Attacking the efficiency issue

Achieving energy efficiency is a two-pronged attack, according to Lee Wilson, vice president of international sales at Alliance Laundry Systems — a world leader in manufacturing commercial laundry equipment.

He believes that increasing utility costs have spurred laundry equipment manufacturers to focus even more on efficiency in their designs. However, it’s up to laundry managers and vended laundry owners to ensure the dryers operate efficiently after installation.

“Our approach to drying technology is simple,” says Wilson. “We blend the three components of heat, airflow and tumble to produce the fastest and most efficient results possible.”

Alliance has developed efficient tumblers to match the trend toward larger capacity washer-extractors in coin and on-premise laundries. The company’s stacked tumbler (30/30) is rated at 14kgs per cylinder, giving 28kgs of drying capacity in less than 1m2 of floor space.

Jay Klemm, product manager at Alliance, stresses the importance of balancing those three elements. “Heat, airflow and tumble must work in unison with each other for optimum results,” he said.

“Some competing models boast heavy BTU input (a BTU or British thermal unit is a unit of energy used in the USA), but without proper airflow and tumble, that extra energy is wasted.”

But efficiency isn’t something that begins and ends when the tumbler is constructed, however. Wilson says it is up to laundry managers to ensure that productivity is maintained after the dryer is installed.

“Managers must stay on a regular maintenance schedule to keep dryers performing at the highest level,” he says. “They should make sure their distributor provides them with a preventative maintenance brochure from the manufacturer. It can serve as an invaluable resource to help protect their investment.”

Lint screens should be cleaned as often as after every other load, for instance. Monthly vacuuming of the duct also keeps airflow at its peak and the tumbler operating efficiently, as restricted airflow is a major drain on the performance of dryers. Managers should discuss setup and make-up air with their distributor to ensure the unit’s continued efficiency.

Efficiency can also be a simple matter of being careful to not over-dry loads. For this reason, part of the maintenance schedule should be to evaluate drying times. Many OPLs find through this assessment they are over-drying. Managers need to adjust drying times from summer to winter. Summer’s humid air normally forces longer drying cycles, which results in over drying in winter (when the air is dryer) if settings are not changed.

Mauricio Lima, head of International Sales at American Dryer says that in today’s competitive environment, one of the most obvious issues is rising energy costs.

American Dryer has been at the forefront of technology development for dryers over the past 40 years.

“Our Solaris Line of dryers are up to 30% more energy efficient than conventional dryers,” says Lima. “Solaris machines specifically target the pressing need for energy savings worldwide. With these machines, dramatic savings are immediately seen through reduced utility and gas costs.” The range includes the SL20 and SL31, as well as their stacked versions the SL2020 and SL3131.

“The accomplishment of up to 30% more energy efficiency has been achieved through a newly redesigned basket with 100% axial air flow,” says Lima. The 100% axial airflow pattern forces all of the warm air through the load. Hot air that dries the clothes comes from the back of the dryer, goes through the clothes, and after passing through the clothes the remaining hot air exits through the front of the dryer. The result is maximum usage of heat and high performance drying results. Automatic drying features, such as those using residual moisture control, prevent over-drying. The load is dried as quickly as possible as well as avoids excess utilities being wasted.

The expanded SLI dryer range from Girbau of Spain benefits from a drum that provides an axial airflow. The airflow enters the dryer from the top and is distributed around the drum over a non-perforated surface by different heat sensors. This greater capacity for heat retention means less energy is used to achieve excellent drying, says the company.

The SLI series is composed of the SLI-9 (9kg), SLI-14 (14kg), SLI-14D (double 14kg for coin-op), SLI-23 (23kg) and SLI-34 (34kg).

All Girbau’s SLI dryers have the SAFE system inbuilt as standard, although regulations demand such systems only in dryers with a net volume of more than 3,500l.

The SAFE system activates water sprinklers inside the machine if either fire is detected or the temperature inside the dryer rises excessively. Once the fire is out, SAFE automatically shuts off avoiding the risk of damage caused by excess water.

SLI dryers are also fitted with a double glass door, which remains cool to the touch and prevents heat affecting the surroundings.

The stainless steel drum has a smooth finish to help reduce the build up of fibrin.

The CD range of dryers from Ipso keeps energy consumption to a minimum thanks to diagonal airflow and the extra insulated double side panels. The Ipso brand is produced by Alliance International BVBA based in Wevelgem, Belgium.

According to sales manager John Balman, the Ipso CD range is being extended. The present dryer line, consisting of models with 165litre (CD165), 220litre (CD220) and 350litre (CD350) capacities will now be joined by models of 450litres (CD450), 550litres (CD550) and 700litres (CD700) capacity. Coin-op or OPL versions can be equipped with electric, gas or steam heating.

The dryers are controlled by DX3, a microprocessor with three adaptable programs, or by PRO HC, a professional control to set time, temperature, cool-down, anti-wrinkle or residual moisture.

