Issue 6/2021

One of the key problems with buildings in tropical climates is the overheating of interior spaces due to an inappropriate building envelope. In the design of a school building in Zambia, possible roof assembly variants were assessed to find their thermal performance under real boundary conditions. For this purpose, a thermally insulated test box was built on the roof of the CTU university. In this way, six roof samples can be measured simultaneously in one test run. The roof assembly, made of a pure steel sheet with Zn coating, was considered to be the reference case. This case was then modified step-by-step for either a colour change, adding additional material layers, or ventilating a 2 cm thick air cavity. Reed boards were used as thermal insulation and unburnt earth boards served as the heat storage layers. In total, 18 roof assemblies were tested in three consecutive test runs (three-week periods between June and November 2020). The white paint and ventilated air cavity were proven to be the most effective solutions for reducing the heat gain through the roof. One roof assembly was selected for use in the school building project.

In 2020, the PRVOK residential sculpture was created using 3D printing from a concrete mix. In addition to its artistic mission, this endeavour serves to test how and whether modern technologies can be used in the construction of future buildings. The object is used for short-term public accommodation in a holiday resort in South Bohemia and, in addition, as a part of research projects, it is used for experiments to monitor its performance under different operating conditions. This paper summarises the results of a holistic assessment of the indoor environmental quality, carried out using the HAIEQ certified methodology. The HAIEQ methodology takes various parameters of the building into account to assess the current state and to suggest potential areas for improvement. The results show that the quality of the indoor environment is such a complex issue that the construction method alone does not have a major impact on the overall assessment.

One way of increasing the energy efficiency of buildings is through projects related to their thermal retrofitting. Activities related to the reduction of the energy consumption of buildings should be correlated with the improvement of the indoor environmental conditions. However, errors in the implementation of an energy efficiency programme may result, inter alia, in the deterioration of the indoor air quality and the appearance of the sick building syndrome phenomenon. The paper presents the results of studies carried out in several educational buildings before and after thermal retrofitting. The studies included the energy performance of the buildings and the selected parameters of the interior microclimate. This analysis was carried out in order to assess the impact of energy-saving measures on the conditions of the indoor microclimate. During the study, negative symptoms,identified with the long-term usage of rooms in the buildings, were observed. It was found, in many cases that the commonly used gravity ventilation is not able to ensure the proper air quality in rooms, and the carbon dioxide concentration recorded in the tested rooms exceeded the applicable standards.

Self-drying insulation for cold piping is based on the capillary suction of a fibre fabric to remove condensed water vapour from cold pipe surfaces to the outer surface of the insulation, from where it will evaporate to the ambient air, as long as the ambient conditions allow for evaporation. The wick keeps the insulation dry, allowing it to maintain its thermal performance. The long-term accumulation of moisture in the insulation material is avoided. This paper describes the principle of the wick-concept insulation and also the results of an experiment. The results show that this type of open cell insulation works for pipes with temperature above 0 °C.

This paper presents the results of a combined space and water heater simulation analysis. An analysis was performed for an out-of-the-box water heater integration into the combined space and water heating system. Model of the combined system was built, and a simulation analysis was performed in TRNSYS . The quality of the water heater simulation model was verified against the manufacturer’s data and draw-off and performance tests were performed.