Issue 3/2015

The article presents the results of the unique calorimetric tests for individually built stoves made in the calorimeter chamber. The main objective of the tests was to determine the course of the heat output of the stove with glass and solid fire door at a full periodic fuel loading. The next main objective of the tests was the verification of stove sizing according to EN 15544:2013.

The article deals with the issue of system header (SH) in summary form used both in heating systems and cooling systems. Summarizes current knowledge regarding the design and sizing based on the results of a mathematical simulation provides new insights and recommenda tions for practice.

Carbon dioxide is the classic refrigerant known since the late 19th century which was pushed by halogenated substances with the development of the chemical industry in the 30s of the 20th century, but came back into the spotlight in the last 25 years. There are described properties and characteristics which affect the construction, operation and energy consumption of chillers and are mentioned negatives limiting its larger and faster expansion. The article deals with supercritical thermal cycle and with optimization of the discharge pressure to maximize coefficient of performance.

The paper is second part of the short series describing new methods used within facility management. While the introduction paper discussed the nature of these modern practices, this text focuses on their practical application, legal background and examples from the world.

The paper presents the basic features of the international research project SINPHONIE (Schools Indoor Pollution and Health: Observatory Network in Europe), which was focused on the environment and health of schoolchildren. The aim of project was to unify the procedures and the methods of evaluation of the quality of the indoor environment and on the basis of the obtained data evaluate the impact of the indoor environment in classrooms on the children’s health and produce recommendations. The SINPHONIE survey was conducted in 23 European countries in the years 2010–2012. There were measured chemical pollutants in indoor (and related outdoor) air (formaldehyde, benzene, pinene and limonene, naphthalene, nitrogen dioxide, carbon monoxide, carbon dioxide, radon, trichloroethylene, tetrachloroethylene, selectively PAH, particulate matter (PM10 and PM2.5). Biological contaminants (e.g. mold, allergens and bacteria) were detected in classes. Selected microclimatic parameters (temperature, humidity, ventilation, carbon dioxide) were also monitored. An important objective was to obtain data on health status of children by questionnaire surveys, and also by c linical tests.

The paper deals with aerodynamic noise which is generated at low Mach numbers, respective low Reynolds numbers, by air flowing over a blade grill commonly used as a terminal diffuser of air-distributing systems. The experiment was performed for five angles of blade rotation and two directions of air flow. The evaluatioN of the sound power levels was performed on the basis of sound pressure levels measurement in the semi-reflective environment in the field of direct wa ves from the source of sound.

Clean rooms, i.e. spaces with controlled air purity, are a phenomenon of the modern age and their use has been extending into more and more fields. With their rising utilization raise also the requirements on their quality, design and implementation of investors’ specific demands. One of the specific fields where the clean rooms are used is the field of production and preparation of pharmaceutics, medical equipment and other specific areas of the health service. The article presents general requirements on the clean rooms and also the experience with c lean room realiza tion and commencement for this field of use.

The paper is the first part from a series about ventilation systems in nuclear power plants (NPP). The author, who is a leading expert on the ventilation systems in nuclear power plants, briefly describes the history of nuclear power plants construction in the Czech and Slovak Republics, requirements on HVAC systems and main ventilation systems in buildings with radioactive environment and their concepts. The following parts will deal with the devices, system elements, habitability of control rooms, an active contribution to reduction of accidents including severe reactor accident, experience from the operation and requirements on the designer. They will also inc lude the current sta te of the art in the field.

To determine the effectiveness of heat recovery of ventilation unit in EU Member States you need to use several different methods. This article aims to highlight the differences in the values efficiency of the heat recovery for the same ventila tion unit obtained by different methods.

The author presents to professional community a broad experience, which he has acquired over the past decades during his work in the field of environmental engineering as a designer, implementer, systems operator and later also as a consultant. He informs the readers of his paper in the form of a personal message about the measures that he took based on his long time experience in order to improve current air-conditioning devices. The first part of the paper discusses practical experience with use of induction diffusers for air distribution in rooms. It concerns the experience with installation of induction units in window sills and discusses how does the location of the intake opening of secondary (induced) air in the front of the sill influences the air quality in the room. In the second part are described atypical installations of nozzles/jets arrays in suspended ceilings and partition walls, with possibility to quantitatively regulate the supply air volume according to the temperature and CO2 concentration in the room. These installation are suitable for „draught- free“ removal of bigger heat loads from heat sources scattered in the space, which cannot be ventilated locally and which are constantly operated. In the third part is described experience from dealing with problems concerning ceiling diffusers.