Revving Up HVAC Efficiency


A controller allows rooftop units, a corn-fired boiler and radiant floor heating to work as a single system.

A unique control solution that integrates heating, ventilation and air conditioning (HVAC) with other systems keeps the Zylstra Harley-Davidson dealership in St. Charles, Ill., comfortable and energy efficient. The new dealership is one of the largest in the country, covering some 80,000 sq. ft. on 37 acres of land, and includes a retail showroom, two customer lounges, classrooms and a playhouse for mini-bikers.

Dealership owner Tommy Zylstra selected Admiral Heating and Ventilation to develop a premium design-build HVAC solution. His main requirement: The equipment had to be efficient. In response, Admiral specified radiant floor heating and high-efficiency rooftop equipment from Lennox Industries (L Series rooftop units), both of which met Zylstra’s criteria.

The owner also wanted the facility to be heated with a corn-fired boiler. For the Zylstra family, which owns and farms land in Iowa and Minnesota, using corn for fuel was a natural decision.

“We believe in fully supporting agriculture in the Midwest,” Zylstra said. “And corn is a renewable natural resource we are proud to utilize.”

The decision to use a corn-fired boiler as opposed to the more conventional natural gas, which is what most radiant floor-heating systems use, resulted in the need to integrate controls across the different heating systems. All Lennox premium rooftop units, including the model used in the dealership, come with a factory-installed controller (the Integrated Modular Controller, or IMC), which allows flexibility to configure the unit for each application.

To solve the control across the different systems issue, the rooftop units at the dealership feature Lennox’s LonTalk Module option. It allows the rooftop units to work with the corn boiler and radiant floor heating as a single system, keeping the store comfortable while maintaining a high degree of efficiency.

The equipment provides a high level of control and has the integration capability needed for the project.

“The rooftop units bring in fresh air and heat and cool it to meet fresh-air building codes,” added Ron Reichert, project engineer, Admiral Heating, who noted that the units can also be used to heat an area if needed.

As for the in-floor radiant-heating system, it is extremely efficient, according to Reichert, with a concrete slab that stays heated for long periods of time.

The use of a Web server (from Tridium) gives the dealership owner total control of the floor-heating system and the rooftop units, without having to buy or install controls software on a computer.

“The owner can control the temperatures in the building from one Web page,” Reichert said. “A calendar allows flexibility for scheduling or non-store hours. It’s a very convenient way to manage comfort control and save even more money on building-operating expenses.”

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