KEY AREAS TO LOOK AT FOR ENERGY IMPROVEMENTS

1. ENERGY MANAGEMENT:

  • Payback should be calculated for all measures
  • Non-energy savings should be included within payback calculations

Involving employees:

  • Raise awareness in company targets and employees use of energy and how employees can help.

2. SPECIFIC AREAS:

SPACE HEATING AND COOLING:

CHP (combined heat and power)-

  • This is the most energy efficient method of providing heat and electricity- it is most useful to larger users. This should generally be used where heat and power are needed together for a minimum of 4 000 hours per annum.

Radiators

  • Thermostatic radiator valves should be fitted to all new radiators
  • Such valves should not be set too high
  • Place reflective sheets behind radiators on outside walls
  • Remove all obstructions in front of radiators.

Heat pumps

  • Pay back for these is often over long periods. Should the application be worthwhile such as for waste heat from an air conditioning plant, further advice from a manufacturer of thus should be sought.

Ventilation

  • The number of fresh air changes within a building should be kept to a minimum.

Air conditioning

  • Keep air volume handled to a minimum
  • Set the room cooling temp to 24 degrees Celsius or above
  • Rely upon air recirculation where possible
  • Keep all ducts, evaporators, condensers etc clean
  • Change filters on a regular basis
  • Don't heat and cool air at the same time

PROCESS HEATING AND COOLING

Drying

  • Check dryer performance regularly
  • Set energy consumption targets for dryers
  • Check dryer instrumentation is working properly
  • Keep dryers well maintained and ensure preventive maintenance
  • Automatic end-point detectors should be fitted to batch dryers
  • Investigate drying time reduction through de-watering the product in a previous process

Recycling waste heat

  • Using any process that generates uncaptured heat is wasteful of energy. Attempt to capture this heat (where feasible)- specialist companies / consultants can help.

Kilns and furnaces

  • Existing furnaces should: monitor energy consumption regularly; set consumption targets for each furnace; benchmark performance; shorten holding times through altering production schedules; undertake a detailed energy audit; look into waste heat recovery.
  • Refurbished / new furnaces should design plant to use the most efficient burners and the optimum insulation.

Flows controls

  • Steam, water and other fluids should be monitored at several locations around their distribution networks for pressure and flow. Following this, a programme should be implementing comprising of: monitoring and targeting to identify any leaks; regular inspection of flow controls; regular calibration of flow meters.

Waste steam

  • Such waste can be ducted to an area where it can be condensed back to water by spraying cold water over it. The hot water is then collected and reused.
  • Energy recovery from high temperature steam or waste gases from kilns using heat exchangers, for example.

Industrial cooling

The checklist below should be used to identify energy wastage:

  • Are products being over cooled?
  • Are cold store doors left open?
  • Are door seals in place and in good condition?
  • Do blast freezer fans stop when the line stops?
  • Could strip curtains be used on doors?
  • Is the condenser regularly checked for dirt and leaves?
  • Has the defrost cycle been optimised?
  • Could electronic expansion valves be fitted?

Plant insulation

  • Specialist advice should be sought as insulation materials vary greatly.

MOTIVE POWER

High efficiency motors

  • These should be used for all high use new plant and equipment.

Variable speed drives

  • Motor type should be checked on all new equipment- it is best to buy a machine with a VSD, rather than retrofitting at a later date.
  • A feasibility study into retroffiting refurbished machines should be undertaken.

Controllers

  • Where electric motors run for long time periods at low loads, motor controllers should be considered.
  • New controllers should be considered with new and refurbished equipment. Fitting VSD's is perhaps most feasible for old equipment.
  • Load sensing control systems should be considered for idling plant to turn plant off over a specified period.

COMPRESSED AIR

Air intake

  • Air should be taken in from outside the building as it is colder and thus the compressor will work more efficiently. The inlet should be protected from extreme temperature and weather conditions, on a north wall. The ducting from the air intake and the compressor should be as short and straight as possible, and the diameter as large as possible.

Distribution networks

  • Ring mains are the best and most efficient systems, and designed for a maximum pressure drop of 0.1 to 0.2 bar at points of use at maximum demand. Air receivers can be installed for short periods of high demand.
  • The system should be zoned using isolation valves (electronically controlled isolation valves are preferable to manually operated valves).

Compressor sizing

  • Compressors should be sized in order for capacity to match demand for compressed air.
  • Different sizes of compressors should be used for installations with multiple compressors.

Leakage

  • Make regular checks on compressed air use
  • Train shop floor personnel in leak detection
  • Fix all leaks promptly
  • Investigate leaks during quiet periods / shutdown
  • Tag all leaks
  • Isolate machinery that is leak prone
  • Get rid of redundant pipework

Heat recovery

  • Heat can be recovered by ducting the air outlet into the factory during winter and outside in summer.

