Energy Efficiency A - Z
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Good energy management is important to the optimum running of your business. Considerable cost savings can be made by adopting better practices and developing an energy management strategy.
This document will help you to prepare a practical energy management strategy for your business.
Control and management of costs is vital for a successful business. Energy is a controllable cost and it is important to keep a close check on the amount of energy used within your business. Better control of energy use is possible only if you base your decisions about it on accurate information.
Regular monitoring of energy use will also enable you to assess the effectiveness of any energy efficiency measures you implement.
Often companies do not consider the fuels they use. The choice of fuel is not a simple matter, as a number of factors must be considered including installation, operating and maintenance costs.
Another area to look at is the price of your energy supplies. You may be able to realise substantial cost savings by changing to an alternative fuel or to a different tariff or by 'shopping around' for the cheapest fuel supplier.
As technology is developing, more and more electrical equipment is being used in Offices. Although modern office equipment often uses less energy than many people expect, leaving it on unnecessarily should be actively discouraged.
When purchasing new equipment always examine its energy consumption, as some brands are considerably more energy efficient than others.
Choosing, controlling and maintaining a lighting system is an important step in achieving good energy management. Lighting is one of the major uses for electricity and many businesses could reduce their lighting costs by at least 30%.
Simple good housekeeping measures, such as switching lighting off when leaving rooms - cost nothing to implement but save money immediately!
Compressed air accounts for approximately 10% of electrical power used in industry. It is one of the most expensive utilities and its high cost more than justifies a regular programme of checks to minimise losses.
Despite the cost, large amounts of compressed air are simply lost from compressed air distribution systems through leaks. Simple checks can reduce air compressor energy use by up to 20%.
In some cases, it is possible to dispense with expensive compressed air systems altogether by switching to rechargeable electric power tools.
Examining the way in which energy is used in processes can highlight areas where savings can be made. Often waste energy from industrial processes can be used in other systems e.g. the building's water heating system.
Electric motors and drive systems account for over 60% of industrial electrical demand. Most of this is used by production machinery, drive fans, pumps and compressors. Small improvements in motor efficiency and management can make very large savings in energy costs.
The simplest way of achieving savings is to switch off motors when not required. Automatic load sensors can ensure this happens.
If a building is to be heated economically, and maintained at a comfortable temperature for employees, effective insulation, up-to-date controls, correctly sized heaters and efficient boilers must be installed. Good temperature control is particularly essential, as a 1oC reduction in thermostat settings could reduce your heating bills by up to 7%.
For air-conditioned buildings, good temperature control is equally important.
Most fossil fuel supplied to industry and commerce is used in boilers, but many are ignored as long as they continue to operate reliably. As a result, many boilers are operated at lower efficiencies than possible - due to a lack of maintenance.
Another cause of waste is poor control, and substantial fuel savings can be made simply by adjusting time switches and temperature set-points.
In many cases, poor insulation is a major area of energy loss in buildings and simple improvements can save considerable amounts of money.
The amount of heat lost can easily be calculated if the construction details of walls, roof and windows are known. A simple 'U' value calculation can also be used to predict the reduction in heat loss that will be realised by improved insulation.
Simple heat loss detection should be part of your energy survey.
Many employees do not realise how much hot water is used and how much it costs. Make sure your employees are aware of how much it costs.
In small and medium sized companies, the main reasons for heating water are hand washing and cleaning. Substantial energy savings can be made by changing:
1. The temperatures to which the water is heated.
2. The way hot water is distributed.
3. The method used to heat water.
However your first priority should be to minimise the amount of hot water used in your business - by persuading employees to use less.
In the catering industry, substantial amounts of energy are used in cooking and mechanical ventilation. Unlike many of the other costs in a catering establishment, such as rents and rates, energy costs are controllable.
Increased energy awareness in the kitchen, and associated food serving and storage areas could save 20% of your catering-related energy bill.
Vehicle fuel is a significant part of most companies costs and since fuel prices will inevitably rise in the future, you should look at your fuel management controls now. A few simple management measures could realise big savings and improve profitability.
You should also consider swapping to more efficient forms of transport, greater use of public transport and eliminating some journeys altogether by teleconferencing. These options require careful planning, but will considerably reduce your company's impact on the environment.
Generating waste during manufacturing means lost profit. As well as affecting raw material and energy use, product and processing time, waste can create handling and disposal problems too.
Many companies are unaware that up to 10% of turnover can be lost to waste after lost sales revenue and disposal costs are included. Every process that produces waste should be a target for waste minimisation activities, and may yield sustained cost savings and increased profits if tackled systematically via a process of continuous improvement.
However sustained cost savings will only be realised if you systematically tackle the causes of waste at their source via a process of continuous improvement.
An action plan is central to your energy efficiency programme, as it will form the basis for minimising your company's bill for energy and related utilities such as water, telecommunications and transport. Your action plan should also ensure that energy management is treated as a process of continuous control and improvement, not just a one-off exercise. To ensure maximum acceptance, your Directors should publish a clear policy outlining the importance of effective energy management to the business.
