Study of Characteristic of Evacuated Flat Plate Type Solar Collector With Flow Boiling

2007 ◽  
Author(s):  
Masahiro Taniguchi ◽  
Shigeki Hirasawa ◽  
Shunsaku Nakauchi ◽  
Tadayoshi Tanaka
Keyword(s):  
Flat Plate ◽  
Solar Collector ◽  
Flow Boiling ◽  
Saturation Temperature ◽  
Solar Irradiation ◽  
Working Fluid ◽  
Collector Plate ◽  
Collector System ◽  
Heat Collector ◽  
Collector Efficiency

An evacuated solar collector system with flow boiling in tube has high collector efficiency of solar energy. In this paper, we present experimental and simulation results for characterizing an evacuated flat plate solar collector. By comparing the experiment results with six boiling heat transfer correlation equations, we found that Sani’s correlation is closest to our experimental results. Subsequently, this paper reports on how various factors impact collector efficiency. Collector efficiency decreases with decreasing flow rate of the working fluid, with decreasing solar irradiation, with reduction of thickness and thermal conductivity of the heat collector plate. Collector efficiency increases with decreasing saturation temperature of the working fluid, with decreasing vacuum pressure in the collector, with small bending angle of the heat collector tube. Collector efficiency does not change with change of inside diameter of the heat collection tube, and with change of inlet subcooling temperature of the working fluid.

Experiment on Flow Boiling Heat Transfer in Tube and Study of Performance of a Vacuum Solar Collector

2007 ◽  
Author(s):  
Shigeki Hirasawa ◽  
Masahiro Taniguchi ◽  
Shunsaku Nakauchi ◽  
Tadayoshi Tanaka
Keyword(s):  
Heat Transfer ◽  
Flow Rate ◽  
Boiling Heat Transfer ◽  
Solar Collector ◽  
Flow Boiling ◽  
Saturation Temperature ◽  
Collector Plate ◽  
Flow Boiling Heat Transfer ◽  
Boiling Heat Transfer Coefficient ◽  
Inclined Angle

A high-vacuum solar collector system with flow boiling in tube has high collector efficiency of solar energy. In this paper flow boiling heat transfer coefficient in tube was measured by changing mass flow rate (30–80 kg/m2s), heat flux (5–30 kW/m2) and inclined angle of collector plate. Inside diameter of tube is 4.4 mm, and saturation temperature is 100°C. Flow boiling heat transfer coefficient is about 8000 W/m2K and decreases at low flow rate. Effect of the inclined angle of collector plate is small. Experimental results of boiling heat transfer coefficients are similar to Sani’s correlation equation. The collector efficiency of vacuum solar collector systems with flow boiling in tube is analyzed and the efficiency is 69% at a standard calculation condition. There is 50°C temperature difference in the collector plate. Effects of the mass flow rate and the vacuum pressure on the efficiency are large. The efficiency decreases at high saturation temperature and at low solar radiation.

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.

scholarly journals Experimental Investigation on Evaluation of Thermal Performance of Solar Heating System Using Al2O3 Nanofluid

2020 ◽  
Vol 10 (16) ◽  
pp. 5521 ◽  
Author(s):  
Youngho Lee ◽  
Hyomin Jeong ◽  
Ji-Tae Park ◽  
Antonio Delgado ◽  
Sedong Kim
Keyword(s):  
Power Systems ◽  
Electronic Conductivity ◽  
Heating System ◽  
Solar Irradiation ◽  
Working Fluid ◽  
Solar Systems ◽  
Collector System ◽  
Thermal Changes ◽  
Transfer Properties ◽  
Al2o3 Nanofluid

Over the years, solar collecting systems have gained interest in renewable energy. This study investigated improving the efficiency of the working fluid in thermal solar systems by using nanofluids with three concentrations of alumina, 0.1, 0.3, and 0.5 wt%. The UV-vis absorbance, electronic conductivity, and thermal transfer properties of the nanofluids were analyzed, and the thermal changes with exposure to solar radiation in an experimental collector system were measured by pyranometer. The electronic conductivity, thermal conductivity, and UV-vis absorbance increased with the alumina concentration. Moreover, the temperatures of the nanofluids increased more under solar irradiation than that of distilled water. This implies that the alumina nanofluids absorb solar energy more efficiently than water. The findings of this study suggest that the use of both alumina nanofluids and nanoparticles will improve the efficiency of thermal solar power systems.

