Dishwashers that get the dishes clean aren't good enough any more. They've got to do the cleaning while using up as little energy and water as possible, and with minimal impact on the environment. John Porter reports
There was a time, not so long ago, when the buyer's checklist for a new warewasher installation was fairly brief: a) does it clean properly, and b) does it fit into the space available? Beyond that, the only pertinent question was c) how much does it cost?
Times have changed. Not only do catering businesses now have to do everything possible to prevent detergent, grease and food waste being flushed into the mains water supply, they also need to ensure that equipment uses energy as efficiently as can be achieved.
Faced with a range of machines, all boasting hi-tech features given impressive-sounding names, operators could be forgiven for a certain amount of confusion. "The increase in jargon in warewashing reflects the rapid development of new technologies," says Paul Crowley, marketing manager at Winterhalter. "There have been big changes in recent years, not only to do with reducing consumption of energy, water and chemicals, but also in improving wash results."
The heat used in warewashing is the biggest factor in energy consumption. Heat exchange or recovery systems convert the energy from waste steam and waste water and use it to reheat the cold water supply, resulting in energy savings.
A machine with a steam condenser, such as Miele's G 7859 model, uses a sealed device to condense and remove moisture. This ensures that no steam containing vaporised cleaning agents and other potentially dangerous chemicals is released. The steam condenser operates as a heat exchanger so there is no additional water consumption.
The Comenda LC411CRC, from Dawson, includes the CRC steam condenser and heat recovery system. This condenses vapours expelled when the dishwasher is opened, cooling it quickly and so improving working conditions. The heat recovery system enables the unit to reduce energy consumption, with the heat produced by the machine recovered and transferred back to the cold water used for washing. This results in savings of up to 25% on both emissions and energy use.
Many Hobart warewashers, including its new UP Series, have the option to include drain or exhaust heat recovery systems. Drain heat recovery heats fresh rinse water using the waste heat from the machine drain water, while exhaust heat recovery removes the steam from the wash chamber at the end of each cycle with an exhaust fan, and recycles the energy.
The new Speedwash Advantage range of undercounter dishwashers from Nelson Dish & Glasswashing Machines features a new patent-pending heat recovery system, which uses heat from waste water to raise the temperature of new wash water by approximately 20°C, claimed as a big advance on existing technology. Further energy saving features include thermal insulation to the wash tank, wash chamber and boiler.
Ease of use
In a busy catering operation, with high staff numbers and turnover, ease of use is an important consideration.
Hobart's Smartronic system is a single button control which means machines are simple to understand and staff can master using them easily. A single colour-coded button controls filling, the cycle start and draining, giving operators a clear indication of the machine status. Additional functions such as cycle selection and temperature indication can also be accessed.
Winterhalter developed the Communicator Touchscreen for its UC Series. To begin washing, staff touch the square start pad, which also has a progress panel showing the stage the wash cycle has reached. To adjust the wash program, the user touches the corresponding symbol in the screen - delicates, heavy soil and so on. Animated operating instructions and tips mean new staff can quickly familiarise themselves with the machine, with no time-consuming training.
Filtration systems filter dirt and food waste out of the water so that it lasts for more washing cycles, making a big impact on water consumption.
Meiko's recently launched M-iQ flight dishwasher includes the M-iQ Filter system, which removes filtered food waste from the wash water during the cleaning process. The filter collects food waste and then rinses any residual debris cyclically from the tank. Additional fresh water is not needed for rinsing, resulting in a more efficient washing process, cleaner dishes, and reduced water use. The M-iQ can be slotted together on-site like a jigsaw, allowing installation of a large machine into tight spaces. The machine also has inbuilt heat recovery, while its high-pressure washing dynamics mean the machine uses one third less chemicals, one third less water and one third less energy than previous Meiko machines in this class while offering 30% improved cleaning power.
