scholarly journals Combined Experimental and CFD Investigation of the Parabolic Shaped Solar Collector Utilizing Nanofluid (CuO-H2O and SiO2-H2O) as a Working Fluid

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Ketan Ajay ◽  
Lal Kundan
Keyword(s):  
Heat Transfer ◽  
Solar Collector ◽  
Volume Concentration ◽  
Working Fluid ◽  
Ansys Fluent ◽  
Heat Transfer Fluids ◽  
Different Types ◽  
Average Size ◽  
20 Nm ◽  
Good Agreement

Nanoscience application plays a major role in heat transfer related problems. A nanofluid is basically a suspension of fine sized nanomaterials in base fluids like water, Therminol VP-1, ethylene glycol, and other heat transfer fluids. This paper evaluates the possible application of nanofluid in parabolic shaped concentrating solar collector using both experimental and CFD analysis. Different types of nanomaterials used are SiO2and CuO of 20 nm average size. Nanofluids of SiO2-H2O (DI) and CuO-H2O (DI) of 0.01% volume concentration are used. Flow rates of 40 LPH and 80 LPH are used. ANSYS FLUENT 14.5 is used for carrying out CFD investigation. 3D temperature distribution of absorber tube is obtained using numerical investigation and the result is compared with the experimental one. Improvement in efficiency of collector of about 6.68% and 7.64% is obtained using 0.01% vol. conc. SiO2-H2O (DI) nanofluid and 0.01% vol. conc. CuO-H2O (DI) nanofluid, respectively, as compared to H2O (DI) at 40 LPH while at 80 LPH improvement in efficiency of collector of about 7.15% and 8.42% is obtained using 0.01% vol. conc. SiO2-H2O (DI) nanofluid and 0.01% vol. conc. CuO-H2O (DI) nanofluid, respectively, as compared to H2O (DI). Both experimental and CFD temperature results are in good agreement.

scholarly journals Influence of types of nanoparticles, nanoparticles volume concentration and types of cooler metals on the heat transfer in a mini-channel cooler

10.30544/457 ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 121-135
Author(s):  
Kamel Chadi ◽  
Nourredine Belghar ◽  
Belhi Guerira ◽  
Zied Driss
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Volume Concentration ◽  
Volume Fraction ◽  
Electronic Component ◽  
Average Heat Transfer Coefficient ◽  
Ansys Fluent ◽  
Average Heat ◽  
Different Types

In the present work, we have studied the effect of three different types of nanoparticles, nanoparticles volume concentration and types of cooler metals on heat transfer in a mini channel cooler numerically. In these simulations, we have considered the Cu-H2O, the Ag-H2O and the Diamond-H2O with different volume fractions in the range of 0,02%-0,1% and for two types of cooler materials for cooling an electronic component. In these conditions, the inlet velocity is constant for the three different types of nano-fluids. The power of the electronic component is equal to 130 W. The numerical results are developed for a Reynolds number equal to 1414 and a steady-state. The simulation was performed using commercial software, ANSYS-Fluent 15.0. The obtained results show that the average heat transfer coefficient increases with the increase of the volume fraction of the nanoparticles (Cu, Ag, Diamond) and with the decrease of the temperature of the electronic component. In these conditions, the average heat transfer coefficient is the highest for the H2O–diamond nanofluid compared with the other nanofluids the Cu-H2O and the Ag-H2O. Furthermore, the types of cooler metals have considerable effects on the amelioration of the temperature of the electronic components.

Performance of heat transfer fluids with nanographene in a pilot solar collector

Solar Energy ◽  
2018 ◽  
Vol 172 ◽  
pp. 171-176 ◽  
Author(s):  
F.E.B. Bioucas ◽  
S.I.C. Vieira ◽  
M.J.V. Lourenço ◽  
F.J.V. Santos ◽  
C.A. Nieto de Castro
Keyword(s):  
Heat Transfer ◽  
Solar Collector ◽  
Heat Transfer Fluids ◽  
Performance Of Heat Transfer

Performance Optimization and Parametric Analysis of a Class of Solar-Driven Heat Engines

2010 ◽  
Author(s):  
Houcheng Zhang ◽  
Lanmei Wu ◽  
Guoxing Lin
Keyword(s):  
Heat Transfer ◽  
Heat Loss ◽  
Performance Optimization ◽  
Solar Collector ◽  
Heat Engine ◽  
Working Fluid ◽  
Convection Heat ◽  
Combined System ◽  
Heat Engines ◽  
Internal Irreversibility

A class of solar-driven heat engines is modeled as a combined system consisting of a solar collector and a unified heat engine, in which muti-irreversibilities including not only the finite rate heat transfer and the internal irreversibility, but also radiation-convection heat loss from the solar collector to the ambience are taken into account. The maximum overall efficiency of the system, the optimal operating temperature of the solar collector, the optimal temperatures of the working fluid and the optimal ratio of heat transfer areas are calculated by using numerical calculation method. The influences of radiation-convection heat loss of the collector and internal irreversibility on the cyclic performances of the solar-driven heat engine system are revealed. The results obtained in the present paper are more general than those in literature and the performance characteristics of several solar-driven heat engines such as Carnot, Brayton, Braysson and so on can be directly derived from them.

