Paint Drying: Emission Reduction and Energy Efficiency Through Load-Dependent Volume Flow Adjustment
At the 34th working conference “Karosserielackierung 2017”, organised by Automotive Circle and held from 6 to 7 November 2017 at the CONPARC Hotel & Conference Centre in Bad Nauheim, Dr.-Ing. Olaf Neese of CVET GmbH presented the latest results on load-dependent volume flow adjustment (LAVA) on paint dryers.
His presentation on 7 November 2017 was titled
“Paint Drying Systems in Automotive Production: Emission Reduction and Energy Efficiency Through Load-Dependent Volume Flow Adjustment (LAVA) – A Field Report”
and formed part of the programme block “Energy- and Resource-Efficient Processes”.
Full Load Is the Exception, Not the Rule
Paint drying systems in the automotive sector are designed for a maximum load case — yet in normal production this “full load” condition is rarely reached. In most cases the load fluctuates over the course of the day between idle and a reduced maximum.
LAVA, developed by CVET GmbH together with Crone Wärmetechnik GmbH, addresses precisely this issue: a control system continuously modulates the exhaust and fresh air volume flows in line with the dryer’s actual heat demand — taking into account not only the load but also the position of every individual skid inside the dryer. In this way LAVA compensates for dynamic fluctuations in heat demand in real time and keeps the dryer permanently in an energy-optimised state, without compromising product quality. Implementation takes place without interrupting ongoing production.
Results from 15 Installations
At the time of the presentation, LAVA had already been successfully implemented in 15 automotive paint shops, with three further installations in commissioning and additional projects planned for 2017/18. The savings achieved:
25 to 50 % natural gas (thermal exhaust air treatment and heat generation)
up to 80 % electrical energy for the fans (by means of variable frequency drives)
average payback period: 1.96 years (range: 0.8 to 3.2 years)
an average of 605 t CO₂ saved per year and installation (range: 230 to 1,250 t/a)
In total, the LAVA installations completed at the time of the presentation were saving around 690 kW of electrical power and more than 5,000 kW of natural gas capacity — equivalent to more than 9,000 t/a of avoided CO₂ emissions.
As further development stages, Neese identified the inclusion of the recirculation fans and the integration of the cooling zone into the LAVA control system.
CVET —
Processes must be understood before they can be sustainably improved.