Supported by EIE/04/246/S07.38678

Benchmarking and Energy management Schemes in SMEs

Measure List Industrial laundries

(scroll down for a more comprehensive description)

To download this list in Excel format click here

Process-related Improvement Opportunities

Energy Efficiency Measure	Description
The power of Ozone for industrial laundries	Use of Ozone to reduce water consumption
Humidity sensors	Reduction of dryer gas use
Boiler efficiency measures	Reduction of gas
Batch washers	Monitoring of batches to avoid energy and water waste.
Water monitoring	Monitor the quantity of water used per kilos of goods produced
Re-use of water	An improvement method that contributes to improved efficiencies and cost savings.
Recovery of latent heat from drying process	Recovery and reuse of the latent heat at the drying stage
Hot Oil Systems	More efficient in maintaining and operating systems
Optimise warm rinsing	Increase the temperature of the final rinse/reduce drying time
Optimize dryer recirculation	Totally switch of the recirculation by adjusting a valve
Properly adjust wringer extractor	By readjusting the extractor equipment, reduce the extraction debit from the wringer rollers
Measure drying parameters	Compare drying parameters to moisture
Optimize dryer loads	Optimally loading the dryer can conserve a significant amount of energy
Optimize wringer loads	Optimising loads meaning that controlling the energy consumption of the wringer will conserve energy
Warm soaking	A measure to reduce the washing period.
Optimize balance between preliminary drying and wringing	When setting the preliminary drying period, an optimal energetic balance must be sought between the preliminary drying period and the efficiency of the wringer drying process
Replace steam dryers with gas dryers	Gas dryers are more efficient that the ones with steam since they do not suffer fro losses
Install wringer hoods	Minimizing the escaping warm air
Reuse residual heat for dryers	Directly heat the dryer
Shorten drying periods	Relevant to measure 20
Install end point detector for full drying	Use proper equipment to detect the end point and make the drying period as short as possible
Lift wringer rollers during breaks	Energy conservation technique
Do not mix low-value and high-value energy flows	Mixing of these two procedures costs in energy
Use a heat pump in drying process	A heat pump is highly suitable for recycling the heat and the drying air needed in a drying process
Use targeted extraction	Targeted extraction can be used, for example, by using local extractor hoods for process baths
Establish standards for loading washers	A common base of energy methods has to be prepared in order to for the personnel involved in laundries to be in line
Soften water	Softening reduces water, chemical and energy use.
Extract as much water before dryer	Energy efficiency method
Washing Machines, Loads, and Temperature Settings	Usage of the most appropriate and adequate equipment

Full description method

1. The power of ozone for industrial laundries 

This new method saves hot water consumption. Normally laundry temperatures operations range from 60 to 75C. The use of ozone can potentially decrease this temperature to 30 to 35C and use cold water in following water cycles. This is because ozone leads to the production of oxygen which increases detergents potential in cleaning permitting to reduce the temperature. This reduction of hot water consumption will save costs of your hot water bill. Furthermore, it will cause less damage to clothes.

More efficient laundry operations: The use of ozone reduces the rinse cycle times. In addition, it reduces the drying time as ozone opens fibres of the clothes allowing more water to be removed in the extraction cycle. Ozone reduces the consumption of detergents, water and energy meaning a cut up to 50% in costs. The use of hot water reduces the need of ironing time and permits the washing of colour and non-colour fabrics at the same time.

Environmentally friendly and better working conditions: Better quality of outlet water injected in the sewage system (i.e. less residual pathogens, PH balance, less residual chemicals) and the reduction of water and energy consumption (i.e. less rinse and drying cycles) contributes to sustainable development. 
Working conditions are less hard and safer (ex. less temperature operations and use of chemicals), thus employees feel more comfortable in their working environment.

