Issue 2/2026

This paper addresses the forecasting of solar irradiance and its importance for optimizing the operation of photovoltaic systems. It summarizes the fundamental physical principles of solar radiation propagation through the atmosphere and defines key variables such as direct, diffuse, and global irradiance. Available approaches for irradiance prediction are described, including numerical models, satellite-based observations and ground-based observations. Attention is also given to data processing methods, particularly statistical post-processing. The aim is to provide an overview of current irradiation prediction options with respect to their accurac y and the time horizon of usability .

The paper deals with the noise aspects during the opera tion of convectors with forced discharge in living spaces. The design of convectors as a heating element is not only limited to satisfaction of heating load requirements of the heated space, but in particular fulfilment of the noise aspects given for the space in regard to the valid legislation of the Czech Republic. The paper elaborates the design process of these devices and typical mistakes made during design including performance assessment of the installed devices in operation. The authors discussed the topic based on laboratory experiments, numerical simulations as well as measurements of real opera tion of various types of these convectors.

The European Commission has proposed new versions of the Ecodesign Regulation for hot-water boilers and local solid fuel heating appliances, which should apply to combustion sources in this category placed on the EU market from 1. 7. 2027. If approved, the proposed significant tightening of technical and emission requirements would bring revolutionary changes to this segment of domestic heating. For new combustion sources, it would no longer be sufficient to simply improve their existing designs; they would have to be equipped with new, sophisticated systems for particulate matter separation and for reducing gaseous emissions below the levels achievable with existing technologies, or with significantly more complex electronic control. Even if the requirements are relaxed during the ongoing preparatory procedure, the proposed revolutionary tightening of regulations is a clear indication of the direction in which biomass combustion sources are heading in the coming years.

The article provides an overview of respiratory protective equipment, including its basic classification, components, and representative examples. The first part describes facepieces, types of filters with their classification and labelling, and the first group of equipment - filtering respira tory protective devices. For all components, the relevant currently valid standards are specified.

The article presents recent changes in hygiene regulations applicable to premises, facilities, and establishments used for education and training. It focuses primarily on Decree No. 160/2024 Coll. and Decree No. 43/2025 Coll., which replaced Decree No. 410/2005 Coll., as amended, and Decree No. 6/2003 Coll., as amended. The aim of the paper is to introduce these changes from the perspective of general requirements, requirements for sanitary fixtures, water supply, lighting, microclimatic conditions, ventilation, and cleaning.