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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 you are refurbishing old furnaces or selecting new ones, check that you have the most efficient burners for your task and the best type of insulation.
Gas oil is generally the lightest and least viscous grade of commercial heating oil, although kerosene is used in some smaller commercial units. It will remain in liquid form even in winter, and hence is not normally heated.
As with other grades of oil, it is often cheaper than gas, but capital costs are higher as storage tanks are required. Maintenance costs are also higher than for gas fired boilers. It is less polluting than heavier grades of fuel oil. Typical uses include space & process heating, and plastics production.
A heat pump is a device for converting low grade heat into usable high grade heat. It can extract heat from ground water, lake water or atmospheric air, and convert it to high grade heat at 70oC or above.
For example, heat pumps can be used to recover low grade or waste heat from large refrigeration plant, air compressors and air conditioning units. In 1982, Allied Breweries installed small low cost heat pump systems in six of their licensed premises. The systems were designed to cut fuel costs by simultaneously cooling the beer cellar and producing domestic hot water.
Only five of the six installations were successful, but average savings were 38% in public houses, and 50% in small hotels. Payback periods of between 4 and 7 years were realised, although the payback on the additional capital cost over a more conventional cooling system ranged from 0.8 to 1.5 years. The payback period on heat pumps can be fairly long, so they are probably not worth considering unless you have a good use for the high grade heat generated.
Heavy fuel oil is often cheaper than gas and lighter oils, but capital costs are higher due to storage, heating, circulation and filtration requirements. Maintenance costs are generally higher than for lighter fuels and it produces more pollution. Typically it is used in large boilers.
Higher efficiency induction motors consume less electricity than comparable standard motors for any given load. A typical energy saving when using these motors is around 6% of the motor's running costs.
There is no longer any premium on higher efficiency motors, so when replacing motors it should be company policy to specify them, as the financial benefits are immediate. They are slightly more expensive, but if the motor has a high duty cycle then these additional costs can be recovered in well under a year. .
Higher efficiency motors should be considered for all new plant and equipment that will have a high duty cycle (in terms of hours run/year). If you are planning to retrofit high efficiency motors then check the level of energy savings first, as payback periods can be long in some applications.
At Delta Extruded Metals Company in West Bromwich, five motors were replaced with high efficiency motors at a cost of £670. Energy savings of £408 per year were realised and the overall payback period on the project was less than 20 months. (Of the five motors, the shortest payback periods were obtained on 3 motors that were run continuously throughout the year).
Industrial cooling or refrigeration is mainly found in:
1. Food and chemical processes.
2. Food storage and retailing.
3. Air-conditioning.
Although each of these applications use different types of refrigeration systems, the same basic vapour compression cycle is used.
Regular maintenance is important if a refrigeration system is to operate efficiently. Often refrigeration systems use 30% more electricity than is necessary. Most common faults can be fixed with little capital expenditure.
Use the following check list to identify waste.
1. Are you over cooling your product?
2. Are cold store doors left open regularly?
3. Are door seals intact? - look for ice & draughts.
4. Do your blast freezer fans slow/stop when the line stops?
5. Could you use strip curtains on doors?
6. How often is your condenser checked for dirt and leaves?
7. Have you optimised your defrost cycle?
8. Could you fit electronic expansion valves?
The simplest way to check if your refrigeration system is working efficiently, is to monitor its electricity consumption on a regular basis.
Remember that each 1oC rise in cooling temperature will reduce your energy costs by 2%.
A small cold store in a food processing factory was using £30,000 a year in electricity. The company discovered that more than half of these costs were due to the cold store's doors being open. By altering working practices and improving employee awareness, the company was able to save £10,000 a year - just by closing the cold store's doors more often!
Determining appropriate control limits for your process is the first step in obtaining better control. This generally requires a study of the different production factors that affect energy and raw material usage, product quality, yield, and throughput.
Once proper control limits have been set, statistical process control (SPC) techniques can be used to minimise out of specification product. You may also need to review the effectiveness of your automatic control systems and arrange for them to be tuned or upgraded.
Waste production often occurs when operating parameters are too loosely controlled. Modern control technology is a particularly effective means of improving process efficiency and reducing waste.
Running the process closer to the optimum improves product quality while reducing costs and it usually improves product quality as well.
A simple design change could eliminate the use of hazardous materials during production, allowing you to cut handling, storage and disposal costs. Alternatively, you could reduce waste and costs by negotiating changes to product specifications with your suppliers or customers.liers or customers.
British Sugar's Wissington Factory achieved savings of £94,000 a year by installing a predictive control system on its sugar beet animal feed dryers. This ensured products were not over-dried, thus reducing energy use and increasing yield at the same time. The payback period was 18 months.
Ensure that your roof space has adequate insulation above the ceiling level. The optimum thickness of insulation is 150mm (6 inches). Consider fitting insulation to roofs when general repairs are being carried out.
This can be done by fixing insulating panels on the inside or outside of the roof. Alternately, an insulating material can be applied directly to the roof, again on either the inside or outside. This can also improve weather proofing.
Further insulation can be added by laying fibrous mats in the roof or by blowing loose mineral fibre, or a treated cellulose fibre, into the roof space area.
1. Check that roof spaces are insulated correctly to a minimum depth of 150 mm (or 6 inches).
2. If the job is large, consider hiring a contractor to install adequate insulation.
When the White Horse pub in Witham (Essex) was carrying out general repairs to its roof, the opportunity was taken to fit insulation in the roof space. This resulted in annual energy saving worth about £595. The cost of fitting the insulation was £1,680, giving a payback period of under 3 years.
All employees, staff as well as managers, are energy users, and it is vital to obtain their support at an early stage of your energy efficiency programme. So keep them informed of your actions, invite suggestions, and congratulate and thank them for their help and ideas.
Its also a very good idea to post a regular progress report on the total amount of energy savings realised on the staff notice board to encourage your staff to support future actions.
You will also need to 'lead from the front' and set an example for your staff and managers to follow. So don't forget to switch the office lights off when you go out to lunch! hen you go out to lunch!
The Rover Group saved £1 million over six months at its Longbridge site, simply by raising employee awareness. They achieved this by printing a special newsletter on energy efficiency for a relatively low cost. As well as providing information and advice about energy consumption on the site, the newsletter also included advice on saving energy at home, and a poster design competition, open to all employees and their families. A considerable number of energy suggestions were received as a result.
