Issue 5/2020

The paper deals with the current topic related to the ongoing CO VID-19 pandemic. On the basis of the available information sources, the article summarizes the recommendations for the operation and maintenance of building systems used mainly for control of the indoor environment at the time of the occurrence of the disease.

The article deals with the development of a mathematical model for predictive control of heating by a concrete core activation system (TABS – Thermally Activated Building System). To verify the theoretical assumptions of the model, an experimental building equipped with the TABS system was built. The mathematical model was validated with real measured data from the building. Subsequently, the model was calibrated and a suitable model was crea ted for predictive control of hea ting by the TABS system.

Requirements for energy demand reduction in buildings place greater emphasis on the airtightness of the building envelope and the associated need to ensure adequate ventilation and adequate indoor environment quality. The aim of the article is to compare approaches towards the issue of airtightness and ventilation of residential buildings in various European countries. Approaches and requirements for airtightness and ventilation in selected countries have been examined by analysing the national legislation and technical standards. It was found that the requirements and their binding nature vary considerably from country to country. For example, different countries use different quantities to set requirements for ventilation of buildings, although there is a European standard [6] that sets out the indoor environment requirements and parameters for the design and assessment of the energy performance of buildings with regard to indoor air quality. Different countries approach the issue of buildings ventilation differently and, with respect to different quantities used, the requirements are not completely comparable across Europe.

Improvement of the indoor environment quality in existing buildings is one of the priorities of HVAC Engineering. One option is to use decentralized units for local ventilation, which can be installed in inhabited rooms without major building modifications. Controlled ventilation then ensures delivery of sufficient amount of fresh air and at the same time creates a healthy and comfortable environment for occupants. The paper demonstrates the practical use of CFD simulations for the development of a compact ventilation unit for local ventilation of rooms. It describes the preparation of numerical model for CFD simulation, presents the approach to simulation, including the calculation settings, and discusses in detail the device optimization with the help of variant numerical analyses. The study is a part of a project supported by the EU under the Operational Program Enterprise and Innovation for Competitiveness. The output of the research is a new type of small compact ventilation unit RECU AIR DC40 for local ventilation of rooms with the heat and humidity recovery. An increase in the device efficiency and a reduction of its acoustic power were achieved, with the help of CFD simulations, while maintaining its compact dimensions.

The paper deals with the protruded installation of windows. It includes an extensive computational analysis of 2D temperature field of the contact between the window panel and the building structure. It evaluates the lowest internal surface temperature and the linear heat transfer coefficient under different offsets of the window from the external building wall with different types of load-bearing structures. Based on the evaluation, a suitable position of the window is recommended (so-called protrusion) and window types suitable for protruded installation are presented. The paper compares classic and protruded installation in relation to heat losses. It introduces a calculation tool for calculation of financial savings for heating due to the implementation of protruded installa tion.

This article sums up the technical and the norma tive conditions of ventila tion duct penetra tions through fire separation structures, where mistakes both in design and assembly occur all too many times. The article gives the principles and rules for the correct design and assem bly. It also describes the construction details that influence the fire resistance the most.

Due to the growing popularity of obtaining cryptocurrencies in a number of countries, including the Czech Republic, it is appropriate to address ways to increase its energy efficiency through the use of waste heat generated during this activity. As a part of this case study, a so-called mining device for obtaining cryptocurrency was assembled and installed in a family house, in which long-term measurement and use of waste heat for hea ting of the family house took place.

The article deals with the use of waste heat from information technology in a particular residential building. It summarizes the research of the authors on the topic, describes the parameters of data centres from the point of view of heat generation and evaluates the potential of its utilization. The heat recovery from the data centre is designed with the building in mind. In conclusion, potential financial and energ y savings are quantified.