Energy audit is a vital process, which enables a comparative estimation of future energy efficiency improvements. In energy conservation project a systematic audit ensures that every opportunities of benefiting from project synergies are explored.Stepwise Energy Audit Process
There are four important stages in an audit,
- I) Initiating the Audit
This involves the following steps,
- a) Objective & Scope of the Audit
The objective of the audit is defined by the top management. It includes defining the breadth i.e. the level of details essential for energy consumption and depth i.e. the organizational and physical boundaries of the audit.
Scope of audit is the boundary or a "black box" defining the audit area to be focused on by examining the energy activity in terms of outflow, inflow and within the box. The black box could cover a single operation or the entire foundry. The scope is dependent on the foundry's staff size, capability, availability, capability of the outside consultant and finally time and cost considerations.
- b) Selection of the Auditors
Ideally the selected auditor should possess skills such as good judgment, high personal integrity, effective communication, and excellent people management skills to help him perform successfully.
- The auditor can be an outside consultant or an in-house foundry staff depending on the budget. However while appointing an in-house staff it important to evaluate factors such as interference in routine responsibilities and considering the learning curve involved along with the risk of bias in some situations.
- c) Estimation of budget and duration
The budget is calculated on the basis of person-days and weeks considering the physical extent, objectives, complexity, resources and time factors.
- a) Objective & Scope of the Audit The objective of the audit is defined by the top management. It includes defining the breadth i.e. the level of details essential for energy consumption and depth i.e. the organizational and physical boundaries of the audit.
- II) Audit Preparation
Audit preparation includes the following,
- a) Timing
The audit is planned in consultation with foundry management to offer accurate estimations of energy inefficiencies and losses. A suitable time frame is selected considering optimal production period and eliminating distortions.
- b) Determining Production Baseline
The audit should reflect a comparative base for determining energy consumption levels which would facilitate future energy management tasks.
- c) Recording available data
Existing historical information aids in identifying the primary end users. Information such as cost of fuel, raw materials, labor data etc are easily accessible. This data is very critical in estimation of material and energy balances.
- d) Procuring the Tools
While conducting an audit it is required to check for the consistency and calibration of any monitoring equipments that are employed in the foundry except for those that are managed by specific utility providers. Some commonly used audit tools are process layout, simulations, spreadsheets, natural gas distribution diagrams etc.
- a) Timing
- III) Conducting the Audit
Before initiating the audit a through check on foundry practices and procedures is essential. It is helpful to observe the staff work or interview them to obtain accurate information.
Establishing energy and material balances is also important. Balances reflect the effect of development plans and energy saving projects. They can be for entire foundry or one of its key processes for example melting furnace or boiler efficiency.
The purpose of the audit is to highlight opportunities of energy optimization especially in areas where energy is used to maximum. It also emphasizes on areas where energy is underutilized or highly paid for, so that corrective actions are implemented to curb them. It is essential for the auditor to review the manufacturing process and equipments having a large impact on energy efficiency. It is important to evaluate the usage of scrap and analyze the cast yield ratio, which is proportional to energy consumption.
- iv) Audit Report
Reporting the audit results in the right format completes the audit. The final report includes,
- a) Verbal report given at the end of the audit emphasizing on key observations and conclusions and,
- b) Written report given after careful completion and consideration of audit findings.
- a) Objective and Scope
- b) Location and duration of the audit
- c) Details of personnel and resources
- d) Operating conditions of the foundry at the audit
- e) General Observations
- f) Energy usage data, calculations, balances
- g) Conclusions and evaluations and finally
- h) Recommendations.
The structure of the audit report usually displays the following,