Issue 4/2025

The paper presents a study evaluating design fires in the context of installing fixed sprinkler fire suppression systems, which represent one of the most advanced and effective measures for ensuring comprehensive fire protection of buildings. The study was conducted using fire engineering calculations to determine the activation time of sprinkler heads and was subsequently validated through the Consolidated Fire and Smoke Transport (CFAST) fire model. The findings of the study will serve as a basis for further research into fire d ynamics related to the installa tion of fixed sprinkler fire suppression systems.

The paper describes a preserved warm air heating system of a Neo-Gothic church from the early 20th century. In the second part of the paper, the system is analysed with use of CFD simulations performed in Autodesk CFD 2024. The study aims to verify the functionality of the system under various boundary conditions and to identify its limita tions in hea ting the main nave.

This paper focuses on examples of design solutions addressing non-standard hot water preparation requirements for a residential building and a hotel. In both cases, building modifications significantly changed the hot water demand without considering the capacity of the original heat sources or existing plumbing systems during the implementa tion of these construction adjustments.

The paper focuses on the behaviour of rotary heat exchangers at low heat wheel rotation speed in terms of their control capabilities. The analysis shows the relationship between the sensible effectiveness and heat wheel rotational speed for different rotor geometries. A total of 7 different heat wheel geometries were investigated in the wide range of rotational speed. Extensive measurements of rotary regenerative heat exchangers (for HVAC applications) were carried out. The measurements results were compared with the results of CFD simulations as well as with the results of standard e-NTU calculation methods. It was found that the results of the standard e-NTU models and the measured data are not corresponding. On the other hand, a very good agreement was found between the measured results and the CFD simulations. Based on the analyses, a new e-NTU correlation was proposed, which describes the exchanger behaviour very well even at low rotational speeds of the heat wheel (0 to 4 rpm). It was shown that the sensible effectiveness of the rotary heat exchanger predicted by the proposed correlation corresponds well with the measured values. The proposed correlation method can be used to compare different rotor winding geometries prior to their production. An accurate description of the heat exchanger reduces costs associated with optimiza tion and testing of new designs.

Today, technology control systems are increasingly using third-party services for their function. These include connectivity, data storage and processing, visualisation and transmission of alarm messages. The operator thus bears not only the costs but also the risks that this concept entails. In this text, we will recall what control system suppliers and operators should know in order to grasp and address these risks – especially in the context of the requirements of quality mana gement and c yber security standards.