Showing papers on "Heat sink published in 2019"
TL;DR: In this article, the authors present a critical review of heat transfer applications of nanofluids, including radiators, circular tube heat exchangers, plate heat exchanger, shell and tube heat exchange, and heat sinks.
Abstract: This paper presents a critical review of heat transfer applications of nanofluids. The effects of nanoparticle concentration, size, shape, and nanofluid flow rate on Nusselt number, heat transfer coefficient, thermal conductivity, thermal resistance, friction factor and pressure drop from numerous studies reported recently are presented. Effects of various geometric parameters on heat transfer enhancement of system using nanofluids have also been reviewed. Heat transfer devices covered in this paper include radiators, circular tube heat exchangers, plate heat exchangers, shell and tube heat exchangers and heat sinks. Various correlations used for experimental validation or developed in reviewed studies are also compiled, compared and analyzed. The pros and cons associated to the applications of nanofluids in heat transfer devices are presented in details to determine the future direction of research in this arena.
388 citations
TL;DR: In this article, the authors focused on various flow and heat transfer modes of nanofluid, metal foam and the combination of the two, with the physical properties of nanophluid and metal foam summarized.
252 citations
TL;DR: In this paper, the authors evaluated the thermohydraulic attributes of a hybrid nanofluid containing graphene-silver nanoparticles in a microchannel heat sink equipped with the ribs and secondary channels.
208 citations
TL;DR: In this article, the effects of phase change material (PCM) and a nano/nano-PCM on the thermal performance of an electronic chipset have been investigated in passive and active operating modes.
160 citations
TL;DR: In this paper, the authors present a correlation to estimate the optimum number of fins and optimum PCM volume fraction in a phase change material (PCM) based heat sink, where the objective function is defined as the longest safe operating time of the device prior to reach the critical temperature.
139 citations
TL;DR: In this article, a critical review of different heat sink designs, limiting factors, effectiveness, limitations of various techniques and recent advancements in the field of innovative heat sinks is presented. But, the focus of the review was not on the design of the heat sink, but rather on its suitability for present day heat dissipation issues, statistical data of various heat sinks designs and a rich discussion of the work so far.
122 citations
TL;DR: In this paper, the numerical simulation of a segmented annular thermoelectric generator (SATEG) is investigated using three-dimensional finite element analysis and the performance of the generator is compared with non-segmented ANNs.
120 citations
TL;DR: In this article, the state-of-the-art cooling methods of photovoltaic (PV) modules and the performance of the radiative cooling method in detail are evaluated.
Abstract: This paper reviews the state-of-the-art cooling methods of photovoltaic (PV) modules and evaluates the performance of the radiative cooling method in detail. Higher operating temperatures of PV modules cause degradation of conversion efficiency and long-term reliability. To overcome this drawback, active or passive cooling methods using heat pipe, natural/forced air flow, forced water flow, phase change material, direct liquid immersion/submerging, and passive heat sink have been studied. In this paper, the methodologies and cooling effects of various cooling methods in the literature are summarized to provide a comprehensive overview of the current cooling technologies. Then, the performance of the radiative cooling method, which is simple and passive (zero power consumption) method, is quantitatively evaluated based on a detailed heat transfer model considering sky radiation properties in four typical climate conditions. Daily heat budgets of the PV modules with different surface emissivity spectra are simulated to estimate the solar cell temperature. The results indicate that modification of the surface emissivity spectrum hardly contribute to the radiative cooling enhancement under any climate conditions, as compared to the conventional glass cover. The present findings serve as a guide for future research and development of better cooling methods.
118 citations
TL;DR: In this article, the performance of TiO2 nanofluids as coolant in wavy channel heat sinks having three different channel configurations was investigated and the results indicated that for all heat sinks, Nanofluid showed better heat transfer characteristics than distilled water.
Abstract: The present study comprises experimental investigation on heat transfer and hydrodynamic characteristics of TiO2 nanofluid as coolant in wavy channel heat sinks having three different channel configurations. The performance of TiO2 nanofluids having concentrations of 0.006, 0.008, 0.01 and 0.012 vol% is compared with that of distilled water under laminar regime at heating powers of 25 W, 35 W and 45 W. Results indicated that for all heat sinks, nanofluids showed better heat transfer characteristics than distilled water. With an increase in heating power, TiO2 nanofluid thermal performance was decreased. Using 0.012% TiO2 nanofluids, minimum wall base temperature and maximum enhancement in Nusselt number are noted as 33.85 °C and 40.57%, respectively, for heat sink with wavelength of 5 mm and amplitude of 0.5 mm corresponding to Reynolds number of 894 at heating power of 25 W. Pumping power requirement is function of flow rate and pressure drop, and its maximum value of 0.0284 W is associated with heat sink with minimum wavelength. Moreover, variation in wavelength of channel is found to have dominating effect on heat transfer performance of heat sink as compared to the width of channel.
