Energy Audit and Mgt UNIT 2

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


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


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


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


Plan of action


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


Plan of action


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


Plan of action


Step-VI:

Analysis of energy use

Purpose/ results

Energy and material

balance and energy loss /

waste analysis


Plan of action


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


Plan of action


Step-VIII:

Cost benefit analysis

Purpose/ results

Asses technical feasibility

Select most promising

projects

Priorities by low, medium,

long term measures


Plan of action


Step-IX:

Reporting and

presentation to top

management

Purpose/ results

Documentation , report

submission and

presentation to top

management


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


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


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 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.


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 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


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


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.


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


Compressed Air System

Engineering

Energy Audit and Mgt UNIT 2