Issue 5/2017

Indoor air exchange rate is the crucial factor affecting also the averted dose for people hidden in a house after the occurrence of an extraordinary event resulting in contamination of the outdoor air by gaseous and aerosol form of radionuclides. After introduction of theoretical approaches giving the key formula for relationship between indoor air exchange rate and the averted dose the results of an average air exchange rate from conducted weekly screening measurements in 70 houses sorted according to tightness of their envelope and heating season are published. Based on realistically observed indoor air exchange ra tes the size of the a verted dose from inhala tion for general radioactive contaminants in both gas and aerosol form and for the different times of the hiding time of persons after the measured external air contamina tion in buildings is given.

The article deals with the transmission thermal characteristic of the whole building. The transmission thermal characteristic of the whole building relates transmission heat loss through the building enclosure to one cubic meter of building volume and the unit temperature difference. The value of the thermal characteristic is influenced both by the thermal insulation level of the building enclosure (mean thermal transmittance of the building enclosure) and by the compactness of the building shape (shape factor). The transmission thermal characteristic is therefore a more complex expression of the thermal insulation quality of the whole building than only the mean thermal transmittance of the building enclosure. Parametric expression of the transmission thermal characteristic of the whole building is derived for buildings of common geometric shapes. Examples illustrate the sensitivity of the thermal characteristic to the change in geometrical parameters, its historical development and values of the transmission thermal characteristic achievable nowadays. The following discussion logically justifies why the currently established assessment of building enclosure thermal insulation quality only according to the thermal transmittances of individual building components and mean thermal transmittance of building enclosure can be considered as entirely sa tisfactory for its purpose.

An important mission of memory institutions is to ensure adequate care of cultural heritage objects during their long-term storage. However, many of these institutions are located in historical buildings, where it is not easy to maintain proper indoor environment and required microclimate conditions, given especially by relative humidity and temperature. The paper presents results of experiment of heating by the “Conser vation Heating” method for two selected rooms of the Kunštát Lower Castle. The experiment was continuously running in the building from middle of the year 2013 until May 2017. Presented case study was made in the year 2015 and it is targeting the year 2014. Experimental measurement was supplemented by numerical simulations, in order to evaluate efficiency of the above-mentioned heating method in more extreme outdoor climatic conditions and thus predicted electricity consumption. It is not known that this system would be previously tested in the Czech Republic.

In the case of stationary fire extinguishing systems operating on the principle of inert gas discharge, the generated noise can negatively affect function of information technology (hard discs malfunction and possible failure). This issue needs to be addressed and the impact on discs minimized by reduction of the noise and increase of the discs’ resistance. The article presents results of noise measurements carried out during testing of the fire extinguishing system.

The goal of the article is to identify and analyse the causes of excessive dynamic loading of CGU’s, their transmission of low-frequency waves into surrounding structures, and the subsequent radiation to nearby residential areas, where residents are expressing annoyance during mental work, relaxation and throughout the evening. The character of the noise manifests itself as a constant rumbling noise, which may greatly reduce quality of life of nearby dwellings. Frequency analysis of the CGU mountings and reciprocating parts were performed. The vibration transmission through the silentblocks and via vibro-isolation of the base as well as the acoustic efficiency of the CGU covering were measured and analysed. Causes of vibration and noise were identified and effective measures were proposed based on the th eoretical and experimental analysis.

The contribution summarizes findings regarding implementation of predictive control algorithms of a hybrid GEOTABS system with time variable price of electric power. The real case study demonstrates that the direct control of the heat pump output according to the dynamic price can bring financial savings. However, for the full utilization of the potential, it is necessary to ensure sufficient accumulation for all types of energy consumption – the TABS system has high storage ability from its nature, yet there arises a problem with accumulation for HVAC and DHW systems.

The issue of electromagnetic compatibility is very important not only when designing experimental devices. The aim of this article is to show the most common mistakes in the design of switchboards and other technologies in terms of interference, and in particular to show the possibility of preventing the problems that interference may cause in the ina ppropriate design of s witchboard and other components.