacturing operation
where lighting ventilation and air conditioning are the
major energy uses.
• While at the other end there are integrated process
units like the refineries and petrochemical plants
where cascading of energy and complex energy
balances are involved.

12. . Analyze present consumption and past trends in detail
• Review lighting requirements
• Produce and energy balance diagram for the firm
• Check working of controls
• Check capacities and efficiencies of equipments
• Review energy storage and handling
• Determine adequacy of maintenance
• Introduce life cycle costing
• Examine need for energy saving incentives
• Examine and monitor new energy saving techniques
Typical points considered in EA

13. Energy Audit Team
1] Expert licensed engineers for auditing
2] They should have good knowledge about :
i)Process
ii)Operating experience of unit.
iii)The plant utilities and plant material and
energy balances and the assistance from
research and development wing should also be
available to them

14. Instruments needed for Energy Audit
The following are the typical instruments needed for
energy audit:
• Power meters( Clip-on-meters and direct connected meters).
• Power factor meters( clip-on-meters).
• Lux meters—To measure the illumination level.
• Energy meters, ammeters( Clip-on-meters also), Voltmeters.
• Stop-Watch
• Tachometer
• Bearing stethoscope to see the conditions of bearings
• Portable temperature indicators

15. 15

16. Energy Audit methods based on
•Flow of energy – energy balance
• Flow of material - mass balance

17. 17
CEOs

18. 18
Table of Summery of energy saving
recommendation

19. 19
Prioritize recommendations

20. 20
Example: saving in terms of fuel

21. Types of load for energy audit
• Electrical load
• Heating load
• Cooling Load
• Lighting load

22. Energy Efficiency in
Lighting

23. Electricity for lighting
• About 15% of total electricity produced is used for lighting
purposes
• India’s energy intensity per unit GDP is higher than that of
Asia, Japan and USA by 1.47, 3.7, 1.55 respectively
 inefficient use of energy
Sector % of total
electricity used
% Lighting
component
Industry 49 5-15
Commercial/public 17 5-15
Domestic 10 50-90
Other 24 2
• up to 40% electricity saving in lighting can be achieved by
retrofitting efficient ballast, lamps, reflectors etc.

24. Optical performance
Human factors
• Optical performance of
eye
• Color perception
• Condition of eye
Environmental factors
• Relative brightness of the
task and its surrounding
• Glare from the task and
its surrounding
• Movement of the task
• Our visual ability is to see the objects is affected by
human and environmental factors
Ref: Light Right by M.K. Halpeth, T. S. Kumar, G. Harikumar, TERI press

25. Units of lighting
• Units of lighting are derived from the human response to light
and its physical power; units can not be directly related to
physical units
• There are four units of lighting
-Light output (luminous flux), (lumen, lm)
-Luminous intensity (candela, cd)
-Light level (illuminance) (lux, lx;
1 foot-candle=10.76 lux)
- brightness (luminance) (cd/m2)
About the source
(pressure in tank, flow
rate from tank)
About illuminated
surface
(amount of water per
unit area of spray,
amount bouncing off
the surface)

26. illuminance
(lux)
Light output
(lumens) Brightness
(cd/m2)
Brightness of source
(candela)

27. Type of light
Type of source Color temperature (K)
Incandescent lamps 2700
Fluorescent-warm white 3000
Fluorescent-cool white 4000
Daylight 6000
• Color temperature of light source given in terms of Kelvin
equivalent to blackbody temperature that would emit the
light same as light source
• Color rendering index (CRI)- ability of light source to convey
accurately a sample of eight colors relative to standard source
Type of source CRI
Fluorescent-cool white 58-62
T8 lamps 75-98
High pressure sodium lamp 27

28. Efficacy
• Number of lumen output of a light source per unit power
consumed by source and its ballast (if any) is called as
efficacy of the source
• A 100 W incandescent lamp with 1500 lumen output will
have 15 lm/W efficacy
• Higher is the efficacy better the source is
• Ballast power should be included in efficacy calculation

29. Types of light sources
Light source
incandescent Discharge lamps Solid state
• conventional
• Halogen
• Fluorescent
• Mercury (high &
low pre.)
• Metal halide
• Sodium
(high & low pre.)
• LED
Glow due to
Filament Heating
Gas Ionization and
discharge
Transition of electron from
high energy to low energy
Operating principle