Action Plan (Energy Management)
1. Define a simple Energy Policy
2. Assign responsibilities.
3. Involve all employees.
4. Set up an energy monitoring system.
5. Conduct an energy audit.
6. Conduct an energy survey.
7. Take action on 'no cost' measures immediately
8. Set energy consumption targets / yardsticks.
9. Appraise 'low cost' and 'major cost' projects.
Ensure that all actions and savings are recorded.
Compressors should be sized so that generation capacity matches demand for compressed air as closely as possible. It is not economical to run any compressor for long periods at low loads, due to electrical motor losses.
For new installations with multiple compressors, a selection of different sized compressors should be considered, so that different levels of compressed air demand can be met while still ensuring that compressors are running at close to full load.
When companies buy a new compressor, they often purchase one with more capacity than is needed. Large compressors are generally more efficient than smaller ones, although a better solution in some instances may be to buy a number of smaller compressors so that the capacity of the system can be changed to match the load required - this avoids the need to run compressors very inefficiently at low load.
The correct configuration for any site will require careful consideration, but substantial savings can be achieved. If your current compressor is fairly old, you should consider the purchase of a more efficient model. In order to increase production capacity by 25%, J H Ashworth & Son, a small company who assemble textile yarns, needed to increase the capacity of its compressed air system.
Following consideration of alternative options, the managers decided that it would be more cost effective to replace two of their existing compressors with a more efficient larger compressor rather than to fit another small compressor. The capital cost was higher at £44,700, but cost savings of £14,250 a year were realised. The payback period was 3.1 years.
Air conditioning is increasingly being installed in buildings because of the heat generated by computers and other electrical equipment. However the need for air conditioning can be localised and energy costs minimised, by careful design.
Having air conditioning on at the same time as space heating is a mistake. This means that both systems will be working against each other and this wastes energy. The problem can be avoided by installing thermostatic controls to both the heating and air conditioning systems and ensuring that an appropriate 'dead band' is provided between their set-points. ed on all day or all year round.
1. Check that all pipework is insulated.
2. Fit insulation jackets to valves and pipe joints.
3. Ensure insulation is replaced after pipework repairs
Look for unlagged pipework and lag it !
A ring main system is preferable to feeding spurs, since this will help to balance the pressure throughout the distribution system. The distribution system should be designed for a maximum pressure drop of 0.1 to 0.2 bar at the points of use, when at maximum demand. Air receivers or reservoirs can be installed on the system to handle short periods of high air demand.
Enough valves should be fitted to allow the main branch lines to be isolated, and the compressed air system to be effectively zoned. Electronically controlled isolation valves are preferable to manually operated valves. hould be fitted to allow the main branch lines to be isolated, and the compressed air system to be effectively zoned. Electronically controlled isolation valves are preferable to manually operated valves.
Compressed air is generally distributed to it's various points of use by a pipework system, and considerable amounts of energy will be wasted if this system is not airtight or properly designed. It is essential that all pipes, valves and other pipework components are adequately sized to prevent over pressure. All systems should be designed for minimum pressure drop.
Sometimes it is necessary to maintain the air supply in one area of pipework at all times, but the remainder of the distribution system can be isolated during non-productive periods, to prevent energy wastage due to leaks.
At Creda Ltd in Stoke-on-Trent, an energy survey identified that the site's compressed air system was larger than needed. A two stage rationalisation programme was carried out to remove 'redundant' lines, to divide the distribution network into zones to minimise leaks and to rationalise overall compressor usage. The total cost was £24,500, but cost savings of 12.2% or £11,390 per year were realised. The payback period was 2.2 years.
The air entering a compressor should be cool, clean and dry, as this will lead to more efficient compression and lower energy use. Wherever possible, air should be taken from outside the building because its temperature will be lower and this could increase the compressor's efficiency by up to 2%.
Preferably, air should be taken from outside the building because its temperature will be lower and thus the compressor will work more efficiently. A sheltered inlet protected from rain on a north wall is desirable. Dust can clog filters and waste energy. Ducting between air intake and the compressor should be short, straight and of generous diameter. Make sure that if cooling air is being discharged outside, it is away from the intake.
To minimise the amount of drying needed to produce high quality compressed air, it is also important to site a compressor's air intake well away from sources of water vapour. At the Kilmeaden Creamery in Waterford (Ireland), compressed air costs suddenly rose from between £200 - £220 per week to over £300 a week.
Investigations revealed that the air intake on the main compressor was blocked and that a second compressor was being used to meet demand. When the filter was replaced costs dropped to under £200 per week.
Compressed air leaks are often overlooked, but huge savings can be made if they are found and plugged. Smaller leaks can be identified using an appropriate leak detection fluid.
Leaks frequently occur at air-receiver valves, pipe and hose joints, shut-off valves, quick-release couplings, tools and equipment. In most cases these leaks are due to poor maintenance and can be fixed relatively cheaply.
