Specifying an Energy-Efficient Warewasher

Because they use water, gas and electricity, warewashers tend to be among the largest consumers of resources in any commercial kitchen. For foodservice operators wanting to get a better handle on their operating costs, specifying an energy-efficient warewasher is a good place to start.

The vast majority of foodservice operations have warewashers to help keep items clean and sanitary for serving customers and preparing food. As a result of their key role in helping maintain a food safe environment, warewashers can consume significant amounts of water, gas and electricity. The good news is that during the past five years, this product category has evolved considerably and now affords operators the opportunity to run their businesses more efficiently.

For example, newer models of conveyor-type (or continuous flow) warewashers can generate up to $16,000 a year in energy savings. That's because the foodservice equipment manufacturers have been able to reduce water consumption by as much as 65 percent. While the savings in the batch-style machines are not as significant because they do not use as much water, progress has been realized in this area, too. Today's newer batch units typically consume roughly 25 percent less water per cycle than older models.

While this product segment has made progress, the fact remains that not every unit is right for every foodservice operation. In order to find the unit that will function most efficiently and subsequently impact the environment the least, it is important to understand how the foodservice operator actually uses this machine.

And because the warewasher sits in the back of the house, out of the customers' view, it tends to be a piece of equipment that many operators take for granted and try to buy on price alone, not realizing the impact these units have on operating expenses. Here are some tips for foodservice operators and their supply chain partners to use when specifying energy-efficient warewashers.

Go with the Flow: Is the warewasher running constantly or are staff pushing items through it once an hour? It is important to know whether the staff is constantly washing full racks or single items. The machine uses the same amount of water regardless of whether one plate or 18 are going through it.

Understanding how staff uses the machine will help address a number of factors, including whether a batch-style warewasher requires a maintenance heater. Maintenance heaters keep the water in the wash tank at proper temperatures between washes. The need for one really depends on the foodservice operation's workflow. For example, in operations where traffic flow is steady and the warewasher is consistently used, then the maintenance heater is not as important. If customer traffic is not as consistent, which leads to longer lag times between warewash cycles, then perhaps a tank maintenance heater is important. Why is it important to keep the water at a specific temperature? If the water temperature drops below 150 degrees F, it will not properly clean and sanitize the items being washed. So if a machine without a maintenance heater sits idle for a while, the operator will need to run an empty cycle to get the water back up to temperature. This results in additional expense in the form of water, sewage and more.

Know the Menu Construction: This will help determine whether the operation requires a high- or low-temp machine. For example, if the menu consists of greasy, waxy product, then high-temp machines are appropriate. Also, take into consideration whether wine and cocktails are a big part of the menu mix.

Choosing Between Conveyor and Batch-Type Machines: This decision is based on the volume an operation will process. For example, the slowest conveyor units will process 144 racks per hour while the fastest batch units will clean 50 racks per hour. But when it comes to understanding how environmentally friendly a unit is, it is important to look beyond racks per hour. In reality, most facilities only run their machines at 70 percent capacity. So when trying to drive efficiency a better metric to consider might be gallons per rack or gallons per dish, depending on the unit under consideration. And taking this approach allows operators to make an apples to apples comparison when evaluating multiple manufacturers.

Maintenance Matters: It's fairly common for foodservice operators to not clean the warewasher's tanks as often as they should. This impacts energy consumption in a number of ways. First, scaling build up makes it harder to heat the water in the tank and drives costs higher. Also, the chemicals that go into the tank are distributed based on a computer sensor. So if the sensor generates a reading that indicates lower water quality, additional chemicals will be introduced to the tank until the proper levels are achieved. This, too, results in higher costs. And too much scaling and debris in the tanks can lead to clogged rinse nozzles, which means items won't be washed correctly the first time, requiring multiple trips through the machine. That's why when researching new warewashers it is important to understand the maintenance requirements.

Don't Get Stars in Your Eyes: The good news is that there is an Energy Star standard for batch type warewashers, which make up the bulk of the installed base in the foodservice industry. The bad news is that there are no Energy Star regulations for flight type conveyor dishmachines, which use a lot more water and run continuously -— up to 15 hours a day in some cases. As a result, foodservice operators will need to look past Energy Star and other regulations to determine the most energy-efficient option for their business, particularly when specifying conveyor units. Some points to consider include:

  • What is the machine's idle energy and water consumption rates?
  • How long does the rinse water run when it is in the zone?
  • What activates the rinse water?
  • When comparing two different machines, look at the differences in the size of their booster heaters and the energy they consume.
  • How long does it continue to run rinse water after it leaves the zone?
  • Understand how the recycled water is used and subsequently heated, if need be.
  • When looking at conveyor units would a pre-wash or dual rinse be a good option? If so, understand how these features affect water and energy consumption.
  • Look at the belt to make sure it can accommodate your dishes and other items appropriately.
  • Is the machine recycling or reusing as much energy as possible?

When it comes to conveyor machines, energy recovery is a feature that many expect will continue to grow in popularity in the coming years. These recovery units take the hot air the warewasher generates and uses a fan to divert it to a coil containing cold water. The water in the coil absorbs the heat and is directed to the booster, ostensibly becoming free heat and reducing the need to heat the water. This is one area that Energy Star and other regulatory bodies are not paying attention to as of yet. But most industry observers believe that it is only a matter of time before this feature becomes a standard part of energy efficiency.

Foodservice operators and their supply chain partners should leverage the resources available to them in order to make informed purchasing decisions. For example, the EPA has an energy saving cost/life cycle cost calculator on its website that allows foodservice operators to compare and contrast various warewasher manufacturers. In addition, many manufacturers and dealers can help with energy audits to understand which one works better.
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