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ENERGY AUDITING, CONSERVATION & MANAGEMENT

By K.MEENENDRANATH REDDY

I believe talent is like electricity. We don't understand electricity. We use it.

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CONTENTS Unit I - Basic principles of Energy audit Energy audit- definitions, concept , types of audit, energy index, cost index ,pie charts, Sankey diagrams , load profiles, Energy conservation schemes- Energy audit of industriesenergy saving potential, energy audit of process industry, thermal power station, building energy audit. Unit II - Energy management Principles of energy management, organizing energy management program, initiating, planning, controlling, promoting, monitoring, reporting- Energy manger, Qualities and functions, language, Questionnaire - check list for top management. Unit III - Energy efficient Motors Energy efficient motors , factors affecting efficiency, loss distribution , constructional details, characteristics - variable speed , variable duty cycle systems, RMS hp- voltage variationvoltage unbalance- over motoring- motor energy audit. Unit IV - Power Factor Improvement, Lighting and energy instruments Power factor. methods of improvement , location of capacitors , Pf with non linear loads, effect of harmonics on p.f. , p.f motor controllers - Good lighting system design and practice , lighting control, lighting energy audit - Energy Instruments- watt meter, data loggers , thermocouples, pyrometers, lux meters , tongue testers ,application of PLC.s Unit V - Economic aspects and analysis Economics Analysis-Depreciation Methods , time value of money , rate of return , present worth method , replacement analysis , life cycle costing analysis - Energy efficient motorscalculation of simple payback method , net present worth method - Power factor correction, lighting - Applications of life cycle costing analysis, return on investment . Reference Books: 1) Energy management by W.R. Murphy & G. Mckay Butter worth, Heinemann publications. 2) Energy management by Paul o. Callaghan, Mc-graw Hill Book company-1st edition, 1998. 3) Energy efficient electric motors by John C. Andreas, Marcel Dekker Inc Ltd-2nd edition, 19954) Energy management hand book by W.C.Turner, john Wiley and sons. 5) Energy management and good lighting practice: fuel efficiency- booklet12-EEO.

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Unit I Basic principles of Energy audit: Energy audit- definitions, concept , types of audit, energy index, cost index ,pie charts, Sankey diagrams , load profiles, Energy conservation schemes- Energy audit of industriesenergy saving potential ,energy audit of process industry, thermal power station, building energy audit. Unit II Energy management-I Principles of energy management, organizing energy management program, initiating, planning, controlling, promoting, monitoring, reporting. Unit III Energy management-II Energy manger, Qualities and functions, language, Questionnaire - check list for top management. Unit IV Energy efficient Motors Energy efficient motors , factors affecting efficiency, loss distribution , constructional details, characteristics - variable speed , variable duty cycle systems, RMS hp- voltage variationvoltage unbalance- over motoring- motor energy audit. Unit V Power Factor Improvement, Lighting Power factor – methods of improvement, location of capacitors, Pf with non linear loads, effect of harmonics on p.f., p.f motor controllers - Good lighting system design and practice, lighting control, lighting energy audit. Unit VI Energy Instruments Energy Instruments watt meter, data loggers, thermocouples, pyrometers, lux meters, tongue testers, application of PLC’s Unit VII Economic aspects and analysis Economics Analysis-Depreciation Methods, time value of money, rate of return, present worth method, replacement analysis, life cycle costing analysis - Energy efficient motors Unit-VIII Computation of Economic Aspects Calculation of simple payback method, net present worth method - Power factor correction, lighting - Applications of life cycle costing analysis, return on investment. Reference Books: 1) Energy management by W.R. Murphy & G. Mckay Butter worth, Heinemann publications. 2) Energy management by Paul o’ Callaghan, Mc-graw Hill Book company-1st edition, 1998 3) Energy efficient electric motors by John C. Andreas, Marcel Dekker Inc Ltd-2nd edition, 19954) Energy management hand book by W.C.Turner, john Wiley and sons 5). Energy management and good lighting practice : fuel efficiency- booklet12-EEO 948

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UNIT – I BASIC PRINCIPLES OF ENERGY AUDIT

1.1 Energy audit:The main purpose energy audit is to increase energy efficiency and reduce energy related costs. Energy audit is not an exact science. It involves collection of detailed data and its analysis. (or) It is an official scientific study/ survey of energy consumption of a region/ organization/ process/ plant/ equipment aimed at the reduction of energy consumption and energy costs, without affecting productivity and comforts and suggesting methods for energy conservation and reduction in energy costs. (or) An energy audit is an inspection, survey and analysis of energy flows for energy conservation in a building, process (or) system to reduce the amount of energy input into the system without negatively affecting the output(s). Energy audit is a fundamental part of an energy management program (EMP) in controlling energy costs. It will identify areas of wasteful and inefficient use of energy. The aims of energy audit are as follows:  To identify the main energy s and quantity their annual energy consumption  To ascertain the optimized energy data  To determine the availability or energy/production data  To investigate the distribution systems for the site services and note any existing metering  To prepare energy and process flow diagrams for the site

1.2 Energy Audit Definitions:1. Energy ing:Energy audit simply means an orderly month by month ing of energy used in a building for comparison against a budget or another standard of performance. 2. Means To Achieve Conservation:Energy audit deals with specific ways and means to achieve energy conservation.

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3. Systematic Approach to Decision Making:Energy Audit is the key to systematic approach for decision – making; in the areas of energy management it attempts to balance the total energy inputs with its use and serves to identify all the energy streams in a facility. It quantities energy usage according to its discrete functions. 4. Effective Tool for Energy Management:Industrial Energy Audit is an effective tool in defining and pursuing comprehensive energy management programmer. In this field also, the basic functions of management like planning, decision – making, organizing and controlling, apply equally as any other management subject. These functions can be effectively performed, based on reliable information which can be available to the top management by applying Energy Audit techniques. 5. Ways of usage of Energy:Energy Audit will help to understand more about the ways energy and fuel or used in any industry, and help in identifying the areas where waste can occur and where scope for improvement exists. 6. Construction and Stream Lining:The Energy Audit would give a positive orientation to the energy cost reduction, preventive maintenance and quality control programmer which are vital for production and utility activities. Such an Audit program will help to keep alive variations which occur in the energy costs, availability and reliability of supply of energy, decide on appropriate energy mix, and identify energy conservation technologies, retrofits for energy conservation equipment and the like. 7. Ideas and Feasible Solutions:In general, Energy audit is the translation of conservation ideas into realities, by blending technically feasible solutions with economic and other organizational considerations within a specified time frame. This technique will be more beneficial than piece – meal injection of short – term measures, without adopting a scientifically evolved strategy including gearing up of organizational structure and other infrastructural requirements. 8. Use and Opportunities:Energy Audit is an in-depth study of a facility to determine how and where energy being used or converted from one form to another, to identify opportunities to reduce energy usage, to evaluate the economics and technical practicability of implementing these reductions and to formulate prioritized recommendations for implementing process improvements to save energy. 948

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9. Definition as Per Bureau of Energy Efficiency Guidelines:Energy Audit is defined as “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”.

1.3 Types 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 Thus Energy Audit can be classified into the following two types. i) Preliminary Audit ii) Detailed Audit i)

Preliminary Energy Audit Methodology:Preliminary energy audit is a relatively quick exercise to:  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

ii)

Detailed Energy Audit Methodology:A comprehensive audit provides a detailed energy project implementation plan for a

facility, since it evaluates all major energy using systems. This type of audit offers the most accurate estimate of energy savings and cost. It considers the interactive effects of all projects, s for the energy use of all major equipment, and includes detailed energy cost saving calculations and project cost. In a comprehensive audit, one of the key elements is the energy balance. This is based on an inventory of energy using systems, assumptions of current operating conditions and calculations of energy use. This estimated use is then compared to utility bill charges. Detailed energy auditing is carried out in three phases: Phase I, II and III. Phase I - Pre Audit Phase Phase II - Audit Phase Phase III - Post Audit Phase 948

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1.4 ENERGY INDEX:Energy index is the figure obtained by dividing energy consumption by production output.

The index may be calculated weekly, monthly or annually. EXAMPLE: - To find the energy index we shown below example, here three types of energy with energy consumption and also produces 100x103 tons of a particular product. Calculate the energy index? Energy type

Consumption

Energy (Wh)

Oil

10x103 gal

0520x109

gas

5x103 therm

0.146x109

Electricity

995x103 kwh

0.995x109

Total

1.661x109

ANS: - oil energy index is 0.520x109 wh/100x109 = 5.20x103 wh/ton of product Gas energy index is 0.146x109 wh/100x109 = 1.46x103 wh/ton of product `

Electricity energy index is 0.995x109 wh/100x109 = 9.95x103 wh/ton of product Total energy index is 1.661x109 wh/100x109 = 16.61x103 wh/ton of product

1.5 COST INDEX:The cost index is defined as the cost of energy divided by the production output.

Same example for calculate the cost index in place of total energy, the cost will be used.

1.6 PIE CHART:Energy usage is plotted on a circular chart where the quantity of a particular type is represented as a segment of a circle. The size of the segment will be depends upon the usages of the product. For example, the company uses 25% of gas, 30% of the oil and 45% of the electricity.

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Sales oil gas electricity

1.7 SANKEY DIAGRAM:The sankey diagram represents all the primary energy flows in to a factory. The widths of the bands are directly proportional to energy production, utilization and losses. (or) Sankey diagrams are a specific type of flow diagram, in which the width of the arrows is shown proportionally to the flow quantity. They are typically used to visualize energy or material or cost transfers between processes. They are also commonly used to visualize the energy s or material flow s on a regional or national level. Sankey diagrams put a visual emphasis on the major transfers or flows within a system. They are helpful in locating dominant contributions to an overall flow. Often, Sankey diagrams show conserved quantities within defined system boundaries, typically energy or mass, but they can also be used to show flows of nonconserved quantities such as energy. Sankey Diagrams drop their arrows when energy is being used. For example the steam flows from input to output and also the electrical energy uses by showing the sankey diagram is shown in below figure,

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1.8 LOAD PROFILES:For the purpose of monitoring and checking energy consumption on a time dependent basis is to use load profiles. In electrical engineering, a load profile is a graph of the variation in the electrical load versus time. A load profile will vary according to customer type (typical examples include residential, commercial and industrial), temperature and holiday seasons. The below load profiles shows the day by day increases the usages the products is drawn the graph by taking the products with percentage.