30. Light sources: Incandescent
• Incandescent lamp- tungsten filament, N2 and some inert
gas, comes in various shapes and sizes, life is strongly
affected by voltage (lower voltage increases life)
Life – 750 – 2000 hours
• Halogen (quartz) lamp – halogen gas (Iodine or bromine)
is added to normal gas to avoid evaporation of tungsten,
avoid gradual blackening of lamp
Life- 2000 – 3500 hours
• efficacy of both type of incandescent lamps are similar –
10 to 30 lm/W

31. Light sources: Discharge
• Current through gas ionizes it, light is emitted by discharging
of ionized gas
• Ballast is required to supply the required voltage for ionizing
• High intensity discharge (HID) lamps : discharge between
two electrodes in a tube containing various metallic vapors
(Hg, Na)

32. Efficacy and CRI of various lamps
0
20
40
60
80
100
120
140
0 1 2 3 4 5 6
efficacy
CRI

33. Incandescent vs fluorescent lamp: Case
study
Cost of electricity 4 Rs/unit
Lumens of light required 1000 lm
Wattage of incandescent lamp 100 W
wattage of fluorescent lamp 25 W
Life of incandescent lamp 1000 hours
Life of fluorescent lamp 8000 hours
daily usage 6 hours
hours of usage in a month 180 hours/month
Cost of incandescent lamp 25 Rs
cost of fluorescent lamp 250 Rs
• Estimate the cost of usage for 1, 2, 4 years of usage,
when does the breakeven occurs ?

34. Incandescent vs fluorescent lamp
0
500
1000
1500
2000
2500
3000
3500
4000
2 6 10 14 18 22 26 30 34 38 42 46 50
Number of months
Cost
(Rs)
150
250
350
450
2 4 6
florescent
incandescent

35. • Reduce illumination in storage and non working
area.
• Make use of timer and clock switches for turning
on a particular light for particular time.
• Photo cell controlled switches could be installed
for road security and open area lighting .
• Check the height of light.
Good Lighting Habits

36. Energy Efficiency in
Electrical Load

37. Current, Voltage and Power
Watt
I
kV
or
I
V 


• Apparent power (kVA) - power supplied from a
source
• Single phase
• Three phase Watt
I
kV
or
I
V 



 3
3
Watt
PF
I
V 


• Reactive Power (kVAr) - power that does not do any work,
• Single phase
• Three phase Watt
PF
I
V 


 3
• Active Power (kW) – Power component that does the real work
PF = Active power/ apparent power
2
2
AP
RP
ApparentP 


38. The conditions on which the efficiency of operating motor
depends are
1) Health of stator & rotor iron parts
2) Conditions of the electric supply
3) Efficiency of the cooling system
Retrofitting of Electric Motors
Rated power/nameplate
rating or HP
(o/p rating)
Current, voltage, PF
(i/p rating)
Motor

39. EFFICIENCY CONSIDERATIONS:-
• An AC 3-phase induction motor has 5 components
of energy losses:
•
Sr.
no.
Motor component loss Total loss
1. Stator Cu loss 37%
2. Rotor Cu loss 18%
3. Iron loss 20%
4. Friction & windage loss 9%
5. Stray loss 16%

40. 1) Stopping idle or redundant running of motors
2) Oversized motors
- Higher investment cost due to large size
- Higher running cost due to decrease in efficiency at partial
loaded conditions
- Higher maximum demand due poor p.f.
- Higher cable losses & demand charges
- Higher switchgear cost
- Higher space requirement
- Higher installation cost
OPPORTUNITIES FOR ENERGY SAVING IN
MOTORS

41. REPLACEMENT OF OVERSIZED MOTORS
Many times oversized motors are procured for no. of
reasons as follows,
1) To ensure against motor failure in critical processes
2) when the actual load is not known, thus selecting a
larger size motor
3) To build in capability to accommodate future increase in
production.
4) When the correct size motor is not available
5) When process requirements have been reduced

42. Problem: A 10 kW motor has the name plate
details as 415 V, 18.2 amps and 0.9 PF. Actual
input measurement shows 415 V, 12 amps and
0.7 PF which was measured with power
analyzer during motor running.
What is:
Rated o/p power
Rated i/p power
Efficiency at rated power
% Loading of the motor

43. Motor efficiency and part-load