Constructal Placement of Discrete Heat Sources With Different Lengths in Vertical Ducts Under Natural and Mixed Convection

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Bugra Sarper ◽  
Mehmet Saglam ◽  
Orhan Aydin
Keyword(s):  
Heat Transfer ◽  
Mixed Convection ◽  
Hot Spot ◽  
Experimental Studies ◽  
Vertical Channel ◽  
Working Fluid ◽  
Heat Sources ◽  
Ansys Fluent ◽  
Cooling Performance ◽  
Spot Temperature

In this study, convective heat transfer in a discretely heated parallel-plate vertical channel which simulates an IC package is investigated experimentally and numerically. Both natural and mixed convection cases are considered. The primary focus of the study is on determining optimum relative lengths of the heat sources in order to reduce the hot spot temperature and to maximize heat transfer from the sources to air. Various values of the length ratio and the modified Grashof number (for the natural convection case)/the Richardson number (for the mixed convection case) are examined. Conductive and radiative heat transfer is included in the analysis while air is used as the working fluid. Surface temperatures of the heat sources and the channel walls are measured in the experimental study. The numerical studies are performed using a commercial CFD code, ANSYS fluent. The variations of surface temperature, hot spot temperature, Nusselt number, and global conductance of the system are obtained for varying values of the working parameters. From the experimental studies, it is showed that the use of identical heat sources reduces the overall cooling performance both in natural and mixed convection. However, relatively decreasing heat sources lengths provides better cooling performance.

scholarly journals Heat transfer in a low latitude flat-plate solar collector

2012 ◽  
Vol 16 (2) ◽  
pp. 583-591
Author(s):  
C.O.C. Oko ◽  
S.N. Nnamchi
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Solar Collector ◽  
Design Parameters ◽  
Working Fluid ◽  
Fluid Temperature ◽  
Port Harcourt ◽  
Collector Efficiency ◽  
One Year ◽  
Flat Plate Solar Collector

Study of rate of heat transfer in a flat-plate solar collector is the main subject of this paper. Measurements of collector and working fluid temperatures were carried out for one year covering the harmattan and rainy seasons in Port Harcourt, Nigeria, which is situated at the latitude of 4.858oN and longitude of 8.372oE. Energy balance equations for heat exchanger were employed to develop a mathematical model which relates the working fluid temperature with the vital collector geometric and physical design parameters. The exit fluid temperature was used to compute the rate of heat transfer to the working fluid and the efficiency of the transfer. The optimum fluid temperatures obtained for the harmattan, rainy and yearly (or combined) seasons were: 317.4, 314.9 and 316.2 [K], respectively. The corresponding insolation utilized were: 83.23, 76.61 and 79.92 [W/m2], respectively, with the corresponding mean collector efficiency of 0.190, 0.205 and 0.197 [-], respectively. The working fluid flowrate, the collector length and the range of time that gave rise to maximum results were: 0.0093 [kg/s], 2.0 [m] and 12PM - 13.00PM, respectively. There was good agreement between the computed and the measured working fluid temperatures. The results obtained are useful for the optimal design of the solar collector and its operations.

Study on Heat Transfer Characteristics of Loop Heat Pipe for Solar Collector

2012 ◽  
Author(s):  
Shota Sato ◽  
Shigeki Hirasawa ◽  
Tsuyoshi Kawanami ◽  
Katsuaki Shirai
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Heat Transfer Rate ◽  
Solar Collector ◽  
Transfer Rate ◽  
Thermal Conductance ◽  
Filling Ratio ◽  
Working Fluid ◽  
Loop Heat Pipe ◽  
Single Tube

We experimentally study the thermal conductance of single-tube and loop heat pipes for a solar collector. The evaporator of the heat pipe is 1 m long, 6 mm in diameter and has 30° inclination. The thermal conductance is defined as the heat transfer rate divided by the temperature difference between the evaporator-wall and the condenser-wall. Effects of heat transfer rate, saturation temperature of the working fluid, liquid filling ratio, inclination angle, and position of the evaporator on the thermal conductance are examined. We found that the thermal conductance of the 30°-inclined loop heat pipe with an upper-evaporator is 40–50 (W/K), which is 1.8 times higher than that of the vertical loop type and 3 times higher than that of the single-tube type. Thus, the inclined loop heat pipe is preferable for a solar collector. There is an optimum liquid filling ratio. When the liquid filling ratio is too small, a dry-out portion appears in the evaporator. When the liquid filling ratio is too large, the liquid flows in the condenser to decrease heat transfer area. Also we numerically analyze the thermal conductance of a vertical loop heat pipe.

