scholarly journals Potential of Solar Collectors for Clean Thermal Energy Production in Smart Cities using Nanofluids: Experimental Assessment and Efficiency Improvement

2019 ◽  
Vol 9 (9) ◽  
pp. 1877 ◽  
Author(s):  
M. Sarafraz ◽  
Iskander Tlili ◽  
Mohammad Abdul Baseer ◽  
Mohammad Safaei
Keyword(s):  
Flow Rate ◽  
Thermal Performance ◽  
Tilt Angle ◽  
Thermal Efficiency ◽  
Smart Cities ◽  
Heat Pipes ◽  
Filling Ratio ◽  
Working Fluid ◽  
Solar Thermal Collector ◽  
Evacuated Tube

In this article, an experimental study was performed to assess the potential thermal application of a new nanofluid comprising carbon nanoparticles dispersed in acetone inside an evacuated tube solar thermal collector. The effect of various parameters including the circulating volumetric flow of the collector, mass fraction of the nanoparticles, the solar irradiance, the tilt angle and the filling ratio values of the heat pipes on the thermal performance of the solar collector was investigated. It was found that with an increase in the flow rate of the working fluid within the system, the thermal efficiency of the system was improved. Additionally, the highest thermal performance and the highest temperature difference between the inlet and the outlet ports of the collector were achieved for the nanofluid at wt. % = 0.1. The best tilt angle and the filling ratio values of the collector were 30° and 60% and the maximum thermal efficiency of the collector was 91% for a nanofluid at wt. % = 0.1 and flow rate of 3 L/min.

A Comprehensive Experimental Investigation of the Performance of Closed-Loop Pulsating Heat Pipes

2017 ◽  
Vol 139 (9) ◽  
Author(s):  
M. Halimi ◽  
A. Abbas Nejad ◽  
M. Norouzi
Keyword(s):  
Thermal Resistance ◽  
Flow Regime ◽  
Thermal Performance ◽  
Closed Loop ◽  
Heat Pipes ◽  
Filling Ratio ◽  
Working Fluid ◽  
Physical Parameters ◽  
Two Phase ◽  
Laboratory Conditions

Closed-loop pulsating heat pipes (CLPHPs) are a new type of two-phase heat transfer devices that can transfer considerable heat in a small space via two-phase vapor and liquid pulsating flow and work with various types of two-phase instabilities so the operating mechanism of CLPHP is not well understood. In this work, two CLPHPs, made of Pyrex, were manufactured to observe and investigate the flow regime that occurs during the operation of CLPHP and thermal performance of the device under different laboratory conditions. In general, various working fluids were used in filling ratios of 40%, 50%, and 60% in horizontal and vertical modes to investigate the effect of thermo-physical parameters, filling ratio, nanoparticles, gravity, CLPHP structure, and input heat flux on the thermal performance of CLPHP. The results indicate that three types of flow regime may be observed given laboratory conditions. Each flow regime exerts a different effect on the thermal performance of the device. There is an optimal filling ratio for each working fluid. The increased number of turns in CLPHP generally improves the thermal performance of the system reducing the effect of the type of the working fluid on the aforementioned performance. The adoption of copper nanoparticles, which positively affect fluid motion, decreases the thermal resistance of the system as much as 6.06–42.76% depending on laboratory conditions. Moreover, gravity brings about positive changes in the flow regime decreasing thermal resistance as much as 32.13–52.58%.

THERMAL PERFORMANCE OF FLAT PLATE PULSATING HEAT PIPES WITH MINI- AND MICROCHANNELS

2014 ◽  
Vol 22 (04) ◽  
pp. 1450025 ◽  
Author(s):  
DONG SOO JANG ◽  
EUN-JI LEE ◽  
SANG HUN LEE ◽  
YONGCHAN KIM
Keyword(s):  
Cross Section ◽  
Working Conditions ◽  
Thermal Performance ◽  
Strong Influence ◽  
Heat Pipes ◽  
Input Power ◽  
Filling Ratio ◽  
Hydraulic Diameter ◽  
Working Fluid ◽  
Optimum Working

This study presents the thermal performance of pulsating heat pipes (PHPs) using distilled water with mini- and microchannels. The PHPs were fabricated with the channels of square cross section which had hydraulic diameters ranged from 1.6 to 3.2 mm in minichannels and from 0.714 to 0.941 mm in microchannels. The performance of the PHPs was measured and analyzed by varying hydraulic diameter, number of turns, filling ratio, and input power. The filling ratio of the working fluid varied from 0% to 100%. The input power was controlled in the range between 3.6 and 150 W. The hydraulic diameter, number of turns, filling ratio, and input power showed strong influence on the performance of the PHP. In the PHP models with mini- and microchannels, optimum working conditions, such as filling ratio and heat input, were quite different according to channel size.

scholarly journals Experimental Study on the Thermal and Electrical Characteristics of an Air-Based Photovoltaic Thermal Collector

