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Case Study

GROSSMANN Construction Wood glue construction

Double keeps you warmer. Variable adaptation to the heating requirements by virtue of the cascade connection of two boilers

The gluing of thin layers of wood into glulam for timber construction is actually a relatively young process. Otto Hetzer had applied for the first patent in 1906 and over the next few decades load-bearing glued laminated timber construction developed into a significant branch of the building industry. The 2nd generation of Grossmann Bau GmbH & Co. KG was significantly involved in the further development of the manufacturing processes in the person of Emeran Grossmann. Grossmann was one of the first companies ever to receive the "large glue permit". More than 100 years after the company was founded, the timber division with glulam production and timber engineering is a mainstay of the Rosenheim company alongside building construction, turnkey construction and civil engineering, with renowned, partly award-winning references. In 2017 and 2018, the wood glue construction sector was extensively renovated and brought up to date in terms of fire protection and energy efficiency. Part of the energy concept was also a highly efficient ENDRESS wood combustion system, which can react flexibly to changing heat demands by virtue of the cascade arrangement of the two boilers. By virtue of continuous investments in energy efficiency measures and energy-saving plant technology, such as a modern lumber dryer and an extraction system with, the nominal heat output fell to 900 kW. The aging, inefficient and no longer environmentally sound predecessor plant was dimensioned for 2 MW plus an oil boiler as a reserve.

  • Combustion technology

    TWO | Underfeed combustion units USF-W 500 | 400-550 kW

  • Filter technology

    TWO | Bag Fabric Filter RGF 500

  • Conveyor technology

    Distribution tank type VB

  • Buffer tank


  • Fuel


  • Fuel

    Wood chips

  • In operation

    since 2018

The challenge:flexible wood combustion for process heat and heating energy

The wood combustion system provides heating for the production halls, locksmith's shop, administration and a staff dormitory. Depending on the weather and season, as well as the demand for process heat for drying the sawn timber in the drying kilns, the system has to react to strongly fluctuating load peaks. In addition, two further criteria played a decisive role in the selection of the system: it had to fall within the scope of the 1st BImSchV and thus remain permit-free and also operate as sound- and emission-free as possible out of consideration for the residents.

The solution:Double boiler system in cascade arrangement plus flue gas silencer

Due to the possibility of load-dependent boiler control and the excellent efficiency, Grossmann Bau decided in favour of ENDRESS' proposal to install a USF-W underfeed combustion system as a double boiler system with a nominal heat output of 450 kW each. By virtue of the cascade connection of the two boilers and the possibility of reducing down to 20 % of the nominal heat output, it easily covers heat consumptions between 180 kW and 900 kW. A 25m3 buffer storage tank can also provide large amounts of heat quickly if required. The compact design made it possible to install the entire system on one level; the previous system had extended over 2 floors in the boiler house. The ENDRESS particulate matter filter RGF ensures that emissions always shall remain below the limit value of 0.02 g/m³ (according to 1st BImschV).

Due to the inner-city location, it was important to Grossmann Bau that noise and pollutant emissions always remain at a minimum. The particulate matter filter therefore had to be able to be operated without a bypass in any case. Exhaust silencers installed between the filters and the flues reduce the already low noise emissions - the values measured on the ground during the system design were between 56 and 62 dB(A) - by up to 25 dB(A).

"It was very important to us that the filter system is not bypassed in any operating condition."

Josef Bauer, who is responsible for heating technology at Grossmann Bau

After the first heating period, it was confirmed that the ENDRESS system technology is extremely easy to maintain and has low wear. A maintenance contract also ensures permanent operational reliability. The highly competent heating technology team at Grossmann can access the system control via the online service I-SPY and react immediately in the event of a fault.

Do you have any questions or would you like to receive individual advice from our professionals?

ENDRESS adapts your new combustion plant individually to your annual heat requirements, the type and quantity of waste wood produced and the space available on your site. Each offer is combined with a specific installation proposal.

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