Parametric study of the method for determining the thermal diffusivity of building walls by measuring the temperature profile

Owczarek, M.

doi:10.1016/j.enbuild.2019.109426

Cited by 3 publications

(1 citation statement)

References 23 publications

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“…It has semiconductor temperature sensors Pt1000 at several depths as shown in Figure 1. Measurements were performed using the setup described in detail in [19][20][21]. The sensors are positioned with spacing c = 10 cm apart parallel to the wall.…”

Section: Methodsmentioning

confidence: 99%

Thermal Fluxes and Solar Energy Storage in a Massive Brick Wall in Natural Conditions

Owczarek

2021

Energies

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The thermal state of building elements is a combination of steady and transient states. Changes in temperature and energy streams in the wall of the building in the transient state are particularly intense in its outer layer. The factors causing them are solar radiation, ambient temperature and long-wave radiation. Due to the greater variability of these factors during the summer, the importance of the transient state increases at this time. The study analysed heat transfer in three aspects, temperatures in the outer, middle and inner parts of the wall, heat fluxes between these layers and absorption of solar energy, heat transfer coefficient on the wall exterior was also calculated. The analysis is based on temperature measurements at several depths in the wall and measurements of solar radiation. The subject of research is a solid brick wall. The results show that the characteristics of heat flow in winter and summer for the local climate show distinct differences. In the winter, the maximum temperature difference between the external and internal surface of the wall was 10 °C and in summer, 20 °C. In the winter, the negative flux on the internal surface reached 10 W/m2 and on the external 40 W/m2 and was constant throughout the day. The mean heat transfer coefficient on the exterior surface for winter week was 8 W/(mK). A Nusselt and Biot number for dimensionless convection analysis was calculated. The research contributes to the calculation of the variability of heat or cold demand in a daily period and to learn about the processes of energy storage in the wall using sensible heat.

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Section: Methodsmentioning

confidence: 99%

Thermal Fluxes and Solar Energy Storage in a Massive Brick Wall in Natural Conditions

Owczarek

2021

Energies

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Optimal Thermal Diffusivity of Residential Building Envelopes to Improve Cooling Energy Efficiency for Saudi Arabia’s Climate Zones

Alqahtani,

Alshahrani,

Alaidroos

et al. 2024

J. Archit. Eng.

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Measurement Method of Thermal Diffusivity of the Building Wall for Summer and Winter Seasons in Poland

Owczarek

Baryłka³

et al. 2021

Energies

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The thermal diffusivity of building materials is an extremely important parameter influencing the subsequent thermal comfort of building users. By definition, thermal diffusivity describes how quickly heat from a hot source can flow through a material. Therefore, this parameter includes both the thermal conductivity and the heat capacity of the material. This parameter is often neglected in heat-related calculations which, in the case of dynamic problems, leads to unreliable results. It should be taken into account that heat flows through all materials at a finite speed. On the other hand, knowing the correct thermal diffusivity value of building materials, it is possible to accurately determine the internal parameters in rooms over time. There are several methods for determining thermal diffusivity, most of which are destined to determine this property in laboratories. The aim of the present research is to show how the thermal diffusivity of materials can be determined in existing buildings. The presented method can be used to determine more real thermal parameters used for thermal calculations in buildings, for example, during energy audits or when calculating the demand for cooling for air conditioning or heat for space heating. This research presents the results for a 60 cm brick wall. Thermal diffusivity was determined for specific summer and winter days—most representative of the whole year. This research has shown that the applied method should be used in the summer period, due to the fact that the wall has greater temperature fluctuations. The obtained results are comparable with the previously mentioned laboratory methods. However, due to the fact that the materials analyzed on the spot, the results are more reliable, and also take into account changes in the value of thermal diffusivity resulting from the use of binders, inaccuracies in joining and external layers made of other materials.

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Parametric study of the method for determining the thermal diffusivity of building walls by measuring the temperature profile

Cited by 3 publications

References 23 publications

Thermal Fluxes and Solar Energy Storage in a Massive Brick Wall in Natural Conditions

Thermal Fluxes and Solar Energy Storage in a Massive Brick Wall in Natural Conditions

Optimal Thermal Diffusivity of Residential Building Envelopes to Improve Cooling Energy Efficiency for Saudi Arabia’s Climate Zones

Measurement Method of Thermal Diffusivity of the Building Wall for Summer and Winter Seasons in Poland

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