scholarly journals Applications of nanotechnology with hybrid Photovoltaic/Thermal systems

2020 ◽  
pp. 1-15
Author(s):  
Mohammed Alktranee
Keyword(s):  
Thermophysical Properties ◽  
Base Fluid ◽  
Volume Fraction ◽  
Working Fluid ◽  
Spectral Filter ◽  
Thermal Systems ◽  
Cooling Fluid ◽  
Numerical Studies ◽  
The Impact ◽  
T System

This paper appears potential of use nanofluids as a working fluid with the photovoltaic/thermal (PV/T) systems as an alternative of the conventional liquids in improves the efficiency of the hybrid PV/T system. The review highlights the impact of some parameters (base fluid, volume fraction, the concentration of nanoparticles, surfactants, shape, and size of nanoparticles) on nanofluids' thermophysical properties and their effect on the PV/T system's efficiencies. Hence, it discusses the PV/T behavior, which uses different nanofluids based on previous experimental, analytical, and numerical studies. The review concluded that using nanofluid as a cooling fluid or spectral filter contributes by enhancing the performance and increasing the PV/T system's efficiency. Thus, each type of nanofluids has certain features that contribute to removing the PV cells' excess heat by cooling it, contributing to its work's stability, and increasing its productivity. Nanofluids thermophysical properties play an intrinsic role by enhancing nanofluids' performance, thus positively reflecting on the PV/T system's performance. Despite the variation in the values of thermal and electrical efficiency, Most of the studies that used nanofluids have achieved encouraging results that appeared by improving the performance of PV/T systems.

scholarly journals Applications of nanotechnology with hybrid photovoltaic/thermal systems: A review

2021 ◽  
Vol 19 (2) ◽  
pp. 292-306
Author(s):  
Mohammed Alktranee ◽  
Péter Bencs
Keyword(s):  
Thermophysical Properties ◽  
Base Fluid ◽  
Volume Fraction ◽  
Working Fluid ◽  
Spectral Filter ◽  
Thermal Systems ◽  
Cooling Fluid ◽  
Numerical Studies ◽  
The Impact ◽  
T System

This paper appears potential of use nanofluids as a working fluid with the photovoltaic/thermal (PV/T) systems as an alternative of the conventional liquids in improves the efficiency of the hybrid PV/T system. The review highlights the impact of some parameters (base fluid, volume fraction, the concentration of nanoparticles, surfactants, shape, and size of nanoparticles) on nanofluids' thermophysical properties and their effect on the PV/T system's efficiencies. Hence, it discusses the PV/T behavior, which uses different nanofluids based on previous experimental, analytical, and numerical studies. The review concluded that using nanofluid as a cooling fluid or spectral filter contributes by enhancing the performance and increasing the PV/T system's efficiency. Thus, each type of nanofluids has certain features that contribute to removing the PV cells' excess heat by cooling it, contributing to its work's stability, and increasing its productivity. Nanofluids thermophysical properties play an intrinsic role by enhancing nanofluids' performance, thus positively reflecting on the PV/T system's performance. Despite the variation in the values of thermal and electrical efficiency, Most of the studies that used nanofluids have achieved encouraging results that appeared by improving the performance of PV/T systems.

scholarly journals CONVECTIVE HEAT TRANSFER AND POWER SAVING APPLICATION OF SI BASED NANOPARTICLES IN A CIRCULAR PIPE

2020 ◽  
Vol 50 (4) ◽  
pp. 321-327
Author(s):  
Md Insiat Islam Rabby ◽  
Farzad Hossain ◽  
S.A.M. Shafwat Amin ◽  
Tazeen Afrin Mumu ◽  
MD Ashraf Hossain Bhuiyan ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Base Fluid ◽  
Volume Fraction ◽  
Numerical Study ◽  
Convective Heat Transfer Coefficient ◽  
Circular Pipe ◽  
Working Fluid ◽  
Pumping Power

A numerical study of laminar forced convection heat transfer for the fully developed region inside a circular pipe filled with Si based nanoparticle is presented for investigating the parameters of heat transfer. Four Si based nanoparticles Si, SiC, SiO2, Si3N4 with 1-5% volume fraction have been mixed with water to prepare nanofluids which is used for working fluid to flow over a circular pipe with 5mm diameter and 700mm length. Heat transfer characteristics and pumping power have been calculated at fully developed region with constant heat flux condition on pipe wall to identify the heat transfer enhancement ratio and pumping power reduction ratio among base fluid water and each nanofluids. It is worth mentioning that utilizing SiC nanoparticle shows not only the highest increment of Nusselt number and convective heat transfer coefficient but also the highest decrement of pumping power requirement and FOM in comparison to the base fluid.