Any leaks you can hear are costing money, as is blowing off compressed air to clean objects - which is particularly wasteful and costly. By monitoring the amount of compressed air used you will be able to identify waste.nd costly. By monitoring the amount of compressed air used you will be able to identify waste.
At the Rover Group's Solihull site, a monitoring system was installed on the compressed air system. This system alerted the site's engineers to a large use of compressed air out of hours - equivalent to 40% of production usage! This was due to leakage and was quickly remedied saving Rover £21,000 a year.
The most cost-effective control system will depend on:
1. The occupancy patterns of your building.
2. The main activities in each area of the building.
3. The amount of natural light available.
A survey and some research will be needed to gather this data (for Energy Surveys see under Energy Management topic).
Regular maintenance checks on the combustion efficiency of the boilers at the Department of Employment Office in Sheffield showed that stable combustion conditions could not be maintained from month to month.
The fault was identified as a faulty gas pressure regulator which was duly replaced. The cost of the investigations and remedial actions were recovered within a heating season as the result of improved fuel efficiency.
The repairs have also ensured that any health and safety hazard associated with incomplete combustion have been avoided. Employ a CORGI registered company to maintain your boiler, if it is gas fired.
To ensure efficient combustion, they should inspect and service your boilers at least once a year. On oil fired boiler plant servicing should be undertaken twice yearly (or more frequently if indicated by high flue gas temperatures).
Operate a regular and planned maintenance procedure to ensure economic and efficient working of boilers. You should monitor boiler fuel consumption regularly. On oil-fired boiler plant, flue gas temperature should be regularly recorded to indicate when soot cleaning is necessary.
Combined Heat and Power (CHP) units make use of a single, relatively low-cost fuel (usually natural gas), to generate both heat and electricity. The latter would otherwise have to be purchased at a relatively high cost from an electricity supply company.
Large CHP units have been successfully used in industry for process heat and power for many years and more recently, small-scale CHP units have been developed that can be easily cost effectively applied to certain smaller industrial and commercial operations for space heating.
Generally, the units are slightly less efficient than boilers at generating heat, and therefore consume more fuel. However, this disadvantage is offset by direct savings in electricity unit costs and often, maximum demand charges.
In offices, up to 20% of illuminance can be lost because of dust in the light fittings themselves, and because of dust and dirt on walls and ceilings. In foundries and in heavy engineering works, accumulated dust and dirt in light fittings can reduce the light levels by up to 40% or more.
Dirty windows also reduce the light available from natural sources. A regular schedule should be established to clean:
1. Lamps, shades and fittings.
2. Windows.
3. Walls and ceilings
Replacing lamps at the same time will minimise labour costs. In addition to cleaning light fittings, it is also important to ensure that room surfaces are kept bright and clean.
Before installing the new lighting scheme at their Penge factory, Muirhead Vactric Components made sure that their walls were repainted in pale colours. Fawn coloured floor tiles were also laid. The overall effect of these measures was to increase the quantity of light reflected from the room surfaces and thus to increase overall lighting efficiency (by about 20%).
The main use for coal is in boilers and industrial furnaces. Coal is the cheapest fuel to buy, but capital costs are higher than for other fuels as bulk storage and handling facilities are required.
Coal produces considerable amounts of smoke, soot and dust when burnt. Thus coal fired boilers must be cleaned more frequently and maintenance costs are significantly higher than for other fuels. Anthracite is a cleaner fuel, but has the same basic characteristics.
A compensator adjusts the heating circuit's flow temperature, as the outside temperature rises or falls, thus reducing fuel use. The flow temperature is usually varied by the installation of a motorised three port mixing valve in the heating circuit.
In some situations, however, a simplified arrangement is possible whereby the compensator is used to directly alter the boiler's operating temperature. Compensators are often combined with an optimiser in a single heating controller.
1. Ensure that frost thermostats are working properly.
2. Verify that external temperature sensors are working.
3. Check that your frost thermostats are correctly set.
4. Ensure that all pipework is properly insulated.
Weather compensation may not be applicable to heating system which incorporate fan convectors
1. Check that a compensator has been fitted to your heating system.
2. Ensure heating circuit flow temperature is being adjusted correctly.
3. Verify that external temperature sensors are working.
At the BHS store in Oxford Street, a building energy management system (BEMS) was installed in 1992. The BEMS controlled the heating system and compensated for outside temperatures. The store's gas consumption was reduced by 46%!
The siting of compressors is very important. There are two main options:
1. Site all compressors in a central compressor house.
2. Site a compressor near to each main user.
The best choice depends upon the size and volume of compressed air needed. Siting compressors near to the main users is often more cost effective, because short pipe runs reduce both capital and running costs. If you want to recover heat from a compressor remember that it is much more difficult to move heat over long distances than compressed air - so site your compressors accordingly. If you are not recovering waste heat, then compressors should be sited near to the biggest users of compressed air. Operate your compressed air system at the minimum acceptable pressure. If you have one or two small users that require a higher pressure than the majority of your site, consider providing them with local compressors, thus allowing the general system pressure to be reduced.
