Drying remains one of the most energy-consuming processes in the laundry and OPL operators are now seeking ways of further reducing their bills.
This point is not lost on machine manufacturers. “Tumble dryers count among the most power-hungry of all laundry machines,” observes Malcolm Martin at Miele Professional. Laundries are under enormous cost pressure, he says and adds that dryers very often attract additional installation costs because of the need to install vent ducting.
Energy efficiency is becoming a great concern for managers of any laundry, OPL or otherwise, says Peter Marsh, MD of Girbau UK. The cost of fuels has risen dramatically in the last two years and he believes that there is no real sign that the rate of increase will slow.
This, coupled with the uncertain economic outlook, is leading Girbau’s customers to look much more closely at running costs. “Better-informed operators are looking for improved control systems on OPL dryers as the initial purchase price is no longer the controlling factor on overall cost of ownership,” says Marsh.
He explains that many OPL customers are seeking dryers with ever-more sophisticated control mechanisms, rather than traditional manual controls. Marsh sees this trend continuing with the ever-increasing cost of energy, worldwide.
He also stresses that the drying requirements of the UK care and healthcare sector are very different from those of the hospitality market.
In a care home, much of the drying is of residents’ own clothing, which means that the type of garments being dried is outside the home’s control. Typically, It can include everything from fragile silks and woollens through to synthetics and cotton products.”
“ In the hospitality sector there is less variation in the type of work, which tends to be cottons, polycottons and towelling.
So in the care sector it is even more important that the dryer is controllable to prevent damage to garments and to stop them being over-dried or under-dried.”
This problem of over-drying has significant cost implications for laundry operators, says Armstrong Commercial Laundry Systems.
The company, which supplies and supports the Alliance Laundry Systems range in the UK, says that Alliance’s Huebsch dryers now feature Overdrying Prevention Technology (OPT). This is said to cut energy costs, prolong the life of linens and, perhaps most importantly, reduce labour costs, which Armstrong says can amount to as much as half the cost of any laundry operation.
OPT technology allows the operator to specify the moisture content – the dryness – of the load and the machine delivers it accurately, using the optimum balance of drying time and energy consumption and so minimising costs.
However, minimising energy consumption is not the full story. If the drying process is designed solely to use the least possible amount of energy, it can take an unnecessarily long time. This reduces productivity and increases labour costs, which can be as much as ten times those of energy.
With OPT, sensors within lifters supply moisture content/dryness data to the rotary transfer switch thousands of times a second. This system is maintenance-free and gives an accurate reading of the dryness throughout the load, not just a sample.
Step drying allows a high temperature at the start of the process so the load reaches the half-dry stage quickly. The temperature is then reduced until the specified drying level is reached when the dryer switches off automatically.
Over-drying has other cost implications. In addition to wasting energy, it stresses the fabrics, causing fibre loss and leading to a shorter life. Armstrong says OPT technology has been shown to reduce the loss of fibre by as much as 31%, so prolonging the life of the textiles.
Armstrong can already supply Huebsch OPT dryers in capacities of 50, 75, 120 and 170lb. The smaller models are expected in early 2012.
In addition, the full Huebsch range has 11 models up to 170lb including the recently introduced Huebsch 55 and the Super Twinstar. Armstrong also supplies and supports the Schulthess 7kg machine, which complements the Schulthess washer-extractor.
At Girbau UK, the Pro Series II range of tumble dryers features an advanced control unit, with four time-dry or auto-dry cycles and a no-heat cycle. The auto-dry feature reduces over-drying by automatically cooling loads once pre-determined levels of dryness are reached. The Pro Series II range consists of six models with capacities from 13.5 – 70kg.
For energy efficiency and cost-effective operation, the four largest capacity dryers in the range incorporate instant electronic ignition, which reduces drying time and conserves energy. An extra large reversible door allows easy loading and unloading.
The Pro Series II dryers also feature advanced airflow systems to cut drying times and reduce fabric wear. The four large capacity models use radial airflow, which captures heated intake air and distributes it evenly throughout the cylinder. This ensures maximum load separation so that the load is dried evenly.
