Steady-state and unsteady-state moisture regime of enclosing structure

The desiccator method for products like mineral wool has a low accuracy, which is due to the small mass of the samples and the uneven content of the binder between the samples. The standard method does not involve testing materials at different temperatures. However, the value of sorption moisture depends not only on the nature and structure of the material, but also on the temperature conditions. At the moment, the regularities of changes in the sorption moisture content of materials depending on the air temperature have been studied only in separate scientific works and do not cover the entire spectrum of modern building materials. The paper presents the results of a study of the sorption moisture content of modern mineral wool products at various temperatures above 0 ºС. The results show an increase in sorption humidity with decreasing temperature from 22 ºС to 0 ºС. The greatest increase in humidity occurs at values of relative air humidity in the range of 90–97 %. It is shown that the standard desiccator method for studying sorption moisture requires scientific development and increased control of test conditions with decreasing temperature.

Section: Introductionmentioning

confidence: 99%

Study of the dependence of equilibrium sorption humidity of heat-insulating products on temperature

Petrov

Kupriyanov

2021

Study of heat protection of external envelopes of a residential building in the cold period

Zhangabay,

Giyasov,

Ybray

et al. 2024

In the study a full-scale thermovisional survey was carried out in the cold period of time of a multi-apartment residential building located in the Northern part of the Republic of Kazakhstan. The result of the survey showed the presence of significant problems on heat protection, where according to the analysis of thermograms of external wall envelopes it was revealed that almost all living rooms have envelopes with a negative value of heat protection, which does not meet existing standards. The analysis of thermograms of all rooms showed the existing problems on thermal stability of external wall envelopes, as the temperature difference between the inner surface of the external envelope and the internal air temperature ranged from 5.5 °C to 19.7 °C, where the difference reached 49 times in some places, depending on the living room. Analysis of thermograms of window openings also showed a lot of deviations. Thus, thermograms of window apertures showed deviations from sanitary-hygienic norms on dew point value from 12°C to 26.2°C depending on the living room. The revealed deviations on thermal protection of external envelopes are the main sources of heat energy loss and indicate the presence of problems on thermal stability of external envelopes in the cold period, which require special attention. In this regard, the obtained results of this study will be further taken into account in the development of new and optimization of existing wall envelope structures, taking into account the climatic features of the Republic of Kazakhstan.

Study of heat protection of translucent external envelope in winter period

Zhangabay,

Giyasov,

Ybray

et al. 2024

This article presents the results of thermophysical studies conducted in the cold period by non-destructive testing of translucent exterior building envelopes for heat protection and illumination of the room with natural light. As an object of study was chosen 3-room apartment on the fifth floor of the 17-storey residential complex “Sport Towers”, located in Astana, where the survey was conducted in the daytime. The window openings of the respective rooms were selected as translucent exterior envelope. As a result of the survey it was found that the internal temperature of the living rooms has a deviation of 3.5% from the optimal norm on the parameters of microclimate of the premises, which leads to a violation of the norm and overconsumption of heat energy for heating due to inadequate thermal protection of translucent exterior envelopes. At humidity 48.1% and internal temperature of the room 19.3 °C that the dew point was 8.1 °C. The value of the surface temperature including in the zone of adjoining to opaque elements of the considered structures showed deviation from -16.3°C to 8.0°C, which exceeds the dew point temperature in some cases in 3 times. The total area that does not meet the norm of the examined fragments of translucent exterior envelopes was from 5.9% to 100%. It is noted that the above deviations in heat protection of buildings can lead to the appearance of mold on the inner surface of the envelopes. The qualitative and quantitative indicators obtained as a result of thermophysical studies are the basis for the design of translucent parts of the exterior envelope when they work together with the blind wall part of the façade systems and in the future will be taken into account by designers in the development of new energy-saving exterior envelope structures, which are planned to be implemented throughout the Republic of Kazakhstan, taking into account climatic features.