HVLS fans deliver energy savings from the top down

Dot Foods, the nation’s largest food redistributor, offers nearly 105,000 products from over 600 food industry manufacturers. Originally called Associated Dairy Products, the company was founded in 1960 by Robert Tracy, who started by selling products out of the family station wagon.

Over the past 50 years the company has grown from a regional, dairy products-only provider into a national operation handling all types of foods, virtually inventing the “redistribution” business model in the process. Today, it buys from food manufacturing companies and delivers to distributors nationwide in less-than-truckload (LTL) quantities. This “redistribution” model gives independent foodservice distributors access to products with lower purchase minimum requirements and shorter lead times. Customers can buy a mix of products (including dry, refrigerated, and frozen) with a combined minimum of just 5,000 lbs.

Warehouse operations have always been a key to this innovative, customer-centric formula, as summarized in Dot’s “Trusted Values. Innovative Solutions. Shared Growth.” brand promise. Dot Foods views its warehouse space as an extension of its customers’ facilities, allowing them to sink less money into buildings and inventory and more into building sales. The company currently has 2.8 million sq ft of warehouse space in eight distribution centers around the country, serviced by a fleet of 1,320 trailers and 830 tractors.

An innovative solution

This dedication to innovative, quality warehouse space was evidenced recently when Dot underwent a massive, 145,000-sq-ft warehouse expansion at its Mt. Sterling, Illinois, headquarters. While any expansion of that magnitude poses challenges, this one was uniquely complex from an energy consumption standpoint.

Not only did Mt. Sterling endure cold Midwestern winters, the facility had extremely high ceilings—47 to 64 ft tall, which meant pushing heated air to the employees’ levels would be an issue. To make matters worse, the new section was going to be even taller, with ceilings up to 67 ft high. Another significant consideration was the area’s energy supply; the community did not have natural gas, which is generally considered the most efficient energy source for heating. Dot Foods’ only obvious option was electric heat, a less efficient alternative.

"I certainly wasn't interested in heating the ceiling, particularly with electric heat" said Nader Khalil, Dot Foods’ corporate engineering manager. “We needed to look at all available options to keep our energy costs down.”

As he began analyzing ways to design the most efficient HVAC system possible, Khalil learned of an incentive being offered by the local utility, Ameren Energy Illinois. Through its ActOnEnergy program, Ameren was offering customers a five-cent per kilowatt hour reduction of electric costs for each kilowatt hour the customer saved. Considering that the existing Mt. Sterling warehouse was using more than 25 million kWh of electricity per year, it’s understandable why this got Khalil’s attention.

Determined to find an engineering approach that would qualify for this incentive, Khalil soon became intrigued with the potential of incorporating high-volume, low-speed (HVLS) fans to complement the facility’s new heating system. Though the existing warehouse had made some use of traditional high-speed fans, he felt that HVLS fans had much more potential to improve air movement and reduce energy use.

Better use of heated air

HVLS fans help save energy and improve comfort during the colder months of the year because they make better use of heated air. During the heating season, there is often more than a 20° F floor-to-ceiling temperature difference at most manufacturing plants and warehouses as a result of warm, light air rising and cold, heavy air settling. Typically, the air temperature will be one-half to one degree warmer for every foot in height. As such, a heating system must work hard for extended periods to maintain the temperature near the floor or at the thermostat setpoint, wasting precious energy and dollars.

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