Waste heat recycling cuts up to 30 per cent of energy consumption

Troldtekt has installed a heat exchanger that utilises the waste heat from the production drying process. The pilot project has resulted in a 30 per cent reduction in energy consumption in the sections of the drying oven where the trial was conducted.


At Troldtekt’s factory in Troldhede, one of the more energy-intensive processes involves passing the acoustic panels through the approximately 60-metre-long drying ovens. For this reason, a technique that can cut consumption by 30 per cent is well worthwhile. This can be achieved using a exchanger, which ensures that the excess heat returns to the drying process instead of being wasted.

Troldtekt was able to identify the potential in a pilot project with Nordic Green Solutions and Rokkedahl Energi, supported by the Danish Energy Agency. To realise that potential, a large heat exchanger was installed on the roof over sections of one of Troldtekt’s two drying ovens. The results of the completed pilot project showed that energy consumption in these sections fell by 30 per cent.

"This is a very significant reduction, allowing us to cut the amount of biomass needed for process heat. That's good news from a resource point of view and saves money," says Ole Busk Sørensen, PTA manager at Troldtekt A/S.

All process heat for drying Troldtekt acoustic panels comes from Troldtekt’s own biomass furnace.




A permanent solution for production

The heat exchanger works by combining hot, moist exhaust air from the drying ovens with cold supply air from outside. When this happens, a large amount of heat is transferred from the exhaust to the supply air.

The challenge so far has been to find a heat exchanger that does not clog when the moist and hot air containing fine dust is blown through the heat exchanger. But now we have come up with a heat exchanger design that can be washed, even automatically, using the condensation that occurs in the heat exchanger. This makes it possible for us to retain the heat within the production process instead of conducting it to the outside," says Ole Busk Sørensen.

Rokkedahl Energi supplied and installed the heat exchanger, while Nordic Green Solutions was the energy consultant which led to the right solution.

The pilot project is in line with Troldtekt’s business strategy, which is based on the Cradle to Cradle Certified® design concept. The focus here is on resource consumption, circular processes and renewable energy.