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

Owczarek, M.; Owczarek, Stefan; Baryłka, Adam; Grzebielec, Andrzej

doi:10.3390/en14133836

Cited by 10 publications

(8 citation statements)

References 36 publications

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“…Average thermal diffusivity values comparisons indicated that thermal diffusivity and thermal conductivity were directly proportional, where, for aerogel sample with thermal conductivity of 0.082

\frac{W}{normalm . normalK}

, thermal diffusivity was

1.920 \times 10^{- 7}

, whereas for the sample with thermal conductivity of 0.076

\frac{W}{normalm . normalK}

, thermal diffusivity value was

1.690 \times 10^{- 7}

. Moreover, findings proved that calculated thermal diffusivity values (α × 10 −7

\frac{{normalm}^{2}}{s}

) has excellent correlation with specific heat capacity and thermal conductivity decrement guides to thermal diffusivity reduction 15 . As stated, low thermal diffusion of general aerogel insulators in contrast with high‐performance thermal insulators inspired objective of nanoencapsulated paraffin wax (PW) PCM core/PU shell replacement instead of some novolac aerogel colloids.…”

Section: Introductionmentioning

confidence: 65%

“…Moreover, findings proved that calculated thermal diffusivity values (α Â 10 À7 m 2 s ) has excellent correlation with specific heat capacity and thermal conductivity decrement guides to thermal diffusivity reduction. 15 As stated, low thermal diffusion of general aerogel insulators in contrast with high-performance thermal insulators inspired objective of nanoencapsulated paraffin wax (PW) PCM core/PU shell replacement instead of some novolac aerogel colloids. PW/PU NPCMs have been synthesized via interfacial polymerization technique as mentioned in the former work of this research group.…”

Section: Introductionmentioning

confidence: 99%

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Novolac aerogel thermal diffusion and efficiency enhancement using paraffin wax core/polyurethane shell phase‐change material nanocapsules

Abdeali

Bahramian

2021

Intl J of Energy Research

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Summary Aerogels are one of the most promising nano‐dimension open‐cell foams with considerably varied characteristics such as high porosity, super large specific surface area, low density, and super low thermal conductivity. Aerogel's high porosity and microstructure consisting of micro‐ and nanoparticles as well as pores in nanometer dimension are the origin of distinctive properties. However, the main challenge of aerogels is their low density (0.05−0.50 gcm3), which leads to equal thermal diffusion (normalα×10−7) compared with general thermal insulators. To minimize aerogel thermal diffusion and to enhance thermal insulation, replacing some aerogel colloids with phase‐change material nanocapsules (NPCMs) (while aerogel IUPAC definition and at least porosity of 80% is preserved) is proposed in this work. While NPCMs undergo a physical change during phase transfer, temperature becomes persistent, and as a consequence, specific heat capacity (Cp) getting close to an infinite number and thermal diffusion (normalα=knormalρCp) will tend to very low values. Results have demonstrated that by only applying 4.5 wt.% of paraffin wax core /polyurethane shell (PW/PU) NPCMs instead of some novolac aerogel colloids, aerogel has experienced temperature decrement as well as stability. During NPCMs' melting process, thermal diffusivity has reached 2.5×10−12 and temperature increment delay rate has become 40%.

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\frac{W}{normalm . normalK}

, thermal diffusivity was

1.920 \times 10^{- 7}

, whereas for the sample with thermal conductivity of 0.076

\frac{W}{normalm . normalK}

, thermal diffusivity value was

1.690 \times 10^{- 7}

. Moreover, findings proved that calculated thermal diffusivity values (α × 10 −7

\frac{{normalm}^{2}}{s}

Section: Introductionmentioning

confidence: 65%

Section: Introductionmentioning

confidence: 99%

Novolac aerogel thermal diffusion and efficiency enhancement using paraffin wax core/polyurethane shell phase‐change material nanocapsules

Abdeali

Bahramian

2021

Intl J of Energy Research

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show abstract

“…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

Self Cite

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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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“…It should be noted that the requirements set in [4,5] due to the durability of tanks are much more stringent than in [2,10] or [6]. The construction of tanks based on the requirements set out in [1,4,5] ensures longer durability of the objects, which was discussed in the article [17,20,22].…”

Section: Solutions That Ensure Durability and Tightnessmentioning

confidence: 99%

Analysis of structural solutions of reinforced concrete tanks used in agricultural farms

Żakowicz

Ziminski

Obolewicz³

2023

iboa

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The article presents the types of the most common underground or partially sunken tanks used on farms. The analyzed tanks were designed for the storage of zoonotic fertilizers. Solid or semi-liquid fertilizers should be stored in livestock premises in sealed tanks, protected from leakage into the ground. Basic static schemes of tanks and types of loads acting on tanks were considered. The durability and leak-tightness of the tanks were also addressed, and the insulation used to protect the walls and bottom plate of the tanks was discussed. A computational example presents the values of loads acting on the various elements of the tank at two computational schemes, and compares the results obtained by two computational methods, i.e., the separated plate method and the finite element method. The discrepancies in the obtained results were pointed out. Recommendations were formulated for the design of tanks in terms of meeting the tightness criterion. FEM calculations were made for two cases: with and without consideration of the soil stiffness.

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

Cited by 10 publications

References 36 publications

Novolac aerogel thermal diffusion and efficiency enhancement using paraffin wax core/polyurethane shell phase‐change material nanocapsules

Novolac aerogel thermal diffusion and efficiency enhancement using paraffin wax core/polyurethane shell phase‐change material nanocapsules

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

Analysis of structural solutions of reinforced concrete tanks used in agricultural farms

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