3500% 3000% 2500%

2000%

gas

1500%

oil

1000%

electricity

500% 0% 2005

2009

2011

2012

Load profiles can be determined by direct metering but on smaller devices such as distribution network transformers this is not routinely done. Instead a load profile can be inferred from customer billing or other data. An example of a practical calculation used by utilities is using a transformer's maximum demand reading and taking into the known number of each customer type supplied by these transformers. This process is called load research.

1.9 ENERGY CONSERVATION SCHEMES:Development of an energy conservation program can provide savings by reduced energy use. The energy conservation measures may be classified on an economic basis and fall into the following three categories, (a) Short term (b) Medium term (c) Long term (a) Short term energy conservation schemes:These measures usually involve changes in operating practices resulting in little or no capital expenditure.

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i) Furnace efficiencies ii) Heat exchangers iii) Good housekeeping iv) Use of steam v) Electrical power (b) Medium term energy conservation schemes:Low cost modifications and improvements to existing equipment where the payback period is less than two years and often less than one year. i) Insulation ii) Heating systems iii) Replacing air compressors iv) Instrumentation v) Process modifications vi) Burners vii) Electrical power savings (c) Long term energy conservation schemes:Modifications involving high capital costs and which frequently involve the implementation of new techniques and new technologies. i) Heater modifications ii) Improved insulation iii) Heat recovery

1.10 ENERGY AUDIT OF INDUSTRIES:An energy audit is a key to assessing the energy performance of an industrial plant and for developing an energy management program. The typical steps of an energy audit are: i) Preparation and planning ii) Data collection and review iii) Plant surveys and system measurements iv) Observation and review of operating practices v) Data documentation and analysis vi) Reporting of the results and recommendations. An overview of the procedure for a detailed industrial energy audit is shown in Figure. A preliminary audit (walk-through audit) contains some of the same steps of the procedure shown, but the depth of the data collection and analysis might be different depending on the scope and objectives of the audit.

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Overall, there are three main steps (excluding the post-audit activities) each of which has several sub-steps. These three main steps are energy audit preparation, execution, and reporting.

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1.11 ENERGY SAVING POTENTIAL:We estimate the energy savings potential for each of the selected industries. Methodologically such an exercise involves use of (energy) efficiency benchmark of some of the best performing units within the concerned industry. Energy efficiency benchmarking for an industry is a process by which energy performance of an individual firm/unit within the industry or a sector comprising of similar units are compared against a common metric which represents a standard. It may entail, comparing for a sector or industry, energy performance of a number of units against each other in any given year or comparing the performance of an individual unit or industry over time or comparing its performance if it were using the best available or state of the art technology or comparing its performance via units/sectors in other countries and so on. As benchmarking is used as a tool for comparison it should have an important characteristic that the metric used should be independent of unit size. In the present study the metric used for benchmark analysis is energy intensity. There are a large number of units/firms of varying sizes within an industry. Comparing energy intensity of a small unit with that of a large one may not be meaningful because of the scale of operation. In order to overcome the problem of comparing dissimilar units, units within an industry are grouped/classified into different groups on the basis of a) share in final energy consumption (measured in kgoe), b) share in electricity consumption (measured in Kwh), and c) total output (measured in rupees), so that units within a group are all similar. Energy savings potential is then calculated for each group within the industry. Having classified the units within an industry into different groups, units within a group are ranked in order of their energy intensities. Energy intensity of a unit is defined as total final energy consumed for generating one unit of output. Since the output is measured in monetary units, energy intensity is defined as energy consumed for generating Re. 1 worth of output. Two measures of energy intensity has been used depending on the way in which the units are grouped. These are

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1.12 BUILDING ENERGY AUDIT:The energy audit in a building is a feasibility study. For it not only serves to identify energy use among the various services and to identify opportunities for energy conservation, but it is also a crucial first step in establishing an energy management programmed. The audit will produce the data on which such a programmer is based. The study should reveal to the owner, manager, or management team of the building the options available for reducing energy waste, the costs involved, and the benefits achievable from implementing those energy-conserving opportunities (ECOs). The energy management programmed is a systematic on-going strategy for controlling a building's energy consumption pattern. It is to reduce waste of energy and money to the minimum permitted by the climate the building is located, its functions, occupancy schedules, and other factors. It establishes and maintains an efficient balance between a building's annual functional energy requirements and its annual actual energy consumption. The energy audit may range from a simple walk-through survey at one extreme to one that may span several phases. These phases include a simple walk-through survey, followed by monitoring of energy use in the building services, and then model analysis using computer simulation of building operation. The complexity of the audit is therefore directly related to the stages or degree of sophistication of the energy management programmed and the cost of the audit exercise. The first stage is to reduce energy use in areas where energy is wasted and reductions will not cause disruptions to the various functions. The level of service must not be compromised by the reduction in energy consumed. It begins with a detailed, step-by-step analysis of the building's energy use factors and costs, such as insulation values, occupancy schedules, chiller efficiencies, lighting levels, and records of utility and fuel expenditures. It includes the identification of specific ECOs, along with the cost-effective benefits of each one. The completed study would provide the building owner with a thorough and detailed basis for deciding which ECOs to implement, the magnitude of savings to be expected, and the energy conservation goals to be established and achieved in the energy management programmed. However, the ECOs may yield modest gains. The second stage is to improve efficiency of energy conversion equipment and to reduce energy use by proper operations and maintenance. For this reason, it is necessary to reduce the number of operating machines and operating hours according to the demands of the load, and fully optimize equipment operations. Hence the ECOs would include the following: 948

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i) Building equipment operation, ii) Building envelope, iii) Air-conditioning and mechanical ventilation equipment and systems, iv) Lighting systems, v) Power systems, and vi) Miscellaneous services. The first two stages can be can be implemented without remodeling buildings and existing facilities. The third stage would require changes to the underlying functions of buildings by remodeling, rebuilding, or introducing further control upgrades to the building. This requires some investment. The last stage is to carry out large-scale energy reducing measures when existing facilities have past their useful life, or require extensive repairs or replacement because of obsolescence. In this case higher energy savings may be achieved. For these last two stages, the audit may be more extensive in order to identify more ECOs for evaluation, but at an increased need for heavier capital expenditure to realize these opportunities.

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UNIT II ENERGY MANAGEMENT-I 2.1 PRINCIPLES OF ENERGY MANAGEMENT:Energy

management includes

planning

and

operation

of

energy-

related production and consumption units. If energy productivity is an important opportunity for the nation as a whole, it is a necessity for the individual company. It represents a real chance for creative management to reduce that component of product cost that has risen the most since 1973. Those who have taken advantage of these opportunities have done so because of the clear intent and commitment of the top executive. Once that commitment is understood, managers at all levels of the organization can and do respond seriously to the opportunities at hand. Without that leadership, the best designed energy management programs produce few results. In addition, we would like to suggest four basic principles which, if adopted, may expand the effectiveness of existing energy management programs or provide the starting point of new efforts. The first of these is to control the costs of the energy function or service provided, but not the Btu of energy. As most operating people have noticed, energy is just a means of providing some service or benefit. With the possible exception of feedstocks for petrochemical production, energy is not consumed directly. It is always converted into some useful function. The existing data are not as complete as one would like, but they do indicate some surprises. In 1978, for instance, the aggregate industrial expenditure for energy was $55 billion. Thirty-five percent of that was spent for machine drive from electric motors, 29% for feedstocks, 27% for process heat, 7% for electrolytic functions, and 2% for space conditioning and light. As shown in Table 1.1, this is in blunt contrast to measuring these functions in Btu. Machine drive, for example, instead of 35% of the dollars, required only 12% of the Btu. In most organizations it will pay to be even more specific about the function provided. For instance, evaporation, distillation, drying, and reheat are all typical of the uses to which process heat is put. In some cases it has also been useful to break down the heat in of temperature so that the opportunities for matching the heat source to the work requirement can be utilized. In addition to energy costs, it is useful to measure the depreciation, maintenance, labor, and other operating costs involved in providing the conversion equipment necessary to deliver required services. These costs add as much as 50% to the fuel cost.

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It is the total cost of these functions that must be managed and controlled, not the Btu of energy. The large difference in cost of the various Btu of energy can make the commonly used Btu measure extremely misleading. In November 1979, the cost of 1 Btu of electricity was nine times that of 1 Btu of steam coal. Table 1.2 shows how these values and ratios compare in 2005. One of the most desirable and least reliable skills for an energy manager is to predict the future cost of energy. To the extent that energy costs escalate in price beyond the rate of general inflation, investment paybacks will be shortened, but of course the reverse is also true. A quick glance at Table 1.2 shows the inconsistency in overall energy price changes over this period in time. Even the popular conception that energy prices always go up was not true for this period, when normalized to constant dollars. This volatility in energy pricing may for some business decisions that appear overly conservative in establishing rate of return or payback period hurdles. Availabilities also differ and the cost of maintaining fuel flexibility can affect the cost of the product. And as shown before, the average annual price increase of natural gas has been almost three times that of electricity. Therefore, an energy management system that controls Btu per unit of product may completely miss the effect of the changing economics and availabilities of energy alternatives and the major differences in usability of each fuel. Controlling the total cost of energy functions is much more closely attuned to one of the principal interests of the executives of an organization controlling costs.