Thermal-Hydraulic Performance of SiC-Water and Al2O3-Water Nanofluids in the Minichannel

2015 ◽  
Vol 138 (2) ◽  
Author(s):  
Ji Zhang ◽  
Yanhua Diao ◽  
Yaohua Zhao ◽  
Yanni Zhang
Keyword(s):  
Heat Transfer ◽  
Single Phase ◽  
Volume Concentration ◽  
Working Fluid ◽  
Al2o3 Nanoparticles ◽  
Particle Sizes ◽  
Enhance Heat Transfer ◽  
Flow And Heat Transfer ◽  
Effective Particle Size ◽  
Effective Particle

The single-phase flow and heat transfer behaviors of SiC and Al2O3 nanoparticles dispersed in water were studied experimentally in a multiport minichannel flat tube (MMFT). The volume concentrations of the two nanofluids ranged from 0.001% to 1%. Their effective particle sizes, thermal conductivities, and viscosities were also measured. Results indicated that these nanofluids as a working fluid could enhance heat transfer but increase pressure drop and the Nusselt number by up to 85%. The two nanofluids exhibited a common optimal volume concentration of 0.01% for heat transfer. Effective particle size was also found to have a significant effect on heat transfer.

scholarly journals Heat transfer and pressure drop evaluation of different triangular baffle placement angles in cross-corrugated triangular channels

2020 ◽  
Vol 24 (1 Part A) ◽  
pp. 355-365
Author(s):  
Koray Karabulut
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Heat Exchangers ◽  
Navier Stokes ◽  
Working Fluid ◽  
Inlet Temperature ◽  
Ansys Fluent ◽  
Number Range ◽  
Plate Heat ◽  
Corrugated Channel

Plate heat exchangers have a widespread usage and the simplest parallel plate channel structures. Cross-corrugated ducts are basic channel geometries used in the plate heat exchangers. In this study, the increasing of heat transfer from the cross-corrugated triangular ducts by inserting triangular baffles with different placement angles into the channel upper side and pressure drop have been numerically investigated. Numerical calculations have been carried out to solve Navier-Stokes and energy equations by employing k-? turbulence model as 3-D and steady with ANSYS-FLUENT program. While inlet temperature of the air used as working fluid is 293 K, constant surface temperature values of the the lower corrugated channel walls are 373 K. The height of the baffle and apex angle of the corrugated duct have been taken constant as 0.5 H and 60?, respectively. Investigated Reynolds number range is 1000-6000 while the baffle placement angles are 30?, 45?, 60?, and 90?. Numerical results of this study are within 3.53% deviation with experimental study existed in literature. The obtained results have been presented as mean Nusselt number temperature and pressure variations of the fluid for each baffle angle. The temperature and velocity vector contour distributions have been also assessed for different Reynolds numbers and baffle angles. The value of the Num for the corrugated channel with 60? baffle angle is 8.2% higher than that of the 90? for the Re = 4000. Besides, for Re = 1000 the value of the pressure drop is 39% lower in the channel with 60? baffle angle than that of 90?.

scholarly journals Thermal Performance of Three Sided Artificially Roughened Double Duct Parallel Flow Solar Air Heater

2018 ◽  
Vol 7 (1) ◽  
pp. 5-15
Author(s):  
Chander Kant ◽  
Prashant Kumar ◽  
Ankur Gill ◽  
Dhiraj Parkash Dhiman
Keyword(s):  
Heat Transfer ◽  
Reynold Number ◽  
Parallel Flow ◽  
Working Fluid ◽  
Solar Air Heater ◽  
Absorber Plate ◽  
Navier Stokes Equation ◽  
Ansys Fluent ◽  
Air Heater ◽  
Relative Roughness

A solar air heater is basically a heat exchanger, which intercepts the incident solar radiation, converts it into heat and finally transfers this heat to a working fluid for an end use system. The mode of air flowing in the ducts of a solar air heater is one of the most significant aspects concerned with solar air heater which dominantly affect. A double duct parallel flow artificially roughened solar air heater with three sides of the absorber plate is investigated in the current study. Unlike the conventional model of solar air heater with only one sided roughened absorber plate, a novel solar air heater with three artificially roughened absorber plate is used so that the surface area of the absorber plate is increased which ultimately increases the rate of heat transfer. Additionally, a double duct parallel flow arrangement through inner and outer duct of solar air heater is considered order to enhance the heat transfer rate. A numerical investigation of the heat transfer and friction factor characteristics of a double duct parallel flow three sided artificially roughened solar air heater has been carried out. A commercial finite volume CFD code ANSYS FLUENT is used to simulate turbulent air flow through artificial roughened solar air heater. Governing equations of the fluid flow and heat transfer i.e. Navier-Stokes equation and energy equation are solved with RNG k-ε turbulence model. Nine different configuration of square rib are studied with relative roughness pitch (P/e = 5-10) and relative roughness height (e/D = 0.03-0.06). The Reynold number of the flow is varied from 2500 to 16000.

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