The Classeq Hydro H957 pass-through dishwasher has a filter system that keeps the wash water cleaner for longer, resulting in fewer water changes, cleaner plates and lower fuel bills. A self-draining wash pump ensures no dirty water is left in the machine at the end of use. The Hydro H957 has been re-engineered with a bigger heating element, to achieve 1.5-minute wash cycles throughout the wash period, with no need for recovery time between cycles. This makes the H957 especially suitable for busy sites as it can now process up to 40 racks per hour, every hour.
Winterhalter's Cyclo Mediamat filtration system is integral to many of the brand's range. The four-stage system keeps the wash water fresher for longer, meaning it cleans more effectively yet also lasts for more cycles. This reduces water and energy consumption while giving better results.
Reducing water consumption during warewashing not only reduces utility costs, but is also a contributor to environmental responsibility.
Intended as a first step into commercial dishwashing for business such as B&Bs and tearooms, the Classeq Duo 500 has a very low capacity wash tank at only 10 litres. This means a quicker start-up time and lower bills as there is less water to heat than in comparable models. The front-loading dishwasher has a footprint of just 470mm x 550mm and height of 760mm and takes only three minutes per cycle. Another energy-saving feature is its full-coverage filter system which keeps the wash water cleaner for longer.
Conventional rinsing typically uses between 2.5 litres and 3 litres per cycle to rinse and sanitise. The Hobart Vaporinse system combines traditional rinsing with steam to dramatically reduce water consumption. An initial rinse using just 1.5 litres of water is followed by steam rinsing using just 0.1 litres of water, which removes any remaining residues of detergent. Figures calculated using an FXP dishwasher show this method uses 36% less water and 40% less rinse aid than in conventional machines.
Fitting a machine into the (usually small) space made available for the wash-up area is one of the biggest challenges for many operators.
The Comenda AC2A, supplied by Dawson Food Service Equipment, is billed as the world's first corner pass-through washer. With a capacity of 1,800 dishes per hour, it has an operational footprint of just over one square metre, and can be reconfigured, even after installation, to operate in a left-to-right or right-to-left corner configuration. It is also fully automated, eliminating the waiting times required to re-load at the end of the previous washing cycle, and stops automatically when a washing process has been completed and there are no racks on the track, saving energy.
For businesses struggling to find space for a dedicated utensil washer, Winterhalter has launched the GS 630, which it believes to be the world's smallest utensil washer. The GS 630 utensil washer has a footprint of only 870 x 600mm and a height of just 835mm. Despite its size it can tackle full gastronorm containers, trays and grease filters, and can also be programmed to wash dishes, cutlery and glasses if required. To further save space, the machine has a lock-in-position door, which can be locked slightly ajar, for the interior to be ventilated.
Mick Shaddock, chair of the Catering Equipment Suppliers Association (CESA) advises that before considering the features on offer, it's important to know what type of machine is needed. "When it comes to understanding the jargon, the first thing to get your head around is the various different names of each category of machine."
There are four basic categories of warewasher:
● Undercounter machines, also known as back bar and front-opening warewashers, are compact and can be fitted in the workplace, such as behind a bar or below a counter.
● Door-type, pass-through, hood or stationary rack machines are amongst the most common types of warewasher, because of their size and versatility. Typically, these can wash up to 62 racks of dishes an hour.
● For larger volumes, rack conveyor-type warewashers use a conveyor to move racks of soiled dishes through the machine and are capable of washing 125 to 360 racks per hour.
● Flight-type systems, also called rackless machines or belt conveyors, are for the largest-scale warewashing. Dirty crockery is loaded on to a conveyor; the systems typically measure up to 18 meters long and are capable of washing as many as 24,000 dishes per hour.
The performance stats claimed for machines can sound impressive, but Shaddock also advises operators to approach them cautiously. "If the wash cycle lasts two minutes, the theoretical performance is 30 racks per hour. To get a realistic picture, assume an operator efficiency of 70%. In other words, if a machine is theoretically capable of washing 100 racks per hour, assume it will do 70."
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