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A second principle of energy management is to control energy functions as a product cost, not as a part of manufacturing or general overhead. It is surprising how many companies still lump all energy costs into one general or manufacturing overhead without identifying those products with the highest energy function cost. In most cases, energy functions must become part of the standard cost system so that each function can be assessed as to its specific impact on the product cost. The minimum theoretical energy expenditure to produce a given product can usually be determined en route to establishing a standard energy cost for that product. The seconds of 25-hp motor drive, the minutes necessary in a 2200°F furnace to heat a steel part for fabrication, or the minutes of 5-V electricity needed to make an electrolytic separation, for example, can be determined as theoretical minimums and compared with the actual figures. As in all production cost functions, the minimum standard is often difficult to meet, but it can serve as an indicator of the size of the opportunity. In comparing actual values with minimum values, four possible approaches can be taken to reduce the variance, usually in this order: 1. An hourly or daily control system can be installed to keep the function cost at the desired level. 2. Fuel requirements can be switched to a cheaper and more available form. 3. A change can be made to the process methodology to reduce the need for the function. 4. New equipment can be installed to reduce the cost of the function. The starting point for reducing costs should be in achieving the minimum cost possible with the present equipment and processes. Installing management control systems can indicate what the lowest possible energy use is in a well-controlled situation. It is only at that point when a change in process or equipment configuration should be considered. An equipment

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change prior to actually minimizing the expenditure under the present system may lead to over sizing new equipment or replacing equipment for unnecessary functions. The third principle is to control and meter only the main energy functions—the roughly 20% that make up 80% of the costs. As Peter Drucker pointed out some time ago, a few functions usually for a majority of the costs. It is important to focus controls on those that represent the meaningful costs and aggregate the remaining items in a general category. Many manufacturing plants in the United States have only one meter, that leading from the gas main or electric main into the plant from the outside source. Regardless of the reasonableness of the standard cost established, the inability to measure actual consumption against that standard will render such a system useless. Sub metering the main functions can provide the information not only to measure but to control costs in a short time interval. The cost of metering and sub metering is usually incidental to the potential for realizing significant cost improvements in the main energy functions of a production system. The fourth principle is to put the major effort of an energy management program into installing controls and achieving results. It is common to find general knowledge about how large amounts of energy could be saved in a plant. The missing ingredient is the discipline necessary to achieve these potential savings. Each step in saving energy needs to be monitored frequently enough by the manager or first-line supervisor to see noticeable changes. Logging of important fuel usage or behavioral observations are almost always necessary before any particular savings results can be realized. Therefore, it is critical that an energy director or committee have the authority from the chief executive to install controls, not just advise line management. Those energy managers who have achieved the largest cost reductions actually install systems and controls; they do not just provide good advice. As suggested earlier, the overall potential for increasing energy productivity and reducing the cost of energy services is substantial. The 20% or so improvement in industrial energy productivity since 1972 is just the beginning. To quote the energy director of a large chemical company: “Long-term results will be much greater.” Although no one knows exactly how much we can improve productivity in practice, the American Physical Society indicated in their 1974 energy conservation study that it is theoretically possible to achieve an eightfold improvement of the 1972 energy/production ratio. Most certainly, we are a long way from an economic saturation of the opportunities. The common argument that not much can be done after a 15 or 20% improvement has been realized ought to be dismissed as baseless. Energy productivity provides an expanding opportunity, not a last resort. The chapters in this book provide the information that is necessary to make the most of that opportunity in each organization. 948

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2.2 ORGANIZING ENERGY MANAGEMENT PROGRAM:All the components of a comprehensive energy management program are depicted in Figure 2-1. These components are the organizational structure, a policy, and plans for audits, education, reporting, and strategy. It is hoped that by understanding the fundamentals of managing energy, the energy manager can then adapt a good working program to the existing organizational structure. Each component is discussed in detail below. The organizational chart for energy management shown in Figure 2-1 is generic. It must be adapted to fit into an existing structure for each organization. For example, the presidential block may be the general manager, and VP blocks may be division managers, but the fundamental principles are the same. The main feature of the chart is the location of the energy manager. This position should be high enough in the organizational structure to have access to key players in management, and to have knowledge of current events within the company. For example, the timing for presenting energy projects can be critical. Funding availability and other management priorities should be known and understood. The organizational level of the energy manager is also indicative of the management is willing to give to the position.

Energy Manager One very important part of an energy management program is to have top management . More important, however, is the selection of the energy manager, who can among other things secure this . The person selected for this position should be one with a 948

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vision of what managing energy can do for the company. Every successful program has had this one thing in common one person who is a shaker and mover that makes things happen. The program is then built around this person. Energy Team The coordinators shown in Figure 2-1 represent the energy management team within one given organizational structure, such as one company within a corporation. This group is the core of the program. The main criteria for hip should be an indication of interest. There should be a representative from the istrative group such as ing or purchasing, someone from facilities and/or maintenance, and a representative from each major department. This energy team of coordinators should be appointed for a specific time period, such as one year. Rotation can then bring new people with new ideas, can provide a mechanism for tactfully removing nonperformers, and involve greater numbers of people in the program in a meaningful way. Employees Employees are shown as a part of the organizational structure, and are perhaps the greatest untapped resource in an energy management program. A structured method of soliciting their ideas for more efficient use of energy will prove to be the most productive effort of the energy management program. A good energy manager will devote 20% of total time working with employees. Too many times employee involvement is limited to posters that say “Save Energy.” Employees in manufacturing plants generally know more about the equipment than anyone else in the facility because they operate it. They know how to make it run more efficiently, but because there is no mechanism in place for them to have an input, their ideas go unsolicited. ENERGY POLICY A well written energy policy that has been authorized by management is as good as the proverbial license to steal. It provides the energy manager with the authority to be involved in business planning, new facility location and planning, the selection of production equipment, purchase of measuring equipment, energy reporting, and training—things that are sometimes difficult to do. If you already have an energy policy, chances are that it is too long and cumbersome. To be effective, the policy should be short—two pages at most. Many people confuse the policy with a procedures manual. It should be bare bones, but contain the following items as a minimum: i) Objectives—this can contain the standard motherhood and flag statements about energy, but the most important is that the organization will incorporate energy efficiency into

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facilities and new equipment, with emphasis on life cycle cost analysis rather than lowest initial cost. ii) ability—this should establish the organizational structure and the authority for the energy manager, coordinators, and any committees or task groups. iii) Reporting—without authority from top management, it is often diffi cult for the energy manager to require others within the organization to comply with reporting requirements necessary to properly manage energy. The policy is the place to establish this. It also provides a legitimate reason for requesting funds for instrumentation to measure energy usage. iv) Training—If training requirements are established in the policy, it is again easier to include this in budgets. It should include training at all levels within the organization.

2.3 PLANNING:Planning is one of the most important parts of the energy management program, and for most technical people is the least desirable. It has two major functions in the program. First, a good plan can be a shield from disruptions. Second, by scheduling events throughout the year, continuous emphasis can be applied to the energy management program, and will play a major role in keeping the program active.

2.4 REPORTING:There is no generic form to that can be used for reporting. There are too many variables such as organization size, product, project requirements, and procedures already in existence. The ultimate reporting system is one used by a chemical company making a textile product. The Btu/lb of product is calculated on a computer system that gives an instantaneous reading. This is not only a reporting system, but one that detects maintenance problems. Very few companies are set up to do this, but many do have some type of energy index for monthly reporting. The energy Coordinator shall keep the Energy Office advised of all efforts to increase energy efficiency in their areas. A summary of energy cost savings shall be submitted each quarter to the Energy Office. The Energy Manager shall be responsible for consolidating these reports for top management.

2.5 CONTROLLING:Controlling is

one

of

the

managerial

functions

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According to modern concepts, control is a foreseeing action whereas earlier concept of control was used only when errors were detected. Control in management means setting standards, measuring actual performance and taking corrective action.

2.6 MONITORING:Monitoring information on energy use, in order to establish a basis for energy management and explain deviations from an established pattern. Its primary goal is to maintain said pattern, by providing all the necessary data on energy consumption, as well as certain driving factors, as identified during preliminary investigation (production, weather, etc.). Energy monitoring and targeting is primarily a management technique that uses energy information as a basis to eliminate waste, reduce and control current level of energy use and improve the existing operating procedures. It builds on the principle "you can't manage what you don't measure". It essentially combines the principles of energy use and statistics. While, monitoring is essentially aimed at establishing the existing pattern of energy consumption, targeting is the identification of energy consumption level which is desirable as a management goal to work towards energy conservation. Monitoring and Targeting is a management technique in which all plant and building utilities such as fuel, steam, refrigeration, compressed air, water, effluent, and electricity are managed as controllable resources in the same way that raw materials, finished product inventory, building occupancy, personnel and capital are managed. It involves a systematic, disciplined division of the facility into Energy Cost Centers. The utilities used in each centre are closely monitored, and the energy used is compared with production volume or any other suitable measure of operation. Once this information is available on a regular basis, targets can be set, variances can be spotted and interpreted, and remedial actions can be taken and implemented. The Monitoring and Targeting programs have been so effective that they show typical reductions in annual energy costs in various industrial sectors between 5 and 20%.

The essential elements of M&T system are: i) Recording -Measuring and recording energy consumption ii) Analyzing -Correlating energy consumption to a measured output, such as production quantity iii) Comparing -Comparing energy consumption to an appropriate standard or benchmark iv) Setting Targets -Setting targets to reduce or control energy consumption 948

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v) Monitoring -Comparing energy consumption to the set target on a regular basis vi) Reporting -Reporting the results including any variances from the targets which have been set. vii) Controlling -Implementing management measures to correct any variances, this may have occurred.

