Appliance Design - January 2009 - (Page 24)

COMMERCIAL APPLIANCES Middleby Marshall’s WOW oven uses vertical columns of heated air blown by squirrel cage blowers. The Middleby WOW conveyor oven features three idle energy modes. A PLC and an ‘energy eye’ photosensor controls the conveyor belt, burners, and blowers. Part of the energy efficiency is derived from the method by which it creates steam. A typical steam cooker continuously generates steam to cook the food. Market Forge’s product, on the other hand, offers steam on demand. The unit creates steam as needed through a water column pressure control system. When cold product is placed into the compartment, in-shot burners fire continuously to put heat energy into the product. As the product absorbs the heat, the demand for steam decreases by the rise in temperature of the product. The water column pressure rises, which causes the burners to cycle off. By cycling on only when the burners are needed, the unit was able to generate an idle energy rate of 5,694 BTU/hr, which is one of the best in the industry, according to David Zabrowski, senior research engineer/senior project manager for the FSTC, which tested Market Forge’s ETP cooker. In addition to saving gas, the unit also saves on water. A typical steam cooker of this size requires about 100 gallons plus per hour to quench the drain water temperature, which is required to be less than 140 DegF. By not generating as much steam that needs to be disposed of the ETP’s water requirement dropped to less than 15 gallons per hour. The unit mixes condensate with 5-gallons of cold water in a reservoir and when the water reaches 130 DegF, it is flushed down the drain. Another workhorse in the commercial 24 applianceDESIGN January 2009 kitchen is the fryer, but it is also a workhorse that has peaks and valleys of use. According to an EPA report, fryers are some of the most-idle pieces of equipment in some restaurants, staying inactive about 75 percent of the time. At least one fryer has helped mitigate this problem, the PF-12S gas fryer from Paloma, a Japan-based company. While in use, the fryer has an input rate of 72,000 BTU/hr, and a 62.1 percent efficiency rate while producing 72.1 lb/hr of potatoes. During slow times, the unit drops down to an idle energy rate of 3,420 BTU/hr. The system is able to fry at these high levels, and then drop down to a low idle rate, because of its unique high-pulse combustion system, says Bob Hitchner, director of Tankless Sales for Rheem Mfg., Montgomery, Ala., a subsidiary of Paloma. With the system, gas and air enter a combustion chamber at the front of the fry vat where it is lit by an electronic spark igniter. This process produces rapid burning and a pressurized pulse of heat that is sent through heat exchanger tubes that wrap around the outside of the fryer vat. Once fired, the chamber closes, another round of gas and air enter the chamber, is ignited, and is fired again. Hitchner says the unit is more efficient than a system that uses a constant flow of heat partly because of the intense bursts of heat propelled through the heat exchanger tubes. He says it is not just the transfer of heat from molecule excitation; the heat is proactively being pushed into the oil. This fast transmission of heat to the oil is a reason that the unit offers fast startups in the morning, averaging about 10 minutes to reach a ready-to-cook temperature of 350 DegF, and recovery times between loads of about 18 seconds. Another place to save energy is in refrigeration. Electrolux Professional has released a suite of energy efficient products, including refrigerators, chillers, and freezers. The company is the Italian arm of Electrolux and has U.S. offices in Ft. Lauderdale, Fla. The air-o-chiller for example, continuously monitors the temperature of the food it is chilling to make sure that the operation does not last longer than necessary. Using dynamic evaluation through 5 different points along a core temperature probe, the chillers will automatically switch to refrigeration- or freezerhold mode after the chilling/freezing is complete, says Angelo Grillas, product manager for Electrolux Professional. The air-o-chill will chill product from 90 DegC to 3 DegC in less than 90 minutes; it will freeze product from 90 DegC to –18 DegC in less than 240 minutes. Not all efficient products are found in traditional food service equipment. Another www.applianceDESIGN.com http://www.appliancedesign.com

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Appliance Design - January 2009 Contents Editorial Shipments/Forecasts News Watch Supplier Spotlights Commercial Appliances Plastics & Parts Electronics Motors Design Marts Association Report: NAFEM Advertiser’s Index

Appliance Design - January 2009

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