The article presents verification and validation of a numerical model of conjugated heat and mass transfer processes and aerodynamics in a fixed "honeycomb" type regenerator with square channels for heat recovery from the exhaust air of a local ventilation system. The processes in the regenerator are simulated by the CFD method. The influence of the processes of condensation and evaporation of moisture in the humid air on the efficiency of the regenerator has been investigated through these simulations and is shown in the article. The calculations of the fixed regenerator's thermal efficiency and pressure losses are made by known analytical models and the results are compared with those of the numerical model. The article compares the model simulation results with experimental data and data from reference sources.

The fourth industrial revolution is already a fact. It is manifested in the emerging automation of many processes in shipping, which until recently have been highly dependent on the competence of the people who manage them. The analysis of navigational accidents invariably touches the human factor and involves it in the reasons for their occurrence. The statistics are discouraging and the lack of competence of seafarers is always present in the reports of the investigating authorities. The idea of creating and implementing autonomous ships is cited as a lifeline to overcome the shortcomings that disturb the industry due to the human factor. A few authors in their publications point out many unresolved issues, one of which is related to the education and competence of service personnel. The existing International Convention for Standards of Training, Certification and Watchkeeping of Seafarers does not cover unmanned ships. The mandatory and recommended competencies in it are addressed to the people on board. Some maritime educational institutions have introduced the concept of “autonomous ship” in their curricula, such as Nikola Vaptsarov Naval Academy, Varna and Faculty of Maritime Study, Split. There are probably others who think ahead, but this approach is not enough because unmanned ships are already a fact in the maritime industry. This article aims at exploring the possibilities for supplementing the curricula of maritime training institutions with appropriate subjects for the new realities in shipping.

The article considers the possibility to use different types of polymer thermal store materials for regenerative heat exchangers in local ventilation systems. The research provides evidence for the benefits of the replacement of the most commonly used metal and non-metallic materials in the manufacture of the regenerator honeycomb matrix. It does so by presenting the results of calculations and comparative analysis of the influence of thermo-physical properties of a wide range of polymers on the thermal efficiency of a fixed counter-flow regenerator operating with humid air. In order to evaluate the efficiency, we have used a numerical solution of the system of mathematical physics equations describing the process in the regenerator. The system also includes an appropriate CFD model of the evaporation-condensation phase change process.

Various solutions are currently being offered to modernize the ventilation in old residential buildings. In small apartments, it is very appropriate to use decentralized ventilation units - for example with regenerative heat exchangers. Theoretical and experimental studies of such devices show a significant impact of the operational mode of regenerators (determined by the environment) on their efficiency. The aim of this article is to demonstrate the impact of the buoyancy forces in multi-storey buildings on the efficiency of a regenerative air handling unit for decentralized residential ventilation with heat recovery. Numerical solutions are presented for close to the real operating modes, airflow rates and air temperatures of the supply and the exit air, and the temperature ratio.