In most offices, computers are often left on when they are not in use, for example over lunch. This wastes energy directly and it also puts an extra demand on space cooling systems.
Some modern computers switch off monitors after a set period to save energy and these machines should be purchased in preference to other types.
Employees should also be encouraged to switch off computers and their monitors when they are not needed.
The Energy Star logo shows that the computer system will automatically switch to a low power standby mode after a fixed period of inactivity.
1. Educate employees to switch off computers and monitors when not in use.
2. If computers are networked, then display a 'switch it off' message whenever users 'log off'.
3. When purchasing computers look for the 'Energy Star' logo.
To motivate staff to switch things off, IBM has programmed its computers to display a 'switch it off' message when staff 'log off' for the day. This message also reminds operators of the costs of leaving equipment on.
Gas fired condensing boilers are generally the best option for providing space heating. In larger premises, condensing boilers can be combined with high efficiency conventional boilers to provide base load and part load capacity respectively.
Condensing gas boilers are the most efficient type of boiler, and are capable of operating at thermal efficiencies of 90% or more.
Although they cost more initially, this additional cost can be recovered in around 2 years.increase in the whole systems cost is quickly paid back. Reliability and performance are now confirmed in a number of monitored installations.
During refurbishment, a condensing boiler was installed at the White Horse pub in Witham to provide space heating for both public and private areas of the pub. The additional cost of the boiler over a conventional boiler was £290. The savings achieved were £130 a year, thus the payback period was just over 2 years.
By setting energy consumption targets, you can measure how well you are controlling your energy usage.
All companies should have a business plan in which energy use is related to the other aspects of the business e.g. kWh used per widget produced, kWh per pound of turnover - or other similar measures of energy efficiency performance.
To set consumption targets you need to ensure that:
1. All data relevant to your energy usage is collected.
2. You know what period of time this data covers.
3. The targets you set are realistic and achievable.
Remember that unachievable targets will quickly demotivate! At Strines Textiles Ltd. near Stockport, a monitoring system was put in place to check how much energy was used on each machine. Consumption targets were set and achieved, giving an energy cost saving over 6 years of around £250,000.
Suitable applications for motor controllers are those in which electric motors run for long periods at low load, e.g. refrigeration compressors, conveyors or mixers.
New controllers should be considered when purchasing new, or refurbishing old equipment. Retrofitting new motor controllers can be cost-effective in some applications, but variable speed drives may be a better investment.
Where plant runs idle for long periods of time, consider installing a load sensing control system to turn plant off automatically after a pre-set period of inactivity. Automatic switching systems can be applied to larger items of equipment.
These contain load sensors that automatically switch off motors and pumps after a set period of inactivity and they can prevent idle running for example during lunch hours, if programmed correctly.
Ortho Cilag, a pharmaceutical company, decided to sub-contract its catering, and contractors were appointed.
Gas consumption in the kitchens immediately doubled without any increase in catering service. Discussions with the catering contractors regarding their working practices resulted in the gas consumption of the kitchens being reduced back to its previous levels!
Cooking is an area where a few simple good housekeeping measures can yield large savings. All kitchen staff should know the 'heat up' times of hobs, grills and ovens, and you should check periodically that cooking equipment is being switched off when it is not needed. Ideally food should also be served as soon as it is cooked.
A range of different cooking appliances are available and in many cases, when you purchase catering equipment, you will have a choice of models that could equally satisfy your needs.
Some of these are likely to be more energy efficient than others, so you should always check the energy use of each before making a final decision.
You should also consider options such as fan assisted ovens, infra-red grills, microwave cookers and combination ovens.
1. Turn off extraction fans when they are not needed.
2. Don't switch ovens, hobs or fryers on until they're needed.
3. Minimise hot storage of cooked foods.
4. Keep hot plates and burners clean.
5. Service cooking appliances regularly.
6. Check the accuracy of thermostats and timers.
7. If possible, switch ovens off before cooking times end.
8. Consider installing sub-metering for kitchen areas.
Microwave ovens can cut energy usage dramatically. Consider installing fan or air circulation ovens, they not only save energy, they also cook at lower temperatures with less food loss due to shrinkage.
At the Safeway's food store at Oakwood (Leeds), the frozen foods section consists of a number of large multi-deck frozen food and meat cabinets, from which large amounts of cold air was traditionally lost. By fitting glass doors to the cabinets, this Safeway store saved more than 5% of their annual electricity consumption. The store also saved 50 % of its space heating bill, by retaining the cold air in the refrigerated cabinets.
Dishwashers are labour saving devices that help a kitchen to run smoothly. However they use large amounts of energy and water. Keeping a check on how they are used, and a regular service will ensure efficient operation.
1. Maximise dishwasher loads with correct stacking.
2. Clean filters and service dishwashers regularly.
3. Ensure the dishwasher incorporates adequate insulation.
You could also consider using sanitising liquids and water softeners to reduce boost temperatures.