Source : GPCS 214
Employees need to be made aware of:
1. Why and how energy is consumed at work.
2. Why it is important to reduce energy costs.
3. How their behaviour affects energy usage.
4. What effect saving energy will have on them.
Make full use of freely available promotional material such as posters, stickers, awareness videos and EMMA to convey these messages. Also consider specific energy efficiency training for staff who have the greatest influence on energy use, e.g. plant operators, janitors, security staff and cleaners.
INFORMATION
about your company's
ENERGY CONSUMPTION
is needed to promote
UNDERSTANDING and to create an AWARENESS of energy costs.
MOTIVATION is needed to translate
AWARENESS into effective ACTIONS and to change employee
ATTITUDES towards energy use.
PLANNING
is essential to MAXIMISE the impact of your
ACTIONS and to ensure the most COST EFFECTIVE use of your resources........
speak louder than WORDS so you need to set an
EXAMPLE to obtain the
COMMITMENT of your employees.
should begin in the BOARD ROOM
with the adoption of an ENERGY POLICY
that includes clear TARGETS for reducing fuel bills........
A variety of management
TECHNIQUES can be used to INCREASE the long term impact of
YOUR ACTIONS will help employees to
ACHIEVE TARGETS and to
UNDERSTAND the implications of their
ACTIONS on fuel bills.
When boiling kettles it is important to use only the minimum amount of water necessary. Individual kettles should be discouraged and replaced with a single machine or urn. Vending machines often have more 'display' lights fitted than are really needed.
When purchasing a new machine you should ask how much energy it uses and demand the most efficient. It is a good idea to fit 7 day time switches to vending machines, urns and water boilers - to ensure that they are turned off at night and weekends.
An 'over ride' button that allows limited out of hours use is also a good idea. Old tea urns can be notorious energy wasters, particularly if left to boil away throughout the day.
When the Foreign & Commonwealth Office decided to replace its tea urns with instantaneous water boilers, they realised the triple benefits of lower energy costs, reduced condensation within the tea rooms and improved health and safety. The instantaneous water boilers cost £350 each to purchase and the energy savings alone will lead to a payback within 3 years.
1. Educate employees about the cost of overfilling kettles.
2. Replace personal kettles with communal urns or water boilers.
3. Fit time switches to vending machines & communal urns.
4. Ask suppliers for details of the energy use of their machines.
Remember that employers must test the safety of kettles under the Electricity at Work Regulations. So banning kettles will reduce the number of tests you need to do each year, as well as saving energy.
Kilowatt hours (kWh) is the standard unit for measuring energy consumption. When analysing consumption figures it is a good idea to convert all consumption figures to kWh so that they can be readily compared and easily added together to give total energy usage.
NOTE : You should also consider the environmental impact of your company by working out the amount of carbon dioxide that is released into the atmosphere as a result of your energy use. Include fuel production and delivery losses in your calculation.
Liquid petroleum gas is used for space and water heating in industry, in commerce and in the home where natural gas is not available. Liquid petroleum gas burns with less smoke and soot than oil, so boiler maintenance costs may be lower in comparison.
However LPG is often wasted through inadequate maintenance of boilers and steam systems. LPG supply costs can be minimised by making sure that you buy in bulk rather than in bottles and by shopping around different LPG suppliers.
At Tulip International (Danepak) in Thetford, the existing light fittings in the bacon factory's joints packing hall were modified to take modern troposphere fluorescent lamps and high frequency control gear.
This produced energy savings of 57% and reduced maintenance costs by 25%. The payback period was 18 months. There are many types of different lamps, the most common being, in decreasing order of efficiency:
1. Low pressure sodium (street lighting)
2. High pressure sodium (for warehouse etc.)
3. Fluorescent (for offices etc.)
4. Tungsten filament (domestic use only)
Lighting costs can be minimised by selecting the most efficient type of lamp and light fitting consistent with your aesthetic or colour rendering requirements but remember that:
1. Tungsten filament lamps should be replaced by compact fluorescent lamps.
2. Tungsten spot lights should be replaced by tungsten halogen lamps.
3. Standard 38mm diameter fluorescent tubes should be replaced with 26mm tubes in switchstart fluorescent fittings.
4. When refurbishing warehouses or factory premises consider using high pressure sodium in preference to fluorescent lighting.
5. In areas where fluorescent lighting is most appropriate, specify high frequency ballasts which use 20% less electricity than older types.
One of the simplest ways of saving money in lighting costs is to train people to turn lights off when they are not needed. Unfortunately most employees are largely oblivious to the true cost of lighting as they don't have to pay the bills.
So a close check should be kept on manually controlled lighting - and a 'switch it off' reminder issued to employees periodically. When light switches are grouped together it is often difficult to know which switch controls which group of light fittings.
When the Cathkin Inn in Glasgow was refurbished, the opportunity was taken to fit purpose made labels to the light switches to overcome this problem. This simple measure has helped the Inn to realise a 25% reduction in lighting energy use after refurbishment. Ways of achieving more efficient usage of lighting include:
1. Putting up posters.
2. Energy awareness sessions.
3. Distribution of leaflets e.g. inside wage packets.
4. Make energy efficiency part of the employees code.
5. Include energy management in the supervisors tasks.
You could also put a main isolation switch near to the exit door so that the last out can switch everything off. Dairy Crest Ltd (nr Wrexham) changed from a general to a localised lighting scheme, by modifying existing light fittings to provide the recommended illuminance in work areas and a lower illuminance in non-working spaces. This reduced the factory's lighting bill by 47%. The payback period was 2.25 years.
You should check the loading patterns of your boilers to make sure that they are only being used when needed, i.e. during the working day or process operation. In general, the higher the load on a boiler, the higher its efficiency.
Thus if boiler load varies considerably during the year, a single large boiler is not very efficient - as it will be operating on part load for most of the year. In this case, a modular boiler system should be considered since this will allow better load matching.
At Liverpool Hope University College, three heating boilers were found to be firing randomly with rapid on/off cycling. Adjustment of the boiler thermostats to establish a differential between each boiler enabled one boiler to act as lead, firing steadily for most of the time. The other boilers now cut in infrequently when required to supply peak heat loads. The overall efficiency of the boiler house has been increased by approximately 5%.
1. Review the loading patterns of your boiler.
2. Check how often your boiler operates at partial load.
3. Isolate surplus boiler plant in mild weather and turn off its pilot light (if applicable).
4. Examine the benefits of fitting a modular boiler system.
Identify any areas of your buildings that are occupied intermittently and check if lights are on when empty. If so, then better control could save your money. Also check that lighting is turned off when sufficient daylight is available, and if not - then check if it can be switched off easily - without affecting other tasks.