Four of Girbau UK’s Pro Series II gas dryers were installed along with four of its 6 Series high-speed washers at Care UK’s Manor Lodge care home in Chelmsford. The home handles a large volume of sheets and towels as well as residents’ clothes.
According to Graham Baty, assistant facilities manager for Care UK, high productivity and energy efficiency were key factors in selecting Girbau equipment. “Continuity is very important to us and it is reflected by the strong relationship that we have with Girbau UK stretching back almost 15 years.
Baty adds that Girbau’s warranty package is just as important for the business. He believes that it offers outstanding value and is one of the best on the market.
Electrolux Laundry Systems says that in the hospitality sector, customers require significant reductions in the cleaning and drying process whilst still achieving the highest standard of finishing.
In response to the findings of its extensive market research, Electrolux has developed the T5000 series of dryer, which is said to achieve extensive savings in time, cost and space.
The series consists of three models: the T5290 with a drum capacity up to 16kg; the T5550 with a capacity up to 30kg; and the T5675 with a capacity up to 37kg.
Shorter drying times
On average the drying time is ten minutes shorter than that on similar models from previous ranges whilst at the same time using up to 20% less energy.
The machines also take up less wall space than previous models. Other features include magnetic door catches, repositioned lint filter systems and hatches that are said to be amongst the largest on the market.
T5000 machines have an average life of 30,000 and the range features several improvements – support rollers at the front; an optional exhaust on the top; a handle on the back plate for easier removal and two motors as standard (fan and drum motor).
Electrolux has also added its Compass Pro program interface to the T5000-series. Operators can select an Eco button, which saves 10% more energy than a regular cycle; the Care button, which gives a better finish to the linen; or the Speed button, which gives the shortest possible cycle.
Miele Professional has also focussed on energy efficiency with its heat-pump technology which can produce up to 60% energy savings. According to Miele, the heating of the air during a typical drying cycle represents roughly 90% of the drying energy, with the remaining 10% for electric motors.
The greatest opportunity for improving dryer energy efficiency lies in reducing the heat input per kilogram of laundry, says Miele.
The heat pump principle
The principle behind its Heat Pump Technology is simple. The dryer features a closed circuit and hot moisture-laden air from the dryer is passed through the heat-pump where is it cooled and dehumidified through condensation in a heat-exchanger.
The air then proceeds through a second heat-exchanger, where it is re-heated before it is passed through the drum. Because the system uses a closed air circuit, there is no need for vent ducting, so reducing installation costs.
According to Miele, the system has great advantages over vented and traditional condenser dryers. The cooling and dehumidifying air releases energy that is captured and used to pre-heat cold, dry air. This approach retains the latent heat within the process and thorough dehumidification means that the temperature of the process air can be kept at very low levels.
Electricity consumption is reduced as heat-pump dryers do not require electrical heating elements.
Because most of the moisture is removed by the evaporator, air can be recirculated back into the drum, so allowing for a vent-free design.
Miele currently offers three heat-pump dryers.
The PT 8257 has a drum volume of 250litres with a load capacity of between 10 – 13kg.
The PT 8337 WP with a drum volume of 325litres has a load capacity of 13 – 16 kg. Both models have short cycle times and Miele says that 10kg of linen can be completely dried in 44 minutes (with a reduction in residual moisture level from 50% to 0%).
Later this year, Miele will introduce the PT 5137 WP heat-pump dryer to its Little Giant range. With a load capacity of 6.5kg, this dryer is said to achieve savings in electricity consumption of up to 50% compared with a conventional condenser dryer.
Miele Professional says the machines provide extremely gentle laundry care and guarantee a perfect finish even on very delicate items. It says the intensive dehumidification achieved by the heat-pump system gives similar results to those of a conventional dryer but at lower process air temperatures.
The Miele machines feature the company’s patented honeycomb drum. The sculptured hexagonal pattern on the drum and the SoftLift ribs lift the laundry high and cushion garments gently on pockets of air as they fall. The ribs form part of Miele’s electronic moisture sensing system called PerfectDry, which monitors drying progress and ensures spot-on drying results. Axial airflow in the drum prolongs the contact time with laundry, resulting in intensive and uniform drying.
