energy audit and mgt unit 2
TRANSCRIPT
Energy Audit and Management
Prepared by
Prof. Jagdale H.D
Mechanical Engg. Dept.
ICEM
UNIT –II
Energy Auditing
CONTENT:
Need of Energy Audit, Types of energy audit,
Components of energy audit, Energy audit methodology
Instruments, equipment used in energy audit,
Analysis and recommendations of energy audit -
examples for different applications
Energy audit reporting, Energy audit software
Energy conservation opportunities in Boiler and steam
system, Furnace, DG sets, HVAC system, pumping
system, Cooling tower and Compressed air system
Energy Audit
“The verification, monitoring and analysis of use of
energy including submission of technical report
containing recommendations for improving energy
efficiency with cost benefit analysis and an action plan
to reduce energy consumption".
Need for Energy Audit
The three top operating expenses are energy (both
electrical and thermal), labour and materials.
Energy Audit will help to understand about the ways
energy and fuel are used in any industry, and help
in identifying the areas where waste can occur and
where scope for improvement exists.
Energy Audit would give a positive orientation to
the energy cost reduction, preventive maintenance
and quality control programmes which are vital for
production and utility activities
Need for Energy Audit
The primary objective of Energy Audit is to
determine ways to reduce energy consumption per
unit of product output or to lower operating costs
provides a reference point for managing energy in
the organization
provides the basis for planning a more effective use
of energy throughout the organization.
Type of Energy Audit
The type of Energy Audit to be performed depends
on:
Function and type of industry
Depth to which final audit is needed, and
Potential and magnitude of cost reduction desired
Following are the two types Energy Audit
i) Preliminary Audit
ii) Detailed Audit
1. Preliminary Energy Audit Methodology
Establish energy consumption in the organization
Estimate the scope for saving
Identify the most likely (and the easiest areas for attention)
Identify immediate (especially no-/low-cost) improvements/ savings
Set a 'reference point‘
Identify areas for more detailed study/measurement
Preliminary energy audit uses existing, or easily obtained data
2. Detailed Energy Audit Methodology
Detailed energy auditing is carried out in three phases:
Phase I - Pre Audit Phase
Phase II - Audit Phase
Phase III - Post Audit Phase
There are ten steps for conducting Detailed
Energy Audit
2. Detailed Energy Audit Methodology
Plan of action
Phase-I: Pre audit phase
Step-I:
Plan and organize
Walk through audit
Informal interview with
energy manager /
production / plant
manager
Purpose/ results
Establish /Organize
energy audit team
Organize instruments
Know the plant /
process activities
2. Detailed Energy Audit Methodology
Plan of action
Phase-I: Pre audit phase
Step-II:
Conduct brief meeting /
awareness programs
with all divisional heads
and peoples
Purpose/ results
Build up cooperation /
communication
Awareness creation
2. Detailed Energy Audit Methodology
Plan of action
Phase-II: Audit phase
Step-III:
Primary data collection
Process flow diagram
Energy utility diagram
Purpose/ results
Baseline data collection
Prepare process flow charts
Utility system diagram (single line power distribution, water , compressed air and steam distribution )
Design, operating data and schedule of operation
2. Detailed Energy Audit Methodology
Plan of action
Phase-II: Audit phase
Step-IV:
Survey and monitoring
Purpose/ results
Measurements:
Motor survey, insulation and lighting survey for collecting accurate data
Confirm and compare operating data with design data
2. Detailed Energy Audit Methodology
Plan of action
Phase-II: Audit phase
Step-V:
Conduct detailed trials/
experiments
Purpose/ results
Trials and experiments:
- 24 hr monitoring (MD, PF, kWh)
- Load variations in pumps, fan and compressors
- Boilers efficiency
- Equipment performance experiments
2. Detailed Energy Audit Methodology
Plan of action
Phase-II: Audit phase
Step-VI:
Analysis of energy use
Purpose/ results
Energy and material
balance and energy loss /
waste analysis
2. Detailed Energy Audit Methodology
Plan of action
Phase-II: Audit phase
Step-VII:
Identification and
development of Energy
Conservation
( ENCON) opportunities
Purpose/ results
Identification ( ENCON) measures
Develop and refine ideas
Review previous ideas suggested by energy audit
Use brainstorming and value analysis techniques
Contact vendors for new / efficient technology
2. Detailed Energy Audit Methodology
Plan of action
Phase-II: Audit phase
Step-VIII:
Cost benefit analysis
Purpose/ results
Asses technical feasibility
Select most promising
projects
Priorities by low, medium,
long term measures
2. Detailed Energy Audit Methodology
Plan of action
Phase-II: Audit phase
Step-IX:
Reporting and
presentation to top
management
Purpose/ results
Documentation , report
submission and
presentation to top
management
2. Detailed Energy Audit Methodology
Plan of action
Phase-III: Post Audit
phase
Step-X:
Implementation and
follow up
Purpose/ results
Assist and implement
ENCON recommendation
measures and monitor
performance
- Action plan, schedule for
implementation
- Follow up and periodic
review
The information to be collected during the detailed audit
includes: -
1. Energy consumption by type of energy, by
department, by major items of process equipment,
by end-use
2. Material balance data (raw materials, intermediate
and final products, recycled materials, use of scrap
or waste products, production of by-products for re-
use in other industries, etc.)