2. Humidity sensors used to reduce dryer gas usage by preventing over-drying.
3. Boiler efficiency measures, which have resulted in an approximate 10 percent reduction in natural gas use for the primary boiler, and an approximate 4 percent reduction in natural gas use for the standby boiler.
4. Modern Compressed Batch Washers: An improvement method of washers monitoring that contributes to improved efficiencies and cost savings.
5. Water monitoring, meaning frequent and close monitoring of water and energy used per kilogram of goods processed.
6. Water re-use system: Water savings can be obtained by re-using of water from the last rinse(s) to the next wash program
• The tank can also be used for other types of liquids, which should be re-used in the wash process
• Control microprocessor and one extra inlet for re-use liquid
• The industrial laundry equipment and associated process automation systems, should have launched a new micro-processor controlled, LPG direct fired dryer that promises greater energy efficiency and improved throughput capacity.

7. Recovery of latent heat from drying process: An energy-efficient process for the recovery of latent heat from a drying process comprising (1) contacting a material containing a volatile liquid with a gaseous drying medium and supplying heat to said drying medium or to said material and thereby producing an exhaust mixture of noncondensable gas and condensable vapor, (2) separating the condensable vapour in said exhaust mixture by passing it through a nonporous nonionic polymeric membrane which is substantially permeable to said condensable vapour and substantially impermeable to said noncondensable gas, (3) transferring said separated condensable vapour, together with the latent heat of condensation contained therein, to a compressor, (4) compressing in said compressor said separated condensable vapor, and (5) condensing said separated condensable vapour by heat exchange, thereby recovering the latent heat of condensation of said separated condensable vapour.

8. Hot Oil Systems for Laundries: While steam systems generally operate to 350°F, thermal oil systems can easily provide 450°F – with the pump discharge providing only enough pressure to overcome pipe friction. To compare, oil heated 3-chest ironer with parallel flow can provide about the same output as a 5-chest steam-heated unit. And because of the low pressures common in thermal oil systems, the chests can be fabricated of steel rather than the cast-iron required for steam systems. Not only is this a cost savings, but heat transfer is improved with steel, and the lower number of chests saves valuable floor space. Thermal oils will not corrode the materials commonly used in laundry systems. In fact, oils pro-vide a protective coating to metals in the system and offer high lubricate to moving parts. And barring leaks or spills, no make-up is necessary. The water used in a steam system must be treated to reduce corrosion and increase lubricates, among other requirements. The chemicals used, in some cases, are considered regulated and/or hazardous wastes. Blowdown and system leaks must be closely monitored, and the system’s water cannot be allowed to enter floor drains or flow into waterways. There is no blowdown in thermal oil systems. And spills can be handled using the procedures used for releases of lubricating oils

9. Optimise warm rinsing: If warm water is available for washing, increasing the temperature of the final rinse is recommended, reducing the drying period required.

10. Optimise dryer recirculation: The recirculation percentage in dryer is determined by a valve. Sub-optimal adjustment of this valve increases energy consumption. If the recirculation is completely switched off, optimisation can reduce energy consumption by up to 70%.

