© ÖkoFEN

Effi­cient pellet heating: With Zero to hero

ÖkoFEN is a specialist in pellet heating. The latest high­light is “ZeroFlame,” flame­less and emis­sion-free combus­tion.


Pioneering spirit is at the core of ÖkoFEN, a family-run company in Austria. In 1997, Herbert Ortner, the founder of the company, launched to market the first type-approved pellet heating system in the world. Pellet condensing tech­nology then followed, which cools the hot exhaust gas, re-uses the energy, and also reduces emis­sions. Today, the current product, the Pellem­atic Condens, is 15 percent more effi­cient than its prede­cessor and has an unprece­dented effi­ciency level of 98.7 percent.

So what drives ÖkoFEN? Their commit­ment to not rest on their laurels at such a high level, but to keep advancing in order to draw out the last quantum of effi­ciency and clean­li­ness from their pellet heating systems. Zero emis­sions here we come!

Over the years we have reduced the emis­sions from our prod­ucts more and more.

Stefan Ortner, CEO of ÖkoFEN

“We are working for the energy revo­lu­tion,” says Stefan Ortner, CEO of ÖkoFEN. “Over the years we have reduced the emis­sions from our prod­ucts more and more. With our new tech­nology ZeroFlame, we have even managed to get to the point where they can only be veri­fied using high-tech measuring instru­ments in a lab.” ÖkoFEN is addressing the hotly debated topic of particle and dust emis­sions with ZeroFlame, as ever-decreasing emis­sions values are required for air pollu­tion control.

The Pellem­atic Condens together with the addi­tional ZeroFlame option has an annual average dust emis­sion value of just two mg/m3 (based on 13 percent oxygen). Comparing this with other sources of fine dust shows that per year it only creates a tenth of what is caused by the tire wear on an average car alone. The aim of zero emis­sions is there­fore within reach.

Re-inventing fire

But how does it work? ZeroFlame gets to work directly in the combus­tion process. This means that the process does not produce the compo­nents that expen­sive partic­u­late filters have to filter out again at a later point. It is — as the name implies — flame­less, and there­fore emis­sions free. The resulting heat alone is suffi­cient to burn the pellets. The high­light is a new, x-shaped flue design and the divided recir­cu­la­tion of the exhaust air.

“We feed part of the exhaust air back to the supply air from below,” explains Stefan Ortner. “We inject another part from above directly into the high-temper­a­ture zone of our combus­tion chamber.” Getting the ratio of the air fed from below and above right is crucial to ensuring that there is no chance for a flame to develop. What was needed for this was a blower that controls the applic­able draft condi­tions with preci­sion.

ZeroFlame is inno­v­a­tive because of the special flue design, as well as the divided recir­cu­la­tion of the exhaust air from the combus­tion process. This exhaust air is fed into the primary air and injected into the high-temper­a­ture burnout zone. As a result, you have minimal emis­sions thanks to the specially devel­oped air flow — without the need for any filters. (Graphic | ÖkoFEN)

Effi­ciency meets effi­ciency

“The topic of effi­ciency has always been key for us. It is why we have been working together with ebm-papst for decades,” explains Stefan Ortner, illus­trating the collab­o­ra­tive rela­tion­ship. “The company’s highly effi­cient compo­nents have a posi­tive impact on the current consump­tion of our devices. It means every­thing comes together perfectly.” Tech­nology from ebm-papst can there­fore be found in every Pellem­atic Condens, for example, in the form of the gear motor which drives the conveying screw in the pellet burner.

The induced draft fan as a special devel­op­ment

When it came to the ZeroFlame tech­nology, ÖkoFEN and ebm-papst together opted for an addi­tional special devel­op­ment: an EC induced draft fan with special soft­ware. This fan can be controlled taking into account the applic­able draft condi­tions, in line with the air flow require­ments, and it can also draw the residual combus­tion exhaust gases to the outside.

“EC tech­nology is ideal for this as it is extremely effi­cient and easy to control. This starts from just ten percent output,” explains Project Coor­di­nator Thorsten Hartl, from ebm-papst Motoren & Venti­la­toren GmbH in Austria, and adds: “It also runs really quietly.” This is impor­tant because the flue of the pellet boiler is routed inside the building. The flow condi­tions in the induced-draft housing there­fore have to be perfect so that the air inside travels quietly. The impeller and scroll housing under­went the appro­priate noise opti­miza­tion measures to achieve this.

EC tech­nology is ideal for this product as it is extremely effi­cient and easy to control.

Thorsten Hartl, from ebm-papst Motoren & Venti­la­toren GmbH in Austria

Added to this are the higher require­ments placed on the compo­nents by condensing tech­nology. The cooled exhaust air condenses on the cooler surfaces, which can cause deposits to form. Ensuring that the design is right is essen­tial to help coun­teract this, espe­cially when it comes to the fan impeller. “In this case, however, the element that was the most specific was the posi­tion of the motor,” says Hartl. “If it is placed directly in the air flow, it is put at risk by sulfurous gases and high temper­a­tures. This is why the motor is attached with a shaft outside the air flow.”

Stefan Ortner empha­sizes how impor­tant working together with ebm-papst was: “For our pioneering work, it is absolutely crucial that we have a partner who is brave enough to develop things with us that no one else has done before. When my son is 30, he will come to expe­ri­ence the conse­quences of climate change. I want to be able to say to him that we did every­thing humanly possible to protect the envi­ron­ment.” We are looking forward to the next pioneering steps. 

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