Impinging jet ventilation (IJV) systems have attracted significant attention due to their potential to augment indoor thermal comfort and airflow distribution. Previous studies have primarily investigated corner and mid-wall IJV installations; however, comparative analyses focusing on different diffuser geometries remain limited. Accordingly, this study examines the combined effects of IJV diffuser geometry and installation location on thermal comfort indices and airflow characteristics. A full three-dimensional computational fluid dynamics (CFD) model, without the use of symmetry, is developed to simulate a realistic office environment (3 × 3 × 2.9 m³), operating in cooling mode under hot summer climatic conditions. Three IJV diffuser cross-section geometries—triangular, square, and circular—are evaluated at four installation locations (two corners and two mid-wall positions), assuming a fixed occupant location. A combined return and exhaust outlet configuration is adopted. The results indicate that the IJV location influences airflow and temperature distributions more strongly than the diffuser geometry. Nevertheless, the circular diffuser exhibits superior performance compared to the triangular and square geometries. The mid-wall location placed behind the occupant and away from the hot exterior wall demonstrates reduced thermal stratification, improved airflow characteristics, and weaker vortex formation, making it the most favorable configuration. From an architectural perspective, these findings highlight the importance of early coordination between ventilation design and office spatial planning, as diffuser placement directly influences occupant comfort zones and furniture layout. Moreover, the preference for mid-wall installations supports a more flexible façade design and allows for greater freedom in organizing workspaces without compromising thermal performance.

This investigation attempts to develop a tower solar collector-based system designed for the cogeneration of cooling and desalination. The traditional organic Rankine cycle (ORC) integrated with the ejector refrigeration cycle generates limited power and cooling at a single temperature. Acknowledging their limitations, our present study uses an organic flash cycle (OFC) supported by solar heat combined with the two-phase ejector cycle and the reverse osmosis (RO) desalination unit. Since the OFC turbine is fed with two extra streams of fluid, therefore, it provides greater power to run the compressor of the ejector and pumps of the RO unit, resulting in the production of cooling at two different temperatures (refrigeration and air conditioning) and a higher mass flow rate of fresh water. A mathematical model is employed to assess the impact of coil curvature ratio, Rib height, and direct normal irradiation (DNI) on the temperature of the collector’s oil outlet. ANSYS-FLUENT conducts numerical simulations through computational fluid dynamics (CFD) analysis. The results indicate an ultimate increase in oil outlet temperature of 45% as the DNI increased from 450 to 1000 W/m² at a curvature ratio of 0.095 when employing the 1st Rib. Further, a steady-state energy and exergy analysis is conducted to evaluate the performance of the proposed cogeneration, with different design parameters like DNI, coil curvature ratio, rib height, and OFC turbine inlet pressure. The energetic and exergetic efficiencies of the cogeneration system at DNI of 800 W/m² are obtained as 16.67% and 6.08%, respectively. Exergetic assessment of the overall system shows that 29.57% is the exergy produced as cooling exergy, and the exergy accompanied by freshwater, 68.13%, is the exergy destroyed, and 2.3% is the exergy loss. The solar collector exhibits the maximum exergy destruction, followed by the ejector and RO pumps. Integrating multiple technologies into a system with solar input enhances efficiency, energy sustainability, and environmental benefits.

Z- and U-type parallel pipe network configurations are widely used in engineering applications such as solar collectors, fuel cells, microchannels, spargers, and irrigation systems. Although the Z configuration is more commonly employed, the U configuration may provide advantages under specific operating conditions. This study presents a comparative analysis of the two configurations in terms of flowdistribution uniformity and pressure drop. A three-dimensional computational fluid dynamics (CFD) model was developed to simulate realistic solar collector conditions, including both fluid and solid domains together with detailed inlet and outlet junctions. The system consists of manifolds and headers with a diameter of 20 mm and a length of 1150 mm, connected to ten parallel tubes of 7 mm diameter and 1780 mm length. The analysis was conducted over a wide range of inlet Reynolds numbers (Re_D = 100–5000) to represent diverse practical operating conditions. The CFD model was validated against experimental data from the literature and showed good agreement. Flowdistribution uniformity was evaluated using two quantitative indicators. The results show that flow maldistribution increases with Reynolds number in both configurations; however, the U configuration exhibits significantly improved flow uniformity at higher Reynolds numbers. In addition, both configurations exhibited comparable pressure drop characteristics over the investigated operating range. The findings suggest that the U configuration is better suited to high-flow-rate applications that require improved hydraulic and thermal uniformity, while the Z configuration remains effective at lower Reynolds numbers.

