The electronic industry’s shift towards multicore processor technology which leads to an increase the power densities of the chip. In multicore processors the hotpot location arises depending on the computational load which leads to the generating the non-uniform heat flux. The uneven cooling of a multicore processor will affect the reliability and life span of the chip. In this study, employed parallel microchannel cooling systems (PMCHS) with different flow configurations by numerical simulations. The objective of the present work is to investigate the thermos-hydrodynamic characteristics of a PMCHS under a non-uniform heat load, the heat load is considered from an actively running 8-core processor. Here, considered that three types different flow configurations (U, I and Z) to determine the flow maldistribution, in additions the thermal performance of each flow configuration was analysed at non-uniform heat conditions. The size and shape of the PMCHS is equal to the octa-core processor which has been mimicked, and real-time heat load data of the processor has been retrieved. The present study exhibits that non-uniform thermal load creates additional non-uniform temperature distribution along with flow maldistribution in the PMCHS. Each flow configuration has a different flow maldistribution pattern, whereas the sometimes intended flow maldistribution helps to give better uniform cooling on the chip.

This study aims to analyze the cooling performance of parallel microchannel heat sinks (PMCHS) under uneven heat flux distributions, taking into account different flow configurations including I, U, and Z. The objective is to demonstrate the potential of utilizing the flow maldistribution inherent in each configuration to effectively manage and mitigate the effects of uneven heat flux distributions. Four different heating arrangements have been considered, namely uniform, non-streamline, streamline, and across-streamline to generate the uneven heat flux distributions. A three-dimensional numerical simulation has been performed to analyze the combined effect of uneven heat flux distributions and flow maldistribution characteristics on the thermal performance of PMCHS. To assess the thermal performances; thermal resistance (R), Nusselt number (Nu), temperature nonuniformity (?), and fin efficiency (?) have been employed. The results show that all three flow configurations exhibit similar thermal performances for uniform heat load conditions (0.1 K/W for R, 5.5 kW for Nu, 0.3 for ?, and 0.98 for ?). However, in the case of uneven heat flux distributions, the thermal performance of each configuration is observed to be varying with respect to hotspot positions. This study reveals that each configuration has a huge discrepancy in terms of thermal performance with respect to uneven heat flux distributions. Also, the study concludes that a single flow configuration alone is insufficient to address the cooling challenges that arise due to uneven heat flux distributions. The cooling capability of any configuration to handle uneven heat distributions mainly depends upon the flow maldistribution characteristics of the respective configurations.

Cooling methods for multiple hotspots with high heat flux pose a reliability threat to electronic devices. This study investigates the microchannel-based heat sink performance under various non-uniform heat load conditions for different geometry with three different flow configurations (I, U and Z). An in-house designed Heater Array Unit (HAU) facilitates the generation of both uniform and non-uniform heat loads using a heater power supply. Two different microchannel geometries were employed, namely, microchannel-1 (MC-1) with channel and fin widths of 0.6 mm and 0.33 mm, respectively, and MC-2 with dimensions of 0.64 mm and 0.572 mm. Each microchannel incorporates three manifold configurations (I, U, and Z). Each flow configuration is regulated by flow control valves. Various non-uniform heat load patterns were considered, including streamline, non-streamline, and across-streamline conditions. To assess the thermal performance of the heat sinks the parameters used are thermal resistance (R th ), Nusselt number ( Nu ), and temperature non-uniformity (?). Experimental findings indicate that the MC-2 design with an I flow configuration is more suitable for uniform heat load conditions. On the contrary, for some non-uniform heat load cases MC-1 also showed up as a suitable design over MC-2.

The parallel microchannel heat sink stands as a pivotal solution in managing high heat flux electronics due to its efficient heat transfer characteristics and ease of manufacturing. While numerous studies have explored the thermal performance and flow characteristics of microchannel heat sinks, most have focused on uniform heat loads or relied heavily on numerical methods. This study presents an experimental system tailored to generate data for analyzing the thermal performance of microchannel heat sinks under various conditions. Leveraging this dataset, four distinct machine learning models Artificial Neural Network (ANN), XGBoost, LightGBM, and K-nearest neighbor (KNN) were trained using 22 input features, totalling 560 data points categorised into geometry parameters, heating patterns, and boundary conditions details. The models were tasked with predicting six response variables: the average base temperature of the heat sink, temperature change (?T), hotspot temperature, heat transfer coefficient (h), Nusselt number (Nu), and thermal resistance (Rth). Among the four machine learning models, XGBoost exhibited a good predictive accuracy of an average R2 value of 0.98 and MAE values of 2.1 across all responses. Furthermore, the study delved into the impact of varying input features on prediction accuracy, revealing a consistent enhancement in accuracy with the inclusion of more features across all models. © 2024 Elsevier Ltd

