The increased utilization of solar energy has gained the attention of researchers to develop the solar chimney (SC) technology in recent years. Many studies have been conducted in this aear both experimentally and theoretically, whereas experimental studies are mainly focused on small-scale systems. This work provides a comprehensive and updated review that include most of the experimental studies, analytical and simulation works, the solar chimney applications, hybrid systems and geographical case studies based on extended references, citation of the updated works and the specified way of looking at different sections. The technological gaps in differnet sections are identified and a summary of suggestions is given for the future work, including more experimental works on the large-scale systems, and CFD analyses for optimization between the geometrical parameters and the output power. More studies on new applications of solar chimney technology including hybrid systems are also recommended.
The big data performances of Organic Rankine Cycle (ORC) system is widely used in avariety of industrial applications. In some processes, the axial flow turbine at the low temperature heatsource is crucial. The goal of this work is to increase the high efficiency of a tiny axial turbine poweredby an Organic Rankine Cycle (ORC) utilizing numerical studies and deep learning method. To providethe best performance for the Organic Rankine Cycle (ORC) application, various turbine stages aresuggested. Three-dimensional RANS computations are recommended for five different rotational speedsand four mass flow rates ranging from 0.2 to 0.5 kg/s with an inlet temperature of 365 K in order todescribe the hydrodynamic and thermodynamic capabilities and get a big data. The analysis show that thetwo-stage turbine with a fixed rotational speed delivers the highest power output value of 10000W, hasthe highest turbine efficiency of 86%.In a three-stage turbine arrangement operating at steady state, theefficiency of the turbine and its output are 89% and 12000 W, respectively. The maximum values forturbine efficiency and power production are 88% and 12000W, respectively, as a result of the transientcomputational procedure. These results demonstrate the potential for exchanging low temperature heatsources using micro-three-stage axial turbines in Organic Rankine Cycle (ORC) systems .
Thermodynamic analysis of energy efficiency, especially those utilizing the second law ofthermodynamics, is focus of scientific inquiry, particularly given the interest in the efficient use of heatedenergy sources. In this work, we characterize the geometry in terms of entropy generation witch due tothe heat transfer and fluid friction as function of generalized Reynolds number under the effects ofdifferent inlet temperatures.This work has been performed for the important parameters in the following ranges: generalizedReynolds number (Reg = 1 to 60). As generalized Reynolds number increases, the entropy generation dueto heat transfers decreases, which reveal that the effect of the generalized Reynolds number on heattransfer performance is substantial. These results verify that the T-shaped channel can effectively enhancethe heat transfer performance for all cases. Overall, the entropy generation and synergy angle aresignificant characteristics to consider when building micromixers for thermal efficiency and misciblefluid mixing.
Heat and mass transfer in many systems are widely accomplished applying natural convection process due to their low cost, reliability, and easy support. Typical applications include different mechanisms in various fields such as (solar energy, solar distiller, stream cooling, etc…). Numerical results of turbulent natural convection and mass transfer in an open enclosure for different aspect ratios (AR = 0.5, 1, and 2) with a humid-air are carried out. Mass fraction and local Nusselt number were proposed to investigate the heat and mass transfer. A heat flux boundary conditions were subjected to the lateral walls and the bottom one make as an adiabatic wall, while the top area was proposed as a free surface. Effect of Rayleigh numbers (106≤????????≤108) on natural convection and mass flow behavior are analyzed. The governing equations are solved using CFD Fluent code based on the SIMPLE algorithm. The results showed that the cavity with an aspect ratio of AR = 2 has a significant enhancement to raise the rates of both heat and mass transfer. When the Rayleigh number increases, maximum heat transfer rates were observed due to the fluid flow becomes more vigorous. However, mass transfer improves as the Rayleigh number decreases.
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