Supported by EIE/04/246/S07.38678

BESS - Benchmarking and Energy management Schemes in SMEs

Measure List Bakery

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Production-related opportunities

Dough mixing

Opportunity	Description
Compressed air reduction for Β«skinningΒ» dough	Reduce energy to provide compressed air to Β«skinΒ» dough in the moulder. Strategies are: reduce number of holes, reduce whole size, optimise pressure, check direction of flow, and turn off if not needed for some time.
Control lighting in ingredients store by occupancy	Ingredients store are often accessed by forklift truck drivers and dough mixing staff. Lighting typically runs all day. Infrequent access to this area could represent an opportunity for lighting occupancy control.
Shut down conveyors during extended stoppages/after hours	Conveyors may run continuously during stoppages, changeovers and on weekends. Delegate responsibility for switching off at a single point of control per line during extended stops. Design appropriate signage to facilitate this.
Tag and repair compressed air leaks	Equipment where leaks may occur includes divider, compressed air hose reels, and air nozzles/guns. Savings for this initiative are incorporated into Β«leak reduction programΒ» by maintenance.
Raw material consumption program	The rational use / consumption of raw material is necessary since it is observed that growth rates of raw materials consumption sharply increased in industrial countries.
Reduction of oil losses	Some recommended action to reduce the oil losses are: a) Modifications to tin sprayers - The tin sprayers could be modified to collect and reuse the excess oil. b) Teflon coating - The need for white oil to prevent sticking of dough could be eliminated by coating the bin that lifts the dough from the mixers to the divider with a Teflon surface.

Main baking process

Opportunity	Description
Plant shutdown procedure	Load profiles show 25% of load running at night/weekend. Check conveyors, cooler and oven fans, tin cooling fans, vacuum pumps, tin storage.
Reduce depanner compressed air usage	Use air knives and solenoid control to use air when mechanical arms are open, turn off when arms are closed.
Oven start-up procedure	Where controls allow, hold burner on low fire until bread in prover, no conveyors running in oven until required.
Tag compressed air leaks	Equipment where leaks may occur includes depanner and hose reels used for equipment cleaning.
Shut down conveyors during extended stoppages/after hours	Conveyors may run continuously during stoppages, changeovers and on weekends. Delegate responsibility for switching off at a single point of control per line during extended stops. Design appropriate signage to facilitate this.
Process monitoring	Monitor prover, oven and cooler periodically for instrument calibration, process efficiency.
Raise staff awareness and place signs near equipment.	Switch off your equipment when not in use.
Repair door seals.	Check condition of oven and prover door seals. Damaged seals increase heat loss, wasting money and energy.
Repair damaged insulation.	Check whether insulation is defective as a result of damage.
Determine the minimum heat up time for ovens and provers and adjust baking schedule accordingly.	DonΒ»t switch on ovens and provers earlier than necessary.
Adjust baking schedule where appropriate.	Schedule ovens and provers to operate at full capacity.
Discuss equipment running costs as well as capital costs with your supplier.	When purchasing new equipment, consider ongoing energy costs. On the long run, energy costs are higher than initial investment costs.
Clean and repair radiant surfaces.	Clean electrical elements and carry out resurfacing of worn radiant surfaces.
Heat from ovens	Gas and Oil ovens usually have a combustion temperature of 250-300Β°C and steam temperature of about 250Β°C. This energy represents 20-40% of input energy necessary for baking. This energy can be used again while maintaining high safety requirements for gas and oil ovens.
Use of pellets in ovens	Pellets (the raw material in ovens) are part of the natural recycling process. When they burn, solar energy stored in the cells of the raw materials will be released and the carbon dioxide, absorbed during the growth of the tree, will be returned to nature, where it is utilised by other plants. Even the ash from pellets and heat logs is useful, because it is rich in minerals, and can be recycled to fertilise forests, parks or gardens.
Reduction of heating period	The heat-up time, previously two hours each day, has now been reduced to 45 minutes. Due to the fact that the consumption of fuel oil is 35% lower than before, the bakery now avoids 325 tonnes of the greenhouse gas CO2 per year.