When buying a new dishwasher, check its energy consumption and consider buying one with a heat recovery cycle.
The dishwasher in the British Home Stores restaurant in Oxford Street has been fitted with a high level of insulation and a heat recovery system. This and better control of lighting has assisted the store to reduce its electricity consumption by 8% despite an increase in trading hours.
The way water is distributed is important, because if it is not planned carefully then large heat losses will occur.
Long lengths of pipework should be avoided and pipe work and joints should be insulated. Hot water should be circulated on larger systems to prevent 'dead legs' and protracted draw off times.
Opening doors allows heat to escape into different parts of the building or even to be lost completely. People often leave doors open unnecessarily, so it is important to look at ways of minimising the number of doors in use.
Doors should be fitted properly and draught-proofed. Automatic closure devices should be fitted where possible.
1. Fit draught-proofing to doors.
2. Consider using automatic closure devices.
3. Try to minimise the number of doors being used.
4. Where frequent access is required through doorways, consider installing plastic strip curtains or fast acting doors.
The Welsh Development Agency fitted insulated loading doors with good sealing systems to a range of new "low energy use" factory units to prevent air infiltration.
Compared with conventional loading door designs, these new doors cut about 11% off the unit's annual energy bill (per door). The payback period was between 2 and 3 years.
The main areas in need of draught proofing are around doors and windows. Draught proofing strips can be purchased from most DIY stores and only a little DIY skill needed to fit them.
Only a small cash layout is needed. Where doors and openable windows are no longer required, they can be most effectively draught proofed by sealing them shut.
Unless draughts are minimised, the time and temperature settings of your heating system will probably be higher than necessary.
Draught-seals for doors and windows are supplied as extruded plastics, rubbers or as brush-strips. These cut down on draughts without restricting operation or access.
During refurbishment of the White Horse pub in Whitham (Essex), draught strips were applied to existing windows and a new draught lobby was constructed at the rear of the building.
This resulted in an immediate improvement in customer comfort and realised annual energy savings of £175 or 1.5 % of the pub's total energy bill for the year.
Drivers should be trained to reduce fuel use by:
1. Starting their engines only when ready to travel
2. Releasing the choke as soon as possible
3. Gentle acceleration and braking
4. Using the most appropriate gear
5. Maintaining the most economical speed
6. Turning the engine off immediately on arrival
7. Taking the most economical route to their destination
The key to achieving good fuel economy is to ensure your drivers want to save fuel. An incentive scheme can be a good way to encourage this and a weekly competition can be used to highlight that poor driving techniques can increase fuel costs by 20%.
Training can then be used to raise driving standards, although this should be offered tactfully - as few people like having their driving criticised! TDG McKelvie and Co. implemented an in-house driver training programme to improve safety and fuel economy.
Drivers were given both classroom and on-road training and encouraged to set their own performance targets. By the end of the third year, fuel savings had reached 8% and the accident rate was halved. Maintenance costs also fell and the higher standard of driving improved customer relations.
Dryers are notoriously badly controlled, often resulting in over drying and off-specification product. Tighter control can cut energy costs by 10%. A detailed 'dryer audit' can often result in energy savings of up to 20% with no major capital expenditure.
Other opportunities requiring capital investment include: heat recovery, dehumidifiers and alternative methods of drying e.g. infra-red, microwave or radio frequency heaters.
These options should be considered when changing dryers. Dewatering a product before it reaches the dryer can also make a significant impact on energy consumption and drying times.
1. Make regular checks on dryer performance.
2. Set energy consumption targets for your dryers.
3. Check that dryer instrumentation is working correctly.
4. Ensure that your dryers are properly maintained.
5. Establish a planned maintenance/service schedule.
6. Fit automatic end-point detectors to batch dryers.
Also check if drying times could be reduced by de-watering the product at an earlier stage of the process.
The Paragon laundry at Moreton-in-Marsh (Devon) installed end-point detectors on their tumble dryers realising cost savings of 30% through reduced energy costs and shorter cycle times. The investment cost for two dryers was £3,320 (1990 prices) and the payback period was 7 months.
Many manufacturing processes generate effluent streams that contain a mixture of substances, including heavy metals, organics and other toxic materials. These must be removed by filtration or biological treatment before the effluent can be discharged into the drainage system.
Often it is possible to reduce the overall amount of effluent produced by filtering and reusing waste water. Modern filtration systems can also cost-effectively recover most suspended solids, including washed out raw materials, which can then be reused in the manufacturing process.
Selection of effluent treatment equipment is generally a specialist task and an explanation of the full range of possible separation technologies is beyond the scope of this document.
However Environmental Technology Guide 37 provides a good overview of the possible alternatives. By filtering effluent and reusing it in a washing process, IMI Yorkshire Fittings, Leeds have saved £11,500 a year in disposal costs.
The effluent, which is contaminated with china clay lubricant from the metal forming process, is now filtered using an ultrafiltration membrane system. This has reduced effluent volumes by a factor of seven, saving 60,000 litres of water a year. The capital cost of the system was £2,800, so the payback period was just 10 months.