3. Energy cost and tariff data
4. Process and material flow diagrams
The information to be collected during the detailed audit
includes: -
5. Generation and distribution of site services
(eg. compressed air, steam).
6. Sources of energy supply (e.g. electricity from the grid or self-generation)
7. Potential for fuel substitution, process modifications, and the use of co-generation systems (combined heat and power generation).
8. Energy Management procedures and energy awareness training programs within the establishment.
The audit team should collect the following baseline
data:
- Technology, processes used and equipment details
- Capacity utilisation
- Amount & type of input materials used
- Water consumption
- Fuel Consumption
- Electrical energy consumption
- Steam consumption
- Other inputs such as compressed air, cooling water etc
- Quantity & type of wastes generated
- Percentage rejection / reprocessing
- Efficiencies / yield
Energy Audit Reporting Format
Acknowledgement
1. Introduction about plant:
- General plant details and description
- Energy audit team
- Components of production cost (energy, raw material, manpower etc)
- Major energy use and areas
2. Production process description:
- description of manufacturing process
- process flow diagram
- Major raw materials , Quantity and Costs
Energy Audit Reporting Format
3. Energy and Utility system description:
- Lists of utilities
- Brief description of each utility
Electricity
Steam
Water
Compressed air
Cooling water
4. Detailed process flow diagram and Material & Energy balance:
- Flow chart showing flow rates, temperature, pressure of all input –output streams
- Water balance of entire industry
Energy Audit Reporting Format
5. Energy efficiency in utility and process systems:
- Specific energy consumption
- Boiler efficiency assessment
- Cooling water system performance
- DG set performance assessment
- Electric motor load analysis
- Compressed air system performance
- Lighting system
6. Energy conservation options and recommendations:
- list of options in terms of No cost / low cost, medium cost and high investment cost, annual energy and cost saving, payback period
- Implementation plan for energy saving measures and projects
Annexure
A-1 List of energy audit worksheets
A-2 List of instruments
A-3 List of vendors and other technical details
Energy Audit Reporting Format
Energy Audit Instruments
For identification and quantification of energy
needs measurements and these measurements require
the use of instruments.
Basic Electrical Parameters in AC &DC systems -
Voltage (V), Current (I), Power factor, Active power
(kW), apparent power (demand) (kVA), Reactive
power (kVAr), Energy consumption (kWh),
Frequency (Hz), Harmonics, etc.
Energy Audit Instruments
Also Temperature & heat flow, radiation, air and gas flow, liquid flow, revolutions per minute (RPM), air velocity, noise and vibration, dust concentration, Total Dissolved Solids (TDS), pH, moisture content, relative humidity, flue gas analysis - CO2, O2, CO, SOx, NOx, combustion efficiency etc.
Flue Gas Analyzer
Stroboscope, Tachometer
Ultrasonic Flow Meter, Manometer, Venturimeter
Voltmeter, ammeter, thermocouples
Digital Thermometer (Non-contact and Contact type both)
Anemometer, pH/TDS/Conductivity meter
LUX Meter
Energy Audit Instruments
Energy conservation opportunities
Boiler and steam system
Furnace
DG sets
HVAC and Refrigeration system
pumping system
Cooling tower
Compressed air system
Boiler and steam system
Parameters to be monitored for the calculation of
boiler efficiency by are :
