The demand for energy-efficient housing is on the rise in Egypt. The information about the individual materials used in the construction of typical residential wall assemblies are known in the literature. However, data from lab tests to validate the performance for whole composite walls are limited. Three typical wall types were constructed and tested utilizing a standard experimental evaluation procedure based on thermal convection loads. A research framework combining the validated thermal performance data from the experimental test and the simulated data was developed. The experimental tests were performed utilizing a state-of-the-art guarded hotbox apparatus and following the guidelines of the ASTM C1363-11 standard. The solar radiation load was taken into account in the calculations according to the standard, and the error estimation and uncertainty analysis for the experimental tests are reported. The results of the experimental testing are described and a recommendation of the best wall type is noted. The output of this research will help to initiate a material database of the thermal performance of typical residential wall types used in Egypt that have been validated in the lab. This will be useful for the building industry as a whole to understand the performance of the materials in composite assemblies and their impact on energy efficiency.
Minimizing the entropy generation rate is one of the key performance indicators for enhancing the thermal design of heat exchangers. This paper introduces a comprehensive numerical entropy generation analysis of turbulent water flow inside—newly proposed—conical tubes with dimples subjected to a constant heat flux. The effect of different tube diameter ratios (DR = 1, 1.5, 2, 3, and 5) and flow modes (convergent and divergent tube configurations) on the thermal, viscous, and total entropy generation rates is investigated within Reynolds number (Re) range of 3 × 103–40 × 103 using ANSYS-Fluent package. Realizable k-ε (RKE) turbulence model is adopted in this study. A well-validated 3D model was adopted to estimate the dimensionless indices: Bejan number (Be), enhanced entropy generation ratio (Ns,en), and the irreversibility distribution ratio ($${\phi }_{\mathrm{s}}$$
ϕ
s
) to characterize the entropy generation performance and to compare conical dimpled tubes to smooth ones. The results showed that total entropy production rate values for dimpled tube geometries are lower than those for the corresponding smooth ones, especially for convergent dimpled tubes. Convergent dimpled tubes with DR in the range of 1.5–3 achieved the lowest total entropy production values over the whole Re range, with an average value of 0.20 W K−1, as compared to an average value of 0.34 W K−1 for the smooth configurations. The average Ns,en values for dimpled convergent tubes with DR = 1.5–3 are 0.46 and 0.80 at Re = 3000 and 40,000, with reductions of 50.54% and 3.61% at both Re values, respectively. The study also showed that the entropy generation analysis could provide an effective tool to highlight the optimal design of tube heat exchangers based on the minimum entropy generation and the enhanced entropy generation ratio.
Cooling towers play a vital role in many large-scale process applications, and any decline in their performance has a considerable effect on the underlying process. It is known that the efficiency of a power plant is greatly affected by the temperature difference of the condenser. The objective of this paper was to produce cooling tower design recommendations and considerations that would prevent negative impacts and ensure stable and efficient operation. Computational fluid dynamics (CFD) was used to examine the components that contribute to cooling tower performance, using steady-state simulations and average weather data from the Egyptian Meteorological Authority. Air flow patterns in and around cooling towers were predicted using computational fluid dynamics. The current study includes a numerical analysis of the performance of the cooling tower at different wind speeds and heights of the cooling tower above the ground. This study found that some wind speeds have a negative effect and others have a positive effect, and the height of the cooling tower above the ground has a positive effect on the performance of the tower.
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