In the past 6 years at the mechanical engineering study at the Engineering College of Aarhus we have been practicing project work on 4th Semester in the design of energy technology systems. In my presentation, I will give a description of the project, and the thoughts behind; pedagogic-didactic as well as technical and professional considerations. The project is presently a permanent part of the 4th semester and counts as one third of the semester. The semester's theme is Energy-and System Design. Content on 4th semester is organized in light of which skills an engineer must possess in the field of energy technology. Here, it is vitally important, that the engineer is able to develop energy technology systems, thus being able to design systems, and not just individual components. It is not sufficient, that the engineer is able to calculate eg. a heat exchanger; the engineer must be able to consider the components as parts of a complex system. The semester project design is developed on basis of these considerations. The semester consists of 4 theory courses in: thermodynamics, control- and simulation of dynamic systems, electronics and hydraulic systems. The project work is performed in groups of 4-6 students, and will partly support the general theory being taught in the courses, but will also provide students with skills in teamwork, project work and system building. The pedagogical considerations behind the development of the project are quite simply that students learn best through active work and experiments, after which they can analyze and reflect on the results obtained. It was therefore natural to enable the students to implement projects based on the ideas in the CDIO concept.