105 citations
TL;DR: In this article, two configuration models of porous media are evaluated: metal foam with similar particle diameters (2mm) and different porosities (0.85, 0.95) and similar porosity (0, 2, 3 mm) and the optimal arrangements of metal foam at both models are selected according to the performance evaluation criteria value.
Abstract: Although many studies have addressed the urge of exploring the porous media partially embedded in a channel due to its wide engineering applications, the heat transfer and fluid flow of a channel consisting of multilayered metal foam are relatively untouched. To tackle this research gap, a numerical study is conducted to analyze a channel partially filled with a three-layered porous medium—occupying sixty percent of a heat sink—over the Reynolds numbers ranging from 50 to 150 and water base fluid. To this aim, two configuration models of porous media are evaluated here: metal foam with (A) similar particle diameters (2 mm) and different porosities (0.75, 0.85, 0.95) and (B) similar porosities (0.88) and different particle diameters (1, 2, 3 mm). Darcy–Brinkman–Forchheimer and local thermal non-equilibrium methods are used to solve the momentum and energy equations in the porous region, respectively. The validity assessment of the local thermal equilibrium method elucidates that its accuracy is questionable at higher porosities and particle diameters of the metal foam—highlighting the necessity of incorporating the LTNE method under the mentioned circumstances. Among the considered geometries, the optimal arrangements of metal foam at both models are selected according to the performance evaluation criteria value.
100 citations
TL;DR: In this paper, the impact of nanoadditives volume fraction, Reynolds number, amplitude and wavelength of the channel on the convective heat transfer coefficient, CPU surface temperature, pumping power, as well as the thermal, frictional, and total irreversibilities are investigated.
TL;DR: In this paper, the application of computational fluid dynamic and artificial neural network to analyze the nanofluids jet impingement heat transfer and pressure drop in the micro-channel heat sink has been presented.
TL;DR: In this paper, the authors aim to enhance the hydrothermal performance of a porous sinusoidal double-layered heat sink using nanofluid, and obtain the optimum thickness of metal foam (nickel) for different Reynolds numbers ranging from 10 to 100 for the laminar regime and Darcy numbers from 10−4 to 10−2.
Abstract: The present study aims to enhance the hydrothermal performance of a porous sinusoidal double-layered heat sink using nanofluid. The optimum thickness of metal foam (nickel) for different Reynolds numbers ranging from 10 to 100 for the laminar regime and Darcy numbers ranging from 10−4 to 10−2 is obtained. At the optimum porous thicknesses, nanofluid (silver–water) with three volume fractions of nanoparticles equal to 2, 3, and 4% is employed to enhance the heat sink thermal performance. Darcy–Brinkman–Forchheimer model and the local thermal non-equilibrium model or two equations method are employed to model the momentum equation and energy equations in the porous region, respectively. It was found that in the cases of Darcy numbers 10−4, 10−3, and 10−2 the dimensionless optimum porous thicknesses are 0.8, 0.8, and 0.2, respectively. It was also obtained that the maximum PEC number is 2.12 and it corresponds to the case with Darcy number 10−2, Reynolds number 40, and volume fraction of nanoparticles 0.04. The validity of local thermal equilibrium (LTE) assumption was investigated, and it was found that increasing the Darcy number which results in an enhancement in porous particle diameter leads to some errors in results, under LTE condition.
TL;DR: In this paper, the effects of temperature, microchannel cross-section shape, volume concentration of nanoparticles and Reynolds number on thermal and hydraulics behavior of the nanofluid were investigated in terms of velocity, Nusselt number, pressure drop, friction loss and pumping power.
Abstract: This study aims to model the nanofluid flow in microchannel heat sinks having the same length and hydraulic diameter but different cross-sections (circular, trapezoidal and square).,The nanofluid is graphene nanoplatelets-silver/water, and the heat transfer in laminar flow was investigated. The range of coolant Reynolds number in this investigation was 200 ≤ Re ≤ 1000, and the concentrations of nano-sheets were from 0 to 0.1 vol. %.,Results show that higher temperature leads to smaller Nusselt number, pressure drop and pumping power, and increasing solid nano-sheet volume fraction results in an expected increase in heat transfer. However, the influence of temperature on the friction factor is insignificant. In addition, by increasing the Reynolds number, the values of pressure drop, pumping power and Nusselt number augments, but friction factor diminishes.,Data extracted from a recent experimental work were used to obtain thermo-physical properties of nanofluids.,The effects of temperature, microchannel cross-section shape, the volume concentration of nanoparticles and Reynolds number on thermal and hydraulics behavior of the nanofluid were investigated. Results are presented in terms of velocity, Nusselt number, pressure drop, friction loss and pumping power in various conditions. Validation of the model against previous papers showed satisfactory agreement.
