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A numerical simulation of the heat dissipation performance in photovoltaic (PV) cells with phase change material (PCM) for cooling is performed by COMSOL Multiphysics. A comparative analysis of two T-shaped fin designs in PCM heat sinks is conducted to evaluate their impact on the cooling performance of PV panels. The findings indicate that a 180° T-shaped fin design substantially outperforms a cavity without fin design, reducing the PV cell average temperature by up to 15.1 K and enhancing electrical efficiency by 1.36 %. Further optimization of distal fin distance and secondary length reveals that temperature uniformity and photovoltaic efficiency can be improved, achieving a maximum electrical efficiency increase of 1.40 % and a temperature uniformity enhancement of 71.0 %. Detailed analysis underscores the critical role of the distal fin distance (Scheme 1) in temperature control and PCM convection, highlighting its importance in the design process. In contrast, numerical results of the alternative fin layout (Scheme 2) reveal its unsuitability for PV cooling applications.

A plate-fin heat sink is usually used for the hot side of thermoelectric coolers. The plate-fin heat sink should be optimized to improve its heat dissipation capability and eventually elevate the thermoelectric cooler performance. In this paper, a heat dissipation model of the thermoelectric cooler hot side with a plate-fin sink is established, to explore the performances of the plate-fin sink with two types of fins (rectangular and V-type), two convective conditions (lateral and vertical) and three arrangements (single-row, double-row aligned, and double-row staggered). The results show that under vertical jet conditions, double-row aligned rectangular fins have the best heat dissipation capability for the thermoelectric cooler hot side. In order to optimize the fin geometry and maximize its overall performance, a multi-objective optimization of the fins was performed using a machine learning approach based on artificial neural networks (ANN) and non-dominated sorting genetic algorithm (NSGA-ІІ). The corresponding Pareto front is obtained and the technique for order preference by similarity to ideal solution (TOPSIS) method is applied to take the point. Compared with the base case at the same mass flow rate, the fins designed by this method resulted in a 23.3 % reduction in the mean temperature of the hot side.

The melting process of phase change material (PCM) in horizontal latent heat thermal energy storage (LHTES) units with longitudinal and annular fins was experimentally studied under the same fin volume condition. The PCM melting time of the annular fin unit is reduced by 13.7% compared to that of the longitudinal fin unit. The annular fins are more responsive to the increase in heat transfer fluid (HTF) inlet temperature and the longitudinal fins are more responsive to the increase in HTF flow rate. After that, numerical studies were also performed for the two LHTES units to reveal in-depth the differences in heat storage processes. The results show that the longitudinal fins perform better in the early stage due to their larger contact area with the inner tube and a denser distribution near the inner tube. But it also limits the natural convection in the latter stage. The annular fins have better natural convection performance in the latter stage and therefore have better heat storage performance. Based on the analysis, a composite fin was designed to combine the advantages of longitudinal and annular fins. Numerical results show that the newly designed fin results in a 21.6% melting time reduction compared to the longitudinal fin model and a 9.5% melting time reduction compared to the annular fin model. Finally, two principles to guide the fin design in horizontal shell-and-tube LHTES units were summarized. [ABSTRACT FROM AUTHOR]

Growth in the surfing equipment industry has led to increased scientific interest in this area, yet no current paper has reviewed and synthesized the effects of equipment design on surfing. Therefore, the aims of this study were to: (1) assess the volume and type of scientific literature that is available to the authors specific to surfing equipment and design, (2) summarise all surfing equipment and design studies completed to date specific to outcome measures and key findings and (3) identify knowledge gaps in the topic of surfing equipment design. This review was conducted in accordance with the PRISMA scoping review guidelines. A total of seven electronic databases were searched (PubMed, Embase, CINAHL, SPORTDiscus, Web of Science, SCOPUS, and Ovid). Google Scholar was also searched for grey literature. Inclusion criteria were mention of surfing equipment and relevant surfing outcome measures (physiological and mechanical). Exclusion criteria were no full text availability and works not available in English. Results from these articles were then extracted, summarised and presented. A total of 17 articles were selected for review and organized by theme of board, wetsuit and fin. Fin and wetsuit design were the most prominent themes (seven studies each respectively). Most were written within the past 5 years and written in the USA. Fin design studies were largely computational, whereas board and wetsuit design were mostly field and laboratory based. Within each study theme there were consistencies in outcome measures and measuring devices. Board design studies focused on paddling efficiency (VO2 and HR). Wetsuit design studies primarily assessed thermoregulation, and less so muscle activation and paddling biomechanics. Fin design studies focused on fin shape and configuration to assess lift and drag properties. Three key themes of board, wetsuit and fin design were noted; from this the authors were able to identify several knowledge gaps such as a lack of standardisation in equipment controls and study design procedures. Alongside improving standardisation, the use of wave pools presents as an area of interest in future research. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering for Thermal Energy & Power / Reneng Dongli Gongcheng is the property of Journal of Engineering for Thermal Energy & Power and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper, we have simulated different fin geometries at different flow intensities to study the optimum design for better flow and heat transfer characteristics to be used in transformers' cooling. We use energy density of oil (pressure) as flow intensity parameter being a compressible fluid which is dependent on temperature variation. We observe direct proportionality of shear stresses (pressure drop) with flow intensity. Pressure drop is dominant in rectangular fins with higher height-to-width ratio (h/w), and it decreases sharply for lower h / w ratio especially at bends, whereas it is significantly better in conic-shaped fins especially at a ≥ 1.2. We observe an inverse proportionality of temperature drop with the flow intensity due to transient heat transfer phenomenon. We observe smooth temperature drop for conic-shaped fins. We have also investigated oil-based alumina nanofluids (in different wt/V ratios) as coolant for heat transfer enhancement in transformers. It is observed experimentally that dielectric strength improves with oil-based nanofluids. We obtain about 8.67% better results by adding 0.08% particles in oil. Comparative analysis with previous works shows that alumina-based nanofluids have better results than others. Still, there is a lot of work to be done in their use at commercial level due to their short durability. [ABSTRACT FROM AUTHOR]