Experimental Measurement of Thermophysical Properties of Alumina- MWCNTs/Salt–Water Hybrid Nanofluids

2020 ◽  
Vol 16 (5) ◽  
pp. 734-747 ◽  
Author(s):  
Amir Hossein Sharifi ◽  
Iman Zahmatkesh ◽  
Fatemeh F. Bamoharram ◽  
Amir Hossein Shokouhi Tabrizi ◽  
Safieh Fazel Razavi ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Salt Concentration ◽  
Thermophysical Properties ◽  
Base Fluid ◽  
Volume Fraction ◽  
Ph Value ◽  
Nanoparticle Volume Fraction ◽  
Optimal Conditions ◽  
Hybrid Nanofluids

Background: Hybrid nanofluids are considered as an extension of conventional nanofluids which are prepared through suspending two or more nanoparticles in the base fluids. Previous studies on hybrid nanofluids have measured their thermal conductivity overlooking other thermophysical properties such as viscosity and electrical conductivity. Objective: An experimental investigation is undertaken to measure thermal conductivity, viscosity, and electrical conductivity of a hybrid nanofluid prepared through dispersing alumina nanoparticles and multiwall carbon nanotubes in saltwater. These properties are the main important factors that must be assessed before performance analysis for industrial applications. Methods: The experimental data were collected for different values of the nanoparticle volume fraction, temperature, salt concentration, and pH value. Attention was paid to explore the consequences of these parameters on the nanofluid’s properties and to find optimal conditions to achieve the highest value of the thermal conductivity and the lowest values of the electrical conductivity and the viscosity. Results: The results demonstrate that although the impacts of the pH value and the nanoparticle volume fraction on the nanofluid’s thermophysical properties are not monotonic, optimal conditions for each of the properties are reachable. It is found that the inclusion of the salt in the base fluid may not change the thermal conductivity noticeably. However, a considerable reduction in the viscosity and substantial elevation in the electrical conductivity occur with an increase in the salt concentration. Conclusion: With the addition of salt to a base fluid, the thermophysical properties of a nanofluid can be controlled.

scholarly journals Theoretical and Experimental Evaluation of the Working Fluid Temperature Levels in a CPV/T System

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3077
Author(s):  
Carlo Renno
Keyword(s):  
Thermal Energy ◽  
Integrated System ◽  
Hot Water ◽  
Experimental Comparison ◽  
Working Fluid ◽  
Fluid Temperature ◽  
Cooling Fluid ◽  
Operation Conditions ◽  
Temperature Levels ◽  
T System

A linear focus Concentrator Photovoltaic and Thermal (CPV/T) system can match the thermal demands of a user. The evaluation of the cooling fluid temperature levels of a CPV/T system is fundamental to understand if this system is capable of satisfying the typical thermal requirements of a residential user (heating, cooling and domestic hot water). First, an experimental line-focus CPV/T system, realized in the Laboratory of Applied Thermodynamics of the University of Salerno (Italy), has allowed to determine the cooling fluid temperature at the CPV/T system outlet. Successively, the cooling fluid temperatures, experimentally obtained, have been compared with the same temperatures calculated by means of a theoretical model under the same operation conditions. A deviation in terms of the percentage relative error between theoretical and experimental results included between about 0.5% and 5%, has been found. The goodness of the theoretical–experimental comparison in terms of the temperature of the operation fluid at the CPV/T system outlet has represented a fundamental point to evaluate theoretically, by means of the TRNSYS software, the other levels of temperature of an integrated system, constituted by CPV/T system, thermal tank and user, for different temporal scenarios (hourly, weekly, monthly and yearly). The input data of the TRNSYS model are: Direct Normal Irradiance (DNI), Triple-Junction (TJ) cell temperature and environmental conditions. A tank model is also adopted to satisfy the thermal energy demand peaks, and the temperature stratification in the tank linked to the CPV/T system, as function of the height, is obtained in winter and summer. It is important to define these thermal levels to verify if a CPV/T system is capable to satisfy the residential user energy demands or a thermal energy integration is necessary in some periods of the year. A good stratification has been noted in the summer season, with temperature values that are variable between about 40 and 90 °C. From April to October, the tank average temperature is generally resulted about 10 °C higher than the temperature required by the fluid sent to the residential user, and a very low integration is then necessary. It has been verified that the CPV/T system covers a large part of the thermal energy needs of the residential user during the year; the coverage is limited only in the winter months.