Energies ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2661 ◽  
Author(s):  
Sang-Myung Kim ◽  
Jin-Hee Kim ◽  
Jun-Tae Kim
Keyword(s):  
Flow Rate ◽  
Thermal Performance ◽  
Thermal Efficiency ◽  
Solar Thermal ◽  
Electrical Performance ◽  
Energy Output ◽  
Inlet Flow ◽  
Pv Module ◽  
Solar Thermal Collector ◽  
Inlet Flow Rate

A photovoltaic thermal (PVT) system is a technology that combines photovoltaics (PV) and a solar thermal collector to produce thermal energy and generate electricity. PVT systems have the advantage that the energy output per unit area is higher than the single use of a PV module or solar thermal collector, since both heat and electricity can be produced and used simultaneously. Air-based PVT collectors use air as the heat transfer medium and flow patterns are important factors that affect the performance of the PVT collector. In this study, the thermal and electrical performance and characteristics of an air-based PVT collector were analyzed through experiments. The PVT collector, with bending round-shaped heat-absorbing plates, which increase the air flow path, has been developed to improve the thermal performance. The experiment was done under the test conditions of ISO 9806:2017 for the thermal performance analysis of an air-based PVT collector. The electrical performance was analyzed under the same conditions. In the results, it can be found that the inlet flow rate of the PVT collector considerably affects the thermal efficiency. It was analyzed that as the inlet flow rate increased from 60 to 200 m3/h, the thermal efficiency increased from 29% to 42%. Then, the electricity efficiency was also analyzed, where it was determined that it was improved according to operating condition of PVT collector.

scholarly journals An experimental study of the thermal performance of the square and rhombic solar collectors

2018 ◽  
Vol 22 (1 Part B) ◽  
pp. 487-494 ◽  
Author(s):  
Aminreza Noghrehabadi ◽  
Ebrahim Hajidavaloo ◽  
Mojtaba Moravej ◽  
Ali Esmailinasab
Keyword(s):  
Experimental Study ◽  
Flat Plate ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Thermal Performance ◽  
Thermal Efficiency ◽  
Solar Collectors ◽  
Heating Systems ◽  
Solar Water Heating

Solar collectors are the key part of solar water heating systems. The most widely produced solar collectors are flat plate solar collectors. In the present study, two types of flat plate collectors, namely square and rhombic collectors are experi?mentally tested and compared and the thermal performance of both collectors is investigated. The results show both collectors have the same performance around noon (?61%), but the rhombic collector has better performance in the morning and afternoon. The values for rhombic and square collectors are approximately 56.2% and 53.5% in the morning and 56.1% and 54% in the afternoon, respectively. The effect of flow rate is also studied. The thermal efficiency of rhombic and square flat plate collectors increases in proportion to the flow rate. The results indicated the rhombic collector had better performance in comparison with the square collector with respect to the mass-flow rate.

scholarly journals Utilization of Zinc-Ferrite/ Water Hybrid Nanofluids for enhancing thermal performance of a Flat Plate Solar Collector -An Analytical Study

2021 ◽  
Author(s):  
Prakasam Michael Joseph stalin ◽  
Thottipalayam Vellingri Arjunan ◽  
Mohammed Abdulrahman Almeshaal ◽  
Palaniappan Murugesan ◽  
Balaramachandran Prabu ◽  
...  
Keyword(s):  
Flat Plate ◽  
Thermal Performance ◽  
Working Fluid ◽  
Heat Transfer Fluids ◽  
Solar Thermal Collector ◽  
Energy And Exergy ◽  
Hybrid Nanofluids ◽  
Exergy Transfer ◽  
Flat Plate Solar Collector ◽  
Thermo Physical Properties

Abstract Thermodynamic performance analysis is carried out on a flat plate solar thermal collector utilizing single and hybrid nanofluids. As heat transfer fluids, Fe2O4/water, Zn-Fe2O4/water hybrid nanofluids, and water are used, and its performance are compared based on the energy and exergy transfer rate. The thermo-physical properties are evaluated by regression polynomial model for all the working fluids. Developed codes in MATLAB solve the collector's thermal model iteratively, energy and exergetic performance are evaluated. The system was then subjected to parametric investigation and optimization for variations in fluid flow rate, temperatures, and concentrations of nanoparticles. The findings show that utilizing Zn-Fe2O4/water hybrid nanofluids with a particle concentration of 0.5 percent enhanced the solar collector's thermal performance by 6.6% while using Fe2O4/water nanofluids raised the collector's thermal performance by 7.83% when compared to water as the working fluid. While hybrid nanofluids give a better thermal alternative than water and single nanofluids, they have also produced a 5.36% increase in exergetic efficiency and an enhancement of 8.24 percent when used with Fe2O4/water nanofluids.