Light switches should allow localised control of lighting so that, for example, lights near windows can be switched off during daylight hours, and lighting levels can be reduced in unoccupied areas of open plan offices.
Individual switches should also be fitted to control lights that have been installed to provide higher lighting levels for specific tasks, such as the inspection of artwork. Considerable care should be taken to co-ordinate the lighting layout to task positions as poor lighting will affect productivity.
The lighting implications of any changes to work layout should be carefully considered. In order to reduce lighting costs, Unipart installed microwave sensors in its Cowley warehouse in Oxford. These automatically turned the warehouse lights off when it was unoccupied and reduced the percentage of time that the lights were on from 70% to 21%. The payback period was 1.8 years.
Determining where major heat losses occur in your building is a major step to reducing fuel bills. An infra-red camera is the easiest way of pinpointing specific heat losses due to damaged, poorly fitted or inadequate insulation.
However some losses can be detected by the naked eye - e.g. places where birds congregate in cold weather, or roofs that dry quickly after a shower. Use this checklist during your energy survey:
1. Do all doors close properly (and automatically)?
2. Are there any gaps around doors or windows?
3. Any cracked, broken or missing window panes?
4. Are some windows permanently open due to paint?
5. Are there obvious holes, cracks or leaks in roofs?
6. Can duct covers/skylights/roof lights be closed properly?
7. Have roof/ceiling panels been removed and not replaced?
8. Is roof space insulation at least 150 mm (6 inches) thick?
9. Can you see any obvious holes in the walls or floors????not replaced?
10. Is roof space insulation at least 150 mm (6 inches) thick?
11. Can you see any obvious holes in the walls or floors
Once you have worked out how much heat is lost from your building, you should examine if it is cost-effective to make improvements. A wide range of insulation materials are available to suit different needs (and budgets).
At the Marquis of Granby pub in Sompting, West Sussex, insulating board and plaster skim were applied to the ceilings of its flat roof areas, to reduce heat loss and to improve customer comfort. The payback period was just under 6 years. An energy survey at GEC Alsthom's Rugby plant identified that heat was being lost through the roof and that there were severe draughts in places. As the roof was also leaking, insulation was added when the roof was repaired. Fast acting doors and an air lobby were also fitted to cut down on draughts.
Check that sufficient light switches are available to enable your staff to control their own lighting. The use of individual pull cord switches can provide a cheap and effective solution. In open plan areas, label light switches to facilitate their use.
Product yield is the ratio of useful product out of a process to raw material used. It measures how much (or little) waste is produced too. A high yield not only maximises the amount of saleable product, it also minimises the cost of handling, removing and processing any waste produced, including costs such as landfill charges, re-work, energy, labour etc.
First work out your current yield in terms of:
1. Specific yield i.e. the amount of product produced per unit of raw material e.g. tonnes of beer produced per litre of water used
2. Relative yield i.e. the percentage of raw materials converted into product, e.g. 85% of raw clay is sold as bricks.
Then focus on why the yield is not 100% - where does the waste originate? - can waste be reduced? Yield can be increased by a range of technical methods such as better process control and process redesign.
However the observant employee is equally important. HJ Heinz increased the yield from one stage of its soup manufacturing process, by changing the order ingredients were added during batch mixing. This reduced frothing which allowed better control and lower effluent levels. The total savings were about £100,000 a year.
People spend an average of one hour per day travelling - 80% of which is in cars - but with increasing car usage, these journey times could double over the next 10 years. Thus businesses need to reduce their dependence on road transport and minimise travel wherever possible.
For most journeys, public transport or car sharing should be considered. Alternatives such as audio, video, computer conferencing or telecommuting should also be examined. Here are some ways to minimise travel:
1. Consider using public transport for business trips
2. Encourage car sharing for journeys to and from work
3. Try to combine smaller loads when making deliveries
4. Join up with other neighbouring firms to share transport
5. Look at alternatives to travel such as video conferencing
Small loads should be combined wherever possible to minimise the overall number of journeys. Vehicles should never be overloaded.
Water is often used in many different parts of the manufacturing processes, including cleaning, processing, heating and cooling. It is also a vital ingredient in many food and chemical products.
However it is often needlessly wasted, because no one person is actively managing its use. The average company could save 15% of its water and effluent bill by minimising water use.
Reduced water consumption should also reduce waste water volumes, treatment and disposal costs, and help to reduce the impact of your business on the local environment. Here are some things to look for:
1. Dripping taps, leaking pipes and radiators.
2. Running cold water being used for cooling
3. Washdown hoses without trigger guns
4. Hot water being run continuously
5. Wash water that could be recycled
6. Overflowing tanks/faulty control valves
7. Unexplained water use outside production hours
Also consider replacing wet filtration systems with membrane filtration systems.
Associated Diaries in Accrington saved £18,000 in water and £14,000 in energy costs by changing working practices, fitting trigger guns to water hoses and by reclaiming water and condensate from its bottling plant - and reusing it for crate washing. The savings were realised during a comprehensive energy management programme which paid for itself in just 8 months.
Natural gas is widely used for space and water heating in industry, in commerce and in the home. Another major use is in process heating. Natural gas burns without producing smoke and soot, so boiler maintenance costs may be lower in comparison to other fossil fuels.
However gas is often wasted through inadequate maintenance of boilers and steam systems. Gas supply costs can be minimised by making sure that you are on the right tariff, and, as the market is completely open to competition, by shopping around different gas suppliers.
Good control is the key to the efficient heating of offices. You should check that your heating and air conditioning controls are adequate -one very obvious indicator of poor control is the number of windows that employees open in winter.
Many offices were built before the advent of the modern personal computer and photocopiers. These devices generate heat in offices and cause employees to open windows.
Many companies have installed air conditioning to improve comfort levels but before you consider this - why not check whether you can increase natural ventilation, or use the heat generated in one office area to heat another
1. Close office windows when your space heating is on.
2. Check that employees are happy with room temperatures.
3. Install local thermostats and check their settings regularly.
4. Fit a boiler optimiser with compensation features.
5. Ensure heat is only provided when and where needed.
6. Minimise the number of fresh air changes per hour.
7. Take advantage of natural ventilation wherever possible.
8. Fit blinds or reflective window film to reduce solar gain.
9. Lag heating pipes to prevent local hot spots in offices.
At Quadrant House in Sutton, gas consumption was cut by 66% by careful control of primary air temperatures in the building (to minimise simultaneous heating and cooling), by fine tuning of the optimum start and stop times on the boilers and air conditioning system, and by switching off the boilers in summer and using local electric heaters to provide hot water instead.
