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Numerical and Experimental Investigation of the Influence of External Wall Moisture on Building Temperature Distributions

Urzędowski Arkadiusz, Zaburko Jacek, Gleń Piotr, Łagód Grzegorz

Advances in Science and Technology. Research Journal

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2021

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Vol. 15, no 3

297--308

EN

In this paper, the authors made attempt to analyse the influence of moisture in the external wall of a building on the distribution of the temperature field, using numerical and experimental methods. Studies were carried out in the places of heat leakage occurring in structural joints of a single-family residential building, built in the traditional technology. In this study, the thermal bridge parameters were calculated by determining the values of thermal and moisture identifiers. For this purpose, two three-dimensional models of the building partition were designed based on an existing structure, and the boundary conditions for simulations were determined. The obtained heat flux values made it possible to perform quantitative calculations of heat flux distributions and temperatures of construction joints within the thermal bridge occurrence area. Moreover, the accuracy of the final temperatures obtained after combining the mathematical models with the values determined from thermograms was evaluated. In order to validate the results of numerical simulation, a test model was used taking into account the parameters specified in PL-EN 15026. The analysis aimed to present the handiness of using the simulation at the stage of planning the design and thermomodernisation of buildings in the places particularly exposed to adverse terrain and atmospheric conditions.

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Visual Effects of Surface Emissivity in Thermal Imaging

Urzędowski Arkadiusz, Wójcicka-Migasiuk Dorota, Buraczyńska Barbara

Advances in Science and Technology. Research Journal

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2020

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Vol. 14, no 2

215--222

EN

The article discusses the impact of surface emissivity on the thermograms, obtained from a thermal imaging camera during the measurements of construction objects. The study was carried out as an analysis of the digital and thermal images for three selected materials types of building finishing such as: wood outside doors, cement-lime plaster and glass façade. The images obtained from the exterior and from the interior of the buildings were compared and analyzed in terms of the spectrum intensity within the range of ambient temperature. The result of the conducted research shows how important it is to use both side images for such details as locks, door knobs and handles to properly assess the optional light reflections, especially on glossy surfaces. The influence of the most significant factors on the surface emissivity, such as direction of emission θ, surface temperature TS, radiation wavelength λ, time τ, was discussed on the basis of the experiment. The measurements were made using a Flir T440bx thermal imaging camera, while for the analysis of thermal images and the generation of graphs, the Flir Tools+ 6.4.18039.1003 software was used. For all tested materials, the emissivity value was estimated using a camera and black insulating tape characterized by a known emissivity value ε = 0.98. The study of materials with different emissivity under the reference conditions helped to identify the influence of material reflectivity on the obtained temperature spectrum values and to correctly perform the research. The temperature ranged between 269–293 K, but in particular measurements, the range was reduced. The thermal images reveals additional unexpected details of insulation discontinuity, the indication of which is necessary for building modernization. The wood door joinery research showed the leakage, which disqualifies them from use in low energy buildings in much more definite way because the temperature range resulting from heat outflow approaches even 15 K. The use of glass wind insulation boards can eliminate the wood door icing, which occurs at a temperature of about 268 K, and at the same time, increase the temperature of the shielded door by about 10 K.

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Oddziaływanie warstw wierzchnich ścian wymienników ciepła na ich nagrzewanie.

Morel S.

Inżynieria Materiałowa

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1999

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R. XX, nr 5

429-434

PL

Przytoczono wartości współczynników emisyjności materiałów metalowych i ceramicznych oraz powłok. Dokonano analitycznych obliczeń wpływu współczynnika emisyjności wzajemnej: czynnik nagrzewający (płomień) - ściana bez powłok, a następnie czynnik nagrzewający (płomień) ściana z powłoką (czynnik nagrzewany) na wartości strumienia wymienianego ciepła. W oparciu o wyniki pomiarów podstawowych własności powłok wytypowano najbardziej przydatne do natryskiwania ścian pieców i wymienników warunkujące intensyfikację wymiany ciepła. Powłokami tymi natryskano ściany laboratoryjnego kotła odzysknicowego i dokonano pomiarów wartości strumieni ciepła przejmowanego przez wodę chłodzącą - przepływającą w rurach kotła pokrytych różnymi rodzajami powłok. Obliczenia analityczne i badania laboratoryjne potwierdzono wynikami eksploatacji przemysłowej w elementach urządzeń hutniczych.

EN

In the work it has been pointed out a need of spraying of the coatings which have high absorption ability and high heat conduction on surfaces of recuperators and boilers. Experimentally determined coatings properties have been also presented in this work. The estimation and selection of the coating with the highest applicability for spraying above mentioned installation in aspect of increase of the durability and optimization of their heat work have been discussed. In the experimental part the research stand method of measurements and results of influence of sprayed types of coatings for values of heat stream taken by following water in diaphragm exchanger have been described. It has been found that application of the coating of high absorptivity and conductivity has resulted in 100% increase of value of heat stream taken by flowing water in model (diaphragm) heat exchanger. Laboratory tests were proved industrialy.