Energy audit
Energy audit is the key for decision making in the area of energy management. It balances the total energy inputs with its use. It also serves to identify all the energy streams in the facility.
Energy audit means the verification, monitoring and analysis of use of energy including the submission of technical report for improving energy efficiency and an action plan to reduce energy consumption.
Need for energy audit
In an industry energy ( both electrical and thermal ) Labour and materials are the three important operating expenses. Energy audit will help to identify the areas where waste can occur and where scope for improvement exists.
The energy audit gives a positive orientation to the energy cost reduction, preventive maintenance and quality control Programmes.
An energy audit program will help to keep focus on energy costs, availability and reliability of supply of energy, decide on appropriate energy mix, identify energy conservation equipment.
In energy audit the conservation ideas are translated into realities.
The primary objective of energy audits is to determine the ways for reducing energy consumption or lowering operating costs Energy audit provides a bench mark for managing energy in the organization.
It also provides the basis of planning the use of energy throughout the organization in an effective manner.
Types of energy audit
The types of energy audit are performed by the following factors.
a) Function and type of industry
b) Depth of final audit needed
c) Potential and magnitude of cost reduction desired.
Based on the above factors, the energy audit is classified into two types. they are
1) Preliminary energy limit
2) Detailed energy audit
Preliminary energy audit methodology
This energy audit has the following factors
1) Establish energy consumption in the organization.
2) Estimate the scope for saving
3) Identify the most likely and easiest areas for attention
4) Identify the immediate improvements / savings areas
5) Set a reference point
6) Identify the areas of more detailed study / measurement.
The preliminary energy audit uses existing or easily obtainable data.
Detailed energy audit methodology
This audit provides detailed energy project implementation plan. This audit offers most accurate estimate of energy savings and cost. It considers the following factors.
1) Interactive effects of all projects
2) Accounts for the energy use of all major departments
3) Includes detailed energy cost savings calculations and project cost.
Detailed energy audit is carried out in the following three phases.
1) Phase 1 - pre audit phase
2) Phase 2 - audit phase
3) phase 3 - Post audit phase
The plan of actions for three phases is given below
a) Phase 1 - Pre audit phase
1) Plan and organize
2) Walk through audit
3) conduct informal interview with energy manager production / Plant manager
4) Conduct meeting or awareness programs with all divisional heads and personal concerned.
b) Phase 2 - Audit phase
1) collect primary data
2) Prepare process flow diagram and energy utility diagram.
3) conduct survey and monitoring
4) Conduct detailed experiments for selected energy guzzlers
5) Analysis of energy use
6) Identify energy use
7) Cost benefit analysis
8) Report the document to the top managements.
c) Phase 3- Post audit phase
1) Implement and follow up the activities
Phase 1- Pre Audit phase activities
An initial site visit gives the energy auditor an opportunity to familiarize him with the site and to assess the procedures necessary to carry out the energy energy audit.
During the initial visit the following actions be carried out by the energy auditor/ Engineer.
- Discuss the aims of the energy audit
- Discuss the economic guidelines associated with the recommendations of the audit
- Analysis the major energy consumption data
- Tour the site accompanied by production engineer
The main aim of initial site visit is described below
- Energy audit team is finished
- The main energy consuming areas
- Requirements of additional metering are identified
- Installation of any meters prior to the audit is decided
- Time frame is planned
- Macro data on plant energy resources are collected
- Awareness through meetings is created
phase 2 detailed energy audit activities
Depending on the nature and completely of the site it can take from several weeks to several months to complete.
The audit will include a description of energy inputs and outputs by major department or by major processing functions.
It will evaluate the efficiency of each step of the manufacturing. the audit report should conclude with specific recommendations for detailed engineering studies and feasibility analysis
The following information are collected during detailed audit
- Energy consumption by the type of energy by department by major process equipment.
- Material balance data products, final products, recycled materials, use of scrap or waste products
- Energy cost and tariff data
- process and materials flow diagrams
- Generation and distributions of site service
- Sources of energy supply
- Potential for fuel substitution, process modifications, and the use of cogeneration
- Energy management procedure and energy awareness training programs
The following baseline data should be collected by the audit team
- Technology, processes used and equipment details
- Capacity utilization
- Fuel consumption
- steam consumption
- Electrical energy consumption
- Water consumption
- Amount and type of input materials used
- Quantity and type of wastes generated
- Rejection / reprocessing percentage
- Efficiency
Understanding energy costs
Understanding energy cost is a vital factor for awareness creation and saving calculation. In many industries sufficient meters may not saving calculations.
In many industries sufficient meters may not available so we cannot measures all the energy used. In such cases, invoices for fuels and electricity will be useful. the annual company balance sheet is the other source where fuel cost and power are given with production related information.
Energy invoices can be used for the following purposes
1) They provide a record of energy purchased is a given year. it gives a base line for future reference.
2) They may indicate the potential for savings
3) When electricity is purchased on the basis of maximum demand tariff.
4) they can give ideas where savings are most likely to be made.
5) they can be used to quantity the energy and cost savings in later years.
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