11. Properly adjust wringer extractor. By readjusting the extractor equipment, the extraction debit from the wringer rollers can be significantly reduced. This avoids unnecessary energy losses. In addition to conserving energy, this measure also improves personnel comfort. In general, the energy conservation achieved is insufficient to justify moisture-content controlled extraction equipment.
12. Measure drying parameters. In an energetically optimal situation, drying is performed to a residual moisture percentage of about 5%. If the residual moisture percentage is less than 4%, the energy consumed for drying doubles as compared to a residual moisture percentage of 5%. Thus periodically measuring the moisture content of the clean and dry wash can be highly lucrative, because the drying processes can be adjusted to ensure that drying periods are as short as possible.
13. Optimise dryer loads. The drying process is much less efficient if dryer loads are not maximised. Optimally loading the dryer can conserve a significant amount of energy. When purchasing dryers, taking the batch size of the washed loads from the washing line into account is recommended.
14. Optimise wringer loads. The electricity and/or steam consumption of a wringer depends on the load. Optimising loads will conserve energy.
15. Optimise warm soaking. If warm water is available for washing, increasing the temperature of the pre-soaking is recommended, reducing the washing period required.
16. Optimise balance between preliminary drying and wringing. Preliminary drying is not conducive to energy conservation. The dryer, the wash and the water are heated, but all cool back down before the wringing starts. However, preliminary heating is often essential to problem-free wringing. When setting the preliminary drying period, an optimal energetic balance must be sought between the preliminary drying period and the efficiency of the wringer drying process. On the one hand, the shorter the preliminary drying period, the less energy this process stage consumes. On the other, the shorter this period, the less efficient the total wringer drying stage will be.
17. Replace steam dryers with gas dryers. Gas-fuelled dryers are more efficient than steam-fuelled dryers because no losses are caused by generating, transporting and storing steam. Moreover, gas-fuelled dryers often recirculate drying air and are often equipped with end point detectors. A gas-fuelled dryer is more expensive than a steam-fuelled dryer ( about € 6000 more for a gas-fuelled dryer with a capacity of 100 kg as compared to a steam-fuelled dryer), but in addition to lower energy consumption, it has a shorter drying period. This measure can be particularly interesting for scheduled replacements.
18. Install wringer hoods. If an excessive amount of air escapes during wringing, this means energy is unnecessarily lost. Escaping warm air must be replaced by cold air, which must first be heated. Installing wringer hoods can minimise the escaping warm air. This not only reduces energy consumption but also improves personnel comfort.
19. Reuse residual heat for dryers. It may be possible to use residual heat with a sufficiently high temperature to directly heat the drying air (using a heat exchanger). If the temperature of the residual heat is too low, it can nevertheless be utilised to pre-heat the warming air (via a heat exchanger).
20. Shorten drying periods. As a consequence of measuring the drying parameters.
21. Install end point detector for full drying. Installing a thermostat and a hygrometer in the drying process makes it possible to correctly determine the end point, ensuring that drying periods are as short as possible. Due to their higher energy consumption, with steam dryers more energy can be conserved.
22. Lift wringer rollers during breaks. Lifting the wringer rollers during breaks and turning off the extractor are easy ways to conserve energy.
23. Do not mix low-valve and high valve energy flows. Mixing low-value and high-value energy flows always involves a loss of quality. More can be done with high-value energy, of which electricity has the highest value, than with low-value energy, of which environmental heat has the lowest value. Electricity can be transformed into other types of energy, for example, but heat measuring 40° cannot. Heat increases in value as the temperature increases.
24. Use a heat pump in drying process. A heat pump is highly suitable for recycling the heat and the drying air needed in a drying process. The moist drying air releases its heat to the heat pump's evaporator (the cold side on the heat pump). A large share of condense in the moist drying air then condensates, and this can be re-used as washing water. The heat absorbed in the water pump's evaporator is boosted in temperature and is then released in the water pump's condenser into the primarily dried drying air in the evaporator. The temperature of the drying air increases, causing the relative humidity to decrease even more before being released into the dryer, after which the cycle recommences.
25. Use targeted extraction. Targeted extraction can be used, for example, by using local extractor hoods for process baths. As a result, thermal paths traversed by the heated and moist vapour from the process baths can be optimally utilised. In addition to reducing energy consumption, this reduces the erosion of building parts caused by the moist air. The energy consumption for ventilation and heating/cooling is also reduced.
26. Establish standards for loading washers – Increasing load sizes by 5% increases water consumption at the same rate.
27. Soften water – Softening reduces water, chemical and energy use.
28. Extract as much water before dryer – It takes 1 BTU of energy to raise 1 pound of water 1 degree °F, which would be 112 BTU to go from 100 to 212 degrees °F. However, to convert water at 212 degrees °F in dryers to steam take 980 BTU – 8.75 times more energy.
29. Washing Machines, Loads, and Temperature Settings – Horizontal-axis (H-axis) washing machines, also called front loaders, are far more energy-efficient than conventional top-loading, vertical-axis machines. Some soaps and detergents perform well at lower water temperatures and should be used where appropriate. Temperatures should be checked with an accurate thermometer, and equipment should be adjusted as needed to provide the lowest acceptable temperature. Using equipment efficiently means ensuring that washing machines and dryers are operated with full, rather than partial, loads. To reduce energy use by clothes washers, hot water heaters or boilers should be operating efficiently.

---

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