Issue 1/2017

The article deals with influence of heat losses in distribution system and related cooling of heating water on the design of two-pipe counter-flow heating system. On the numerical reference model was studied the effect of distribution heat losses and cooling of the heating water on the heating system with mass flow rates designed by conventional calculation. In the following part were compared results from conventional design with design based on the numerical model which considered heat losses of the distribution system and cooling of the heating water. Mass flows rates were chosen as the compared variable, as they affect both thermal and pressure beha vior of hea ting systems.

The paper seeks to provide a comprehensive view of counter-flow two-pipe heating system from the design perspective of the temperature parameters and related small or large flow rate through the system. It analyses the work of the thermostatic control valves, zone valves and riser valves in systems with small and large flow rate and on the basis of the analysis it evaluates their advantages and disadvantages. It also deals with hydraulic balancing of heating systems and works with the defined term “sensitivity to changes in flow rate”.

The most significant source of population exposure to ionizing radiation in the indoor environment is radon (Rn-222) and its short-lived decay products [1]. Control of exposure to radon in buildings has always been focused on achieving two basic goals. The first goal is to find buildings with high radon concentrations (OAR) and implement appropriate remedial measures to reduce exposures of individual residents. The second goal of the control is to introduce effective tools of prevention against radon penetration from the geological basement and thereby achieve a reduction in surface exposure of the population in all buildings used for living or stay of occupants. As the prevention are generally classified procedures for radiation protection during construction of new buildings and during reconstruction of existing houses. Ensuring quality prevention is considered, from the efficiency point of view, as the most important regulatory tool for reduction of population exposure to radon in buildings. The article describes basic ways of radon measurement, more space is devoted to special ways of radon diagnostics of buildings and to important practical outcomes of radon measurement in the past few years.

The article is primarily targeting facility managers and other specialists, who are responsible for managing infrastructural and other constructions. It deals with the application of modern technologies for the management and maintenance of these facilities and methods of their use. The first part of the article defines relation of the maintenance to the building law, the obligation of the building owner to maintain the property and also the types of building maintenance. The second part describes modern technologies applicable for maintenance of properties using unmanned aerial vehicles with a mobile monitoring system and equipment for analysis of elemental composition of substances. The article also points out diverse areas of application of these technologies, along with practical examples of their use.

The article summarizes development of large-scale solar systems supplying heat to district systems in Denmark. The first projects were implemented in 1988. Gradual transition from pilot projects to purely commercial implementations that are fully integrated into energy systems is observed against the background of policy changes in the Danish energ y sector.

It is current trend to build energy-efficient and passive houses, while in the near future we can expect development of buildings with nearly zero energy consumption. Investors and developers are adapting to this trend and setting strict requirements on architects, builders, involved professionals and energy specialists since the beginning of projects. It is not difficult to fulfill these assignments from the perspective of the building envelope. Technical standard CSN 730540-2:2011 defines requirements on the building envelope up to the passive standard. However, the selection of a heat source is not so clear. There is a number of alternatives that are more or less economically recoverable. Therefore, the paper deals primarily with the choice of sources of heat/cold for larger urban complex on the riverside of Vltava in Prague from the technical and economical point of view .

The subject of the article is construction-technical solutions of an administrative building with an emphasis on the influence of a hybrid photovoltaic system in the sense of meeting requirements on almost zero-energy building. The building uses for its operation only electricity from the public grid and electricity from hybrid photovoltaic system. It shall not only meet legislative requirements in terms of requirements on nearly zeroenergy buildings, but in the same time also fulfil the technical sense of the term, ensure indoor environment quality and serve as an example of applied technology solutions. The purpose of the specific technical design of the building is to verify the coaction of a hybrid photovoltaic system and smart distribution network, in order to demonstrate the advantages of the solution for operators and users of power systems. The introduced concept was implemented in the full scale and the bu ilding began full opera tion in June 2016.

The article deals with the issue of collectors’ ventilation design. It introduces the requirements on the design from the point of view of the achieving the normative air exchange rate and newly also meeting the minimal airflow velocity. Practical information useful for the design of collectors’ ventila tion are presented in the conclusion.

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