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UNIT III ENERGY MANAGEMENT-II 3.1 ENERGY MANAGER:One very important part of an energy management program is to have top management . More important, however, is the selection of the energy manager, who can among other things secure this . The person selected for this position should be one with a vision of what managing energy can do for the company. Every successful program has had this one thing in common one person who is a shaker and mover that makes things happen. The program is then built around this person. There is a great tendency for the energy manager to become an energy engineer, or a prima donna, and attempt to conduct the whole effort alone. Much has been accomplished in the past with such individuals working alone, but for the long haul, managing the program by involving everyone at the facility is much more productive and permanent. Developing a working organizational structure may be the most important thing an energy manager can do. The role and qualifications of the energy manager have changed substantially in the past few years, caused mostly by EPACT-1992 requiring certification of federal energy managers, deregulation of the electric utility industry bringing both opportunity and uncertainty, and by performance contracting requiring more business skills than engineering. In her book titled “Performance Contracting: Expanded Horizons,” Shirley Hansen give the following requirements for an energy management: i) Set up an Energy Management Plan ii) Establish energy records iii) Identify outside assistance iv) Assess future energy needs v) Identify financing sources vi) Make energy recommendations vii) Implement recommendations viii) Provide liaison for the energy committee ix) Plan communication strategies x) Evaluate program effectiveness Energy management programs can, and have, originated within one division of a large corporation. The division, by example and savings, motivates people at corporate level to pick up on the program and make energy management corporate wide. Many also originate at corporate level with people who have facilities responsibility, and have implemented a good 948

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corporate facilities program. They then see the importance and potential of an energy management program, and take a leadership role in implementing one. In every case observed by the author, good programs have been instigated by one individual who has recognized the potential, is willing to put forth the effort in addition to regular duties will take the risk of pushing new concepts, and is motivated by a seemingly higher calling to save energy. If initiated at corporate level, there are some advantages and some precautions. Some advantages are: i) More resources are available to implement the program, such as budget, staff, and facilities. ii) If top management is secured at corporate level, getting management at division level is easier. iii) Total personnel expertise throughout the corporation is better known and can be identified and made known to division energy managers. iv) Expensive test equipment can be purchased and maintained at corporate level for use by divisions as needed. v) A unified reporting system can be put in place. vi) Creative financing may be the most needed and the most important assistance to be provided from corporate level. vii) Impacts of energy and environmental legislation can best be determined at corporate level. viii) Electrical utility rates and structures, as well as effects of unbundling of electric utilities, can be evaluated at corporate level. Some precautions are: i) Many people at division level may have already done a good job of saving energy, and are cautious about corporate level staff coming in and taking credit for their work. ii) All divisions don’t progress at the same speed. Work with those who are most interested first, then through the reporting system to top management give them credit. Others will then request assistance.

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QUESTIONNAIRE - CHECK LIST FOR TOP MANAGEMENT:In the management system, the questionnaire is different for different companies. For example the top management check list is shown in table below,

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UNIT - IV ENERGY EFFICIENT MOTORS 4.1 ENERGY EFFICIENT MOTORS:Energy-efficient motors, also called or high- efficiency motors, are 2 to 8% more efficient than standard motors. Motors qualify as "energy-efficient" if they meet or exceed the efficiency levels listed in the National Electric Manufacturers Association's (NEMA's). Energy-efficient motors owe their higher performance to key design improvements and more accurate manufacturing tolerances. Lengthening the core and using lower-electrical-loss steel, thinner stator laminations, and more copper in the windings reduce electrical losses. Improved bearings and a smaller, more aerodynamic cooling fan further increase efficiency. Energy-efficient motors generally have longer insulation and bearing lives, lower heat output, and less vibration. In addition, these motors are often more tolerant of overload conditions and phase imbalance. This results in low failure rates, which has prompted most manufacturers to offer longer warranties for their energy-efficient lines. Purchasing an energy-efficient motor can dramatically cut energy costs. The below figure shows the difference between the standard motor and energy efficiency motors with efficiency Vs load and efficiency Vs motor rating (kw).

Figure: standard Vs high efficiency motors The advantages are,  Saves energy and money  Near uniform efficiency from 50% to 100% of full load ensuring energy savings even at part load conditions also  Short payback period  Substantial savings after payback period 948

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The applications of an energy efficient motor are specially suited for industries which are power intensive and equipments which run on constant load for long duration.

4.2 FACTORS AFFECTING EFFICIENCY AND LOSS DISTRIBUTION:Motor efficiency is simply of the watts output divided by the watts input. This is better expressed as the watts output minus the losses, divided by the watts input.

The only way to improve efficiency is to reduce motor losses. The components of motor losses can be broadly defined as no-load and load losses. The typical loss distribution for an AC motor is shown in below as, Percentage Motor Component’s Loss: Sr. No. 1.

2.

Motor component Loss Stator I²R loss( copper loss) Rotor I²R loss( copper loss)

Total Loss %

37%

18%

3.

Iron Loss

20%

4.

Friction and Windage loss

9%

5.

Stray Loss

16%

Description of Motor component’s Losses: Copper Loss: Depends on the effective resistance of motor winding: - Caused by the current flowing through it. - Is equal to I²R - Proportional to Load. - Is equal to I²R + Rotor I²R Loss.

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Iron Loss: Depending on the magnetic structure of the core and results from a combination of hysterisis and eddy current effect due to changing magnetic fields in the motor’s core -

Voltage Related.

-

Constant for any particular motor irrespective of load.

Friction and Windage loss: -

Occurs due to the friction in the bearing of the motor.

-

The windage loss of the ventilation fan, other rotating element of the motor.

-

Depend on the bearing size, speed type of bearing, lubrication used and fan blade profile.

-

Constant for given speed irrespective of load.

Stray Loss: It is very complex and Load related. -

Arises from harmonics and circulating current.

-

Manufacturing process variations can also add to stray losses arises from harmonics and circulating current.

-

Manufacturing process variations can also add to stray losses.

4.3 CONSTRUCTIONAL DETAILS:The efficiency of energy efficient motors is higher due to the following constructional features are, 1) By increasing the amount of copper in the motor (>60%) which reduces the resistance loss in the winding & temperature rise. Performance improves because of increased thermal mass. 2) Use of more & thinner laminations of high quality motor steel reduces core losses in the stator and rotor. 3) Narrowing of air gap between stator and rotor increases the intensity of magnetic flux, thereby improving the motor ability to deliver the same torque at reduced power. Increasing the length of the stator and rotor increases the net flux linkages in the air gap to the same effect. 4) More complex rotor bar designs enable good starting torque with efficient full speed operation. 5) Improved overall design reduces windage losses and stray load losses.

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4.4 CHARACTERISTICS - VARIABLE SPEED, VARIABLE DUTY CYCLE SYSTEMS:The single most potent source of energy savings in induction motor system lies not in the motor, but rather in the controls that govern its operation. Adjustable speed, intelligent controls and other ways of modifying or controlling motor behavior hold great promise for improving performance and efficiency in drive systems. Controlling motor speed to correspond to load requirements provides many benefits, including increased energy efficiency and improved power factor. Adjustable speed capability can significantly improve productivity of many manufacturing processes by reducing scrap, enabling quality manufacturing during transition times and allowing more control over start up and shut down. Following are the benefits of variable speed drives (VSD): 1) Matching motor and load to the output 2) Improved power factor 3) Improved process precision 4) Faster response 5) Extend operating range 6) increased production & flexibility

4.5 RMS HORSEPOWER (RMS HP):The root-mean-square (RMS) value of the horsepower over one cycle can be calculated to estimate the possible heating effect on the motor. The RMS horsepower is the square root of the sums of the horsepower squared, multiplied by the time per horsepower; divided by the sums of all the time intervals. To determine the RMS load on the motor, use the following equation:

As long as the RMS horsepower does not exceed the full load horsepower of the motor used in the application, the motor should not overheat. This, of course, is only true as long as there is adequate ventilation during the entire cycle. To keep it simple, we have disregarded the effect of acceleration time on a self-ventilated motor. Example… To properly size a motor for varying, repetitive duty, you will need to know the duration and 948

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horsepower load for each. It is helpful to develop a graph showing the required horsepower vs. time, as shown in Fig. 1, as well as a visual that lists each time and horsepower, Using the RMS horsepower for this example gives the following result:

4.6 VOLTAGE VARIATION-VOLTAGE UNBALANCE:Voltage variation:National Electrical Manufacturers Association (NEMA) standard recognizes the effect of voltage and frequency variation on electric motor performance. The standard recommends that the voltage deviation from the motor rated voltage not exceed 10% at the rated frequency. The rated motor voltage has been selected to match the utilization voltage available at the motor terminals. This voltage allows for the voltage drop in the power distribution system and for voltage variation as the system load changes. The basis of the NEMA standard rated motor voltages for three phase 60 Hz induction motors is as follows: System voltage

rated motor voltage

208

200

240

230

480

460

600

575

Voltage unbalance:Voltage unbalance can be more detrimental than voltage variation to motor performance and motor life. When the line voltages applied to a polyphase induction motor are not equal in magnitude and phase angle, unbalanced currents in the stator windings will result. A small percentage voltage unbalance will produce a much larger percentage current unbalance.

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Some of the causes of voltage unbalance are the following: 1) An open circuit in the primary distribution system. 2) A combination of single phase and three phase loads on the same distribution system, with the single phase loads unequally distributed. Percentage Voltage Unbalance is defined by NEMA as 100 times the deviation of the line Voltage from the average voltage divided by the average voltage. If the measured voltages are 420, 430 and 440V, the average is 430V and the deviation is 10V. The Percentage Unbalance is given by,

( or ) Voltage unbalance is defined as the NEMA as 100 times the absolute value of the maximum deviation of the line voltage from the average voltage on a three phase system divided by the average voltage.

1% voltage unbalance will increase the motor losses by 5%. Fig shows the increase in motor losses due to voltage unbalance.

Figure: Effect of voltage unbalance on motor losses

4.7 OVER MOTORING:In many instances, the practice has been to over motor an application, i.e., to select a higher horsepower motor than necessary. The disadvantages of this practice are,  Lower efficiency  Lower power factor  Higher motor cost  Higher controller cost  Higher installation costs. 948

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4.8 MOTOR ENERGY AUDIT:The Electrical Motor Energy Audit is the collection of actual electrical motor load data including: voltage, current, active power, total power, reactive power, and power factor under normal operating conditions. Average Energy Conservation ranges from 3 -35% depending on motor load conditions and will always be dependent upon the load. Motor applications that are under loaded or oversized have more electrical losses and therefore more potential for Energy Conservation and dollar savings. If necessary an additional Electrical Motor Energy Audit can be conducted following Implementation to the actual Energy Conservation and dollar savings. The verification process simply entails the collection of an average baseline motor load sample (before process) followed by another comparable average motor load sample with the ECI method (after process), and the evaluation of the difference. Energy Conservation is realized immediately upon Implementation. The process of electric motor management as,  Save energy  Reduce operating costs  Minimize downtime  Increase productivity.

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UNIT - V POWER FACTOR IMPROVEMENT, LIGHTING 5.1 POWER FACTOR:The power factor of an AC electrical power system is defined as the ratio of the real power flowing to the load to the apparent power in the circuit. (or) Power factor is defined as the ratio of real power (kw) to the apparent power (kvA) and cosine of the angle by which the current lags (or leads) the voltage.