Aerial inspection of solar PV plants using Unmanned Aerial Vehicles (UAVs) is gaining traction due to benefits such as no downtime and cost-effectiveness. This technology is proven to be the low-cost alternative to conventional approaches involving visual inspection and I-V curve tracing to identify physical damages and underperforming strings, respectively. Though the use of UAVs for thermographic solar PV inspection is a popular alternative in developed countries, its use in developing economies experience various challenges. Studies emphasizing these challenges especially in the context of rapid evolution of drones are limited. To overcome this limitation, literature scoping, a one-on-one survey, focus group discussion, and a flight campaign using a UAV with a thermal payload is conducted in India to identify the limitations. These are further categorized into Technical, Behavioural, Implementation, Pre-deployment, Deployment, and Post-deployment categories. The relevance and significance of each challenge are analysed using a hybrid multi-criteria framework developed in this study. Findings of this study highlight the importance of drone regulations, technology readiness, and workshops for drone pilots, industry professionals, and solar developers in India. This study aid developing economies in devising strategies that can promote the use of UAVs for solar PV plant commissioning activities.

Designing an effective parallel microchannel heat sink (PMCHS) is necessary for addressing the cooling challenges of high heat-dissipating electronics. This paper presents a shape optimization of PMCHS to minimize the thermal resistance and pressure drop for each U, I, and Z-type inlet/outlet manifold configuration with vertical intake and coolant delivery. The performance of PMCHS influencing design parameters, such as channel width, fin width, and channel height, is designed using the response surface methodology (RSM). In the present communications adopting the Artificial Neural Network (ANN) coupled NSGA-II method, a three-dimensional numerical simulation is executed to minimize the pressure drop and thermal resistance. Numerical simulation is performed using the finite volume method; the computational domain is taken as the entire microchannel system including the inlet/outlet plenum area, ports and microchannels. The overall analysis demonstrated that the pareto optimal design point has better hydraulic and thermal performances than the predefined design. The optimized design showed benchmark thermal resistance of 0.0306 ?C/W, 0.0315 ?C/W, 0.0316 ?C/W and pressure drop of 3.1 kPa, 3.2 kPa, 3.19 kPa for U, I, Z configurations respectively.

A compound parabolic concentrator (CPC) with a flat absorber is widely used in low-concentrating photovoltaic thermal (CPVT) systems. CPC certainly develops non-uniform heat flux distribution over the absorber surface which is significantly reduced by the integration of homogenizer referred as Elongated CPC (ECPC). The objective of the present work is to analyse the effect of homogenizer ratios, truncation ratios and concentration ratios on the heat flux distribution characteristics of a CPC collector. In this paper, a ray tracing simulation is carried out to obtain the heat flux distribution profiles and the same is incorporated within CFD software to obtain the temperature distribution profiles. As a result, it is observed that the optimum truncation ratio would be 0.7 at which uniformity in flux distribution is improved by 3%, with just 2% reduction of average heat flux value. Furthermore, with optimized homogenizer ratio of ?0.35 at concentration ratio of 3, 64% improvement in uniformity of flux distribution has been noticed. From the study, it has been concluded that for different concentration ratios of 1.5, 2, 3, 4, 5, 6, 7 and 8, the optimum homogenizer ratio is observed to be ?0.9, ?0.55, ?0.35, ?0.25, ?0.2, ?0.15, ?0.15 and ?0.05 respectively.

The Compound Parabolic Concentrator (CPC), when coupled with the photovoltaic system, namely the Concentrated Photovoltaic Thermal System (CPVT), makes utilizing solar energy efficient. The major challenge that hinders the electrical and thermal performance of the CPC–CPVT system is the non-uniform heat flux distribution on the absorber surface. In the present paper, detailed ray-tracing simulations have been carried out to understand the heat flux distribution characteristics of CPC with different geometrical conditions, and those are concentration ratio, truncation ratio, incident angle, and average heat flux on the absorber surface. To have a thorough understanding, the analysis has been carried out in multiple steps. First, it is performed by analyzing the effect of concentration ratio and incident angle on heat flux distribution characteristics at a fixed truncation ratio. Second, investigations have been carried out to understand the heat flux distribution characteristics at different truncation ratios and different incident angles by keeping the concentration ratio constant. Local concentration ratio and non-uniformity index have been employed to quantify the non-uniformity of heat flux distribution on the absorber surface. It has been observed that the 0-deg incidence angle is the most effective angle to achieve uniform heat flux distribution on the absorber surface. This paper sheds insight into the heat flux distribution characteristics on the absorber surface of a CPC–CPVT system which can be used by the research community for designing an effective CPVT system from the perspective of uniform heat flux distribution on the absorber surface.