Other production areas

Opportunity	Description
Monitor oven, griddle flame characteristic	Reviews showed poor flame characteristics on some pie/pastry ovens, griddles and the like β€” variable length, sooting, predominantly yellow β€” these can often be checked manually and adjusted accordingly.
Check oven damper setting	Where manual damper control exists, good practice is to print required damper setting for each oven/zone on the oven, operator to check settings for each product type.
Review freezer utilisation strategy	Some freezers were observed to be up to 95% unoccupied during review. Where cross contamination is not a risk, strategies/scheduling should be developed to maximise space utilisation and reduce energy by empty freezers.
Pan washing station	Programmable Logic Control (PLC) with two photo eyes to detect pans entering and leaving the washer
OperatingΒ  conditions	Two storage temperatures - refrigerator 1ΒΊ/4ΒΊC and freezer -18ΒΊ/-21ΒΊC provide ideal back up storage of ingredients such as high risk dough products, and frozen products. Variable retarding temperature options between -4Β° and +4Β°C. Automatic humidity control prevents skinning and weight loss. Sophisticated airflow system ensures even temperature and humidity throughout. Refrigeration equipment selected specially for bakery applications. Temperature options between -10Β°C and +40Β°C: suitable for all applications. Automatic temperature and humidity control: ensures products remain in prime condition.

Maintenance-related opportunities

Major site services β€” core equipment and distribution

Opportunity	Description
Minimise steam delivery pressure	Determine the minimum required pressure for steam delivery and adjust boiler delivery pressure to match.
Minimise compressed air delivery pressure	For example: 50 kPa pressure reduction at compressor saves about 4% energy usage. Test by gradually reducing and reviewing impact on process.
Plant shut-down night, weekend	Shut down air compressors, boiler, lighting, ventilation and A/C.
Blank off unused steam lines	May be applicable where steam has been replaced with direct firing for provers, or products ceased.
Boiler oxygen trim control	Control oxygen content to 2–4% automatically for natural gas systems.
Automate boiler blow down	Increased condensate return may allow for less frequent blow down, else review impurities in feed water and calculate allowable blow down rate.
Monitor boiler combustion efficiency	If oxygen level is known, stack temperature will enable efficiency to be determined and improved; if unknown may need O2 or CO2 analyser.
Condensate return from HX processes	Depending on existing distance from end users ability to install if not already, could provide 3–6% of boiler energy requirement.
Insulate steam lines, valves	Bare surfaces can lose 100–500 watts/m (25–250 mm dia); non insulated pipes/valves should be insulated where economic.
Check steam traps	Leakage at steam traps is expensive (e.g. $5 000 pa for 3.2 mm hole at 700 kPa differential across trap).
Optimise services distribution pressure drops	For example, a 700->550 kPa drop in a compressed air reticulation results in a 36% loss in energy β€” a target of about 50 kPa should be set.
Maintain and lubricate moving parts of oven.	Maintain ovens and provers correctly, including regular lubrication of all moving parts.

Maintenance-related opportunities

On-site services utilisation/ancillaries

Opportunity	Description
Regularly move clips on compressed air hose reels	Several cases of leakage from hose reels were detected, mostly at or close to the clip fixing the hose to the nozzle. The clip hose length can be periodically shortened to eliminate leaks caused by wear and tear.
Standardise compressed air nozzles	A variety of nozzles are found in a typical plant β€” some hoses have no nozzle, just 7 bar air used directly from the hose β€” investing in standard air-guns throughout, or other nozzle is recommended. Special air saving nozzles exist as well.
Compressed air leak reduction	Depends to some extent on tags placed by production β€” carry out quarterly leak tests and quantify % waste β€” repair tagged leaks. The average leakage by using compressed air is 50%.
Optimise glycol pressure	Ice-making machines are often used to increase cooling capacity β€” minimising pressure drops across refrigeration systems may eliminate this need.
Plant shut-down	Cooler, motors, conveyors, crate washer, should all be turned off after use.