Experimental Study of Thermal Performance of Nanofluid-Filled and Nanoparticles-Coated Mesh Wick Heat Pipes

2018 ◽  
Vol 140 (10) ◽  
Author(s):  
Naveen Kumar Gupta ◽  
Arun Kumar Tiwari ◽  
Subrata Kumar Ghosh
Keyword(s):  
Thermal Resistance ◽  
Thermal Performance ◽  
Thermal Efficiency ◽  
Physical Vapor Deposition ◽  
Power Input ◽  
Working Fluid ◽  
Physical Vapor Deposition Method ◽  
The Stability ◽  
Stability Issues ◽  
Time Of Operation

The enhancements in thermal performance of mesh wick heat pipe (HP) using TiO2/H2O nanofluid (0.5, 1.0, and 1.5 vol %) as working fluid for different (50, 100, and 150 W) power input were investigated. Results showed maximum 17.2% reduction in thermal resistance and maximum 13.4% enhancement in thermal efficiency of HP using 1.0 vol % nanofluid as compared to water. The wick surface of the HP was then coated with TiO2 nanoparticles by physical vapor deposition method. The experimental investigation had been also carried out on coated wick HP using water as working fluid. Results showed 12.1% reduction in thermal resistance and 11.9% enhancement in thermal efficiency of the HP as compared to uncoated wick HP using water. Temporal deteriorations in thermal performance during prolonged working (2, 4, and 6 months) of HP were also studied. Temporal deterioration in thermal performance of HP filled with nanofluid depends upon the deterioration in thermophysical properties of nanofluids. The deterioration is due to the agglomeration and sedimentation of nanoparticles with respect to the time. Comparative study shows that after a certain time of operation, thermal performance of HP with nanoparticle coated wick superseded that of the HP filled with nanofluid. Therefore, nanoparticle coating might be a good substitute for nanofluid to avoid the stability issues. The present paper provides incentives for further research to develop nanofluids that avoid the encountered sedimentation or agglomeration.

scholarly journals Effect of Bed Particle Size on Thermal Performance of a Directly-Irradiated Fluidized Bed Gas Heater

Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 967
Author(s):  
Sae Han Park ◽  
Chae Eun Yeo ◽  
Min Ji Lee ◽  
Sung Won Kim
Keyword(s):  
Particle Size ◽  
Fluidized Bed ◽  
Thermal Performance ◽  
Thermal Efficiency ◽  
Gas Velocity ◽  
Bubble Behavior ◽  
Heat Transfer Characteristics ◽  
Maximum Value ◽  
Solar Thermal Collector ◽  
Sic Particle

There is a growing interest in a fluidized bed particle receiver that directly irradiates sunlight to particles in the fluidized bed as a solar thermal collector for heating. Thermal performance of directly-irradiated fluidized bed gas heater is strongly affected by the physical properties of the particles. The effect of SiC particle size on heat transfer characteristics in the solar fluidized bed gas heater (50 mm-ID × 100 mm high) has been determined. The outlet gas temperatures showed a maximum value with increasing gas velocity due to the particles motion by bubble behavior in the bed, and the maximum values were found at 3.6 times of Umf for fine SiC and less than 2.0 times of Umf for coarse SiC. Heat absorption from the receiver increased with increasing gas velocity, showing with maximum 18 W for the fine SiC and 23 W for the coarse SiC at 4.5 times of Umf. The thermal efficiency of the receiver increased with increasing gas velocity, but was affected by the content of finer particles. The maximum thermal efficiency of the receiver was 14% for fine SiC and 20% for coarse SiC within the experimental range, but showing higher for the fine SiC at the same gas velocity. A design consideration was proposed to improve the thermal efficiency of the system.

Experimental Investigation of Thermal Conduction Performance on Silicon-Based Micro Flat Heat Pipe

2015 ◽  
Vol 645-646 ◽  
pp. 1032-1037
Author(s):  
Cong Ming Li ◽  
Yi Luo ◽  
Chuan Peng Zhou ◽  
Liang Liang Zou ◽  
Xiao Dong Wang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Heat Pipe ◽  
Effective Thermal Conductivity ◽  
Thermal Performance ◽  
Axial Direction ◽  
Filling Ratio ◽  
Parallel Structure ◽  
Working Fluid ◽  
Vacuum Degree ◽  
Structure Dimension

There are several factors that affect heat transfer of heat pipe, for example, structure dimension, filling ratio and vacuum degree of charging. This paper studied the thermal conductivity of micro flat heat pipes (MFHPs) with different structure dimension and with different filling ratio, when the charging vacuum degree of MFHP was decided. When electric power was 2W or 4W, MFHPs with parallel grooves and nonparallel grooves, charged by working fluid with different filling ratio, were carried out. And the filling ratio is 30%, 40% and 50%, respectively. The better thermal performance of MFHP can be evaluated by lower thermal resistance and higher effective thermal conductivity. The experiment results show that MFHP has the highest effective thermal conductivity when the filling ratio is 40%; and the thermal performance of MFHP with nonparallel structure in axial direction is better than that of MFHP with parallel structure.

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