Electricity is generally the most expensive fuel, but it is extremely flexible in the ways it can be used. It is typically used for lighting, motive power, refrigeration and air conditioning. Electricity can be easily controlled, but it is often wasted because staff forget to turn off lights, office equipment and machines.
Poorly maintained refrigeration and compressed air systems are another major cause of waste. Electricity supply costs can be minimised by making sure that you are on the right tariff, and by shopping around different electricity suppliers.
An energy audit is the detailed analysis of energy use in an organisation. It involves a structured review of how energy is purchased, managed and used, with the aim of identifying potential cost savings.
The first step in an energy audit is to establish the quantity and cost of the energy and utilities used, by collecting and analysing your energy bills.
Next you should check whether energy is being purchased competitively and whether management controls are in place.
Then you should establish its consumption and cost. To conduct a simple energy audit:
1. Assemble all fuel bills for the last year.
2. Identify the main uses for energy around your site.
3. Calculate energy used per operation/unit production.
4. Check how well energy is used against industry norms.
5. Identify possible energy saving opportunities/measures.
6. Evaluate the cost and payback of each measure.
7. Prioritise the opportunities identified.
Use the results to raise energy awareness among employees. For maximum impact, use bar graphs or pie charts.
See Yardsticks sub-topic for details of how to obtain industry norms.
Following a detailed energy audit, Hampshire Chemical Ltd reduced the amount of energy it used per tonne of product by 22%. These savings were mostly realised by a series of good housekeeping measures, including switching off lights and machinery when not required, adjusting thermostatic heating controls to sensible settings and keeping windows shut during the heating season.
Source : GPCS 265
Larger and more complex energy-consuming-sites will merit sub-metering of electricity and other fuels as could different buildings or business streams.
1. Train two or three of your staff to read the meters.
2. Get them to read your meters on a regular basis.
3. Cross check the accuracy of the meter readings.
4. Train staff to enter meter readings into a computer.
These readings should take place to coincide with your management statistics period. Meter reading takes only five or ten minutes, and could signal major losses or possibly unsuspected ways of saving energy.
Meter readings should be analysed as soon as possible and actual energy use should be compared against consumption targets, yardsticks and industry norms.
Spreadsheets are a good way of recording and analysing meter readings. They may highlight periods of poor performance (output / energy usage).
Pie charts are a good way to show data graphically. Put fuel costs (in £ or kWh) into this chart. and you can see the magnitude of cost and energy used in your business....
However large or small your site or energy usage might be, regular reading and recording of fuel consumed is certainly justified. Using energy bills might be a good starting point, but remember that these are often only an estimate of the actual consumption, and that even if your meters are read, it is rarely on the same day each month.
You will only be able to set accurate targets, if you ensure your meters are read regularly i.e. on a monthly or weekly basis. Considerable benefits can also be realised by installing sub metering on high usage equipment and on each building on your site.
At McKechnie Plastics Components in Stamford Bridge, managers found that they could not get a clear picture of the patterns of electricity use from a single meter. Thus two portable meters were used to investigate the electricity use of the factory and to set energy consumption targets.
This low cost study revealed that the performance of individual moulding machines varied considerably. By introducing new working practices and increasing machine utilisation, a 10% reduction in electricity consumption was realised saving £36,000 a year. The portable metering cost only £640!
An energy survey involves going around the site to look at energy using equipment, working practices, controls etc. - gathering information so that energy saving opportunities can be identified and an action plan prepared.
The energy survey should be undertaken in conjunction with an energy audit. The audit will identify those areas of the site that merit the greatest attention during the survey. ss. You will also be able to identify those areas of the site that merit the greatest attention during the survey.
The survey should be conducted by someone who is familiar with your operations and equipment, and is therefore able to ask sensible questions about energy usage on your site. They should talk to managers, supervisors and key staff - all of whom can be a source of valuable information.
After conducting an energy survey, a depot saved £5000 a year when it realised that it was unnecessary to heat a warehouse which was only used to store goods that could withstand - 20oC. Warm gear and a heated room was provided for operators instead.
Exterior lighting covers floodlighting for car parks, signs for shops and security lighting on the outside of buildings e.g. loading bays.
This lighting is often on for long periods continuously, so installation of high efficiency and long life lamps is very important if lighting costs are to be minimised. For heights greater than 6m (20 ft) high bay fittings are more effective than the general flourescent.
Where a dirty atmostphere exists regular, annual or less cleaning can be beneficial. For car parks and security lighting install low pressure sodium lamps, as these are the most efficient type of lamp.
The quality of the light provided (in terms of colour) will be lower than with other lamp types, but it is adequate for these applications. Use motion detectors and daylight sensitive photoelectic controls wherever appropriate.
For shop signs, use high frequency fluorescent lights as these are the most energy efficient option and fit time switches that ensure signs are turned off at night.