“These energy efficient dryers will have the same attractive look and advatages as the rerst of the line and will prove its outstanding functionality in any OPL and industrial application,” says Balman.

The DT25 -240 batch transfer tumble dryers from Jensen handle capacities of 25kg up to 240kg and can be heated with gas, steam or thermo oil.

The range features four different air circulation principles. When operating an ordinary type of a tumble dryer, the air is completely discharged without any re-use. Choosing a tumble dryer with air re-circulation means that 20-40% of the used air is discharged only.

There is another option available to adjust the mixed temperature for delicate linen individually. The option cool down can be implemented in different ways.

One of the most effective ways to save energy in the drying process is the operation of a Jensen tumble dryer in combination with the RecoCross heat exchanger. The energy of the exhaust air coming from the tumble dryer is re-used to pre-heat the cool fresh air for the drying process. The RecoCross can be used for all Jensen DT60-240 tumble dryer models operated with gas or steam.

By re-using the exhaust air and pre-heating fresh air up to 70C in the RecoCross heat exchanger, the heat required for drying can be reduced by up to 30%, says Jensen.

The saving potential is illustrated by a one-year trial for a RecoCross heat exchanger used in conjunction with a Jensen gas-heated DT60 dryer in the hospital laundry of the Evangelisches Waldkrankenhaus Berlin Spandau in Germany. Tests were evaluated in co-operation with the laundry manager Ulrich Loroff and the independent consulting engineer Manfred Stiskalll from IBMS over one year. They found the average natural gas consumption was reduced by 36.4%.

Jensen also provides an optional Infrared control. The Infrared sensor measures the linen temperature and controls the energy supply depending on the temperatures of each drying program and guarantees an efficient and constant drying of different linen types, even with under- and overloaded batches.

Based in Lamotte, Beuvron in France’s Loire region, Danube International offers a full range of laundry equipment that includes washers, barrier washers, tumble dryers and finishing equipment.

Danube’s dryers range in size from 6kg to 65kg, and are marked out from the competition in using direct drive with a frequency inverter rather than a belt, and in having reverse action as standard. The fact that the machines are inverter-driven and have no belts means maintenance is kept to a minimum, a factor that is also assisted by the large lint compartment on the machine.

Microprocessor control makes the dryer easy to program, and drying cycles can be programmed to stop at the required moisture level.

Its TD range of tumble dryers presently includes the TD10 (drum volume 210litres), TD15 (330l), TD22 (520l), TD30 (753l), TD50 (1,086l) and TD67 (1,676l).

According to Kannegiesser in Germany, the ideal pick-up movement and drop curve of the goods throughout all steps of the drying process has a highly important impact on the quality of the dried items and on the dryer efficiency. Different work classifications require individual cylinder rotation speeds to reach optimum drying results.

That is why a standard feature of Kannegiesser’s PowerDry is a frequency inverter-controlled drive which comes with especially developed software.

This allows the user to create the most appropriate cylinder movement characteristics individually for each type of goods and the relating drying programme by selecting the optimum cylinder rotation speed.

In addition, the PowerDry features basket rotation speeds that relate to the degree of dryness of the garments. This ensures a constant optimum “fall” of goods at any degree of dryness, the longest possible active contact between goods and air flow, efficient hot air penetration and faster as well as uniform drying effect.

A new air guidance system together with the favourable ratio of drum diameter to drum depth ensures an increased evaporation rate, which in turn reduces drying times. The PowerDry gas burner system utilises an atmospheric burner to effectively provide the necessary BTU’s to dry the textiles. The burner is located to encompass the entire width of the dryer basket, ensuring even heat distribution across the complete load.

The surface temperature of the textile is continuously measured during drying by proximity detection with an infrared sensor inside the drum. The data, which is processed in the machine’s PLC control, serves as a regulation value for the energy control source (steam heated or gas burner).

The special control system enables exact and specific drying of a wide variation of fabrics by the easy selection of the required program. The automatic determination of the exact drying point is based on the continuously measured temperature values.

Kannegiesser’s PowerDry also features an Eco energy recovery system, Cool-Down, turbo gas heating, safety sprinklers, touch screen control, tilt unloading, lint filters with and without automatic cleaning and central lint collection.

Primus has introduced new models in its established T-line range of dryers. The latest are the T24 (with a capacity of 24kg), and the T35 (35kg). Like the models T9-11-13-16 and the 2x13kg stacker, both are equipped with the Radax airflow system. The heated air is transferred both through the perforations in the back panel and the side of the drum. The exhaust perforations are located in the front of the drum. A seal divides the front and back perforations so that all the hot air goes through the drum and through the linen, and there is no loss of hot air between the outer tub and the inner drum. Drying time is significantly reduced (up to 15% shorter) says Primus, and energy consumption much lower.

The Primus T24 and T35 also have a Powerdry feature; the lifting ribs are perforated over their full length and on both sides, so reducing the length of the drying cycle and further improving efficiency.