Engineering-related opportunities

Major site services

Opportunity	Description
Daylight control of external lighting	Lighting in out loading docks, storage areas often runs all the time and should be daylight controlled. Costs depend on number of circuits, controllable lamps per circuit, but often cost-effective.
Staging control of air compressors	Often a second or third air compressor runs unloaded for extended periods and can be shut down β€” staging controller can select optimum compressor for a task and bring on additional units when required.
VSD control of refrigeration condenser fans	VSD control typically improves refrigeration efficiency by lowering head pressure when ambient conditions allow; some fan savings may also result.
Air compressor heat recovery	Can be used for boiler feed water preheat or space heating.
Minimise air compressor air intake temperature	Where C air tempο‚°possible draw air from outside rather than the compressor room - 3 reduction = 1% saving in energy.
Use ambient cooling.	Make full use of ambient cooling before further processing or freezing the product.
Reduce exposure of goods to heated area.	Directly load frozen or chilled goods into isolation or refrigerated transport, without passing through a hot baking area.
Consult air-conditioning contractor.	Use waste heat from baking areas in place of independent space heaters in thawing/conditioning rooms.
Improve layout where possible.	Adopt a logical layout for mixing, preparing, baking and cooling.
	Make sure there is enough room to allow ovens to be loaded quickly.
	Make sure refrigeration condenser coils are located in the coolest part of the bakery.
	Make sure cream preparation and finishing areas are located well away from oven areas.
	Make sure offices and other staff accommodation are located away from sources of heat, or draughts.

Engineering-related opportunities

Process equipment

Opportunity	Description
Oven modulating burner control	Used on most large/modern ovens, should be applied to most oven burners to improve combustion efficiency.
VSD or dual speed control of tin cooling fans	These fans often run unnecessarily β€” when tins are not being returned they should be controlled to switch off or turn down.
Prover direct gas firing	Requires spray humidification β€” used in some bakeries.
Cooler supply/exhaust fan control	Process monitoring can identify unevenness in cooling and poor air balance in cooler β€” control strategy for supply/exhaust fans a possible solution.
Oven heat recovery	Can apply to main ovens or crumb ovens β€” recover heat to preheat combustion air or prover.
Procurement of high efficiency equipment	Equipment can include high insulation levels specified on ovens, provers, high efficiency burners, process control equipment, mixers, and dividers.
Investment in monitoring equipment	Monitoring of prover, oven and cooler condition can allow continuous or periodic resetting or recalibration of controls for these processes.
Application of infrared-burner in oven	Infrared-burner for heating the oven, which makes use of a corrosion and heat resistant metal fibre wool.
Install electronical ignition	Replace oven bypass flame that is continuously in operation, by electronic ignition.
Use gas fired heating system for proofing chamber	Use gas fired heating system (e.g. by warm water from space heating system), instead of an electrical heating system.
Humidification by water spray	Use water spray instead of steam for humidification of air in proofing chambers (the heat required for evaporation can be withdrawn from the air that will be humidified).
Optimize energy use of cooling- / freezing tunnel	Adapt cooling capacity of cooling- / freezing tunnel to the quantity and type of product that is used. Use a simulation programme to minimize energy use.
Sanitization and cleaning efficiency improvements	Strong, effective cleaning supplies and well-designed dispensers are essential to the efficiency of the bakery industry operation.
Replacement of the existing equipment	Find and fix leaks, select the optimum compressor for the final application, improve compression techniques, e.g. through the use of multistage compressors, recover waste heat for utilisation in other applications, Improve air purification, e.g. through dryers or filters, service and repair equipment regularly and with care, Improve airflow in the piping system, in order to avoid loss of pressure through friction For this reason, the bakery concerned should decide to replace its existing baking apparatus with modern, energy-optimised equipment. Whereas the old ovens required a thermal output of 1,750 kW to produce 960 kg of bread per hour, the new equipment requires only half as much energy for the same production output. This is possible because the new equipment is designed to have lower radiation heat loss, and, by using thermo oil as a heat conductor instead of air, it achieves much better heating efficiency.

Other opportunities

Hot Water Use

Opportunity	Description
Repair or insulate the tank.	Store hot water in a properly insulated storage tank, with a well-fitted 75mm insulation jacket or sealed plastic foam.
Adjust thermostat to the correct temperature.	Store water at proper temperatures.
Discuss options with electricity suppliers.	Heat water using electricity; make full use of off-peak heating.
Install an efficient instantaneous water heater, where appropriate.	Consider instantaneous water heaters as a replacement for existing systems.
Insulate pipe work.	Make sure hot water pipe work is well insulated to prevent heat loss.
Buy low-flow fittings and install where practical.	Have hand basins and showers fitted with flow reduction nozzles to reduce waste by using hot water more efficiently.
Fix leaks or replace washers	Check for leaking hot water taps.
Use room temperature and chilled water where practical for dough mixing. Do not use combination of hot and chilled water.	If chilled water is used to achieve the right dough temperatures in summer, use room temperature rather than hot water in the mixing process.

