Accurate information plays an important role for the circulation of materials and products. It influences the economically and ecologically successful execution of processes such as reconditioning and the corresponding supply chain management. Digitization concepts, such as digital twins, enable the relevant information to be made available to the right actor at the right time in a decentralized manner. It is assumed that digital twins will play an important role in the future and can contribute, among other things, to the successful implementation of circular economy strategies. However, there is no uniform definition of the term digital twin yet and the exploration and use of digital twins in the context of circular economy products and supply chains is still in its infancy. This article presents potential contributions of digital twins to the circularity of products and the management of circular supply chains. To this end, the derivation and validation of a definition for the term digital twin is described. A stakeholder analysis with a special focus on the processes of the individual stakeholders results in an overview of potentials and information requirements of circular supply chains for a digital twin. The paper concludes that circular supply chains can benefit from digital twins, but that there is still a need for research and development, particularly regarding product and use case-specific implementations of the concept.

The research project "Resource Efficiency through smart Pumps" (ResmaP) aims at increasing the overall resource efficiency of heating pumps with their entire lifespan in mind. While the energy consumption of modern pumps is low compared to previous generations, the resource intensity of the products themselves is increased and the number of different materials used in the parts and components is higher than it previously was. One aspect to increase resource efficiency is prolonging the lifespan through software updates and remote maintenance processes. However, there are cases in which mechanical errors or other physical damage occur that require the exchange of a device. In these cases, the project aims at reusing and refurbishing parts extracted from reclaimed end-of-life pumps. Deciding how to proceed depends on information collected throughout the pump's lifecycle and other factors such as the physical condition of the pump as well as the dismantling process itself resulting in a complex decision-making problem with several steps and decision points. Understanding the decision making for the cycle management process involves three steps: Mapping dismantling processes and identifying decision points helps to understand the processes involved and allows for the following step of Identifying decision problems. For each decision point in the process, the nature of the decision problem at hand is identified. A selection of decision support methods can be applied to support dismantling and recycling decisions and methods for each step. Finally, decision parameters the methods mentioned previously have to be identified and data requirements are derived.