The Sun is the star in our solar system that beams solar energy towards the Earth, shining it during the day. The researcher discovered different ways to enhance the use of solar radiation to meet daily need because they are aware of how abundant it is. The thermal performance of double pass solar collector (DPSC) is higher compared to flat plate solar collector (FPSC) when comparing their thermal efficiencies. There have been several studies done on the experimental and theoretical analysis of DPSC, where different kind of tests have been carried out on different aspects. This paper aims to reviews recent development (5 years) on double pass solar collector (DPSC) where it highlights the improvement methods, functioning parameters, materials used, and design configurations. By reviewing experimental and theoretical analysis on the double-pass collector with various thermal transfer enhancement, it can help the researchers to keep updated on new development of the double-pass collector. Several methods to improve the convective heat transfer for the system were adding fins, phase change material (PCM), improved absorbers and porous media to the DPSC. Other important things that require improvement are increasing the outlet temperature, efficiency enhancement for DPSC and pressure drop reduction. The effect of using various mass flow rates, solar radiation, temperatures and working fluid on DPSC are also discussed. We wrap this review by identifying numerous applications that are possible for the solar air heating such as space heating and conditioning, water desalination process and drying agricultural food product. • Adding phase change material (PCM), can enhance thermal efficiency for double pass solar collector. • Fins can increase convective heat transfer. • Porous media can accelerate the performance of double pass solar collector. • Adding tubular on absorber can helps to increase the heat efficiency. • New novelty double pass solar collector has been found for the last 5 years. [ABSTRACT FROM AUTHOR]

The employment of annular fins and longitudinal fins in latent heat thermal energy storage unit can significantly improve its thermal performance. However, the annular fins can greatly suppress the convection and longitudinal fins lead to severe non-uniform melting. To address this issue, three different types of combinational fins were proposed and applied in a vertical shell-tube storage unit in this study. The numerical model was first built with the adoption of enthalpy-porosity method. The simulation results were then verified with experimental data. Results showed that combinational fins leads to faster melting thorough enhancing both natural convection and conduction compared with only longitudinal or annular fins. This advantage in melting enhancement is even greater with the increase of fin volume. Moreover, the enhancement effect of combinational fins is better with the same longitudinal and annular fins volume and a higher longitudinal fin at the same longitudinal fin volume. The optimum combinational fins in present work has a melting time reduction of 31.0% and 21.2% compared with only longitudinal and annular fins, respectively. The results can provide important reference for the fins design in vertical shell-tube thermal energy storage units. [ABSTRACT FROM AUTHOR]

A key challenge in the development of a practical thermal storage device (TSD) is the low thermal conductivity of common phase change materials (PCM). This low conductivity impedes both heat input and extraction. The most common solution is to use conductive metal fins to spread heat through the device. However, optimizing the effectiveness of the container and the fin arrangement is difficult due to the large number of potential design parameters. This paper develops a strategy to make simulation-based optimization process affordable and accurate. First, numerical techniques are designed to accurately and efficiently compute heat and mass transport in a variety of geometries without generating grids to conform to each geometry. This facilitates rapid prototyping and mitigates the expense of individual simulations. Second, a pre-screening process identifies the independent variables with the largest and most nonlinear effect on the objective function in the optimization process, thus narrowing the parameter space. Finally, a dynamic Kriging-based optimization approach constructs a multidimensional response surface using sparse input datasets; the response surface is then used to identify an optimal design. The combination of the above three strategies is shown to result in an approach that can aid in the design of optimal thermal storage devices that rely on a mixture of PCM and metal fins. [ABSTRACT FROM AUTHOR]