Photoelectric cells can provide a cost effective means of controlling external lighting. At the Yew Tree public house in Widnes, one was used to control the facade lights. It cost approximately £200 to install and has produced savings worth £60 per annum - a payback of 3.4 years.
A "keyswitch" mode, when staff are present before and after trading where normal fluorescent lighting is on. A "trading" mode, where the full display lighting is required. These measure led to a reduction of the electricity bill by about a third.
In all kitchens, some form of extraction should be taking place. Monitoring of extraction systems and a good maintenance procedure should ensure its efficient working. Regular filter changes will maximise extraction efficiency Close doors & windows when operating extraction fans.
Ensure that the gap between the floorboards and the skirting board is sealed to stop draughts.
1. Switch off kitchen extractor fans when not required.
2. Clean extractor filters, grills and fan blades regularly.
3. Ensure correct siting and sizing of extractor fans.
A small bakery plant with an annual energy bill of £7,000 had a problem with extractors sucking air from the whole kitchen. The energy efficient solution to this problem was to fit a screened and filtered wall inlet close to the baking ovens. This supplied the unheated air needed for the extraction without creating draughts in the kitchen. The cost of the air inlet was £550 but this gave annual savings of £942. The payback period was 7 months.
If the occupancy of your factory is not uniform - then you could save money by zoning the building so that only occupied parts of the factory are heated. You should look at the way heat is generated and circulated around the factory and consider whether radiant heaters would be more economical or if destratification fans would help.
Destratification fans can keep heat within the working area of factories with high ceilings and their installation will considerably reduce space heating bills.
Some small and medium sized factories use warm air blowers, but localised radiant heating can be more economical - since it heats employees without heating the surrounding air, providing a pleasing warm feeling without burning the skin, and using least energy.
Reducing the number of air changes will also reduce costs The ideal time to upgrade factory heating is during refurbishment Remember:
1. Check if goods really need heating or cooling.
2. Use zoning to minimise volume being heated/cooled.
3. Minimise number of air changes by closing doors.
4. Consider automatic/fast acting doors for goods entrances.
5. Use radiant heaters to heat employees in warehouses.
Replacing the heating system at JW Arrowsmiths, Bristol factory cost £47,250, but a 47% reduction in fuel cost (worth £24,000 per year) was realised and the simple payback period was 2 years. In the warehouse areas, old, unresponsive water heated warm air blowers were replaced by more responsive gas fired radiant heaters fitted with appropriate zone controls.
Factory units come in all shapes and sizes, and lighting requirements depend on the nature of the manufacturing or assembly process.
The lighting levels in each area of the factory should be checked to ensure that you are not lighting areas of the factory unnecessarily either because of poor control or because light levels are higher than need be for the task being completed.
You should also check the age and type of lighting installed, as considerable savings can be made by replacing older fittings with high frequency fluorescent fittings with mirrored reflectors, or high pressure sodium or metal halide lamps.
Where a dirty atmosphere exists regular, frequent cleaning is essential. L'Oreal Golden Ltd have combined high frequency fluorescent fittings with daylight control and high quality task lighting to reduce their Llantrisant factory's electricity bills by over 70%. The additional cost of achieving this (rather than using a more basic lighting design) was recovered in under two years.
When looking at the financial aspect of a project, remember to:
1. Work out the simple payback time of the measure.
2. Include "non-energy" savings in your payback calculation.
3. Decide if a more detailed financial appraisal is needed.
On large capital projects, such as a new lighting system, remember that the existing system may need to be updated for other reasons, e.g. if it is no longer safe, so some capital expenditure would have to be laid out anyway.
When energy savings are made, try to "ring fence"a portion of the savings for re-investment in further energy efficiency projects. A new lighting scheme costs £4500 to install, and it will give us savings of £1800 per year.
The simple payback time is calculated by dividing the capital cost of the new lighting scheme by the savings (i.e. 4500 / 1800). This gives a simple payback time of 2.5 years. Discounted cash flow (DCF) techniques provide a method of overcoming these weaknesses and gives the organisaton a basis for evaluating all capital expenditure.
A more detailed financial appraisal method is to look at the internal rate of return (IRR) over the economic life of the lighting scheme (say 10 years). For this example the IRR is 38% which is clearly a good investment.
When looking at improving your energy efficiency you must take into account what it will cost you. Costs fall into 3 categories: No cost - These should be done straight away. Low cost - Things which cost less than £100 to implement.
Major cost- Projects that require some capital investment, such as a new lighting system, where you need to perform a financial appraisal to work out how long it will take to get back the money you have paid out. For projects with long payback periods a discounted cash flow method such as Internal Rate of Return (IRR) will give you a better measure of the likely return on your investment
Floor insulation should be carried out at the following times:
1. During construction of new building.
2. During refurbishment of a building.
On older buildings with an under floor space, the gap between the floorboards and the skirting board should be sealed to stop draughts.
