EcoSD network is a French association whose main objective is to encourage collaboration between academic and industrial researchers so they may create and spread advanced multidisciplinary knowledge in the eco-design fields at national and international levels. Among other actions, EcoSD organizes an annual thematic

workshop to enhance collaborative discussions. The present workshop was organized in that frame. It was held in Nantes in 2014. It gathered around 50 participants.

The notion of function in eco-design can have different meanings, according to the discipline (engineering, economy, sociology), and according to the life cycle step. When a product is conceived, eco-designing imposes to foresee the use and end-of-life phases. However, there are differences between the "expected functions", and the actual "usage" of products, that could be compared by analogy to the difference between "supply" and "demand" in economy. This gap between function and usage could be explored to improve environmental performances of products because adjusting the function is a performance axis by itself, as well as to better define comparison basis between similar (but different because multi-functional) products. This problematic is transversal to eco-design: eco-usage, functional economy, Life Cycle Assessment (functional unit and consequential LCA)... It can be resumed by the following key questions: How to define functions? How to predict and quantify functions, utilities and usages? How to compare complex objects?

The objectives of the workshop were to cross different visions from different disciplines gathering the most recent researches in France. Researchers from various research domains such as design for innovation, mechanical design, life cycle assessment (LCA), functional economy or market economy, were invited to present their work in various application fields: agricultural and food industries, waste management, construction, mechanical engineering and transports. Industrial from the automotive and buildings sectors were also invited to explain how they consider functions in their actual practices.