1. Reduce carbon footprint
Only 10% of laundry energy is used for electricity for light or motor drives. However, the cost per unit of electricity from heat energy from natural gases is approximately three times as high so it accounts for around 25% of laundry’s energy bills. This cost can be reduced in two ways by the most efficient laundry facilities.
Gas heating is the basis of all new equipment. This is true for washer extractors as well as tumble dryers. This might be a purchase of a small steam generator, or an in-line gas heater. It is often worth it for the significant savings over the life expectancy of washer extractors.
Part loads use almost the same amount of electricity as full loads. It is therefore important to ensure that each machine is fully stocked. Half-loaded machines double the electricity cost per item. It is common to need to inject small amounts of linen stock monthly to compensate for losses. However, this is necessary and normal.
One machine design tackles the electrical energy demand head-on.
Reducing carbon footprint requires other, non-costly changes that aren’t always apparent but can yield amazing results. Hydro-extraction is an important step after the rinse. It is essential to keep the residual moisture at a minimum. Drying and finishing takes twice the heat energy of washing per kilogram of textile dry. Only a fifth of energy is required to iron, and only one-fifteenth for membrane pressing (after tunnel washing), is needed to squeeze the water out of the spin. You can increase the spin time by increasing it in small increments for no change in moisture retention. The old 24-bar membrane presses require at least 60 seconds at maximum pressure. Newer 40-bar presses only need 30 seconds. This will also reduce alkali transfer to the ironer in areas with hard water, which can improve the life of the calender clothes.
After optimizing the moisture retention, you will be able reduce tumble dryer cycle time and increase calender productivity. The dryers will be more efficient if they have automatic drying cycle terminators that can eliminate over-drying. These are a small investment, but they provide a short return. Operators have discovered that dryer productivity increases are even more important as guests expect heavier towels. The side benefit of towel greying being reduced, which is often associated with over-drying, is also a plus.
A flatwork dryer can also be a low-cost way to reduce your carbon footprint. The washer extractor should be used to transfer work from the ironer directly, which will save both energy and double handling. Ironer’s thermal efficiency is between 90 and 95%, while dryer’s is only about 50%. The slightly lower moisture retention can be offset by increasing the number of lanes or the bed coverage (by edge to edge-feeding).
2. Sustainable water use
Heating wash water typically uses 30% of the total heat energy required in day-today laundering. It makes sense to set wash dips to the minimum levels for each program on each washer extractor (125mm prewash, 75mm main wash), This will reduce both the heat energy and water consumption. Although this can be time-consuming, it is an essential task that is worth the effort of the Laundry Engineer or Manager. Some machines do not require this. The drum is precise and the water is measured into it. Most other designs have level controls.
This task has often surprised launderers, who are often shocked at the immediate benefits it brings. Lower fill times mean shorter cycle times and higher productivity. The lower water requirement can lead to chemical additions being reduced. In areas with good water quality, the biggest benefit can often be found in reducing rinse water levels. The detergent chemistry will need to be rinsed out less if the water is low in dissolved acid.
3. Minimising chemical discharges
Washing chemicals are concentrated in wash liquor. This is what determines the chemistry of washing. To reduce chemical waste to the drain, it is important to minimize the volume of water used in the main wash and pre-wash. You can reduce the volume of pre-wash water by 15% and then reduce each chemical addition by the same percentage.
British Launderers Research Association established the ideal pre-wash dips at 125mm for a 50kg machine. This was to allow for the sluicing and draining of any loose material (such as vomit or faeces). You might be able convert to a “stepped wash” if you are able to separate the heavier soiled items and do a lot of clean work. The pre-wash will be cut shorter, meaning that the main wash dip will only be 75mm. This will allow you to use less chemical additives. This saves time and water, as you don’t need to run water to make the mainwash dip.
Launderers often still judge the value of detergents based on their price, and will buy the lowest priced. It is not always the best option, as modern formulations are more costly per kilo. This is because it is possible to minimize chemical additions and reduce wash temperatures. The net benefits of using less chemicals and heating costs are significant. The benefits are even greater if you get higher productivity and longer fabric life. Modern laundry requires concentrated, pure power. Cheap detergents often contain low-cost fillers.
Are these suggestions actually practical or just theory? You can find average energy consumption ratios from ten years ago in the UK government guide on energy savings in laundering. Large laundries belong to the UK Textile Services Association. This association negotiated an agreement for the waiver of the UK climate change levy in exchange for year-on-year, quantifiable reductions in unit energy use. This led to a 25% industry-wide drop in energy demand over five years. This group includes the majority of large UK laundries. There were many ways to achieve this, but the best ones have been refined and presented here. These principles are not only applicable to large laundries; they can be used for small and medium-sized businesses, both in-house and commercial. There are still many opportunities for sustainability in small and medium-sized laundries. This is evident by the wide variety of performance data.
These opportunities can be leveraged to create sustainability benefits as well as quality improvements, improved productivity, and a better textile life. While most do not require much investment, they all need dedicated management time. Now is the right time to grab these opportunities and reap all the benefits that are now available as the sector recovers from the pandemic. Good luck!