1. Quantity of steam generated per hour (Q) in kg/hr.
2. Quantity of fuel used per hour (q) in kg/hr.
3. The working pressure (in kg/cm2(g)) and superheat
temperature (°C), if any
4. The temperature of feed water (°C)
5. Type of fuel and gross calorific value of the fuel
(GCV) in kCal/kg of fuel
1. Feed Water Preheating using Economiser
2. Combustion Air Preheat
3. Incomplete Combustion
4. Excess Air Control
5. Radiation and Convection Heat Loss
6. Automatic Blowdown Control
Energy conservation opportunities in
Boiler
Energy conservation opportunities in
Boiler
7. Reduction of Scaling and Soot Losses
8. Reduction of Boiler Steam Pressure
9. Variable Speed Control for Fans, Blowers and
Pumps
10. Water treatment process/ Ion-exchange process
(Softener Plant)
11. Proper Boiler Scheduling
12. Boiler Replacement
Energy Saving Opportunities in Steam System
1. Monitoring Steam Traps
2. Continuous steam blow and no flow indicate, there is
a problem in the trap
3. Avoiding Steam Leakages
4. Providing Dry Steam for Process
5. Proper Utilization of Directly Injected Steam
6. Minimising Heat Transfer Barriers
7. Proper Air Venting
8. Condensate Recovery
9. Insulation of Steam Pipelines and Hot Process
Equipments
1. Complete Combustion with Minimum Excess Air
2. Proper Heat Distribution
3. Maintaining Optimum Operating Temperature of
Furnace
4. Prevention of Heat Loss through Openings
5. Control of furnace draft
6. Optimum Capacity Utilization
7. Waste Heat Recovery from Furnace Flue Gases
8. Minimising Wall Losses
9. Use of Ceramic Coatings
Energy Saving Opportunities in Furnaces
1. Ensure steady load conditions on the DG set, and
provide cold, dust free air at intake.
2. Improve air filtration.
3. Ensure fuel oil storage, handling and preparation as
per manufacturers' guidelines
4. Consider fuel oil additives in case they benefit fuel
oil properties for DG set usage.
5. Calibrate fuel injection pumps frequently.
6. Ensure compliance with maintenance checklist.
Energy Saving Opportunities in DG set
7. Ensure steady load conditions, avoiding fluctuations,
imbalance in phases, harmonic loads.
8. Consider parallel operation among the DG sets for
improved loading and fuel economy thereof.
9. Carryout regular field trials to monitor DG set
performance, and maintenance planning as per
requirements.
Energy Saving Opportunities in DG set
1. Cold Insulation
Insulate all cold lines / vessels using economic
insulation thickness to minimize heat gains
2. Building Envelope
3. Building Heat Loads Minimisation
Minimise the air conditioning loads by measures
such as roof cooling, roof painting, efficient lighting
4. Process Heat Loads Minimisation
5. At the Refrigeration A/C Plant Area
Ensure regular maintenance of all A/C plant
components as per manufacturer guidelines
Energy Saving Opportunities in HVAC and
Refrigeration system
1. Ensure adequate NPSH at site of installation
2. Ensure availability of basic instruments at pumps like
pressure gauges, flow meters.
3. Operate pumps near best efficiency point.
4. Modify pumping system and pumps losses to minimize
throttling.
5. Adapt to wide load variation with variable speed drives
6. Replace old pumps by energy efficient pumps
7. In multiple pump operations, carefully combine the
operation of pumps to avoid throttling
Energy Conservation Opportunities in
Pumping Systems
8. Repair seals and packing to minimize water loss by
dripping.
9. Balance the system to minimize flows and reduce pump
power requirements.
10. Avoid pumping head with a free-fall return (gravity); Use
siphon effect to advantage
11. Conduct water balance to minimise water consumption
Energy Conservation Opportunities in
Pumping Systems
1. Optimise cooling tower fan blade angle on a seasonal
and/or load basis
2. Correct excessive and/or uneven fan blade tip clearance
and poor fan balance
3. Replace old spray type nozzles with new square spray
ABS practically non-clogging nozzles
4. Replace splash bars with self-extinguishing PVC cellular
film fill
5. Install new nozzles to obtain a more uniform water
pattern
6. Periodically clean plugged cooling tower distribution
nozzle
Energy Conservation Opportunities in
Cooling Tower
1. Ensure air intake to compressor is not warm and humid by
locating compressors in well ventilated area or by drawing
cold air from outside. Every 4°C rise in air inlet
temperature will increase power consumption by 1
percent.
2. Compressor free air delivery test (FAD) must be done
periodically to check the present operating capacity
against its design capacity
3. Reduce compressor delivery pressure, wherever possible,
to save energy
4. Remove condensate at regular interval.
Energy Conservation Opportunities in
Compressed Air System
5. Avoiding Air Leaks and Energy Wastage
6. Dust Free Air Intake
7. Dry Air Intake
8. Automatic On / Off Control
9. Avoiding Misuse of Compressed Air
Energy Conservation Opportunities in
Compressed Air System