Care should be taken to preserve adequate under floor ventilation. Make sure that if cooling air is being discharged outside, it is away from the intake. A building can lose up to 15% of heat energy through its floor. It is therefore essential that the correct type and depth of insulation is placed into the floor, both in solid and raised floors.
The best time to insulate a floor is during its initial construction. Retro-fitting can be very expensive. As part of a programme of overall improvements, Cambridge University sprayed the underside of the floor panels with an insulating material to reduce heat loss through the floor. This and a number of others energy efficiency measures reduced the amount of gas used for heating by 35%.
The accurate control of flow rates is essential to the efficient operation of most industrial processes. Accurate control will not only minimise energy costs, but it will also maximise throughput and improve product quality.
Accurate control cannot be maintained unless high quality instrumentation is used to measure flow rates. Too many plants have inadequate numbers of meters on key parameters such as steam, water and compressed air flow.
Energy savings of 10% are often realised by the installation of new steam and water meters and the use of an effective monitoring system to spot leaks. The pressure and flow behaviour of steam, water and other fluids should be monitored at several locations around their distribution networks. Then:
1. Monitoring and targeting should be used to spot leaks.
2. Flow controls should be inspected and serviced regularly.
3. Regular calibration checks should be made on flow meters.
A computer package can be used to estimate the benefits of installing new flow controls at particular locations around your distribution networks. This is a specialised job and should be done by an experienced contractor. Ducal Ltd, a manufacturer of furniture produces large quantities of shavings, chipping and dust that must be removed by a large air extraction system.
To reduce costs, the company installed variable speed drives to control the rate of air extraction based on the output of a number of sensors located on its various machines. For an investment of £9,000, the company realised energy savings of £5,800. The simple payback period was 20 months.
Canteens and kitchens generally store food in large fridges and freezers, and these use significant amounts of energy.
There are some simple good housekeeping rules on how fridges should be used, sited and maintained that can reduce running costs considerably.
1. Locate fridges and freezers away from heat sources.
2. Reduce the number of times fridge/freezer doors are opened.
3. Minimise the time that fridge / freezer doors are kept open.
4. Never put hot food in fridges.
5. Adopt a planned defrosting programme.
Fill spaces with paper For multiple fridges/freezers consider fitting motor controllers on the electric motors. Consider installing a heat recovery system to use the waste heat from refrigerator compressors.
A frost protection device is an essential part of all heating systems, which prevents pipes from freezing up during winter or protects building fabric from frost damage.
Many optimisers feature integral frost protection facilities, but in simpler systems a separate frost thermostat is usually used. The thermostat may be located either externally or internally and will turn the heating system on if the temperature drops below a certain level (usually 0oC externally or 4oC internally). il or because operating temperatures are set too high. Remember the lower the set - less fuel will be used.
A frost thermostat setting of 4oC is about right for most buildings. (A few require a higher temperature to protect the building's fabric). Before you change a frost thermostat setting, check that heating pipes in exposed places will not freeze as a result.
A conference room at the British Library was heated by its own small central heating system. Although the room was only occupied intermittently, the heating was left on continuously to prevent condensation or frost damage. The installation of frost protection controls and a time switch have enabled the boiler to turn off when not required. The cost of the controls was recovered within one year.
Ways of achieving good fuel economy are:
1. Maintaining recommended tyre pressures
2. Regular monitoring, servicing and tuning
3. Streamlining to minimise aerodynamic drag
4. Reducing driving speeds to 55 miles per hour
5. Purchasing and using more fuel efficient vehicles
Savings can also be realised by ensuring that vehicles are properly sized, and small loads combined wherever possible to minimise the overall number of journeys.
Vehicles should never be overloaded. The bluff shape and numerous corners of the vehicle generate many vortices, consuming a considerable amount of energy.difications.
The fuel economy of road vehicles varies considerably and you should always check it when purchasing a new vehicle, as you may be able to cut running costs by selecting a more efficient model.
TNT Ltd has substantially improved the fuel efficiency of its fleet of trucks, by improving their aerodynamics. For example, fuel savings of 16% were realised on one route by streamlining one tractor and two trailers at a cost of £3,000 (1991 prices). The payback period was 10 months.
Fuel oils are the heavier and more viscous grades of oil. They must be heated to remove them from the tanks and to ensure proper combustion. This heating requirement reduces the overall efficiency of fuel oil fired boilers, particularly in winter.
Furnace efficiencies in the metalworking industries are notoriously low. Substantial cost savings can be made by simple good housekeeping measures such as controlling air:fuel ratios, preventing air ingress, eliminating holding times and lower temperature operation.
Other improvements such as the installation of low thermal mass insulation, more efficient burners and better controls should also be considered. When buying a furnace or kiln, select an energy efficient one - as otherwise your running costs could be up to 50% higher than necessary.
For existing furnaces you should:
1. Monitor energy consumption regularly.
2. Set energy consumption targets for each furnace.
3 Compare your performance with that of other companies.
4. Change production schedules to shorten holding times.
5. Perform a detailed energy audit to identify faults.
6. Examine opportunities for waste heat recovery.
If