Parametric Analysis of Effective Thermal Conductivity Models for Nanofluids

2012 ◽  
Author(s):  
Mohsen Sharifpur ◽  
Tshimanga Ntumba ◽  
Josua P. Meyer
Keyword(s):  
Thermal Conductivity ◽  
Particle Size ◽  
Brownian Motion ◽  
Effective Thermal Conductivity ◽  
Parametric Analysis ◽  
Base Fluid ◽  
Volume Fraction ◽  
Hybrid Models ◽  
The Impact ◽  
Conductivity Models

There is a lack of reported research on comprehensive hybrid models for the effective thermal conductivity of nanofluids that takes into consideration all major mechanisms and parameters. The major mechanisms are the nanolayer, Brownian motion and clustering. The recognized important parameters can be the volume fraction of the nanoparticles, temperature, particle size, thermal conductivity of the nanolayer, thermal conductivity of the base fluid, PH of the nanofluid, and the thermal conductivity of the nanoparticle. Therefore, in this work, a parametric analysis of effective thermal conductivity models for nanofluids was done. The impact of the measurable parameters, like volume fraction of the nanoparticles, temperature and the particle size for the more sited models, were analyzed by using alumina-water nanofluid. The result of this investigation identifies the lack of a hybrid equation for the effective thermal conductivity of nanofluids and, consequently, more research is required in this field.

scholarly journals Influence of Single- and Multi-Wall Carbon Nanotubes on Magnetohydrodynamic Stagnation Point Nanofluid Flow over Variable Thicker Surface with Concave and Convex Effects

Mathematics ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 104 ◽  
Author(s):  
Anum Shafiq ◽  
Ilyas Khan ◽  
Ghulam Rasool ◽  
El-Sayed M. Sherif ◽  
Asiful H. Sheikh
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Carbon Nanotubes ◽  
Velocity Field ◽  
Base Fluid ◽  
Volume Fraction ◽  
Brownian Diffusion ◽  
System Of Nonlinear Equations ◽  
Multi Wall Carbon Nanotubes ◽  
The Impact

This paper reports a theoretical study on the magnetohydrodynamic flow and heat exchange of carbon nanotubes (CNTs)-based nanoliquid over a variable thicker surface. Two types of carbon nanotubes (CNTs) are accounted for saturation in base fluid. Particularly, the single-walled and multi-walled carbon nanotubes, best known as SWCNTs and MWCNTs, are used. Kerosene oil is taken as the base fluid for the suspension of nanoparticles. The model involves the impact of the thermal radiation and induced magnetic field. However, a tiny Reynolds number is assumed to ignore the magnetic induction. The system of nonlinear equations is obtained by reasonably adjusted transformations. The analytic solution is obtained by utilizing a notable procedure called optimal homotopy analysis technique (O-HAM). The impact of prominent parameters, such as the magnetic field parameter, Brownian diffusion, Thermophoresis, and others, on the dimensionless velocity field and thermal distribution is reported graphically. A comprehensive discussion is given after each graph that summarizes the influence of the respective parameters on the flow profiles. The behavior of the friction coefficient and the rate of heat transfer (Nusselt number) at the surface (y = 0) are given at the end of the text in tabular form. Some existing solutions of the specific cases have been checked as the special case of the solution acquired here. The results indicate that MWCNTs cause enhancement in the velocity field compared with SWCNTs when there is an increment in nanoparticle volume fraction. Furthermore, the temperature profile rises with an increment in radiation estimator for both SWCNT and MWCNT and, finally, the heat transfer rate lessens for increments in the magnetic parameter for both types of nanotubes.

Thermophysical Properties for ZnO-Water Nanofluid: Experimental Study

2021 ◽  
Vol 1025 ◽  
pp. 9-14
Author(s):  
Adnan H. Rasheed ◽  
Hajar Alias ◽  
Sami D. Salman
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Experimental Study ◽  
Zinc Oxide ◽  
Thermophysical Properties ◽  
Base Fluid ◽  
Volume Fraction ◽  
Nanoparticle Volume Fraction ◽  
Heat Transfer Characteristics ◽  
Rotational Viscometer

This paper presents the thermophysical properties of zinc oxide nanofluid that have been measured for experimental investigation. The main contribution of this study is to define the heat transfer characteristics of nanofluids. The measuring of these properties was carried out within a range of temperatures from 25 °C to 45 °C, volume fraction from 1 to 2 %, and the average nanoparticle diameter size is 25 nm, and the base fluid is water. The thermophysical properties, including viscosity and thermal conductivity, were measured by using Brookfield rotational Viscometer and Thermal Properties Analyzer, respectively. The result indicates that the thermophysical properties of zinc oxide nanofluid increasing with nanoparticle volume fraction increasing, as well as the thermophysical properties of zinc oxide nanofluid affected by the change in temperature.