It is a dimensionless number between 0 and 1. Real power is the capacity of the circuit for performing work in a particular time. Apparent power is the product of the current and voltage of the circuit. Due to energy stored in the load and returned to the source, or due to a non-linear load that distorts the wave shape of the current drawn from the source, the apparent power will be greater than the real power. In an electric power system, a load with a low power factor draws more current than a load with a high power factor for the same amount of useful power transferred. The higher currents increase the energy lost in the distribution system, and require larger wires and other equipment. Because of the costs of larger equipment and wasted energy, electrical utilities will usually charge a higher cost to industrial or commercial customers where there is a low power factor. Linear loads with low power factor (such as induction motors) can be corrected with a ive network of capacitors or inductors. Non-linear loads, such as rectifiers, distort the current drawn from the system. In such cases, active or ive power factor correction may be used to counteract the distortion and raise the power factor. The devices for correction of the power factor may be at a central substation, spread out over a distribution system, or built into power-consuming equipment.

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AC power flow has the three components: real power (also known as active power) (P), measured in watts (W); apparent power (S), measured in volt-amperes (VA); and reactive power (Q), measured in reactive volt-amperes (var). The power factor is defined as: active power/apparent power In the case of a perfectly sinusoidal waveform, P, Q and S can be expressed as vectors that form a vector triangle such that:

If φ is the phase angle between the current and voltage, then the power factor is equal to the cosine of the angle, |cosφ|, and:

Since the units are consistent, the power factor is by definition a dimensionless number between 0 and 1. When power factor is equal to 0, the energy flow is entirely reactive, and stored energy in the load returns to the source on each cycle. When the power factor is 1, all the energy supplied by the source is consumed by the load. Power factors are usually stated as "leading" or "lagging" to show the sign of the phase angle.

5.2 METHODS OF IMPROVEMENT:The most practical and economical power factor improvement device is the capacitor. As stated previously, all inductive loads produce inductive reactive power (lagging by a phase angle of 90°). Capacitors on the other hand produce capacitive reactive power, which is the exact opposite of inductive reactive power. In this instance, the current peak occurs before the voltage peak, leading by a phase angle of 90°. By careful selection of capacitance required, it is possible totally cancel out the inductive reactive power when placed in circuit together. To prevent the continual flow of reactive current back and forth between the load and power station, a capacitor, which is in effect a reactive current storage device, is connected in parallel with the load. The reactive current supplied by the power station and used for the magnetic force when the load is switched on does not now return to the power station but instead flows into the capacitor and merely circulates between the latter and the load. Consequently the distribution lines from the power station are relieved of the reactive current. Capacitors can therefore be utilized to reduce kVA and electrical costs. Improved power factor results in: 1. Reduced kVA charges 2. Improved plant efficiency 3. Additional loads can be added to the system 948

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4. Reduced overloading of cables, transformers, switchgear, etc. 5. Improved starting torque of motors 6. Reduce fuel requirements to generate power due to lower losses.

Cosϕ1 is the kVA used before Power Factor Improvement equipment was added to the network. Cosϕ2 is the kVA used after Power Factor improvement equipment was added to the network.

5.3 LOCATION OF CAPACITORS:In general, capacitor banks are installed in power systems for voltage , power factor correction, reactive power control, loss reduction, system capacity increase, and billing charge reduction. This process involves determining capacitor size, location, control method, and connection type (star or Delta). The main effort usually is to determine capacitor size and location for voltage and power factor correction. Secondary considerations are harmonics and switching transients. Any installation including the following types of machinery or equipment is likely to have low power factor which can be corrected, with a consequent saving in charges, by way of reduced demand charges, lesser low power factor penalties: 1. Induction motors of all types (which from by far the greatest industrial load on a. c. mains). 2. Power thyristor installation (for d.c. motor control and electro-chemical processes). 3. Power transformers and voltage regulators. 4. Welding machines 5. Electric-arc and induction furnaces. 6. Choke coils and magnetic system. 7. Neon sins and fluorescent lighting. There are different methods for determining capacitor size and location. 1. The most common method (intuitive) is based on rules of thumb followed by running multiple load flow studies for fine-tuning the size and location. This method may not yield the optimal solution and can be very time consuming and impractical for large systems.

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2. The second method is to use the ETAP Optimal Power Flow (OPF) program to optimize the capacitor sizes based on the candidate locations selected by the engineer. This method requires per-selected locations, since OPF can optimize the capacitor sizes but not the locations. 3. The most effective method is to use the Optimal Capacitor Placement (O) program to optimize capacitor sizes and locations with cost considerations. O employs a genetic algorithm, which is an optimization technique based on the theory of nature selection. O uses the “Present worth Method” to do alternative comparisons. It considers initial installation and operating costs, which includes maintenance, depreciation, and interest rate. Two methods of improving power factor using capacitors are: a) Individual motor compensation (static capacitors) b) Centralized compensation (automatic capacitor banks) a) Individual Motor Compensation:Most effective correction is obtained by connecting individual capacitors directly to the terminals of each motor. The motor and capacitor can be controlled tly by the motor switchgear. The capacitor rating should be matched as closely as possible so that the power factor of the entire plant can be corrected to the optimum value, irrespective of the number of motors switched on. If the magnetizing current is not known, 95% of the motor no-load current can be used as an approximate value. Care should be taken not to exceed the value calculated to avoid dangerous overvoltages and possible self excitation of motors at switch-off. Over compensation can cause higher supply voltages which can cause consequent break down of motor insulation and flashover at motor terminals. To be safe, rather use standard capacitor sizes (as indicated below). For this reason, individual motor compensation is not recommended for motors which are rapidly reversed e.g. cranes, hoists, etc. b) Centralized Compensation (Automatic Power Factor Correction):In large industrial plants where many motors are generally in use or, when the main reason for power factor is to obtain lower electricity bills, then centralized compensation is far more practical and economical than individual motor compensation. In this instance, large banks or racks of capacitors are installed at the main incoming distribution boards of the plant and are sub-divided into steps which are automatically switched in or out depending on specific load requirements by means of an automatic control system, improving the overall power factor of the network. Generally an automatic power factor system consists of: a) A main load-break isolator (or circuit breaker) b) An automatic reactive control relay 948

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c) Power factor capacitors backed by suitable fuse protection d) Suitably rated ors for capacitor switching The automatic reactive control relay monitors the total network and will switch-in the required capacitor banks at pre-determined intervals compensating for capacitor discharge times and load dependant requirements. As capacitor switching subject’s components to exceptionally high stresses it is imperative to correctly size and rate all components utilized in a system.

5.4 PF WITH NON LINEAR LOADS:Applies to those ac loads where the current is not proportional to the voltage. Foremost among loads meeting their definition is gas discharge lighting having saturated ballast coils and thyristor (SCR) controlled loads. The nature of non-linear loads is to generate harmonics in the current waveform. This distortion of the current waveform leads to distortion of the voltage waveform. Under these conditions, the voltage waveform is no longer proportional to the current. Non Linear Loads are: COMPUTER, LASER PRINTERS, SMPS, REACTIFIER, PLC, ELECTRONIC BALLAST, REFRIGERATOR, TV ETC.

5.5 EFFECT OF HARMONICS ON P.F:But for many applications, the classic triangle is oversimplified. That’s because it does not take into the effects of harmonic voltages and currents found in today’s power-distribution systems. Harmonics add a third dimension to the classic power-factor triangle, thereby increasing the apparent power required to do a particular amount of work. The presence of harmonics requires that you change the way you think about–and the way you measure–power factor. When active power is divided by apparent power in the presence of harmonics, the result is known as total power factor (PF). The component of power factor not contributed by harmonics is known as displacement power factor (DPF). Note that PF and DPF are equal in completely linear circuits–such as a 208-V, 3-phase induction motor operating a blower–but are different in nonlinear circuits, for example a variable-frequency drive controlling cooling-tower fans. O&M personnel should understand three practical effects of the PF/DPF definitions: (1) The difference between PF and DPF readings is proportional to the degree of harmonics in the power distribution system; (2) a power meter must provide both PF and DPF readings in order to effectively troubleshoot systems with harmonics; and (3) manufacturers of nonlinear

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equipment often provide only a single power-factor specification for their equipment, and it may be unclear whether the specification refers to PF or DPF. If PF and DPF differ by a factor of 10% or more, the difference is probably caused by harmonics. The degree of difference may also suggest a course of action, depending on the types of loads in the system. Case 1:

Predominantly linear systems. When PF and DPF are essentially the same value,

motors or other linear loads dominate the circuit. In this case, low power factor can be compensated for with kVAr correction capacitance. Use caution in diagnosing problems involving both low power factor and harmonics, because kVAr capacitors may be only part of the solution. Even in systems with low levels of harmonics, kVAr capacitors applied improperly can cause resonant conditions that can lead to overvoltages. Case 2:

Predominantly nonlinear systems. When PF is significantly lower than DPF

correct low power factor by applying line reactors directly to the sources of harmonic current or by using kVAr capacitor networks with series inductors to limit harmonic current in the capacitors. Always exercise caution in the use of kVAr correction capacitors and compensating filters to avoid resonance problems at harmonic frequencies and consult the capacitor manufacturer or an expert in filter design. Case 3:

Systems with kVAr capacitors already installed. When variable-frequency drives

are added to existing motors, and kVAr correction capacitors are already installed, DPF can actually be overcorrected, causing current to lead voltage. Without system modifications, these new components might cause instability and overvoltage problems. Under these conditions take readings in the circuit to determine whether it is necessary to remove the kVAr correction capacitors. s can measure both PF and DPF with a single meter. The best ones show three views of the measured signal: a numeric reading of signal parameters, a visual display of the waveform, and a view of the entire harmonic spectrum.

