Issue 4/2021

the topic of the contribution falls within the area of applied cFd simulations used to assess the thermal comfort and ventilation efficiency of the projected buildings. the contribution describes a CFD simulation analysis of the air-conditioning system of the projected concert hall of Janáček cultural center in brno. attention is focused on both the overall space and the partial parts such as the auditorium, the stage. the output is an assessment of the temperature distribution along the height of the room, a proposal for air distribution and an assessment of thermal comfort and the e fficiency of ventila tion.

Increasing demands on adequate quality of working environment in heavy industry and on the efficiency of technical equipment are leading to optimization of ventilation systems in industrial plants. Considering the complexity of the issue, the use of Computational Fluid Dynamics (CFD) can be beneficial when analysing existing systems and designing new technical solutions. The paper targets the analysis and optimisation of the existing ventilation system of the industrial steel processing plant in the company ŽĎAS in Czech Republic. It is based on combination of the experimental and computational studies. The paper describes the modification and necessary simplification of the geometric model of the analysed plant, creation of the numerical mesh and CFD simulation focused on the efficiency of the ventilation system. The boundary conditions of the simulation are based on experimental measurement at the site. Following the results of the CFD simulation, it is proposed to supplement the ventilation system by a hood for local extraction of pollutants in order to increase its efficiency and to limit the flow of fresh air through the steel processing ladle, as required by the client. The proposed adjustment is analysed with use of CFD simulation and its suitability is verified.

The topic of the contribution can be included into the field of simulation of the efficiency of the use of low-potential energy of the earth for heating and cooling of buildings. The performed studies are based on numerical simulations of a specific office building and its heating and cooling systems in DesignBuilder software. The paper compares different energy sources and methods of control of heating and cooling systems. The results are evaluated in terms of the time during which the required comfort in the building was not achieved, as well as in terms of energy consumption and its price. The possibility of implementing other methods of winding liquid pipes into the energ y pile model in EnergyPlus is discussed.

Building energy flexibility may support a higher penetration of renewable energy sources into electrical grid in the near future. However, assessment of the flexibility potential for demand response management is not a trivial task. In this paper, the thermal inertia of a family house is evaluated using building energy simulation tools. The simulation study assessed the internal air temperature response to a sudden switch-off of the heating source considering theoretical – in this case constant – boundary conditions. This experiment is aimed to assess the energy flexibility potential of both building and heating system. In addition, the simulation analysis elaborates the influence of model parameters such as thermal storage volume, thickness of insulation and inner wall on the internal air temperature response. The results of this study help to understand the properties of thermal capacity in building including the heating system. This work will serve as a background stud y for further development of tools for the maximiza tion of building energ y flexibility.

The paper presents a proposal of a numerical model of adaptive ventilation. The model is able to evaluate the impact of adaptive ventilation on the indoor environmental quality. It in a simplified form works on the physical principles of energy conservation. The article describes the process of numerical model verification by using laboratory measurement. For this purpose, the adaptive ventilation controller named VentNavigator was developed. Center of this controller represents PLC panel, which can collect, store and evaluated data from connected sensors. Sensors measure air temperature, surfaces temperature and relative humidity values. The same algorithm for supply fresh outdoor air was programed and tested in numerical model and PLC panel. The controller VentNavigator, as well as the numerical model, can evaluate the indoor environmental quality in the current time based o n several time steps back.

Computational fluid dynamics (CFD) has been used for the analysis of novel automotive ventilation schemes. The calculations were performed for a summer case with solar radiation. Three different methods of air distribution within the car cabin were calculated: ventilation outlets installed in the dashboard, under-theseat outlets and ceiling-mounted diffusers. The commercial software Star-CCM + v 14.04 (Siemens) with RAN S turbulence modelling approach has been used. The diagrams of comfort zones were evaluated for all regimes based on equivalent temperature according to ISO 14505-2. The best performance in terms of the highest level of human comfort was achieved by the ceiling- mounted diffusers.

Given the favourable temperatures and thermal capacity of the building substructures, there is an interesting potential for its use to cover part of the building’s energy needs. The use of heat and cold of an soil is a non-stationary phenomenon dependent on many parameters, which should be analyzed by a computational model. The article deals with the description of a brand new computing software being developed for this purpose. Multiple levels of the mathematical-physical model are presented. Attention is also focused on the development and implementation of the geometry generator, advanced mesher and automated postprocessor. The verification of sub-parts of the code is also presented and discussed.

The number of inhabitants in big cities increased in the past very quickly. This number and behavior of inhabitants influence the consumption of the energy that is consumed in the area of these cities. The goal was to develop dynamic model which will describe the changes of key parameters of the system. It means to identify principal driving forces and to find the connections with model elements. Main parts of the consumption are covered by these sub models: the energy consumed for housing, services and products for inhabitants, city services and transport. Special attention is given to the description of the energy consumptions in the residential houses and in the buildings providing city service. The model includes also the refurbishment of the existing building stock. The simulation was performed for Prague city. The important sub-system is also the migration of people from rural area and small cities to big cities.