A number of authors recommend selecting the systems design methods to be used depending on the practical tasks to be solved. At the same time, results of studies aiming at clarifying and systematizing practical tasks are very rare. In the frames of the research performed, it was revealed that in the companies four major tasks use to be solved - adapting an existing solution to work in new conditions, refining an existing solution, combining it with previously developed elements and creating a new solution. Resultantly, in the research an integrated model for design of technical systems was proposed. This model was obtained by combining (overlaying) the methods for solving the four main tasks defined and subsequently the content of the different stages in the proposed model was clarified. © Published under licence by IOP Publishing Ltd.