Lower energy greater

The soaring cost of raw materials and energy means that a laundry must continuously review its operational costs and procedures to make economies wherever possible.

Increasing pressure to become “greener” by recycling and reducing the “carbon footprint”, makes such reviews even more important.

The laundry staff use the equipment, water, steam and electricity on a daily basis. If they are doing their job correctly, then the income they are generating, individually, and as a group, should exceed the costs they are incurring.

Several laundries have recognised this by at least ensuring their staff are trained to NVQ Level 2 Laundry Operations using the Government “Train-to-Gain” scheme. This is designed to help the operator understand the implications of doing the job correctly.

However, there are businesses where there is a need to improve, and the most inefficient will consume at least three times more in utilities per piece than the best.

Clearly, the greater the gap between the costs incurred and the revenue generated, the greater the profit. This gap can be widened by increasing prices or by reducing operational costs.

However, price rises may well lose customers by opening the door to a competitor and will serve very little longer-term benefit unless the laundry is already operating as effectively and efficiently as possible.

The first critical step is therefore to review your costs and explore all possible avenues for controlling and managing them.

There are several steps that can be taken to ensure that all the equipment is functioning correctly. Most can be undertaken with very little or no additional cost to the laundry – whilst at the same time significantly improving its “green credentials”.

Removal of moisture

It is worth remembering that by far the greatest amount of energy used in the laundry is in the removal of moisture from the damp textiles.

This energy is used both to produce the heat (steam or gas-fired) to evaporate the moisture, and to provide the electricity for operating the machinery. The laundry can use several methods to achieve remove moisture depending upon the classifications being processed.

Sheets, pillow slips, table linen and other flatwork classifications are often tumbled for 2 – 4 minutes before being fed through a flatwork ironer. Garments will sometimes be partially or fully dried before going through a steam/air tunnel finisher or being pressed, while towelling and blankets will be fully dried in a tumbler. All this equipment uses significant quantities of energy and it is essential to keep energy use to the minimum needed to achieve the desired results.

The amount of energy required to dry or “finish” an item of any classification will be dictated by the amount of moisture remaining in the fabric after the washing and moisture-extraction processes. This applies to both lines using a membrane press and to those using centrifugal extraction.

The amount of moisture remaining in the fabric will be dictated by a combination of factors:

• the type of fabric: for example, 100% cotton retains higher levels of moisture after extraction than polycotton blends as polyester hardly holds any moisture;

• the temperature of the fabric when the moisture is extracted – a warm fabric will shed more water than a cold fabric during this process;

• the pressure applied by the membrane press or the “G” force applied during centrifugal extraction;

• the duration of the moisture extraction process – the time the fabric spends under the membrane press at maximum pressure or in the centrifugal extraction at maximum “G” force.

It is essential to ensure that the maximum amount of moisture is removed from the textiles, without causing fabric damage, at this point.

It costs up to five times more to evaporate the moisture from a sheet on the ironer than to remove it by extraction with either a membrane press or centrifugal extractor – and it costs up to 15 times more to remove moisture in the tumble dryer.

For 100% cotton items, the maximum residual moisture content is 50 – 52% for example a 50kg dry weight load of 100% cotton should weigh no more than 75 – 76kg after moisture extraction, leaving 25 – 26kg (litres) of water to be removed on the finishing equipment.

It follows that for every 1% of additional moisture left in the textiles after extraction, energy consumption for finishing will increase by 4% – this excludes the production losses to remove this extra volume of water.

Moisture retention can be checked simply and relatively quickly. All that is required is a set of scales large enough to accommodate the cheese or cake of damp work from the press or extractor.

The load of damp work should be weighed and then the same load taken to the finishing equipment and fully dried. This may mean that with a load of sheets, for example, all the sheets must be passed twice through the ironer, taking special care to ensure that none are left out from the load or any rejected for rewash.

Once dry, the load can be re-weighed so the moisture retention can be readily calculated. Take the following example:-

• Load of work taken from the tunnel washer when damp = 78kg

• After drying the load is

re-weighed = 50kg

• Weight of moisture removed is 78kg – 50kg = 28kg

• Therefore, the moisture retention percentage (MR%) = the amount of moisture removed divided by the dry weight of the load x 100, in this example, 28/50 x 100 = 56%.

This is far too high, which means that this laundry will be spending 6 x 4 = 24% more energy than it needs to in order to dry and finish this work. In addition, it will be losing production as it will often take longer to evaporate this higher amount of moisture.

The result is that the launderer will pay more for less production.

But a few extra seconds at maximum press pressure or in the centrifugal extractor will make all the difference.

It is not uncommon for some washroom operators to “knock-off” the moisture extraction stage a few moments early or to reduce timer settings on the membrane press, in the belief they are “helping” to increase the production.

Linen may go through the washroom more quickly, but because the work is much wetter, energy costs are raised and the finishing department’s production is reduced.

It is essential that laundry staff understand not only what they are doing, but also the significant financial implications for your business if they fail to follow all procedures correctly. Moisture retention tests should be completed at least once monthly on all washing machinery.

Correct weights

It is also essential that all washing machinery is loaded with the correct target weight.

Accurate scales are an essential part of the equipment for washroom and sorting areas. Underloading washers means that, unless the laundry is already using machinery with in-built sensors that adjust the dip levels and chemicals injections, the laundry will be using virtually the same volume of water, steam, electrical energy and chemicals as it would to process a full load.

To illustrate this, let’s say the typical wash process cost for all utilities and chemicals is 11p per piece based on an average weight per piece of 420g. This means that for a 50kg load of work, the wash process will cost approximately £13.10 in utilities and chemicals.

If the washing machine is under-loaded by just 5kg, for example, the cost per piece will increase from 11p per item to 12.1p.

This may seem a small cost, but where a laundry is processing 100,000 pieces per week, this equates to more than an increase of £57,000 per year.

If a washing machine is overloaded, work will not be washed correctly, often leading to significant increases in re-wash.

It will also often cause work to become entangled and take a lot longer to unload from the washing machinery.

Maintenance costs will increase as the extra strains on the machinery begin to take their toll.

Every piece of re-wash will incur a further 11p cost – which means that it will only take eight items from each 50kg load of work to increase the laundry costs by more than £24,000 per annum, when processing 100,000 items per week.

The Carbon Trust's upcoming in-depth technology guide on managing laundering energy costs will be available from the end of July and will provide much more detailed help and information. Go to www.carbontrust.co.uk to download or order a copy.