This study presents an integrated receiver-level thermal–hydraulic and energy–exergy assessment of conventional Solar Salt and a 5 wt.% MgO–Solar Salt nanofluid in a three-dimensional parabolic-trough receiver. The novelty lies in systematically determining whether the experimentally characterized thermophysical-property modifications associated with MgO addition translate into receiver-level benefits across variations in receiver length, inlet temperature, and solar-thermal loading, while simultaneously considering heat-transfer performance, hydraulic demand, exergy destruction, and entropy generation. Steady turbulent flow was simulated for receiver lengths of 5, 6, and 7.5 m, inlet temperatures of 240–290 °C, and absorbed wall heat fluxes of 159.375, 178.125, and 225.000 kW m⁻², corresponding to direct normal irradiance values of 850, 950, and 1200 W m⁻², respectively. Temperature-dependent density, specific heat capacity, thermal conductivity, and dynamic viscosity were implemented for both fluids, and the mass flow rate was determined separately for each fluid and inlet temperature from the imposed inlet velocity. Across the 108 simulated cases, Solar Salt–MgO reduced the mean absorber-wall temperature by 4.74% and increased the mean exergy efficiency from 85.33% to 89.92%. Mean entropy generation decreased from 37.24 to 24.79 W K⁻¹, corresponding to a 34.0% reduction, while mean pumping power decreased slightly from 8.22 to 8.12 W. The mean fluid heat gain increased by 1.28%, although individual cases ranged from a 3.94% increase to a 4.57% reduction. Despite the improved dimensional convective heat-transfer performance, the nanofluid exhibited lower Nusselt numbers because the increase in thermal conductivity exceeded the increase in the convective heat-transfer coefficient, demonstrating that the Nusselt number alone does not fully represent its thermal advantage. Overall, Solar Salt–MgO reduced receiver temperature and thermodynamic irreversibility without incurring a substantial hydraulic penalty under the conditions investigated. Validation against published turbulent molten-salt tube-flow experiments showed that all 14 numerical predictions remained within the reported ±7.2% experimental uncertainty band.

Uniform and energy-efficient brick cooling is important for product quality, heat recovery, and tunnel-kiln performance. This study examines how vertical heat-source placement affects airflow, convective heat transfer, heated-surface temperature uniformity, pressure loss, and ideal air-side pumping demand in a 1:4-scale tunnel-kiln cooling-zone model. A three-dimensional CFD model was validated against published Nusselt-number measurements over Re = 15,938–30,890. The predicted average Nusselt numbers showed a mean absolute deviation of 6.55%. All configurations contained four complete thermally active brick units: two longitudinal sources (H1–H2) and two transverse sources (H3–H4). In Setting 1, the longitudinal and transverse sources occupied layers 3 and 2, respectively; in Setting 2, they occupied layers 1 and 2; and in Setting 3, layers 3 and 4. The configurations were compared over setting-specific Reynolds numbers of 16,829–30,641 while maintaining identical brick geometry, source number, and total imposed thermal input. Source placement affected thermal performance mainly by changing the exposure of heated surfaces to established high-velocity passages and wake regions. Setting 3 produced the highest average Nusselt number at the lowest and highest operating points, whereas Setting 1 was marginally higher at two intermediate points. At the highest point, where inlet velocities differed by less than 0.6%, Setting 3 increased the average Nusselt number by approximately 7–8% relative to Setting 2 while requiring about 4.5% less ideal pumping power. Under the investigated scaled, steady forced-convection conditions, Setting 3 provided the most favorable combined performance in terms of convective heat transfer, heated-surface temperature uniformity, and ideal air-side pumping demand.