5.6 P.F MOTOR CONTROLLERS:Electric motor savings are achieved in several ways. The first is in the motor design itself, through the use of better materials, design, and construction. Another is by optimizing the mechanical angle between the various rotating magnetic fields inside the motor. This is done using the newer family of motor control algorithms, generally referred to together as space vector control, flux vector control, or field-oriented control. By keeping the magnetic fields of the rotor and stator oriented with the optimal angles between them under various speed and torque conditions (typically near 90 degrees), the motor can always be operated at 948

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peak efficiency. As a side benefit, other characteristics can also be optimized, such as fast and stable dynamic response to load changes, precise control of speed or torque, soft starting and braking, prevention of stalling at low speeds, high starting torques, and fault detection; often without sacrificing much in the way of overall energy efficiency. Some of these features were once obtainable only from a more expensive motor type, but can be achieved with the now ubiquitous, low-cost, and reliable AC induction motor, which comprises 90 percent of U.S. motor sales. One of the most significant advantages of the newer control algorithms is efficient variable speed operation. A very large opportunity for system-level energy savings comes from using variable speed motor drives. A well-designed pump or fan motor running at half the speed consumes only one-eighth the energy compared to running at full speed. Many older pump and fan installations used fixed-speed motors connected directly to the power mains, and controlled the liquid or air flow using throttling valves or air dampers. The valves or dampers create a back pressure, reducing the flow, but at the expense of efficiency. This is probably how the HVAC forced-air system works in your office building; dampers control the airflow into each workspace while the central fan, which is sized for peak requirements, runs at full speed all the time—even if the combined airflow requirements of the building are currently very low. Replacing these motors with variable speed drives and eliminating or controlling the dampers more intelligently can save up to two-thirds their overall energy consumption.

5.7 LIGHTING INTRODUCTION:In today’s cost-competitive,

market-driven economy,

everyone

is seeking

technologies or methods to reduce energy expenses and environmental impact. Because nearly all buildings have lights, lighting retrofits are very common and generally offer an attractive return on investment. “Lighting” is good lighting when it provides adequate illuminance to enable the task to be performed efficiently, is perceived as comfortable, and people have a high level of satisfaction. Good lighting design is not simply about achieving a required illuminance on the working plane; it is about creating and controlling the lit environment. Standards often specify lighting in of the illumination on the horizontal plane, which is the amount of light falling onto a horizontal surface. (Figure 1) This is because it is easy to measure and easy to calculate. It is not a good indicator of the visual environment however, as people generally judge the adequacy of the lighting by the luminance or relative brightness of the vertical surfaces.

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The luminance is the amount of light that leaves a surface, either by transmission through the material or, more commonly, reflection from the surface. (Figure 2) In simple , the luminance is the product of the illuminance and the reflectance of the surface divided by π. The eye sees luminance rather than illuminance. Therefore with the same illumination, by changing the surface reflectance, the luminance of the surface changes proportionally.

Figure 1. Illuminance: a measure of the light falling on a surface

Figure 2. Luminance is a measure of the light leaving a surface.

5.8 GOOD LIGHTING SYSTEM DESIGN:“Design” is the science and art of making things useful to human kind and lighting design is the application of lighting—including daylight when it is specifically used as source of lighting to human spaces. Like architecture, engineering and other design professions, lighting design relies on a combination of specific scientific principles, established standards and conventions, and a number of aesthetic, cultural and human factors applied in an artful manner. The two objectives of the lighting designer are, (1) To provide the right quantity of light, (2) Provide the right quality of light.

5.8.1 Lighting Quantity:Lighting quantity is the amount of light provided to a room. Unlike light quality, light quantity is easy to measure and describe. 5.8.1.1 Units:Lighting quantity is primarily expressed in three types of units: watts, lumens and foot-candles (fc). Figure 5.1 shows the relationship between each unit. 948

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The watt is the unit for measuring electrical power. It defines the rate of energy consumption by an electrical device when it is in operation. The amount of watts consumed represents the electrical input to the lighting system. The output of a lamp is measured in lumens. For example, one standard four-foot fluorescent lamp would provide 2,900 lumens in a standard office system. The amount of lumens can also be used to describe the output of an entire fixture (comprising several lamps). Thus, the number of lumens describes how much light is being produced by the lighting system. The number of foot-candles shows how much light is actually reaching the workplane (or task). Foot-candles are the end result of watts being converted to lumens, the lumens escaping the fixture and traveling through the air to reach the workplane. In an office, the workplane is the desk level. You can measure the amount of foot-candles with a light meter when it is placed on the work surface where tasks are performed. Foot-candle measurements are important because they express the “result” and not the “effort” of a lighting system. The Illuminating Engineering Society (IES) recommends light levels for specific tasks using footcandles, not lumens or watts.

Figure 5.1 Units of measurement. Efficacy:Similar to efficiency, efficacy describes an output/ input ratio, the higher the output (while input is kept constant), the greater the efficacy. Efficacy is the amount of lumens per watt from a particular energy source. A common misconception in lighting terminology is that lamps with greater wattage provide more light. However, light sources with high efficacy can provide more light with the same amount of power (watts), when compared to light sources with low efficacy. Figure 5.2 shows lamp efficacies for various lamp types, based on initial lumen values. 5.8.1.2 IES Recommended Light Levels:The Illuminating Engineering Society (IES) is the largest organized group of lighting professionals in the United States. Since 1915, IES has prescribed the appropriate light levels for many kinds of visual tasks.

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Figure 5.2 Lamp Efficacies for Various Lamp Types. (Source: Effective Lighting Solutions, Inc.)

5.8.2 Lighting Quality:Lighting quality can have a dramatic influence on the attitude and performance of occupants. In fact, different “moods” can be created by a lighting system. Consider the behavior of people when they eat in different restaurants. If the restaurant is a fast-food restaurant, the space is usually illuminated by bright white lights, with a significant amount of glare from shiny tables. Occupants rarely spend much time there partly because the space creates an uncomfortable mood and the atmosphere is “fast” (eat and leave). In contrast, consider an elegant restaurant with a candle-lit tables and a “warm” atmosphere. Occupants tend to relax and take more time to eat. Although occupant behavior is also linked to interior design and other factors, lighting quality represents a significant influence. Occupants perceive and react to a space’s light color. It is important that the lighting designer be able to recognize and create the subtle aspects of an environment that define the theme of the space. For example, drug and grocery stores use white lights to create a “cool” and “clean” environment. Imagine if these spaces were illuminated by the same color lights as in an elegant restaurant. How would the perception of the store change? Occupants can be influenced to work more effectively if they are in an environment that promotes a “worklike” atmosphere.

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The goal of the lighting designer is to provide the appropriate quality of light for a particular task to create the right “mood” for the space. Employee comfort and performance are worth more than energy savings. Although the cost of energy for lighting ($.50$1.00/year/ft2) is substantial, it is relatively small compared to the cost of labor ($100$300/year/ft2). Improvements in lighting quality can yield high dividends for businesses because gains in worker productivity are common when lighting quality is improved. Conversely, if a lighting retrofit reduces lighting quality, occupant performance may decrease, quickly off-setting any savings in energy costs. Good energy managers should that buildings were not designed to save energy; they exist to create an environment where people can work efficiently. Occupants should be able to see clearly without being distracted by glare, excessive shadows or other uncomfortable features. Lighting quality can be divided into four main considerations are Uniformity, Glare, Color Rendering Index and Coordinated Color Temperature. 5.8.2.1 Uniformity:The uniformity of illuminance describes how evenly light spreads over an area. Creating uniform illumination requires proper fixture spacing. Non-uniform illuminance creates bright and dark spots, which can cause discomfort for some occupants. Lighting designers have traditionally specified uniform illumination. This option is least risky because it minimizes the problems associated with non-uniform illumination and provides excellent flexibility for changes in the work environment. Unfortunately, uniform lighting applied over large areas can waste large amounts of energy. For example, in a manufacturing building, 20% of the floor space may require high levels of illumination (100 fc) for a specific visual task. The remaining 80% of the building may only require 40 foot candles. Uniform illumination over the entire space would require 100 fc at any point in the building. Clearly, this is a tremendous waste of energy and money. Although uniform illumination is not needed throughout the entire facility, uniform illumination should be applied on specific tasks. For example, a person assembling small parts on a table should have uniform illumination across the table top. 5.8.2.2 Glare:Glare is a sensation caused by relatively bright objects in an occupant’s field of view. The key word is relative, because glare is most probable when bright objects are located in front of dark environments. For example, a car’s high beam headlights cause glare to oncoming drivers at night, yet create little discomfort during the day. Contrast is the relationship between the brightness of an object and its background.

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Although most visual tasks generally become easier with increased contrast, too much brightness causes glare and makes the visual task more difficult. Glare in certain work environments is a serious concern because it usually will cause discomfort and reduce worker productivity. Visual Comfort Probability (V):The Visual Comfort Probability is a rating given to a fixture which indicates the percent of people who are comfortable with the glare. Thus, a fixture with a V = 80 means that 80% of occupants are comfortable with the amount of glare from that fixture. A minimum V of 70 is recommended for general interior spaces. Fixtures with Vs exceeding 80 are recommended in computer areas and high-profile executive office environments. To improve a lighting system that has excessive glare, a lighting designer should be consulted. However there are some basic “rules of thumb” which can assist the energy manager. A high-glare environment is characterized by either excessive illumination and reflection, or the existence of very bright areas typically around fixtures. To minimize glare, the energy manager can try to obscure the bare lamp from the occupant’s field of view, relocate fixtures or replace the fixtures with ones that have a high V. Reducing glare is commonly achieved by using indirect lighting, using deep cell parabolic troffers, or special lenses. Although these measures will reduce glare, fixture efficiency will be decreased because more light will be “trapped” in the fixture. Alternatively, glare can be minimized by reducing ambient light levels and using task lighting techniques.

Visual Display Terminals (VDTs):Today’s office environment contains a variety of special visual tasks, including the use of computer monitors or visual display terminals (VDTs). Occupants using VDTs are extremely vulnerable to glare and discomfort. When reflections of ceiling lights are visible on the VDT screen, the occupant has difficulty reading the screen. This phenomenon is also called “discomfort glare,” and is very common in rooms that are uniformly illuminated by fixtures with low a V. Therefore, lighting for VDT environments must be carefully designed, so that occupants remain comfortable. Because the location VDTs can be frequently changed, lighting upgrades should also be designed to be adjustable. Moveable task lights and fixtures with high V are very popular for these types of applications. Because each VDT environment is unique, each upgrade must be evaluated on a case-by-case basis.

