Thermal Analysis and Thickness Optimization of Two-Cavity Thermal Insulator in Buildings

Alnahhal, Mohammed; Elnaggar, Mohamed; Edwan, Ezzaldeen

doi:10.1007/s13369-017-2854-y

Cited by 6 publications

(27 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These findings agree with Chen et al who found insignificant effect of small range Rayleigh number on maximum thermal resistance per unit mass, whereas at higher range of Rayleigh number, a significant effect on maximum thermal resistance per unit mass was observed. In another study, Xie et al observed that for a specified strength (i.e., specified number of air gap), increasing the overall Rayleigh number will decrease the maximum thermal resistance per unit volume, and in addition, they found that the decrease in the maximum thermal resistance is smaller in the smaller range of Rayleigh number confirming the findings of present study . 27 Moreover, Baig and Antar found that increasing the aspect ratio of their configuration resulted in an increase of the thermal resistance.…”

Section: Resultssupporting

confidence: 88%

“…27 Moreover, Baig and Antar found that increasing the aspect ratio of their configuration resulted in an increase of the thermal resistance. In summary, we may conclude that increasing the aspect ratio (i.e., decrease cavity thickness) will result a decrease in Rayleigh number and as a consequence of that, the thermal resistance will increase …”

Section: Resultsmentioning

confidence: 91%

“…Therefore, again, this confirms that area can determine the thermal resistance behavior besides that heat‐transferred rates. The results of Alnahhal et al are also included in Figures and for comparison purposes.…”

Section: Resultsmentioning

confidence: 99%

“…The distributions of heat‐transferred rates from environment inside to outside through the roof components with the roof cavity aspect ratios are shown in Figure , investigating the effect of roof cavity length, H = 2, 3, 4, and 5 m. The results of Alnahhal et al of roof cavity length of 1 m are included in the same figure for comparison. As we can see in Figure , the variation of roof cavity length (i.e., H ) has increased the rate of heat transferred.…”

Section: Resultsmentioning

confidence: 99%

“…Figures A to 23G show the distributions of roof components' surface temperatures T 1 , T 2 , T 3 , T 4 , T 5 , T 6 , and T 7 , respectively, with the roof cavity aspect ratios when the heat transferred from environment inside to outside. The results of Alnahhal et al of roof cavity length of 1 m are included in these figures for comparisons. As one can observe, the trends observed in Figures A to 23G support the trends observed in Figure and further confirm the influence of varying the roof cavity length on the distributions of roof components' surface temperatures, similarly as was observed in roof cavity (i.e., Figure , heat from out to in) and thus discussions provided there can be used here to interpret the present results.…”

Section: Resultsmentioning

confidence: 99%

See 4 more Smart Citations

Dimension optimization of two air cavities thermal insulator as an application in buildings

Elnaggar

Alnahhal²,

Edwan

2018

Heat Trans. Asian Res.

Self Cite

View full text Add to dashboard Cite

The present study investigates the use of two air cavities thermal insulator in buildings. The two air cavities insulator structure is supposed to be located within the building's wall and roof forming two separated vertical and horizontal cavity, respectively. In addition, the wall cavity height (or roof cavity length), H, was investigated at H = 2, 3, 4, 5 m to find the influence of wall cavity height (or roof cavity length) on various thermal characteristics and thus to determine the thermal optimum thickness. At each wall cavity height (and roof cavity length), cavity thickness, Lc, was varied from 0.01 m to 0.1 m forming aspect ratio, AR = H/Lc ranges of 20 to 200, 30 to 300, 40 to 400, and 50 to 500 for H = 2, 3, 4, and 5 m, respectively. The present results reveal the presence of the first and second cavities in wall and roof at various thicknesses affecting the development of wall and roof components' surface temperature. In addition, varying the wall cavity height or roof cavity length has further significant effects on the development of these surface temperatures. Moreover, it was found that increasing the wall cavity height leads to increasing the optimum wall cavity thickness, Lc = 0.024, 0.027, 0.029, and 0.031 m at cavity height, H = 2, 3, 4, and 5 m, respectively, whereas in the roof cavity case, the optimum roof cavity thickness seems to reach its asymptotic value at about 0.019 m for the roof cavity length investigated, H = 2, 3, 4, and 5 m despite the optimum wall cavity thickness that was not.

show abstract

Section: Resultssupporting

confidence: 88%

Section: Resultsmentioning

confidence: 91%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 3 more Smart Citations