DFIU - IMPROVE

Mass and Energy Flow Management in the Vehicle Refinishing Sector by IMPROVE 1.0

(Individual computer aided mass and energy flow model for the vehicle refinishing sector)

The photochemical air pollution represents in most industrialised and densely populated regions a major problem of clean air activities. Photooxidants such as ozone are not directly emitted into the atmosphere, but formed under the influence of sun irradiation out of the components nitrogen oxides (NOx) and volatile organic compounds (VOC). The expression VOC relates to a variety of chemical components, which are mainly emitted by mobile sources (road traffic), production, storage and distribution of mineral oil products and by solvent using activities. This represents a major problem due the heterogeneity of the emission sources. A variety of activities is concerned such as coating, surface degreasing, dry cleaning, etc., which are mainly carried out in small enterprises, the contribution to the total emissions of which however is considerable. The operators of such installations often complain about lack of information as regards possible emission abatement measures, which show partly far reaching economic consequences. Moreover, the Solvent Directive of the European Union lays down emission limits for twenty different categories of installations using solvents. These limits are determined depending on the applied production process and the installation capacity. In general, companies have to fulfil the requirements set by the Solvent directive from 2001 (new installations) respective 2005 (existing installations).

Therefore, the companies are obliged to take measures in the close future. In comparison to larger companies, small and medium-sized enterprises are generally not very well informed about the measures which could help them to reduce their costs and emissions, because of their limited personal size and cash flow. Therefore, the diffusion of environmentally sound products and technologies is often insufficient, as an analysis of the sector of vehicle refinishing shows. Especially the lack of appropriate tools for measuring, recording and analysing the characteristic data hampers meaningful analyses with regard to necessary investments, costs savings and environmental benefits, induced by new processes. With the help of a suitable mass and energy model, geared to the special needs of small and medium-sized enterprises in the vehicle refinishing sector, the different process steps can be analysed, and the influence of product or process modifications on other process steps, can be evaluated, in order to reduce the costs and emissions caused by painting activities in body shops.

The developed mass and energy flow model IMPROVE 1.0 (individual computer aided mass and energy flow model for the vehicle refinishing sector) simulates the procedure of vehicle refinishing and enables the flows of materials and energy to be determined and to be more efficiently organised in small and medium-sized vehicle refinishing firms. The model includes 15 different spraying processes each with a maximum of 55 stages from receiving the car to handing it over to the customer and a large variety of products and technologies for each stage. The basis for the model consists of the data of a defined model firm, of which the working structure, spraying processes and corresponding technological equipment have been agreed upon by branch experts from manufacturers and professional associations, and which can be applied to the majority of vehicle refinishing firms in Germany. A large part of the basic data (e.g. consumption figures related to area, components and vehicles, structure of orders, working times and capacity data of the technologies, such as thermal and electrical capacity) was collected in two reference firms in Baden-W?rttemberg. The degree of detail was selected so that on the one hand a relatively exact calculation of the mass and energy flow is possible, and on the other so that it is possible to differentiate between the materials and energy required for a subsequent evaluation.

The spraying processes can be extended and differentiated without any problem. The ratio of incoming and outgoing materials at each individual stage is described by a multitude of mathe-matical equations and parameters. The spraying processes are centrally controlled by approx. 200 parameters, such as material consumption, working time, performance characteristics, machine running-times and paint mixture ratios. Thus every vehicle refinishing enterprise can be depicted relatively simply and quickly with regard to the individual structure of orders, working methods and the products and technologies applied, and the economical and ecological effects of measures to reduce emissions, integrated into production, can be determined in absolute figures. With this model refluxes of materials, such as the reuse of distilled cleaning agents, can also be taken into consideration without difficulty.

The mass and energy flow model IMPROVE 1.0 is implemented with the commercial software UMBERTO 3.x business with SANKEY. The various features of this software mean that it is a suitable and adequate platform for IMPROVE, allowing for a transparent depiction of production processes and to determine and assess the mass and energy flows. The assessment of the mass and energy flows can then be printed out, be further worked on by means of a chart editor, or be exported to following modules, e.g. spreadsheet programmes or databases, for further processing.

For the economical and ecological analysis of the mass and energy flows, the quantity assessment determined by means of the model, i.e. the software, is exported to an evaluation programme especially designed for this purpose. Here on the one hand the individual mass and energy consumption quantities are listed according to special product groups (e.g. quantity of waste which has to be particularly monitored), and on the other they are multiplied with specific material prices, which are based on price lists from manufacturers, suppliers' invoices and billing rates. The wage costs are calculated as a product of the calculated working times and wage cost rates. For IMPROVE 1.0 the normal prices in the branch were determined for approx. 150 incoming and outgoing materials, taking into consideration the usual purchasing quantities, size of packaging and unit. With the evaluation programme it is possible to determine the share of costs of certain product groups and the economical advantage of particular measures for reducing emissions compared to the initial situation. The results can then serve as a basis for company decisions regarding investments. The evaluation programme is based on the Microsoft spreadsheet programme EXCEL 97.

As the experiences from the practical application of IMPROVE to several body shops show, the concept is well accepted by the practitioners, because it makes the process steps transparent with regard to cost savings and emission reduction. Since IMPROVE is currently only concerned with vehicle refinishing, future fields of application may be car body construction work (e.g. welding), lorry refinishing or industrial and general commercial spraying.

Funding:

The research project "Stoffstrommanagement f?r kleine und mittlere Unternehmen aus dem Bereich der Autoreparaturlackierung" has been funded by the Deutschen Bundesstiftung Umwelt (DBU), Osnabrück, from 12/1997 to 12/1999.

Selected References:

• Rentz, O., Blümel, F., Lonjaret, J.-P.: Stoffstrommanagement für kleine und mittlere Unternehmen aus dem Bereich der Autoreparaturlackierung, Endbericht eines Forschungsvorhabens im Auftrag der Deutschen Bundesstiftung Umwelt (DBU), Karlsruhe, 1999.
  
• Bl?mel, F., Lonjaret, J.-P., Rentz, O.: Ein EDV-gestütztes Instrument zur Analyse und effizienten Gestaltung der Stoff- und Energieströme bei kleinen und mittleren Unternehmen im Bereich der Autoreparaturlackierung, in: Rautenstrauch, C., Schenk, M. (Hrsg.): 13. Internationales Symposium "Informatik für den Umweltschutz" der Gesellschaft für Informatik (GI), Magdeburg 1999, Band 23, S. 33-45.
  
• Bl?mel, F., Lonjaret, J.-P., Rentz, O.: Stoffstrommanagement für die Autoreparaturlackierung, Tagungsband zur "Großen Naßlacktagung 1998" am 29./30. Oktober in Bad Nauheim.
• Lonjaret, J.-P., Blümel, F., Rentz, O.: Stoffstrommanagement für kleine und mittlere Unternehmen im Bereich der Autoreparaturlackierung, in: UWF 6(1998)2, S. 90-91.

Contact:

DFIU (Deutsch-Französisches Institut für Umweltforschung)
Universität Karlsruhe (TH)
o. Prof. Dr. rer. nat. O. Rentz
Hertzstr. 16
D-76187 Karlsruhe

Tel.: +49-721-608 4600; Fax: +49-721-758909
Homepage: www-dfiu.wiwi.uni-karlsruhe.de

Contact Person:
Dr. Jutta Geldermann (Tel: +49-721-608 4583)
E-mail: jutta [dot] geldermann [at] wiwi [dot] uni-karlsruhe [dot] de