Many economic and environmental restrictions have resulted in the growth of dry cooling technology. The air-cooled condenser (ACC), which can be used in power plants and other facilities, represents a way toward the minimisation of the water footprint. In the paper, a semi-empirical computational tool devised for the design and thermal assessment of the ACC is introduced. In comparison to commonly used CFD-based models, the presented tool is computationally effective and inexpensive. The model is based on a control-volume computational grid, which is coupled with three sub-models for the solution of steam-side, air-side, and fan-related phenomena. A number of empirical correlations collected in the literature review were incorporated in the model. Besides the underlying functionality, which includes the determination of the steam condensation capacity, the model allows for the consideration of advanced physical phenomena such as the condensate glut control and the influence of air in the steam to the condensation process. The comparison of the model with datasheets from manufacturers of ACCs as well as with experimentally gained data from a municipal solid waste incineration plant demonstrates that the semi-empirical model is a fast and accurate tool applicable for the design and thermal assessment of the ACC. (C) 2019 Elsevier Ltd. All rights reserved.