There's more to choosing a warewashing machine than selecting one that meets your budget - you should also consider how much it will cost to run. Ross Bentley checks out some of the latest money-saving features
A dishwasher or glasswasher is one of the most labour-saving devices in a commercial kitchen, but it also has a tendency to be expensive to run. The costs relate to the amount of water, energy and chemicals used, and operators should take these into account when making a purchasing decision.
There are four main areas where money can be saved on a dishwasher, according to David Clarke, a member of the Foodservice Consultants Society International (FCSI) and director of design consultants CDIS-KARM: how water is used and heated the energy it takes to run a machine the amount of detergent required and the duration of each wash cycle. "All of these are expensive, so any savings that can be engineered will reduce costs and increase the economic, environmental and social bottom line," he says.
The latest technologies can dramatically reduce water consumption and still deliver high-volume throughputs while using less energy and chemicals.
Winterhalter recently announced a series of resource-saving innovations that have been developed for all its machines. These include what it has called its Energy and Energy+ features.
"Energy" is an air-to-water heat exchanger that takes the waste steam from the extraction canopy, found in its larger GS500 range, and uses it to heat the incoming fresh water. The "Energy+" feature adds a water-to-water heat exchanger to the system. So as well as recycling the heat from the waste steam, it takes the heat from the waste water and uses it to heat the incoming fresh water. National sales manager Andy Salter says that, with Energy, savings can amount to £821 per year, and with Energy+ they can be as high as £1,095.
Winterhalter has also developed its Rinse-Aid detergent, so users of its glasswashing machines can wash glasses at only 40°C, instead of the standard 60°C or 65°C. Salter says hygienic, clean glasses can be achieved at this temperature as well as energy savings of up to 2,000kWh a year, reducing operating costs by 16%.
He adds: "It also improves the working environment, since much less water vapour escapes when the door is opened at the end of the washing cycle and the glasses are cooler, so they can be used straight after washing."
The manufacturer has also introduced a new rinse system, which, according to Salter, requires up to 25% less water on the rinse cycle. This has been achieved by rejigging the water jet nozzles on the revolving arms inside the washers. "We've put fewer nozzles on each arm but have made them larger and increased the flow rates, so they give better coverage using less water," says Salter.
He says the rinse system can deliver overall running-cost savings of 13% with the GS200 glasswashing machines and GS300 front-loaders, and up to 20% with the GS500 pass-through washers. On Winterhalter's pass-through washers, Salter says a rinse now requires 2.4 litres of water as opposed to the 3.2 litres it needed originally.
A reduction in the amount of water used can also be achieved with advanced filter systems that remove food soil from the water every cycle, keep the wash water cleaner for longer and reduce the need to drain and refill the machine during operation.
This is one of several new features designed to cut running costs that can be found on Hobart's GXP front-loading machines and FXP under-counter range. The new filtering system has been branded Genius X2 and, according to Hobart's national warewasher manager, Tim Bender, it is a fine mesh basket that is more effective at catching soil and food matter than traditional filters.
Bender says most of the soil is collected in the first five seconds of the initial rinse, so Hobart's machines are designed to flush out the filter eight seconds after activation. Another flush is activated during the washing cycle to ensure the soil is disposed of and doesn't affect the quality of the wash.
Additionally, by improving the rinse cycle and filtering on its machines, Bender says Hobart is able to use the additional energy to ensure the wash tank temperature is maintained at about 62°C during every wash cycle. This, he says, means energy is not wasted in constantly reheating water that has dropped in temperature, and "all research shows that detergents work better at higher temperatures".
Ecotherm, the name given to this system, uses a single-loop element in the water tank, and Hobart claims it can reduce running costs by more than £500 a year and CO2 emissions by 1,250kg.
Ensuring scale does not collect on the heating element is another way of reducing running costs, according to John Nelson, managing director of Nelson Dish and Glasswashing Machines.
All Nelson's Hi-Tec range of glass- and dish-washers can be fitted with water softeners, which remove much of the limescale found in water.
"An element surrounded by scale will not work efficiently and will require more energy to heat the tank. Detergents also work better in soft water, so less is required," says Nelson.
When it comes to detergent, Nelson's machines offer an automatic dispenser that applies amounts of chemical and rinse aid proportionate to the quantity of water being used. This helps ensure detergent isn't wasted, or too little isn't used, and is activated by a timer mechanism or via measuring probes in the rinse water.
A 30-40% reduction in energy consumption can also be achieved through good insulation, according to Nelson. The cabinets of his machines, for example, are double-skinned, and the water boilers are lagged.
Nelson's under-counter washers incorporate a shallow tank, which means they use less water in a wash cycle - about 20 litres, or one-third of the amount needed by older models.
This is the line warewasher manufacturer Classeq has also taken with its Duo under-counter models. For example, its 400mm x 400mm basket machine has a 10-litre wash tank and a six-litre rinse tank, and uses only 2.5 litres of water per cycle.
"Smaller tanks mean less water is used, and less detergent is required," says research, development and technical manager Mark Downing.
At Miele, product manager Malcolm Martin says the company's heritage of producing machines for the consumer sector means its cabinet dishwasher models use a fresh-water system that pumps new water in for every wash, whereas a tank system stores water in the machine and will reuse it over several washes.
"For the small gastropub or guesthouse with a low throughput, fresh-water machines are more cost-effective than those that utilise a tank system," he says.
Meiko also offers two optional heat pumps on these machines, one that it claims delivers a 7kWh per day energy saving and a larger unit that delivers 16kWh per day saving through a heat-recovery system. And although heat pumps can be expensive - anything up to £17,000 at the top of the range - Downie says: "In a busy operation, where these machines are being used 10 hours a day, payback on a heat pump can be achieved within 18 months."
Key maintenance points
•If the inside of your dishwasher has a cloudy, off-white coating, you might have hard water - as two-thirds of caterers do - which will damage heating elements and produce a poor washing result. Check that the water softener is working properly and is regularly filled with salt.
•Dishwashing detergents and rinse aids are formulated to produce a sparkling result - and not just for your dishes they also keep the machine clear of scale and waste products. Use the best-quality chemicals for the best results.
•For safety, make sure that the machine is installed by a qualified electrician and checked regularly each year. Water and electricity can be a dangerous mix, and damaged cables might not be obvious to the operator.
•Clear food waste by scraping or rinsing before putting items in the dishwasher. Excessive food waste will clog the spray arms and reduce the effectiveness of the detergent.
•Clean out the filters as often as you can - at least once a day.
•Check that the filters are not damaged and allowing waste to pass through that will damage pumps and possibly cause blockages. Replace immediately if damage is evident.
•If the machine is displaying operating temperatures which are different from the manufacturer's recommendation, have the machine checked urgently to avoid hygiene risks.
•Buy a machine that is big enough to cope with your heaviest loads and busiest days.
•Make sure you use the most appropriate machine for each job - a glasswasher for glasses, a dishwasher for general crockery, and a potwasher for utensils and cooking containers.
Source: Serviceline (01438 363000)