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5.8.2.3 Color:Color considerations have an incredible influence on lighting quality. Light sources are specified based on two color-related parameters: the Color Rendering Index (CRI) and the Coordinated Color Temperature (CCT). Color Rendering Index (CRI):In simple , the CRI provides an evaluation of how colors appear under a given light source. The index range is from 0 to 100. The higher the number, the easier to distinguish colors. Generally, sources with a CRI > 75 provide excellent color rendition. Sources with a CRI < 55 provide poor color rendition. To provide a “base-case,” offices illuminated by most T12 Cool White lamps have a CRI = 62. It is extremely important that a light source with a high CRI be used with visual tasks that require the occupant to distinguish colors. For example, a room with a color printing press requires illumination with excellent color rendition. In comparison, outdoor security lighting for a building may not need to have a high CRI, but a large quantity of light is desired. Coordinated Color Temperature (CCT):The Coordinated Color Temperature (CCT) describes the color of the light source. For example, on a clear day, the sun appears yellow. On an over-cast day, the partially obscured sun appears to be gray. These color differences are indicated by a temperature scale. The CCT (measured in degrees Kelvin) is a close representation of the color that an object (black-body) would radiate at a certain temperature. For example, imagine a wire being heated. First it turns red (CCT = 2000K). As it gets hotter, it turns white (CCT = 5000K) and then blue (CCT = 8000K). Although a wire is different from a light source, the principle is similar. CCT is not related to CRI, but it can influence the atmosphere of a room. Laboratories, hospitals and grocery stores generally use “cool” (blue-white) sources, while expensive restaurants may seek a “warm” (yellow-red) source to produce a candle-lit appearance. Traditionally, office environments have been illuminated by Cool White lamps, which have a CCT = 4100K. However, a more recent trend has been to specify 3500K triphosphor lamps, which are considered neutral. Table 13.2 illustrates some common specifications for different visual environments.

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Lamp characteristics

5.9 Lighting Controls:A lighting control system is an intelligent network based lighting control solution that incorporates communication between various system inputs and outputs related to lighting control with the use of one or more central computing devices. Lighting control systems are widely used on both indoor and outdoor lighting of commercial, industrial, and residential spaces. Lighting control systems serve to provide the right amount of light where and when it is needed. Lighting control systems are employed to maximize the energy savings from the lighting system, satisfy building codes, or comply with green building and energy conservation programs. Lighting control systems are often referred to under the term Smart Lighting.

Lighting controls offer the ability for systems to be turned ON and OFF either manually or automatically. There are several control technology upgrades for lighting systems, ranging from simple (installing manual switches in proper locations) to sophisticated (installing occupancy sensors). The term lighting controls is typically used to indicate stand-alone control of the lighting within a space. This may include occupancy sensors, time clocks, and photocells that

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are hard-wired to control fixed groups of lights independently. Adjustment occurs manually at each devices location. The term lighting control system refers to an intelligent networked system of devices related to lighting control. These devices may include relays, occupancy sensors, photocells, light control switches or touch screens, and signals from other building systems (such as fire alarm of HVAC). Adjustment of the system occurs both at device locations and through and at central computer locations via software programs or other interface devices. 5.9.1 Switches:The standard manual, single-pole switch was the first energy conservation device. It is also the simplest device and provides the least options. One negative aspect about manual switches is that people often forget to turn them OFF. If switches are far from room exits or are difficult to find, occupants are more likely to leave lights ON when exiting a room. Occupants do not want to walk through darkness to find exits. However, if switches are located in the right locations, with multiple points of control for a single circuit, occupants find it easier to turn systems OFF. Once occupants get in the habit of turning lights OFF upon exit, more complex systems may not be necessary. The point is: switches can be great energy conservation devices as long as they are convenient to use them.

5.9.2 Time Clocks:Time clocks can be used to control lights when their operation is based on a fixed operating schedule. Time clocks are available in electronic or mechanical styles. However, regular check-ups are needed to ensure that the time clock is controlling the system properly. After a power loss, electronic timers without battery backups can get off schedule—cycling ON and OFF at the wrong times. It requires a great deal of maintenance time to reset isolated time clocks if many are installed.

5.10 lighting energy audit:5.10.1 Assess opportunities for increasing lighting energy:a) Turn off lights in unoccupied areas. 1) Post reminder stickers to turn off lights when leaving the area. 2) Install time switches or occupancy sensors in areas of brief occupancy and remote areas (warehouses, storage areas, etc.). 3) Rewire switches so that one switch does not control all fixtures for multiple work areas. 948

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4) Ensure wall-switch timers function properly. b) Determine if existing lighting levels are higher than recommended levels. Use a light meter to measure light levels and consult the Illuminating Engineering Society of North America (IESNA) illumination standards. 1) Reduce lighting levels where appropriate. 2) Reduce lighting hours. 3) Employ uniform or task delamping to reduce power and lighting. c) Review outside lighting needs. 1) Eliminate outdoor lighting where possible and where safety and security are not compromised. 2) Replace exterior incandescent lights with more efficiency lights such as high pressure sodium (HPS) or metal halide (MH). 3) Replace burned out lamps with lower wattage lamps. d) Remove unneeded lamps (delamp). e) Install more efficient lighting. f) Employ more effective lighting settings. g) Follow a regular a maintenance schedule. h) Upgrade exit signs with the help of an expert. i) Use day lighting effectively. j) Remove unnecessary lighting in beverage machines. k) Train staff, especially housekeeping staff, on lighting policies/efficiency.

5.10.2 Top reasons to audit your lighting system:1) To save energy and money with existing equipment by using new light control strategies. 2) To improve your facility's image — go green. 3) To enhance your facility's atmosphere for occupants with added comfort, safety, and productivity. 4) Because lighting uses 39% of electricity in office buildings (EIA Commercial Buildings Energy Consumption Survey, 2003 data, released in 2008). 5) Because you know that older equipment needs to be replaced with more energy efficient Products. 6) Because, sometimes, simple operational changes can impact energy savings dramatically. 7) To re-optimize system operation after facility changes.

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Unit VI ENERGY INSTRUMENTS 6.1 Energy Audit Instruments:The requirement for an energy audit such as identification and quantification of energy necessitates various measurements; these measurements require the use of instruments. These instruments must be portable, durable, easy to operate and relatively inexpensive. The parameters generally monitored during the energy audit may include the following : 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. Parameters of importance other than electrical such as temperature and heat flow, radiation, air and gas flow, liquid flow, revolutions per minute, air velocity, noise and vibration, dust concentration, total dissolved solids, pH, moisture content, relative humidity, flue gas analysis – CO2, O2, CO, SOX, NOX, combustion efficiency etc. 6.1.1 Typical instruments used in energy audits: The below are some of the typical instruments utilized depending on the process or system being audited. The operating instructions for all instruments must be understood and staff should familiarize themselves with the instruments and their operation prior to actual audit use. 6.1.1.1 Electrical Measuring Instruments:These are instruments for measuring major electrical parameters such as kVA, kW, PF, Hertz, kVAr, amps and volts. In addition some of these instruments also measure harmonics. These instruments are applied on-line, i.e., on running motors without stopping the motor. Instantaneous measurements can be taken with hand-held meters, while more advanced models facilitate cumulative readings with printouts at desired intervals.

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6.1.1.2 Thermometers: thermometer: These are thermocouples which measures for example flue gas, hot air, hot water temperatures by insertion of probe into the stream. For surface temperature, a leaf

type

probe

is

used

with

the

same

instrument.

Infrared Thermometer: This is a non- type measurement which when directed at a heat source directly gives the temperature read out. This instrument is useful for measuring hot spots in furnaces, surface temperatures etc.

6.1.1.3 Lux Meter:Illumination levels are measured with a lux meter. It consists of a photo cell that senses the light output, converting it to electrical impulses that are calibrated as lux and indicated by a digital meter.

6.1.1.4 Data logger:A data logger (also data logger or data recorder) is an electronic device that records data over time or in relation to location either with a built in instrument or sensor or via external instruments and sensors. Increasingly, but not entirely, they are based on a digital processor (or computer). They generally are small, battery powered, portable, and equipped with a microprocessor, internal memory for data storage, and sensors. Some data loggers interface with a personal computer and utilize software to activate the data logger and view and analyze the collected data, while others have a local interface device (keypad, LCD) and can be used as a stand-alone device.

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6.1.1.5 Pyrometer:A pyrometer is a non-ing device that intercepts and measures thermal radiation, a process known as pyrometer. This device can be used to determine the temperature of an object's surface. A pyrometer has an optical system and a detector. The optical system focuses the thermal radiation onto the detector. The output signal of the detector (temperature T) is related to the thermal radiation or irradiance j* of the target object through the Stefan– Boltzmann law, the constant of proportionality σ, called the Stefan-Boltzmann constant and the emissivity ε of the object.

This output is used to infer the object's temperature. Thus, there is no need for direct between the pyrometer and the object, as there is with thermocouples and resistance temperature detectors (RTDs).

6.1.1.6 Wattmeter:The wattmeter is an instrument for measuring the electric power (or the supply rate of electrical energy) in watts of any given circuit. Electromagnetic wattmeter are used for measurement of utility frequency and audio frequency power; other types are required for radio frequency measurements.

