An Energy Audit is a plant site survey, involving measurements and analyses of energy and material flows in an industrial plant or building, with the objective of understanding the energy dynamics of the system. Typically an energy audit is conducted to identify opportunities to reduce the energy demand of the system without affecting production volumes, quality or safety.
We employ a systems approach that goes beyond equipment efficiencies and estimates the overall system efficiencies of important processes and supporting utilities. This approach helps identify inefficiencies and hidden losses that may exist due to the design philosophy, system design, existing equipment design and/or operating practices.
Methodology
Our energy audits begin with a briefing to the top management and plant team, wherein we communicate our methodology of work, the inputs needed from the plant and the deliverables from us. This interaction helps clarify the energy audit process and enables smooth flow of information and assistance during the course of work.
The site study involves detailed measurements and analyses of equipment operations and processes; frequent discussions with the plant team help improve our understanding of operations that enables understanding of the measurements and observations in the right perspective. Evolving energy saving ideas are discussed with the plant team so that any operational issues in implementing the measures are understood. Involvement of senior plant team members in the energy audit process is imperative for ensuring the quality of the deliverable of the study.
Board guidelines indicating the methodology for such an energy audit is given below. Possible stages for interaction/conference are also indicated.
Phase-I
- Collections of data on operational parameters, energy consumption both normal and electrical, coal and power quality etc., through a questionnaire.
- Study the existing plant capacities and their performance to assess plant operations.
- Study of the specific energy consumption (both thermal and electrical) department-wise and plant as a whole.
- Study of the power sources, distribution system and drive controls, load factor and efficiency of large motors (above 10 kW), process automations, plant illuminations etc.
- Collection of requisite data and analysis and identification of specific areas with potential for conservation of thermal and electrical energy.
- Field measurements of operational parameters and carrying out heat and mass balance.
- Study of limitations, if any, in the optimal use of thermal and electrical energy.
- Formulation of specific recommendations along with broad system concept for conservation of thermal and electrical energy.
- Preparation of capital cost estimates and establishing techno-economic feasibility for recommended measures.
- No investment and/or marginal investment by doing system improvements and optimization of operations.
- Major investment due to incorporation of modern energy intensive equipment and upgradation of existing equipment.
- Formulating tentative time schedule for implementation of the recommendation.
- Undertaking broad cost benefit analysis in terms of savings in energy consumption per unit of production and pay-back period.
Phase-II
Follow-up with the industry on periodic basis to ascertain the level of implementation of recommendation and assist, if require, in implementation of the measures to achieve energy user efficiency.
Assistance required from Client Side:
- Nomination of one engineer as coordinator from your side and to provide the relevant data / record about equipment etc. (maximum available), during course of the Energy Audit. Any other requirement would be conveyed at site, as & when required.
- As and when required, our team of energy auditors will make visits in building / plant therefore arrangement of entry pass and gate pass for instruments carried by our team.
Preliminary Energy Audit
The Preliminary Energy Audit focuses on the major energy suppliers and demands usually accounting for approximately 70% of total energy. It is essentially a preliminary data gathering and analysis effort. It uses only available data and is completed with limited diagnostic instruments. The PEA is conducted in a very short time frame i.e. 1-3 days during which the energy auditor relies on his experience together with all the relevant written, oral visual information that can lead to a quick diagnosis of the plant energy situation. The PEA focuses on the identification of obvious sources of energy wastage’s. The typical out put of a PEA is a set of recommendations and immediate low cost action that can be taken up by the department head.
Detailed Energy Audit
The detailed audit goes beyond quantitative estimates of costs and savings. It includes engineering recommendations and well-defined project, giving due priorities. Approximately 95% of all energy is accounted for during the detailed audit. The detailed energy audit is conducted after the preliminary energy audit. Sophisticated instrumentation including flow meter, flue gas analyzer and scanner are use of compute energy efficiency.
Scope of work for detailed Energy Audit
- Review of Electricity Bills, Contract Demand and Power Factor: For the last one year, in which possibility will be explored for further reduction of contract demand and improvement of power factor
- Electrical System Network : Which would include detailed study of all the Transformer operations of various Ratings / Capacities, their operational pattern, Loading, No Load Losses, Power Factor Measurement on the Main Power Distribution Boards and scope for improvement if any. The study would also cover possible improvements in energy metering systems for better control and monitoring.
- Study of Motors and Pumps Loading : Study of motors (above 10 kW) in terms of measurement of voltage (V), Current (I), Power (kW) and power factor and thereby suggesting measures for energy saving like reduction in size of motors or installation of energy saving device in the existing motors. Study of Pumps and their flow, thereby suggesting measures for energy saving like reduction in size of Motors and Pumps or installation of energy saving device in the existing motors / optimization of pumps.
- Study of Air conditioning plant : w.r.t measurement of Specific Energy consumption i.e kW/TR of refrigeration, study of Refrigerant Compressors, Chilling Units, etc. Further, various measures would be suggested to improve its performance.
- Cooling Tower: This would include detailed study of the operational performance of the cooling towers through measurements of temperature differential, air/water flow rate, to enable evaluate specific performance parameters like approach, effectiveness etc.
- Performance Evaluation of Boilers: This includes detailed study of boiler efficiency, Thermal insulation survey and flue gas analysis
- Performance Evaluation of Turbines: This includes detailed study of Turbine efficiency, Waste heat recovery.
- Performance Evaluation of Air Compressor: This includes detailed study of Air compressor system for finding its performance and specific energy consumption
- Evaluation of Condenser performance: This includes detailed study of condenser performance and opportunities for waste heat recovery
- Performance Evaluation of Burners / Furnace : This includes detailed study on performance of Furnace / Burner, thermal insulation survey for finding its efficiency
- Windows / Split Air Conditioners: Performance shall be evaluated as regards, their input power vis-a-vis TR capacity and performance will be compared to improve to the best in the category
- Illumination: Study of the illumination system, LUX level in various areas, area lighting etc. and suggest measures for improvements and energy conservation opportunity wherever feasible
- DG Set: Study the operations of DG sets to evaluate their average cost of Power Generation, Specific Energy Generation and subsequently identify areas wherein energy savings could be achieved after analyzing the operational practices etc. of the DG sets
The entire recommendations would be backed up with techno-economic calculations including the estimated investments required for implementation of the suggested measures and simple payback period. Measurement would be made using appropriate instrumentation support for time lapse and continuous recording of the operational parameters.
Completion Period: We usually start the field data collection at site with in one and half months time, from the date of receipt of work order and the draft energy audit report is submitted thereafter in time. Finalization of energy audit report is normally completed within time frame. (After completion of the audit study, the findings and recommendations are discussed with the technical head and the final report with recommendations is submitted.
Objectives of Energy Audit
The Energy Audit provides the vital information base for overall energy conservation program covering essentially energy utilization analysis and evaluation of energy conservation measures. It aims at:
- Identifying the quality and cost of various energy inputs.
- Assessing present pattern of energy consumption in different cost centers of operations.
- Relating energy inputs and production output.
- Identifying potential areas of thermal and electrical energy economy.
- Highlighting wastage’s in major areas.
- Fixing of energy saving potential targets for individual cost centers.
- Implementation of measures for energy conservation & realization of savings.