This accounts for between 20 to 60% of the total energy use of the building and offers substantial scope for reductions both in energy and costs. High productivity in the office needs good levels of lighting, a new properly designed lighting scheme has been shown to improve productivity by 8%.
If your lighting system is more than five years old, you should check that office light levels are correct using a light meter. Most lighting companies will usually check light levels free of charge.
When the Foreign & Commonweath Office decided to replace its ageing twin 1500mm (5ft) fluorescent light fittings, trials showed that satisfactory illumination levels could be maintained using single 1800 mm (6ft) high frequency fluorescent luminaires. This reduced lighting costs by over 50% and created an improved working environment.y a 20W CLF reducing running costs to a quarter and lasts eight times longer.
In mild weather, heating systems do not need to be switched on as early as in colder weather.
An optimiser is basically a special timeswitch that turns boilers on at the latest time to ensure that a building reaches the correct temperature for occupation. Most optimisers measure internal and external temperature, and adjust the boiler start times to allow for the effects of the weather.
However some low cost optimisers use internal temperature only - and can be caught out if the outside air temperature drops suddenly overnight.
1. Check if boiler turn on/turn off is being optimised.
2. Consider fitting an optimiser to 30kW boilers and higher.
3. Ensure that internal and external sensors are working.
4. Consider the installation of an optimiser on air conditioning.
At the Reading College of Technology, new heating controls with optimum start and stop functions were installed instead of simple time switches. These controls which also included an upgraded weather compensation facility, reduced fuel costs for heating by £17,714 a year (1984/85 prices). The payback period was less than six months.
Optimising Usage of Raw Material
Opportunities for reducing raw material costs include:
1. Optimising and re-specifying grades of raw materials
2. Developing and negotiating simpler product designs
3. Recycling partnerships with suppliers/customers
4. Eliminating the use of hazardous materials
5. Greater use of recycled materials
Remember that producing waste is like throwing money down the drain - or into the bin! Also remember to avoid lower quality raw materials that effect product yield, as this may result in increased rework or customer complaints.
To reduce waste, Lewis and Towers Ltd installed a continuous weighing system on its glass bottle manufacturing lines at a cost of £17,600. This automatically weighs the glass gobs before they are turned into bottles and allows operators to maintain tighter control. As a result, product waste has been reduced, realising energy and materials savings of £5,800 a year and £5,700 a year respectively. The payback period was 18 months.
One of the main problems with photocopiers is that they are often left on when they are not being used, this is mainly due to the time it takes for the photocopier to 'warm up' when first switched on.
Photocopiers are often left on overnight because people think it is someone else's responsibility. Most organisations can save money by reducing the amount of photocopying done. A 30% reduction in paper use is often possible.
1. Fit a timer to prevent photocopiers being left on overnight.
2. Reduce the amount of photocopying by circulating documents, using notice boards or electronic mail.
3. Encourage staff to use double sided copying if possible.
When choosing a new photocopier, there are models which are more energy efficient than others. Some switch to a standby mode when not in use.
At Blackburn Town Hall photocopiers are fitted with simple time switches so that the photocopier automatically is switched on at 8.15 in the morning, turns itself off for 1 hour at lunch time and then turns itself off at 5.30 pm. The cost of a time switch is around £15 and the payback period is only a few months if the photocopier is regularly left on overnight.
Insulation of plant and pipework is not only essential for financial and energy efficiency reasons, but it also improves safety - where personnel are likely to come into contact with very hot or cold surfaces.
Insulation can also protect pipes against frost damage and reduce noise emissions. The range of insulation material is large and new products are regularly being developed.
A number of different factors must be considered when selecting the most appropriate insulation material for your plant and specialist advice is best sought before a purchase is made.
Ciba Composites have upgraded their steam pipe insulation to include jackets round pipe flanges, valves and fittings. Losses from these areas of pipework accounted for 18% of the site's steam consumption. For a cost of £21,000, savings worth £27,500 have been made - a payback period of 9 months. The average cost of the insulating jackets used was just £50.
Point of use water heaters avoid the 'dead leg' run-offs losses that occur with traditional hot water storage systems.
They allow water to be heated and delivered almost instantaneously - as and when it is needed. Consider point of use water heaters for areas such as toilets, washing sinks, and locations remote from the hot water storage tanks.
(To spot potential applications look for long lengths of hot water pipe on your energy survey).
Remember that point of use water heaters can be wall mounted both above and below sink units - and out of sight for flush executive designs!ion figures).
At Causton County Primary School in Felixstowe, the existing boiler which provided both space heating and hot water was replaced during a refurbishment with a new smaller boiler for space heating, and 25 point of use water heaters for hand washing. These two measures cut the school's energy bill by 25%.
A low power factor will increase the price you pay for your electricity. Many uses of electricity including motors, welding and lighting, draw more current than is accounted for by the power produced (in Watts).
A system drawing excessive Wattless current compared with its actual power consumption is said to have a low power factor. This low power factor can be improved by installing power factor correction capacitors.
Always check the power factor of new (or refurbished) equipment. HIP Ltd, in Chesterfield, installed power factor correction equipment at a cost of £9,350 (1988 prices). As a result, the average power factor of the site improved from 0.77 to 0.92 - saving about £9,300 a year due to a 13% reduction in electricity charges. The simple payback period was 12 months.
Remember that it is generally cheaper to photocopy documents than to print out multiple copies on a laser printer. Its also faster. Printing can often be more expensive than you realise.
When purchasing printers make sure that running costs are considered. Some modern printers have a 'sleep' mode to save energy when they are not printing. 1. Don't leave printers switched on when not needed. 2. Only buy printers with a low power 'standby mode'.
Whilst opportunities for a complete redesign are comparatively rare, a partial redesign for waste or energy minimisation reasons should always be considered, particularly when plant needs to be upgraded or replaced anyway.
The inclusion of heat recovery, water recycling and modern waste recovery / filtration systems could reduce waste significantly. Often redesigning parts of the manufacturing process is the most cost-effective long term option for reducing waste and eliminating hazardous materials from the production line.