The cooling performance of a 30 kW switched reluctance motor (SRM) has been evaluated numerically to investigate the cooling design for this motor. The physical model of the 3D motor with exact size has been established using Solidworks. Both JMAG-Designer and ANSYS-FLUENT commercial software were employed to study the electromagnetics, velocity and temperature field for numerical analysis. Aluminum cooling fins were fitted on the cooling casing of the motor in order to enhance the convection heat transfer. Fin design with the same heat transfer area has been discussed. Both air cool and water cool designs of the 30 kW SRM have been examined and discussed for comparison as well. Results show that the maximum temperature in SRM cannot be reduced to a requested operating temperature with air cooling only even with fin design on the casing. They also indicate that liquid cooling is a better approach for SRM cooling. In addition, the Reynolds number of liquid coolant is the key parameter which affects the thermal cooling of SRM. In present study, the temperature rise of motor winding in SRM has been reduced to 42% with liquid water cooling and the maximum temperature in SRM is approximately 128.8 °C. [ABSTRACT FROM AUTHOR]

Bioinspired robotic designs have proven to be effective models for autonomous vehicles as well as important research tools in comparative biomechanics. Here we review the process by which we investigated the functional morphology and biomechanics of fish fins using live fish experiments and computational modeling; created and validated independent fins with regard to biological properties like stiffness, kinematics, and fluid dynamics; and constructed an autonomous underwater vehicle with a sensory feedback system to respond to perturbations. [ABSTRACT FROM AUTHOR]

Natural convection heat transfer from fin arrays was investigated experimentally at a wide range of Rayleigh numbers for fin height and different tip-to-base fin spacing ratios (C=St/Sb) . Base fin spacing, fin length and fin thickness were kept fixed at 12, 100 and 3 mm respectively. The ratio C was varied from 0.25 to 1 and fin height was also varied from 15 to 40 mm. It was found that the convection heat transfer rate from fin array takes on a maximum value as a function of the C and fin height for a given temperature difference between fin arrays and surrounding. The results obtained from experimental study showed that the optimum C which yields the maximum heat transfer rate is between C=0.50 and C=0.75. The optimum ratio also depends strongly on the fin height and Rayleigh number. It was observed that fin arrays with an optimum ratio gave higher Nusselt numbers compared to rectangular shaped fin arrays. The increase in the Nusselt number was determined to be about 33%. An empirical correlation for the Nusselt number was derived in the result of experimental study. [ABSTRACT FROM AUTHOR]

Air cooling photovoltaic can be configured as a method to improve the performance of Photovoltaic thermal (PV/T) system. In this article, a series of aluminum rectangular fins were considered as an important augmented medium of heat conduction and convection. The efficiency of the installed fins was obtained by analysis of the general algebraic modeling system, which was validated for different fin heights and thicknesses. Fins were incorporated in reducing the cell temperature that obtained a higher outlet temperature of PV/T with time. It was observed that the collector outlet air temperatures, PV cell temperatures for different air flows and solar radiations under the different fin geometries in an indoor experimental condition. The output PV/T power was compared between 'with fin' and 'without fin' condition. The optimum interrupted length and height of a fin makes a compact relationship for the thermal and electrical performance. Results showed that the heat gain has been increased with the increasing of the solar irradiance at a constant air velocity. The collector heat gain value was found about 159.8W at 700 W/m solar radiation with four fins design. [ABSTRACT FROM AUTHOR]

Optimal design of longitudinal fins augmented to the outer surface of the inner pipe in a double pipe, is investigated for maximizing conjugate heat transfer coefficient. Piecewise Cubic Hermite Interpolating Polynomial (PCHIP) has been used for fin-surface representation at each step of the optimization process with control points as the design variables. Genetic algorithm has been employed as the optimizer together with the Discontinuous Galarkin Finite Element Method (DG-FEM) as the solver of the governing equations. The results show that the optimal fin design is greatly influenced by the characteristic length, the number of fins, the conductivity of the material of heated surface and the number of control points. Optimal designs based on the equivalent diameter give upto 289% improvement in the heat transfer coefficient and those based on the hydraulic diameter render such improvement upto 70%. Optimal fin shape has also out-performed the conventional fin shapes present in the literature and shown upto 203%, 263% and 227% increase in the heat transfer coefficient relative to the equivalent diameter for trapezoidal, triangular and parabolic fins respectively. For the case of hydraulic diameter, these figures are respectively 482%, 70% and 117%. The optimal designs based on the equivalent diameter corresponding to Ω = 500 have proven to be the best in view of cost, frictional loss and heat transfer coefficient. These give upto 39% higher heat transfer coefficient than the corresponding increase in frictional loss due to augmentation of the fins to the double pipe. The validity and accuracy of the present results has been shown by comparison with the available literature results. [ABSTRACT FROM AUTHOR]

Highlights: [•] Optimum fin shape is determined for natural convection and radiation heat transfer. [•] Fin array with the optimum shape has a much greater average heat transfer coefficient. [•] The most important factors affecting the heat transfer coefficient are determined. [Copyright &y& Elsevier]