Evaluating the Influence of Nanofluid Type and Volume Fraction on the Performance of Heat Exchanger

2020 ◽  
Author(s):  
Esam I. Jassim ◽  
Faizan Ahmed ◽  
Bashar Jasem
Keyword(s):  
Reynolds Number ◽  
Heat Exchanger ◽  
Base Fluid ◽  
Volume Fraction ◽  
Positive Impact ◽  
Pure Water ◽  
Cold Side ◽  
Aluminum Oxide Nanoparticles ◽  
Long Life ◽  
The Impact

Abstract The utilization of nanofluid in heat exchanger is of immense interest in the petrochemical and power plant industries due to the durability provided to the exchanger long-life operation. In the present research, an experimental investigation is carried out to study the existence of copper and aluminum oxide nanoparticles in the base fluid and their impact on the performance of the heat exchanger. A comparison with the theoretical outcome is also conducted. Pure water is pumped through the tubes of the heat exchanger unit whereas the nanofluid is pumped into the shell of the unit by means of another impeller pump. Various volume fractions ranging from 0.26%–0.83% are tested to assess the morphology of nanoparticle and volume fraction on the exchanger efficiency. It is observed that the volume fraction of nanofluid has a significant positive impact on the effectiveness of the heat exchanger. An increase in the volume fraction of the nanofluid enhances the effectiveness of the heat exchanger up to 7% for Al2O3 and 10% for Copper. The impact of the Reynolds number is also studied. The Reynolds number for the cold-side nanofluid varies in the range 7000–15000. As the Reynolds number augments, the Nusselt number also increases by ∼13% for Al2O3 and 23% for Cu nanofluids. Additionally, the effect of varying inlet temperatures of hot fluid is investigated. The results indicate an enhancement in the exchanger performance at higher inlet temperatures of the hotside fluid.

scholarly journals Numerical Investigation Of Nanofluids Flow and Heat Transfer in 90 Elbow With square Cross-Section

2015 ◽  
Vol 37 ◽  
pp. 162
Author(s):  
Ayoob Khosravi Farsani ◽  
Afshin Ahmadi Nodooshan
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Cross Section ◽  
Volume Fraction ◽  
Convex Surface ◽  
Solid Volume Fraction ◽  
Horizontal Tube ◽  
Working Fluid ◽  
Energy Equations ◽  
The Impact

In this article, forced convective heat transfer of nanofluid flow in a horizontal tube with a square cross-section and 90-degree elbow under heat flux was investigated in a numerical method. The homogeneous nanofluid of aluminum oxide and water (Al2O3) was used as the working fluid. For the numerical solution of continuity, momentum and energy equations, the finite volume method was used. In this study, the effect of Reynolds number and the solid volume fraction and the impact of the elbow on the flow field and the heat transfer rate and pressure drop was investigated. The results were presented in the form of flow and temperature contours and the Nusselt diagrams, which have a good relation with the experimental results, and showed that by increasing the solid volume fraction and Reynolds number, the heat transfer in the elbow increases. Also the concave surface from inside the tubes had a greater impact on heat transfer than the convex surface.

Experimental study of thermohydraulic characteristics and irreversibility analysis of novel axial corrugated tube with spring tape inserts

2020 ◽  
Vol 92 (3) ◽  
pp. 30901
Author(s):  
Suvanjan Bhattacharyya ◽  
Debraj Sarkar ◽  
Ulavathi Shettar Mahabaleshwar ◽  
Manoj K. Soni ◽  
M. Mohanraj
Keyword(s):  
Heat Transfer ◽  
Experimental Study ◽  
Thermal Performance ◽  
Working Fluid ◽  
The Novel ◽  
Heat Exchanger Tube ◽  
Heat Transfer Augmentation ◽  
Corrugated Tube ◽  
The Impact ◽  
Exchanger Tube

The current study experimentally investigates the heat transfer augmentation on the novel axial corrugated heat exchanger tube in which the spring tape is introduced. Air (Pr = 0.707) is used as a working fluid. In order to augment the thermohydraulic performance, a corrugated tube with inserts is offered. The experimental study is further extended by varying the important parameters like spring ratio (y = 1.5, 2.0, 2.5) and Reynolds number (Re = 10 000–52 000). The angular pitch between the two neighboring corrugations and the angle of the corrugation is kept constant through the experiments at β = 1200 and α = 600 respectively, while two different corrugations heights (h) are analyzed. While increasing the corrugation height and decreasing the spring ratio, the impact of the swirling effect improves the thermal performance of the system. The maximum thermal performance is obtained when the corrugation height is h = 0.2 and spring ratio y = 1.5. Eventually, correlations for predicting friction factor (f) and Nusselt number (Nu) are developed.

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