Some actions to consider include:
1. Recycling rinse water and other cleaning fluids
2. Use of heat recovery and water pinch techniques
3. Free air cooling and/or water cooling of products
4. Recovering and reusing cooling & heating liquids
5. Modifying the process to reduce waste production
6. Product redesign to reduce manufacturing costs
A Carlsberg Tetley brewery saved £87,000 a year by redesigning part of its key washing plant so that rinse water could be recycled. The project cost £95,000, but this was recouped in just over a year, as savings were realised not only through reduced water use and effluent charges, but also via reduced energy and steam use, lower maintenance costs and more efficient operation.
Radiators can lose 10% of their heat output to poorly insulated outside walls. A low-cost method of reducing this heat loss is to fix aluminium foil panels behind the radiators. This will reflect some of the heat back into the building.
If thermostatic valves (TRVs) are not fitted then some employees will open windows to adjust the temperature of their working environment. Then you will end up heating more air and fuel bills will rise.
1. Ensure thermostatic radiator valves (TRVs) are fitted to all new radiators - as it will cost more to retrofit them.
2. Check that TRVs are not set too high and if they are consider fitting locking mechanisms.
3. Where radiators are on outside walls, place a sheet of heat reflecting material behind them to direct heat into the room.
4. Ensure there is free air circulation around all radiators and that they are not obstructed by furniture etc.
The British Library had a common heating system serving both the public reading rooms and the "behind the scenes" storage areas. Thermostatic radiator valves were fitted in the storage areas to enable temperatures to be controlled at a lower level than was required in the reading rooms. The payback period was under 3 years.
Recovering Heat from Air Compressors
Over 90% of the energy used in compressing air is converted into heat. This heat could be recovered and used in hot water or space-heating systems.
A simple way of recovering heat is to duct the air outlet of a compressor into the factory in winter and outside in summer. Possible uses of the waste heat , i.e. warm water or warm air, should be considered when designing a compressed air installation and when selecting a site for a new compressor.
The cost of linking a compressor to a suitable heat user will vary, but payback periods of between one and three years are often possible.
130 kW of heat could be recovered (at between 30 and 40oC) from a 500 litres/second compressed air installation served by an air-cooled compressor. A site with direct gas-fired space heating and operating 48 hours/week, using this heat would produce annual cost savings of around £2,000.
If you are using a process which generates heat that is just expelled into the atmosphere or lost down the drain, you should investigate if it is economical to re-use this heat. Many processes produce waste heat.
Often this is seen as an unwanted by-product, but by recycling the heat into the space heating or water heating systems, significant savings can be made. Simple heat exchangers can be used to achieve this.
Naylor Jennings, a textile firm in Leeds, made considerable savings by installing a heat exchanger to the waste water stream from the plant's dyeing, cleaning and bleaching process.
The heat exchanger was fitted with a filter that removes fibres and prevents it from becoming clogged. The investment cost was £10,300 (1985 prices) and with savings of £9,870, the project had a simple payback period of just over 1 year.
Types of heat recovery devices include: Economisers. Waste heat boiler/shell and tube heat exchangers. Direct contact heat exchangers Tubular (convection) recuperators Thermal wheel (rotating regenerators). Heat pipes. Cross flow air to air heat exchanger. Run-around coils.
Shell and tube heat exchangers Gasketed plate heat exchangers Solid heat recovery Run-around coil J.R.George Ltd - a small engineering works - refurbished an existing furnace using low thermal mass insulation, self-recuperative burners and better controllers. The project reduced energy consumption of the furnace by 73% and increased production capability at the same time. With total cost savings of £20,039 per year and capital costs of £21,175, the simple payback period of this project was just over 12 months.
To reduce the packaging waste you should look at the whole manufacturing process - from the arrival of raw materials to the finished product leaving the factory. You should quickly find that packaging wastes can be reduced and cost savings realised either directly, or indirectly through lower raw materials costs.
Examples include re-using pallets, returning packaging to suppliers for reuse and reducing the amount of packing used on your products. Reduced packaging not only reduces waste costs, it also indirectly saves energy!
Some ways to reduce packaging waste, include:
1. Using the minimum packaging needed
2. Returning product packaging to suppliers
3. Minimising or reusing own product packaging
4. Deposit - return schemes for crates, pallets etc.
5. Reusing cardboard cartons and plastic bags
6. Redesigning packaging so it can be reused
7. Agreeing reduced packaging with customers / suppliers
Note that some European countries insist that manufacturers cover the cost of customers returning product packaging!
A waste minimisation project at Walkers Snack Foods, Peterlee realised packaging savings of £124,000 through equipment and process redesign, sale of waste to recycling companies and redesign of secondary packing boxes. The project team also identified opportunities for water and energy savings, waste reclamation and efficiency improvements at the same time!
Whilst the COST of raw materials is a major issue for most organisations, the amount and quality of raw materials used in a particular process is rarely examined in any detail. New stronger and lighter materials are announced every month and these may offer substantial cost savings. Use of recycled materials and lighter packaging are other immediate possibilities for reducing waste.
Waste can be dealt with in a number of ways. The first option is to reduce its production. The next best option is reuse, but if this is not possible then it should be recycled in-house or sold as scrap for reprocessing.
Paper, cans and bottles are the most common recycled materials, but with a little bit of thought, ways can be found of recycling waste production materials too. Some ways to reduce waste are:
1. Find out what waste is produced on your site
2. Ask if any of this waste be reduced and by whom
3. Make someone responsible for reducing waste
4. Establish waste collection points for recyclable items
5. Provide separate collection bins for each category of waste
6. Consider using an outside company to recycle your waste
7. Join a local waste minimisation club or start one with neighbouring sites!
To encourage your employees to reduce waste, you could also consider donating a percentage of any savings raised to a local charity.
In 1992, 14 companies in the Mersey Basin set up a waste minimisation club with support from the DTI and the BOC Foundation for the Environment. After just two years, members had collectively saved £2.3 million a year by reducing waste disposed to landfill. By mid 1996, the club had saved another £1.9 million a year though reductions in materials, operating and utility costs, and lower capital requirements. Most club projects payback in less than a year.
Relamping at the same time as cleaning minimises the labour costs and is much more productive.
Fluorescent and discharge lamps deteriorate with time, and a programme of planned replacement is often more cost-effective than a 'replace on failure' policy.
Standard tungsten filament light bulbs are the least efficient form of lighting and should be replaced with compact fluorescent lamps wherever practical.
A company who only replaced lamps on failure and cleaned light fittings at irregular intervals - decided to plan a regular programme of maintenance and lamp replacement. By cleaning their light fittings every 2000 hours, and replacing lamps every 4000 hours, they saved 6.5% of their lighting costs. (even after the cost of increased maintenance was included).
