Joseph Vögele has performed a retrofit at KWS Infra in Eindhoven that demonstrates: new investments are often unnecessary. Instead of a new asphalt mixing plant for over 2 million euros, the existing plant received a new drying drum and a modern burner. The upgrade cost around 40% less than a complete new build and brought the technical equipment up to the latest standard.

Why retrofitting makes more financial sense than buying new

KWS Infra operates an asphalt mixing plant in Eindhoven that processes up to 320 tons of material daily. After 15 years of operation, the drying drum showed signs of wear. The old burner no longer met the efficiency values of modern systems. Downtime increased, and energy consumption was 18% above current benchmarks.

Instead of replacing the entire plant, KWS decided to selectively replace both components. The new drying drum from Vögele offers 22% higher throughput capacity. The new burner works with variable flame control and reduces gas consumption by 15%. In concrete terms: With 80,000 tons of annual production, KWS saves around 120,000 cubic meters of gas per year.

Technical details of the upgrade

The new drying drum weighs 18 tons and measures 8.5 meters in length. It features optimized lifting blades that guide the material more evenly through the flame zone. The residence time of the mix decreased from 90 to 72 seconds without any loss in drying performance. This increases possible throughput from 280 to 340 tons per day.

The burner operates at a power level between 6 and 18 megawatts. Unlike the previous model, it controls the flame continuously and automatically adjusts to the moisture content of the granulate. This reduces peak loads and protects the drum lining. The Wirtgen Group, which owns Vögele, supplied the control software that connects the burner to the existing plant controls.

Installation during ongoing operation

The retrofit took place during a scheduled maintenance break. The old drum was dismantled in 12 hours, the new one installed in 16 hours. The burner replacement took an additional 8 hours. Overall, the plant was shut down for 48 hours – significantly less than the 6 to 8 weeks a new build would have required.

Vögele delivered the components pre-assembled and tested. Adaptation to the existing flanges and connections was done to the millimeter. KWS only had to reinforce the foundation anchors because the new drum is 2.4 tons heavier than the old one. The first test batch ran through the new drum 72 hours after work began.

ROI and operating costs comparison

The retrofit cost KWS around 800,000 euros including installation and commissioning. A comparable new asphalt plant would have cost at least 2 million euros, plus foundation work and longer downtime. With annual production of 80,000 tons and energy savings of 1.50 euros per ton, the investment pays for itself in under 7 years.

CO₂ emissions fell by approximately 15% due to the more efficient burner. For KWS, this equals around 1,200 tons of CO₂ annually. For operations working under emissions trading or strict environmental regulations, this can be a decisive factor. Additionally, the retrofitted plant now meets the same exhaust standards as a new build.

When retrofitting makes sense

Not every old paving machine plant is suitable for a retrofit. Vögele recommends retrofitting for plants that are at most 20 years old and whose supporting structure is intact. If foundations, silo system, and control system are in good condition, targeted replacement of worn components is almost always worthwhile.

At KWS, the mixer, silos, and dosing scales were still technically up to date. Only the drum and burner showed signs of aging. This exact constellation makes retrofits economically attractive. Mid-sized operations save themselves from the high investment in a completely new plant while still achieving modern efficiency values.

Outlook: retrofitting becomes increasingly important

The Wirtgen Group now offers retrofits for cold milling machines and recyclers as well. The focus is on components that have the greatest impact on energy consumption and emissions: burners, motors, hydraulic systems. In times of rising energy costs and tightening environmental regulations, targeted modernization becomes a genuine alternative to new investments.

For construction companies, this means: before any replacement investment, it's worth checking whether a retrofit is possible. Manufacturers today provide detailed analyses of which components need to be replaced and what savings are realistic. Anyone investing now should also explore funding opportunities – many federal states financially support CO₂ reduction measures in road construction.