BUILDING

Doors

  • Doors should be made draught proof
  • Automatic closure devices should be considered
  • The number of doors in use should be kept to a minimum
  • Plastic strip curtains/fast acting doors should be used where frequent access is needed.

Roof spaces

  • These should be properly insulated to a depth of 150 mm

BOILERS

Loading patterns

  • The loading patterns of any boilers on site should be investigated
  • The boiler should be checked for frequency of operation at partial load
  • Boiler plant that is not needed in mild weather should be isolated and pilot lights turned off (where relevant).
  • The feasibility of fitting a modular system should be investigated.

Sequencing

  • Boiler operating patterns should be assessed
  • The boiler should be checked for frequency of operation at partial load
  • Boiler thermostats should be adjusted to use only the minimum number of boilers
  • An automatic sequence controller should be considered

Optimisers

  • The boiler on/off should be optimised
  • An optimiser should be fitted to boilers over 30kw
  • Internal and external sensors should be fully operational
  • Consideration should be given to installing an optimiser on air conditioning

Maintenance

  • If gas fired, a CORGI registered firm should be employed for boiler maintenance once a year.
  • Oil fired plant should be serviced twice a year or more (should the flue gas temperatures be high).

Thermal insulation

  • All pipework should be insulated
  • Valves and pipe joints should be fitted with insulation jackets.
  • Insulation should always be replaced following repairs to pipes

Compensation

  • A compensator should be fitted to the heating system
  • Heating circuit flow temperature should be adjusted correctly
  • External temperature sensors should be checked to see if they are working correctly

Frost protection

  • Frost thermostats must be working correctly
  • External temperatures should be working correctly
  • Frost thermostats must be set correctly
  • All pipework must be insulated properly

WATER HEATING

Point of use

  • Point of use heater should be considered for certain areas such as toilets, sinks etc.

Storage systems

  • Hot water should be stored within an insulated tank
  • Electric heating must be made as efficient as possible
  • Should hot water be provided by gas or oil fired boiler, it may be cheaper to use off peak electricity- especially within the summer

Temperature

  • Maintain the temperature to 60 degrees Celsius.

Distribution

  • Avoid dead legs and have pipes as short as possible
  • Lag all pipes, joints and valves

Taps

  • Fit spray restrictors on spray taps with excessively high flow rates.
  • Consider timer/sensor taps on taps that are left running.
  • Repair all dripping taps promptly.

LIGHTING

Lamps

  • Compact fluorescent lamps should replace all tungsten filament lamps
  • Tungsten spot lights should be replaced with Tungsten halogen lamps
  • Standard 38mm diameter fluorescent tubes should be replaced with 26mm tubes in switchstart fluorescent fittings.
  • High pressure sodium lighting is preferential in warehouses and factories.
  • Use high frequency ballasts where flurorescent lighting is necessary (this uses 20% less electricity than older types).

Manual Control

Lighting efficiency can be achieved through:

  • Awareness posters
  • Awareness training sessions
  • Leaflets
  • Company policy
  • Including energy management in supervisor's job descriptions

Relamping

  • Lamps should be changed in groups at specified intervals. They should be changed when their output has decreased by 30% (a light meter can be used to measure this).

OFFICE EQUIPMENT

  • Newer equipment is likely to be more efficient- when purchasing new equipment, energy consumption is now often given for many brands- this should be compared.
  • All equipment should be switched off when not in use.

FUEL TYPE

The type of fuel used itself and price should also be considered. Look at the descriptions below.

Electricity:

This is generally the most expensive fuel, but also the most flexible. It can be controlled easily but is often wasted. The major are of wastage is through poor maintenance and in compressed air and refrigeration applications.

Natural Gas

This is widely used in industry for space, water and process heating. Boiler maintenance costs may be lower in comparison to many fossil fuels using this gas as it is comparatively clean when burnt. Gas is often wasted through poor maintenance of boilers and steam systems.

Fuel oil

These are the heaviest and most viscous grades. They must be heated in order to remove them from their tanks and to ensure proper combustion. This heating requirement reduces the overall efficiency of fuel oil fired boilers- especially during the winter months. Heavy fuel oil is often cheaper than gas although capital costs are higher due to storage, heating, circulation and filtration requirements. Maintenance costs are generally higher than for lighter fuels and more pollution is produced. This fuel is typically used in large boilers.

Gas oil

This is generally the lightest and least viscous. It is cheaper than gas although higher capital costs incurred through its storage are experienced. It is less polluting than heavier grades of oil and typically used for space and process heating and plastics production.

Liquid Petroleum Gas (LPG)

LPGs include Butane and Propane. These are more expensive than natural gas and fuel oils, although are often cheaper than electricity (off peak). Capital costs through storage and maintenance are higher than for natural gas.

Coal

This is used mainly for boilers and industrial furnaces. This is the cheapest source of fuel but has high capital costs through bulk storage. Burning produces smoke, soot and dust and boilers and furnaces need a high level of cleaning and maintenance. Anthracite is cleaner with the same characteristics.

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