In all but the smallest installations, it is sensible to replace lamps as a group, at planned intervals. As a general rule, lamps should be replaced when their output has depreciated by around 30% (use a light meter to check light levels). Similarly, it is usually most economical to replace the starter switches on fluorescent lights in groups, every two lamp lives. On switch-start flourescent lamps, it is usually economical to group-replace the starter-switches every two lamp-lives.
Making someone responsible for energy is the best way to ensure that your energy efficiency policies are implemented.
Choosing the right person from your existing employees is critical. They must be able to communicate equally with senior management and the shop floor. This appointment must be seen to carry with it the authority of the Chief Executive.
The person should be required to report formally and regularly, to senior management, on objectives, progress and problems. The person responsible should have the following tasks:
1. Monitoring the company's energy use.
2. Maintaining detailed energy consumption records.
3. Agreeing energy targets, yardsticks and/or bench marks.
4. Analysing records for management meetings.
5. Reviewing energy performance (against targets).
6. Being aware of energy technology and initiatives.
7. Investigating potential energy saving schemes.
8. Preparing economic justifications for capital projects.
9. Communicating energy issues throughout the company.
This person should also be asked to draw up a detailed energy action plan for your business targets and prepare routine reports.
During the 12 month period following the appointment of a site Energy Manager, Cleveland Potash's Boulby Mine realised a 11.6% reduction in energy use per unit of production. These savings were realised by a mixture of good housekeeping measures, load shedding and capital projects. The Energy Manager developed an energy management plan shortly after his appointment. This plan is regularly updated and has the support of Senior Management, who have made a public commitment to its implementation.
If there is no roof space on a building, i.e. if the room is open up to the roof, a layer of insulation should be fitted to the roof itself. In newer buildings, roof panels are generally insulated already, but the roofs of older buildings are often not insulated - allowing heat to escape easily.
Cumbria Engineering Ltd fitted external insulation on its factory roofs. This resulted in a 66% reduction in space heating costs. The simple payback period was 2.3 years.
Sankey diagrams are a very useful way of visualising energy use. They show all the energy inputs and outputs of a process, building or system. They can be used to identify priority areas for your investigations, to raise employee awareness and for presentations to managers.
They are also a very useful way of visualising energy use for staff / management presentations. To construct a Sankey diagram you first have to find out the total amount of energy that is being used by your company.
The next step is to account for where all the energy is being used. Each energy flow should add up to 100% i.e. Input = Losses + Output. Remember that Sankey diagrams are a useful way to identify 'unexplained' energy use in your company. If your energy purchases exceed known uses, then you should investigate this carefully - but check your figures first!
The quality and profile of heat required throughout the day and week should be reviewed frequently, and boiler controls adjusted so that the minimum number of boilers are operational at all times. On larger installations, an automatic boiler sequence controller can be fitted to monitor and sequence boilers correctly.
1. Review the operating patterns of your boilers
2. Establish how often boilers are operating at partial load.
3. Adjust boiler thermostats to ensure the minimum number of boilers is on.
4. Consider the installation of an automatic sequence controller.
By careful adjustment and continuous monitoring of a modular boiler system at Cambridge University Sidgwick Avenue site, its average efficiency was improved from 77% to 81%. Additionally a considerable reduction in boiler heat losses was achieved by applying insulation and cladding to the boilers' external surfaces and by isolating boilers from the water circulating system when not required.
Some shops are fully air-conditioned in order to ensure comfortable conditions for customers, staff and indirectly products on display. Improving air conditioning control and operation can produce significant energy and cost savings.
The waste heat generated by larger air conditioning or refrigeration systems can also be recovered and used to generate space heating or hot water.
'Open door trading' requires an adequate air curtain equipped with cooling and heating systems to maintain comfort conditions and minimise energy usage.
1. Reduce the temperature of space heating to a minimum.
2. Install time controls with integral optimiser / compensation.
3. Minimise air changes by installing air curtains.
4. Consider using automatic doors to minimise air changes.
5. Maximise use of 'free cooling' from natural ventilation.
6. Install variable speed drives on ventilation fans / pumps.
7. Increase temperature set-point on air conditioning systems.
8. Consider heat recovery for air conditioning and refrigeration systems.
At Sainsbury's in Beckenham, the heating and cooling systems are linked together, and the refrigeration system has a heat recovery system to make use of waste heat. The air conditioning is controlled by a building energy management system that ensures heating and cooling systems are not on simultaneously. These factors have allowed the store's energy consumption to remain steady -despite an increase in store opening hours, and extra refrigeration and lighting loads.
The effective display of retail products is an important topic for shops and stores as well lit displays are eye catching and attract customers. However lighting costs can be substantially reduced by simple good housekeeping measures such as turning display lighting off outside working hours and using reduced lighting levels during cleaning and shelf stocking periods.
Where a dirty atmostphere exists regular, annual or less cleaning can be beneficial. Shop lighting levels typically range from about 300 to 1200 lux depending on the nature of the shop.
Generally high frequency fluorescent fittings with mirrored reflectors behind lamps, are the best for normal ceiling heights of 3 to 4 metres, but metal halide and high pressure sodium lamps can be better for higher ceilings.
Lighting systems should be designed to match the intended layout of the shop, but some flexibility should be retained to allow for changing displays. You should ensure that "Out of hours" lighting is carefully controlled.
A new control system was installed at the Birmingham branch of Saxone. This system has three modes of operation: 1. A trading mode, where the full display lighting is used. 2. A night mode - where only security lighting is on 3. A "keyswitch" mode where only fluorescent lighting is used - this is used before and after trading when only staff are present. At the same time, the display lighting was upgraded from tungsten filament lamps to more efficient low voltage tungsten halogen lamps. These two energy efficiency measures reduced the shop's electricity bill by a third.
Skylights are a useful method of improving lighting, especially if used with photoelectric light controls. However no more than 20-30% of the roof should be glazed.
Consideration should be given to secondary glazing of skylights. A range of lightweight translucent insulation secondary glazing systems are available to choose from - these are mainly formed of a sheet plastic material. Most can be fixed to the underside of existing roof-glazing.
1. Check how much of roof is glazed and insulated.
2. Consider fitting secondary glazing.
3. Ensure that roof and glazing are free from leaks by using soapy water or alternatively using ultrasonic leakage detectors.
Tag all leaks and tackle the worst ones first In the main corridor at Hayes Primary School in Croydon there was a significant heat loss through skylights and cold down draughts. To cure this 6mm thick twin walled polycarbonate sheets were fitted to the underside of the skylights at a cost of £27 per square metre. The payback period was around 4.5 years.
