Gate up, heat out. If logis­tics centers, airplane hangars or factory build­ings used conven­tional heating systems, they would lose heat every time the gates are opened or when large amounts of air are extracted for produc­tion purposes. That’s why they usually use radiant tube heaters that don’t heat the air but instead work like the sun.

Radiant tube heaters include gas-powered heating units that produce heat with infrared radi­a­tion. They are usually suspended under the ceiling at heights of four to twelve meters and heat objects, walls, floors and also people with infrared radi­a­tion. They work by heating a heat-resis­tant tube to a temper­a­ture of 580 degrees. A reflector above the tube deflects the infrared radi­a­tion toward the floor and the people below.

Constant air supply

Until recently, Schwank, the world market leader in gas-powered infrared heaters, used a burner to produce a flame inside a steel tube. To produce the right air-gas ratio for combus­tion, a blower supplied air to the flame. The output was regu­lated solely through the amount of gas supplied.

“I’ve worked a lot with ebm-papst. They were always a step ahead.”

Dr. Fried­helm Schlößer, Managing Director of Schwank GmbH

“If you modu­late by keeping the amount of air constant and reduce only the amount of gas, at low output ranges that unavoid­ably leads to inef­fi­cient combus­tion and lower output,” explains Dr. Fried­helm Schlößer, Managing Director of Schwank GmbH. “That’s better than not modu­lating at all, but it’s not in compli­ance with the current EU product effi­ciency require­ments.” That’s one of the reasons why the company decided a year and a half ago to develop a better solu­tion with ebm-papst.

Radiant tube heaters work at heights of up to twelve meters using infrared radi­a­tion — just like the sun. (Photo: Schwank GmbH)

“I’ve worked a lot with ebm-papst,” says Schlößer. “They were always a step ahead. For our deltaSchwank radiant tube heater, we use ebm-papst’s NRV 118 gas/air composite system for lower outputs and the NRV 137 for higher outputs. Both include a gas valve, an EC gas condensing blower and a gas-air mixer, the so-called Venturi tube. That makes us the first manu­fac­turer of radiant tube heaters world­wide to use EC gas condensing blowers.”

Effi­ciency of 95 percent

The solu­tion has several advan­tages. Since the EC blower can be smoothly modu­lated between three and 30 kilo­watts, the output of the heaters can be adjusted to the building’s actual heating needs without a loss of effi­ciency due to excess air. The heaters can reach effi­ciency levels of up to 95 percent.

The envi­ron­ment also bene­fits. “Modu­lating units do espe­cially well in the tran­si­tional periods of spring and fall or in mild winters when 100 percent output isn’t needed. With the gas/air composite system, now we can achieve the best effi­ciency across all output ranges. That results in a further signif­i­cant drop in gas consump­tion.”

“That makes us the first manu­fac­turer of radiant tube heaters world­wide to use EC gas condensing blowers.”

Dr. Fried­helm Schlößer, Managing Director of Schwank GmbH

Cleaner combus­tion means the heaters emit 20 percent less CO2 and 55 percent less nitrogen oxides. Schwank thus exceeds strict EU guide­lines such as the Ecode­sign (ErP) Direc­tive and can offer its customers a product that’s ready for the future. Thanks to EC motors, the heaters use up to 72 percent less elec­tricity.

All from a single supplier

Schwank used to buy every compo­nent from a different manu­fac­turer. Now it gets the entire gas/air composite system from ebm-papst. “That gives us more time to concen­trate on the heating system,” says Schlößer. “And of course on devel­oping more new prod­ucts.”