HVAC

Opportunity	Description
Set thermostats to an appropriate temperature.	Control heated and air-conditioned areas using a thermostat set at an appropriate temperature.
Check that thermostat temperature and actual temperature are consistent.	Check thermostat operation at least at the beginning of each season to see if  it is working correctly.
Raise staff awareness.	Switch off the air-conditioning or heating during shutdown periods.
Switch off ventilation fans when not required.	Switch off ventilation fans outside baking time.
Install fans and roof vents as required.	Use slow-moving ceiling fans or a roof vent to remove heat or improve heat distribution in high-roofed areas.
Ensure proper fan sizing and replacement.	Balance bakery ventilation or prevent inlet and extractor fans to work against each other (prevent Β«short-circuitΒ» air flows).
PLC controllers	PLC controllers are electronic devices that identify problems in production processes including panning, proofing, baking and also perform complete performance analysis.
Specific energy consumption indicators	In large bakeries, lower specific energy consumption indicator shows less potential for energy savings. In order to increase the above mentioned indicator it is important to ensure continuous baking process related to the assortment of products which plays an important role to the specific energy consumption.

Lighting

Opportunity	Description
Raise staff awareness.	Motivate staff to �switch off� lights.
Use most efficient types of lighting.	Make use of the most efficient and appropriate types of lighting and lighting covers for each application within your business (TL, CFL, LED).
Install individual switches where required.	Have lamps over work areas to be controlled separately.
Install individual switches.	Make the switching system allow lights near windows to be switched off when daylight provides enough light to work in.
Install automatic switches.	Considered automatic lighting.
Install switches in most appropriate position.	Make sure switches are in the right place.
Consider �delamping� in areas where there is sufficient light.	Check whether the lighting levels are correct.
Put in place a program to clean light fittings.	Set up a regular program for cleaning lamps, reflectors and glass panels in lighting systems to minimise light loss and improve lighting levels.

Refrigeration

Opportunity	Description
Service refrigeration equipment.	Make sure refrigeration units are regularly serviced.
Adjust to recommended temperature.	Make sure deep freezers and retarders are maintained at recommended temperatures.
Have coils cleaned and checked as required.	Make sure freezer/refrigerator condensing coils are free of obstructions and dust to ensure clear air flow.
Move freezers and refrigerators to coolest place practical.	Make sure freezers/refrigerators are situated as far as practically possible from baking ovens and other heat sources.
If multiple freezers, fully load freezer and switch off unused freezers.	Make sure freezers/refrigerators are fully loaded whenever possible. Check the possibility to replace two partially used freezer/refrigerator units with one fully loaded unit.
Raise staff awareness and place information notices at entries	Train staff to minimise the time refrigerators and freezers are left open.
Fit automatic switches.	Have freezer fans switched off and lights switched on automatically when doors are opened.
Refrigeration system energy savings	Reduce compressor discharge pressure. Increase suction pressure Installation of electronic temperature controllers. Installation of an evaporative condenser with indoor sump tank and water circulation system.
Refrigeration technology	Refrigeration technology does save energy both directly by reducing evaporator fan energy and indirectly via reduction of compressor energy due to reduced heat gain from the fan motors. The overall potential of this technology is enhanced by the fact that about 75% of all walk-in boxes use low efficiency shaded pole motors.

General Method

Opportunity	Description
Packaging equipment	The needs for packaging over the bakery industry are demanding and cost consuming but with smart, flexible equipment, it is easy to handle day's shifting requirements.
Increased staff awareness	With an informed staff, benefits are many in a voluntary base, since personnel is more aware of the reduced operating costs coming from better waste use andΒ  energy management also connected with reduced environmental impact.
By-products	Treatment of by-products is becoming a very important issue. By-products often can be transformed into valuable components to be added to animal food, e.g. for pets or fishes.

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Note 1 The sole responsibility for the content of this publication lies with the authors. It does not represent the opinion of the Community.  The European Commission is not responsible for any use that may be made of the information contained therein.