Point of use water heaters are best in most circumstances, but sometimes when a very high flow rate is required, hot water must be stored.
1. Pipework needs to be as short as possible to avoid dead legs.
2. All pipes, joints and valves must be lagged.
3. On larger systems ensure hot water is circulated to each draw off point to eliminate dead legs.
Remember that both hot and cold water pipes should be lagged as this stops winter freezing, and also summer warming of cold water in the pipes. If hot water is provided from a gas or oil fired boiler, consideration could be given to using off peak electricity to save boiler fuel. Any storage vessels should be properly insulated, as this makes them more efficient.
Check that tank insulation meets British Standard BS 5615.
1. Check that hot water is stored in a properly insulated storage tank.
2. If electric water heating , then check that full use is being made of off peak heating - check that you have the right tank size.
3. If hot water is provided from a gas or oil fired boiler, check if it is more cost-effective to use off peak electricity, particularly in summer.
4. Check whether a secondary circulation pump would reduce losses.
When the boiler house at the University of York's offices at Heslington Hall were refurbished, the University was able to cut the size of the hot water storage tanks by 65% (from 910 to 315) litres, as the kitchens for which the original hot water system was designed to serve, were no longer in use. If the water heater is electric, then it is more cost effective to heat water overnight on a cheaper tariff than during the day.
A secondary circulation pump should be used to minimise thermal losses, where appropriate, to achieve good paybacks. The Yew Tree public house in Widnes (Cheshire) saved about £80 a year in fuel costs by insulating pipework, its boiler house and the indirect hot water cylinder. The cost of this measure was around £130, so the payback period was 1.6 years.
Standard taps allow both hot and cold water to be wasted in two ways: - by allowing water to flow too long - by allowing too large a flow.
Employees will usually overlook these facts so automatic methods are much more reliable. You can make large cost savings in this area.reas. of water are not used.
Parkside Middle School in West Yorkshire began an energy and water saving initiative in 1990. As part of this, flow restrictors were fitted to all hot and cold hand basin taps to reduce wastage. This simple measure helped the School to reduce its water usage by approximately 45%. Look at the way water is used.
1. If the flow rate is too high then consider fitting an in line flow restrictor or spray taps.
2. If taps are left running then consider timer taps or sensor taps which detect people's hands.
Also ensure that dripping taps are repaired and check that all hand basins have plugs and chains. Remember that washing hands under a running tap is wasteful.
General temperature guide-lines are: 40oC for hand washing and 60oC for other washing. Heating water to 60oC will kill any trace of legionella and all hot water should be stored and distributed at this temperature. In large, well used washrooms, it may be economic to fit mixer taps or thermostatically set spray taps to provide a lower temperature for hand washing. ure. the correct temperature.
When the DTI reviewed the hot water temperatures in one of its London Offices, they were concerned to discover that water temperatures ranged from 40oC to 90oC and hot water was available 24 hours a day. Their immersion heaters were immediately reset to provide a storage temperature of 60oC, and time clocks installed to ensure optimum energy efficiency whilst maintaining hygiene standards. Check your current water heating temperatures, if it is above 60oC then lower it to 60oC (if possible).
Ensure that all boiler, pipework and valves are well insulated to avoid heat loss. Special jackets can be purchased for insulating valves and other fittings. Remember to check that insulation is replaced after any pipework repairs Weetabix Limited saved over 20% of its annual energy expenditure on an energy drive.
One of the things they did was to check the insulation on all the steam pipes in the factory, and replace any defective material with a quality insulation. They also installed modern, pre-set, tamper-proof thermostats to ensure that hot water was being delivered at the correct temperature.
Careful monitoring of fuel consumption is an essential part of effective fleet management, yet many operators have only a rough idea of the fuel consumption of their vehicles. Thus it is difficult to identify poor performance.
Fuel meters and data loggers can be used to monitor vehicle performance. Some charge cards also record vehicle mileage every time fuel is purchased. However details of the load carried, route and weather will need to be recorded on manual log sheets before performance figures can be calculated.
1. Record vehicle fuel usage, mileage and journey details
2. Draw up a league table of miles travelled per litre used for each vehicle/driver allowing for different journey types/loads.
3. Correlate fuel consumption data with tachograph disks
4. Investigate the worst performers first. In larger fleets, the performance of different types and makes of vehicle should also be compared, prior to further purchasing decisions being made.
To improve its fuel efficiency, Thortons plc installed in-house computerised monitoring systems in some of its vehicles. These have been used to identify poor driving technique and to identify the most economical routes. A 6% improvement in fuel use was realised over a 12 month period.
The simplest way of using waste steam is to duct the steam to a point where it may be condensed back to water by spraying cold water over it. The hot water is then collected and used elsewhere in the process.
Energy can also be recovered from high temperature steam or waste gases generated by furnaces and kilns using heat exchangers.
For further details see under topics: Furnaces and kilns and Recycling waste heat.
Very low pressure waste steam can be recovered for use in process or space heating before being returned as condensate to the boiler. Other possibilities on larger sites include sharing of steam between neighbouring sites and localised district heating, although these are major projects.
However it is worth investigating whether you could profitably use a neighbouring plant's waste steam. g of steam between neighbouring sites and localised district heating, although these are major projects.
At Whitechapel Laundry, a washer extractor was modified to allow recycling of heated water and the use of flash steam to heat water for washing and rinsing. Annual water and energy savings of £10,000 were realised for an investment of £19,000 (1985 prices). The payback period was 23 months.
Where a variable output is required from an electrical machine (e.g. different flow rates from a pump or fan), it is more energy efficient to vary the speed of the machine using a Variable
Speed Drive or VSD - than to use alternative methods of control, such as throttling the flow using a valve or damper. A range of cost-effective electronic VSDs are available for both larger and smaller applications.
Typical applications for VSDs include: Pumps Mixers Compressors Machine tools Fans Conveyors Machine tools When purchasing new equipment check what type of motor is fitted, as it is better to buy a machine with variable speed drive than to retrofit one later.
If old machines are being updated or refurbished, then check if it is cost effective to fit variable speed drives to the motors at the same time.
Glasgow Royal Infirmary saved £8,300 a year by fitting a variable speed drive on a boiler fan. Trials showed that the motor's electricity consumption fell from 20,200 kWh a year to 6,500 kWh - a 68% reduction. The VSD cost £7,100 (1989 prices) and simple payback period was only 11 months.