TL;DR: The “When2Heat” dataset is introduced, comprising synthetic national time series of both the heat demand and the coefficient of performance (COP) of heat pumps for 16 European countries, includes the years 2008 to 2018, and features an hourly resolution.
Abstract: With electric heat pumps substituting for fossil-fueled alternatives, the temporal variability of their power consumption becomes increasingly important to the electricity system. To easily include this variability in energy system analyses, this paper introduces the "When2Heat" dataset comprising synthetic national time series of both the heat demand and the coefficient of performance (COP) of heat pumps. It covers 16 European countries, includes the years 2008 to 2018, and features an hourly resolution. Demand profiles for space and water heating are computed by combining gas standard load profiles with spatial temperature and wind speed reanalysis data as well as population geodata. COP time series for different heat sources - air, ground, and groundwater - and different heat sinks - floor heating, radiators, and water heating - are calculated based on COP and heating curves using reanalysis temperature data. The dataset, as well as the scripts and input parameters, are publicly available under an open source license on the Open Power System Data platform.
TL;DR: In this article, the performance of a concentrator photovoltaic Nanoparticle phase change material (CPV-Nanoparticle-PCM) hybrid system is investigated at a solar concertation ratio (CR) of 20.
TL;DR: In this article, a liquid galinstan-based minichannel cooling system was investigated for high heat flux and large heat power thermal management. And the thermal performance and hydrodynamic characteristic of minichannels heat sink using Galinstan as coolant were obtained.
TL;DR: In this paper, a multiphase Lagrangian-Eulerian approach was used to investigate the thermohydraulic properties of Al2O3Cu/water hybrid nanofluid in a micro pin-fin heat sink.
TL;DR: In this article, a numerical investigation is performed on the flow and thermal performance of a heat sink, covered with an open cell metal foam, under the influences of uniform and non-uniform velocity impinging jets.
TL;DR: In this article, the authors have studied the heat transfer and fluid flow behavior in rectangular parallel microchannel heat sinks with varying fin height and found that heat transfer increases with increasing fin height, however, heat sinks of considerably shorter fin heights have less potential to transfer heat.
TL;DR: In this paper, heat transfer and pressure drop characteristics of minichannel heat sink are analyzed experimentally and numerically (two-phase mixture model) by using hybrid nanofluids.
TL;DR: In this paper, the authors investigated the 3D flow of air on the performance of micro-channel heat sinks in which the channels can have five different configurations (e.g., circular, hexagonal, rectangular, triangular and a straight slot).
TL;DR: In this article, an electric/thermal/economic model of concentrator photovoltaic-thermoelectric module is developed to evaluate the efficiency improvement and cost reduction of the hybrid system in comparison to a typical 800x light concentration factor and 36.4% efficiency concentrator-only module.
TL;DR: In this article, experimental results on the heat transfer performance of graphene nano-platelets laden microencapsulated PCM (ME/GnP PCM) in a finned thermal energy storage based heat sink are presented.
TL;DR: In this article, a thermoelectric generator system that utilizes the thermal gradients between the pavement surface and the soil below the pavement and converts it to electricity was designed to generate an average of 29mW of electricity for South Texas conditions.
TL;DR: In this article, a new concentrator photovoltaic system integrated with phase change material heat sink is developed to achieve low and uniform temperature distribution along the solar cell, and experimental and numerical investigations have been carried out to investigate the influence of the over height ratio and inclination angle of the phase change materials heat sink on the temperature distribution.
TL;DR: In this article, the authors analyzed the performance of airfoil shaped pin-fin heat sink employing nanofluids of ferric oxide (Fe2O3) and titania (TiO2), and compared the results with base fluid (distilled water).
TL;DR: In this article, the thermal efficiency and exergy efficiency evaluation plots are developed and are applied to evaluate the thermo-hydraulic performance of nanofluids, and it is found that large depth rectangular groove and staggered arrangement cylindrical bulges are beneficial to heat transfer enhancement.
TL;DR: In this article, a geothermal driven multi-generative system with two organic Rankine cycles and an absorption refrigeration cycle was proposed to solve the problem of high temperature difference between the heat source and the heat sink of the LNG re-gasification process.
TL;DR: In this paper, the combined influence of pin-fin shape variation and utilisation of nanofluid coolants on heat transfer and fluid flow characteristics of a heat sink is investigated through the Lagrangian-Eulerian approach.