Thriving technologies in the electronics industry demands effective cooling systems for proper thermal management of the devices. To propose an effective cooling system, real-time challenges need to be taken into examination. One of the challenges is the non-uniform heat load emitted by the device. In this paper, a multicore processor has mimicked for the heat load and examined with U configured parallel microchannel cooling system (PMCS) for its capacity to cool the processor effectively. A detailed numerical examination has been conceded out by mimicking the AMD Ryzen-7 octa-core processor for its size, shape and heat load. To make it convenient for applying non-uniform heat load, the shape of the PMCS is divided into 4*4 array of a total of 16 heaters. The present has witnessed that, there is an uneven distribution of fluid flow across the channels. The initial channels do get more quantity of fluid whereas the end channels do get a very less quantity of fluid. Why because of the flow maldistribution, it formed the hot spots (high-temperature zones), which will be further intensified due to the non-uniform heat load emitted by the processor. It perceived from the present numerical analysis, there is a formation of hotspots not only due to the random location of active cores but also due to the flow maldistribution across the channels. The flow arrangement of U configuration having worse flow distribution among other existing configuration. The present work conclusively demonstrates that high maldistribution leads towards dropping the uniformity of cooling. But the existing maldistribution can be effectively exploited to tackle the non-uniform heat load released by the processor when the active core location falls in the place of initial channels.

The hydrodynamic performance of microchannel cooling systems has been predicted analytically. The microchannel have a high surface area to volume ratio, due to that it has high heat transfer coefficients. The microchannel cooling systems have received prompt attention from researchers to address the cooling challenges of electronic components. However, due to the diameter of the order of microns, as the pressure drop is inversely proportional to the channel diameter, it leads to more pressure drop in the microchannel. Such that the investigation of flow characteristics in the microchannel is tremendously on-demand to understand hydrodynamics. Unfortunately, the applicability of conventional theories (Darcy pressure drop equations) in microchannel flows is still under debate. Kandlikar has come up with an expression for predicting pressure drop in microchannels by considering the Poiseuille number and aspect ratio of microchannels. This paper concentrated on validating the predictions of the Kandlikar pressure drop equation and Darcy pressure drop equation with experimental work taken from literature. The results show that available analytical methods are under-predicting as those will not consider the surface roughness and uncertainty present while conducting experiments. Among the analytical models, the Kandlikar equation predictions are better than the other methods, and the results of the prediction are well in agreement with experimental results.

Modification and control of the vaporization kinetics of microfluidic droplets can find utilitarian implications in several scientific and technological applications. The article reports the control over the vaporization kinetics of pendant droplets under the influence of competing internal electrohydrodynamic and ferrohydrodynamic advection. Experimental and theoretical studies are performed and the morphing of vaporization kinetics of electrically conducting, paramagnetic fluid droplets using orthogonal electric and magnetic stimuli is explored. Analysis reveals that the electric field has a domineering influence compared to the magnetic field. While the magnetic field is observed to augment the vaporization rates, the electric field is observed to decelerate the same. Neither the vapour diffusion dominated model, nor the field induced modified surface tension characteristics can explain the observed behaviours. Velocimetry studies within the droplet show extensively modified internal ferro and electrohydrodynamic advection, which is noted to be the crux of the mechanism towards modified vaporization rates. A mathematical analysis is proposed, which takes into account the roles played by the concomitant governing Hartmann, Electrohydrodynamic, Interaction, thermal and solutal Marangoni, and the electro and magneto Prandtl and Schmidt numbers. It is observed that the morphing of the thermal and solutal Marangoni numbers by the electromagnetic Interaction number plays the dominant role towards morphing the advection dynamics. The model is able to predict the internal advection velocities accurately. The findings may hold importance towards smart control and tuning of vaporization kinetics in macro and microfluidic systems.

The concentrated solar dish collector is a promising technology for generating both electricity and thermal energy together and it is termed as concentrated photovoltaic thermal. The important component of the parabolic dish collector is the absorber; where all concentrated lights are falling. The present paper has investigated the heat flux distribution characteristics of the flat plate absorber based solar dish collector by using the ray-tracing simulations. In concentrating dish collector, rim angle and dish diameter are significant factor of the flux distributions. The present study reported the average heat flux distribution, maximum flux intensity and non-uniformity of flux distribution for different geometrical conditions. The maximum heat flux rate attains the rim angle between 35 to 55° for any dish diameter. Where the peak flux intensity raises concerning raises of rim angle and peak flux occurred at rim angle 90°. The increase of heat flux intensity causes the non-uniformity of heat flux distribution over the absorber surface. The non-uniformity factor is mainly influenced by the rim angle, not a dish diameter. When rim angle 15 & 75°, the non-uniformity is 2.5 & 10 respectively for whichever dish diameters. A critical rim angle produces the non-uniformity factor. Results shows that optimization of rim angle is a significant contribution for decreasing the non-uniformity index of concentrator; it most valuable for coupled thermal and electricity generating applications.