A regular tuning and service programme will ensure the efficiency of your vehicles and can reduce fuel usage by up to 5%. Remember 90% of all inefficient vehicles can be retuned in 15 minutes.
A badly maintained vehicle will almost certainly use more fuel that is necessary as misaligned steering, worn or under-inflated tyres can increase fuel consumption by up to 3%. Remember 90% of all inefficient vehicles can be retuned in 15 minutes.
To ensure vehicles are properly maintained:
1. Set-up a regular maintenance programme
2. Encourage drivers to check vehicle condition daily
3. Monitor fuel use, speed and mileage per gallon
4. Inspect vehicles for worn tyres, and oil and fuel leaks.
Regular vehicle maintenance is essential, not only for good fuel efficiency but also for safety and reliability. Blagden Packaging realised an 18% fuel efficiency improvement via a bonus scheme linked to vehicle performance.
Each driver was assigned their own truck and can earn substantial bonuses by driving economically. A best appearance competition also encouraged drivers to look after their vehicles, and to avoid damage to bodywork and tyres. This extended vehicle life and reduced maintenance costs.
It is important to remember that when air within a building is replaced by fresh air from outside, this new air must generally be heated or cooled - if room temperatures are to be maintained. Thus, for energy efficient operation, the number of fresh air changes in any building should be reduced to the minimum required for employee comfort and health. By controlling air flow directly, rather than relying on open windows, the rate of fresh air supply can be adjusted to the desired level - independent of external air pressure or wind speed.
Good control of ventilation is essential if the number of fresh air changes are to be minimised and space heating costs contained.
1. Reduce air volume being handled to a minimum.
2. Set the room cooling temperature to 24oC or above.
3. Use as high a proportion of recirculated air as possible.
4. Ensure system running hours are keep to a minimum.
5. Ensure that ducts, evaporators, condensors and cooling towers are kept clean.
6. Ensure that filters are changed regularly.
7. Avoid simultaneous heating and cooling.
Remember that it is always cheaper to use natural ventilation for cooling. The Inland Revenue has recently reviewed the operating temperatures in its computer rooms. Because modern electronic equipment is less susceptible to temperature it was able to increase the set points from 21oC to 24oC.
This will reduce electricity costs by around 15%. A microfilm studio at the British Library was fitted with a ventilation plant to remove heat generated by cameras and lights. By installing a simple time switch to switch off ventilation automatically overnight and at weekends, the studio saved more than £500 a year. The time switch cost about £100 to install.
The insulation of walls should be done in the construction or refurbishment of the building (although cavity wall insulation can be successfully undertaken at any time). This is a specialist job and a contractor will give advice on the type and quantity of insulation needed.
The walls of a building, if uninsulated, can account for up to 50% of the heat lost in a building. Effective wall-insulation can typically reduce this heat-loss by around two-thirds. There are three types of wall-insulation:
1. Cavity wall-insulation (this is the cheapest method)
2. Internal solid wall-insulation
3. External solid wall-insulation (this can be expensive).
The retrofitting of cavity wall insulation by the Bournville Village Trust to the Shenley estate in Bournville not only saved money for the householders, but also made the average temperature of the houses increase by 1.4 oC. The payback on the scheme was well under 2 years.
When controlling the environment of a warehouse, you need to define what is being stored, its specific storage temperature requirements and how often workers need access to different warehouse areas.
Some goods must be stored in a controlled temperature environment, however many other goods can be stored at normal temperature. You should always try to minimise the volume of the warehouse that needs to be heated or air conditioned. You should also minimise the number of fresh air changes by closing warehouse doors.
Warehouses range from small stores, where office lighting systems apply, to high ceiling areas where factory lighting systems are more appropriate. In warehouses, a high density of stacking can obstruct light, and glare from both natural and artificial lighting can be a major problem as employees need to look up when handling goods. These problems can be overcome by selecting a lighting scheme with a good distribution of light at higher levels of the warehouse.
At Powergen's Fiddlers Ferry Power Station, lighting costs in the high - bay areas of the Heavy Stores building have been reduced by 80% through the introduction of timed push button light switches. In another part of this building, where heavy parts on pallets are stored in racks, the use of occupancy sensors has cut lighting costs by 90%. The payback period on the new controls was less than 6 months.
Natural light through extended glazing areas provides a considerable saving in lighting costs during daylight hours, and when multiple-glazed, can provide an additional heat source during the day.
The amount of heat lost through glazing can be roughly halved by double-glazing. Further reductions can be made by using either low-emissivity glass in one of the skins of double-glazing, or by using triple-glazing. Before fitting new secondary glazing, you should always check that the existing glazing and roof are free from leaks.
Although double glazing saves energy, installation costs are very high in comparison with the annual cost savings realised. However you should always consider double glazing at the design stage of a new building, or during replacement of old or broken windows. These are the most cost effective times to install double glazing.
When the Bristol offices of accountants Arthur Young were designed, the windows chosen were aluminium double glazed, with twin casements and clear glass. This aspect of the design combined with other features of the building, meant that the building's energy use rating is almost half of that specified in the CIBSE Energy Code part 4's "Good" level.
Within the paper industry, there is an anonymous comparison of UK paper mill performance provided by the British Paper and Board Industry Federation.
Improvements at individual mills are catalysed by the knowledge that other paper mills with similar products have better energy consumption figures. Common yardsticks are:
1. Energy usage per square metre or foot of floorspace.
2. Energy usage per unit (£) of staff cost or turnover.
3. Energy usage per unit of production.
Choose the yardstick that is most appropriate to your company and use it to track energy usage. This will allow differences in energy performance to be quickly identified and investigated.
Bench marking compares your performance to that of the best performer or competitors. The aim is to close the gap quickly and reach the benchmark.
Yardsticks are very important performance indicators. They allow you to compare your business' energy usage with that of other businesses doing similar work, or using the same process or equipment.
For instance, by working out the average energy used in producing one item, you can compare your performance with other companies in the same sector. A range of yardsticks for different building types / processes are published in Energy Consumption Guides and in the Energy Efficiency in Buildings series of booklets. Some trade associations also publish statistics on the energy usage of their industry.
Good performance
Lower Than (£/m2)
Bad Performance
Higher Than (£/m2)
Factories General Manufacturing Light Manufacturing Warehouses Offices Natural Ventilated - Cellular Natural Ventilated - Open Plan Air Conditioning Shops Non-Food Food Fast Food Restaurants Other Hotels Large Small
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