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6.2 Applications of PLC’s:Power line communication (PLC):Power line communication (PLC) carries data on a conductor that is also used simultaneously for AC electric power transmission or electric power distribution to consumers. It is also known as power line carrier, power line digital subscriber line (PDSL), mains

communication, power

line

telecom (PLT), power

line

networking (PLN), and broadband over power lines(BPL). A wide range of power line communication technologies are needed for different applications, ranging from home automation to Internet access. Most PLC technologies limit themselves to one type of wires (such as premises wiring within a single building), but some can cross between two levels (for example, both the distribution network and premises wiring). Typically transformers prevent propagating the signal, which requires multiple technologies to form very large networks. Various data rates and frequencies are used in different situations. A number of difficult technical problems are common between wireless and power line communication, notably those of spread spectrum radio signals operating in a crowded environment. Radio interference, for example, has long been a concern of amateur radio groups. Power line communications systems operate by adding a modulated carrier signal to the wiring system. Different types of power line communications use different frequency bands. Since the power distribution system was originally intended for transmission of AC power at typical frequencies of 50 or 60 Hz, power wire circuits have only a limited ability to carry higher frequencies. The propagation problem is a limiting factor for each type of power line communications. The main issue determining the frequencies of power line communication is laws to limit interference with radio services. Many nations regulate unshielded wired emissions as if they were radio transmitters. These jurisdictions usually require unlicensed uses to be below 500 KHz or in unlicensed radio bands. Some jurisdictions (such as the EU), regulate wire-line transmissions further. The U.S. is a notable exception, permitting limited-power wide-band signals to be injected into unshielded wiring, as long as the wiring is not designed to propagate radio waves in free space. Data rates and distance limits vary widely over many power line communication standards. Low-frequency (about 100–200 kHz) carriers impressed on high-voltage transmission lines may carry one or two analog voice circuits, or telemetry and control circuits with an equivalent data rate of a few hundred bits per second; however, these circuits 948

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may be many miles long. Higher data rates generally imply shorter ranges; a local area network operating at millions of bits per second may only cover one floor of an office building, but eliminates the need for installation of dedicated network cabling. Programmable logic controller:A programmable logic controller, commonly known as PLC, is a solid state, digital, industrial computer using integrated circuits instead of electromechanical devices to implement control functions. It was invented in order to replace the sequential circuits which were mainly used for machine control. They are capable of storing instructions, such as sequencing, timing, counting, arithmetic, data manipulation and communication, to control machines and processes. According to NEMA (National Electrical Manufacture’s Association, USA), the definition of PLC has been given as, “Digital electronic devices that uses a programmable memory to store instructions and to Implement specific functions such as logic , sequencing, timing, counting, and arithmetic to control machines and processes.” PLCs are used in many industries and machines. Unlike general-purpose computers, the PLC is designed for multiple inputs and output arrangements, extended temperature ranges, immunity to electrical noise, and resistance to vibration and impact. Programs to control machine operation are typically stored in battery-backed-up or non-volatile memory. A PLC is an example of a hard real time system since output results must be produced in response to input conditions within a limited time, otherwise unintended operation will result. Some of PLC applications are,  Equipment Status  Process Control  Chemical Processing  Equipment Interlocks  Machine Protection  Smoke Detection  Gas Monitoring  Envelope Monitoring  Personnel Safety  High-precision Synchronized Control in Crimping Equipment using PLC  Bottle Filling Control using PLC  High-speed Sorting on Conveyors using PLC  Image-processing Inspection of Electronic Components using PLC 948

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 Shopping Mall Fountain Control using PLC  Air Cleaner Control using PLC  Sheet Feeding Control in Packing Machine using PLC  Testing Equipment  Warming Moulding Machines  Annunciator  Lighting Pattern Control  Escalator with Automatic Operation Function  Drilling PCBs with High-speed, High-precision Positioning  Hydraulic Pressure Control in Forming Machine  Temperature Cascade Control in Industrial Furnace  Production Control System

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UNIT VII ECONOMIC ASPECTS AND ANALYSIS 7.1 ECONOMICS ANALYSIS:Energy economics is a broad scientific subject area which includes topics related to supply and use of energy in societies. Due to diversity of issues and methods applied and shared with a number of academic disciplines, energy economics does not present itself as a self-contained academic discipline, but it is an applied sub discipline of economics. From the list of main topics of economics, some relate strongly to energy economics:  Econometrics  Environmental economics  Finance  Industrial organization  Microeconomics  Macroeconomics  Resource economics Energy economics also draws heavily on results of energy engineering, geology, political sciences, ecology etc. Recent focus of energy economics includes the following issues:  Climate change and climate policy  Risk analysis and security of supply  Sustainability  Energy markets and electricity markets - liberalization, (de- or re-) regulation  Demand response  Energy and economic growth  Economics of energy infrastructure  Environmental policy  Energy policy  Energy derivatives  Forecasting energy demand  Elasticity of supply and demand in energy market  Energy elasticity

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7.2 DEPRECIATION:Depreciation refers to two aspects of the same concept:  The decrease in value of assets (fair value depreciation), and  The allocation of the cost of assets to periods in which the assets are used (depreciation with the matching principle). Depreciation affects the “ing procedure” for determining profits and losses and the income tax of a company. In other words, for tax purposes the expenditure for an asset such as a pump or motor cannot be fully expensed in its first year. The original investment must be charged off for tax purposes over the useful life of the asset. A company wishes to expense an item as quickly as possible. The Internal Revenue Service allows several methods for determining the annual depreciation rate. 7.2.1 Straight-line Depreciation:The simplest method is referred to as a straight-line depreciation and is defined as

Where, D is the annual depreciation rate. L is the value of equipment at the end of its useful life, commonly referred to as salvage value. P is the initial expenditure. n is the life of the equipment which is determined by Internal Revenue Service guidelines. ( or ) Straight-line depreciation is the simplest and most often used method. In this method, the company estimates the salvage value of the asset at the end of the period during which it will be used to generate revenues (useful life). (The salvage value is an estimate of the value of the asset at the time it will be sold or disposed of; it may be zero or even negative. Salvage value is also known as scrap value or residual value.) The company will then charge the same amount to depreciation each year over that period, until the value shown for the aset has reduced from the original cost to the salvage value.

7.2.2 Sum-of-Years Digits:Another method is referred to as the sum-of-years digits. In this method the depreciation rate is determined by finding the sum of digits using the following formula:

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Each year’s depreciation rate is determined as follows:

7.2.3 Declining-Balance Depreciation:The declining-balance method allows for larger depreciation charges in the early year, which is sometimes referred to as fast write-off. The rate is calculated by taking a constant percentage of the declining undepreciated balance. The most common method used to calculate the declining balance is to predetermine the depreciation rate. Under certain circumstances a rate equal to 200% of the straight-line depreciation rate may be used. Under other circumstances the rate is limited to 1-1/2 or 1-1 /4 times as great as straight-line depreciation. In this method the salvage value or undepreciated book value is established once the depreciation rate is pre-established. To calculate the undepreciated book value, Formula is used:

Where D is the annual depreciation rate. L is the salvage value. P is the first cost.

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Tax depreciation:Most income tax systems allow a tax deduction for recovery of the cost of assets used in a business or for the production of income. Such deductions are allowed for individuals and companies. Where the assets are consumed currently, the cost may be deducted currently as an expense or treated as part of cost of goods sold. The cost of assets not currently consumed generally must be deferred and recovered over time, such as through depreciation. Some systems permit full deduction of the cost, at least in part, in the year the assets are acquired. Other systems allow depreciation expense over some life using some depreciation method or percentage. Rules vary highly by country, and may vary within a country based on type of asset or type of taxpayer. Many systems that specify depreciation lives and methods for financial reporting require the same lives and methods be used for tax purposes. Most tax systems provide different rules for real property (buildings, etc.) and personal property (equipment, etc.).

7.3 THE TIME VALUE OF MONEY CONCEPT:To compare energy utilization alternatives, it is necessary to convert all cash flow for each measure to an equivalent base. The life-cycle cost analysis takes into the ”time value” of money; thus a dollar in hand today is more valuable than one received at some time in the future. This is why a time value must be placed on all cash flows into and out of the company. Money has time value. A rupee today is more valuable than a year hence. It is on this concept “the time value of money” is based. The recognition of the time value of money and risk is extremely vital in financial decision making.

7.3.1 TECHNIQUES OF TIME VALUE OF MONEY (or) DEVELOPING CASH FLOW MODELS:-

There are two techniques for adjusting time value of money. They are: 1. Compounding Techniques/Future Value Techniques 2. Discounting/Present Value Techniques The value of money at a future date with a given interest rate is called future value. Similarly, the worth of money today that is receivable or payable at a future date is called Present Value.

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7.3.1.1 Compounding Techniques/Future Value Technique:In this concept, the interest earned on the initial principal amount becomes a part of the principal at the end of the compounding period. FOR EXAMPLE: Suppose you invest 1000 Rs for three years in a saving that pays 10 per cent interest per year. If you let your interest income be reinvested, your investment will grow as follows: First year :

Principal at the beginning Rs 1,000 Interest for the year (Rs 1,000 × 0.10) 100 Principal at the end Rs 1,100

Second year : Principal at the beginning Rs 1,100 Interest for the year (Rs 1,100 × 0.10) 110 Principal at the end Rs 1210 Third year :

Principal at the beginning Rs 1210 Interest for the year (Rs 1210 × 0.10) 121 Principal at the end Rs 1331

This process of compounding will continue for an indefinite time period. The process of investing money as well as reinvesting interest earned there on is called Compounding. But the way it has gone about calculating the future value will prove to be cumbersome if the future value over long maturity periods of 20 years to 30 years is to be calculated. A generalized procedure for calculating the future value of a single amount compounded annually is as follows: Formula:

FVn = PV(1 + r)n

In this equation (1 + r)n is called the future value interest factor (FVIF). where, FVn = Future value of the initial flow n year hence PV = Initial cash flow r = Annual rate of Interest n = number of years By taking into consideration, the above example, we get the same result. FVn = PV (1 + r)n = 1,000 *(1.10)*3 FVn = 1331 FUTURE VALUE OF MULTIPLE CASH FLOWS is, The transactions in real life are not limited to one. An investor investing money in installments may wish to know the value of his savings after ‘n’ years. The formulae is\

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Where FVn = Future value after ‘n’ years PV = Present value of money today r = Interest rate,

m = Number of times compounding is done in a year.

The formulae to calculate the Effective Interest Rate is

Where EIR = Effective Rate of Interest r = Nominal Rate of Interest (Yearly Interest Rate) m = Frequency of compounding per year

7.3.1.2 DISCOUNTING OR PRESENT VALUE CONCEPT:Present value is the exact opposite of future value. The present value of a future cash inflow or outflow is the amount of current cash that is of equivalent value to the decision maker. The process of determining present value of a future payment or receipts or a series of future payments or receipts is called discounting. The compound interest rate used for discounting cash flows is also called the discount rate. In the next chapter, we will discuss the net present value calculations. To calculate the present value as, P = Fn (1+i)-n The factor (1+i)-n is known as the single sum, present worth factor or the single payment, present worth factor. This factor is denoted (P|F,i,n) and is read “to find P given F at i% for n years.” SIMPLE AND COMPOUND INTEREST In compound interest, each interest payment is reinvested to earn further interest in future periods. However, if no interest is earned on interest, the investment earns only simple interest. In such a case, the investment grows as follows: Future value = Present value [1 + Number of years × Interest rate] For example, if Rs 1,000 is invested @ 12% simple interest, in 5 years it will become 

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