Flat-Plate Solar Collector in Transient Operation: Modeling and Measurements

2014 ◽  
Vol 7 (1) ◽  
Author(s):  
Ahmad M. Saleh ◽  
Donald W. Mueller ◽  
Hosni I. Abu-Mulaweh
Keyword(s):  
Differential Equations ◽  
Flat Plate ◽  
Solar Collector ◽  
Storage Tank ◽  
Ambient Air ◽  
Fluid Temperature ◽  
Ambient Conditions ◽  
Flow Rates ◽  
Collector System ◽  
Nodal Model

This paper describes a mathematical model for simulating the transient processes which occur in liquid flat-plate solar collectors. A discrete nodal model that represents the flat-plate solar collector's layers and the storage tank is employed. The model is based on solving a system of coupled differential equations which describe the energy conservation for the glass cover, air gap, absorber, fluid, insulation, and the storage tank. Inputs to the model include the time-varying liquid flow rate, incident solar radiation, and the ambient air temperature, as well as the volume of liquid in the storage tank and initial temperature of the system. The system of differential equations is solved iteratively using an implicit, finite-difference formulation executed with Matlab software. In order to verify the proposed method, an experiment was designed and conducted on different days with variable ambient conditions and flow rates. The comparison between the computed and measured results of the transient fluid temperature at the collector outlet shows good agreement. The proposed method is extremely general and flexible accounting for variable ambient conditions and flow rates and allowing for a geometrical and thermophysical description of all major components of the solar collector system, including the storage tank. The validated, general model is suitable to investigate the effectiveness of various components without the necessity of carrying out experimental work, and the flexible computational scheme is useful for transient simulations of energy systems.

scholarly journals Entropy generation analysis for the design of a flat plate solar collector with fins

DYNA ◽  
2020 ◽  
Vol 87 (212) ◽  
pp. 199-208
Author(s):  
Milton Muñoz ◽  
Manuel Roa ◽  
Rodrigo Correa
Keyword(s):  
Flat Plate ◽  
Entropy Generation ◽  
Solar Collector ◽  
Entropy Generation Rate ◽  
Design Parameters ◽  
Outlet Temperature ◽  
Minimum Entropy ◽  
Airflow Velocity ◽  
Collector Plate ◽  
Flat Plate Solar Collector

This article describes the optimal design of a flat-plate solar collector with fins, based on the minimum entropy generation criterion. The design parameters were optimized, considering entropy generation due to heat transfer and airflow. The latter has not been considered in previous works. The flat plate in the collector is assimilated to a finned heat sink. The dimensionless entropy generation variation is analyzed to increase values of the number of fins, as well as for different plate thicknesses and heights. We also considered variations in airflow velocity. Our data shows that airflow velocity greatly influences entropy generation. Values other than the optimum found, caused a considerable growth of total entropy. For a collector area of 4 m2, and an outlet temperature of 50°C, the optimum parameters that minimize the entropy generation rate were: 9 fins on each side of the collector plate, a height of 5 x10-2 m, a thickness of 25x10-3m, and an air velocity variable between 0.015 and 0.046 m/s. This development is relevant to the design of flat plate solar collectors, for grain drying applications.

scholarly journals Flat plate thermal solar collector efficiency: Transient behavior under working conditions part II: Model application and design contributions

2011 ◽  
Vol 31 (14-15) ◽  
pp. 2385-2393 ◽  
Author(s):  
M.C. Rodríguez-Hidalgo ◽  
P.A. Rodríguez-Aumente ◽  
A. Lecuona ◽  
G.L. Gutiérrez-Urueta ◽  
R. Ventas
Keyword(s):  
Flat Plate ◽  
Working Conditions ◽  
Solar Collector ◽  
Transient Behavior ◽  
Model Application ◽  
Collector Efficiency

Investigating the Effect of Al2O3/Water Nanofluid on the Efficiency of a Thermosyphon Flat-Plate Solar Collector

2016 ◽  
Author(s):  
Mohamed Nabeel A. Negm ◽  
Ahmed A. Abdel-Rehim ◽  
Ahmed A. A. Attia
Keyword(s):  
Flat Plate ◽  
Solar Collector ◽  
Fossil Fuels ◽  
Energy Conversion Efficiency ◽  
High Energy ◽  
Green Energy ◽  
Working Fluid ◽  
Steady Increase ◽  
Solar Collectors ◽  
Flat Plate Solar Collector

The world is still dependent on fossil fuels as a continuous and stable energy source, but rising concerns for depletion of these fuels and the steady increase in demand for clean “green” energy have led to the rapid growth of the renewable energy field. As one of the most available energy sources with high energy conversion efficiency, solar energy is the most prominent of these energies as it also has the least effect on the environment. Flat plate collectors are the most common solar collectors, while their efficiency is limited by their absorber’s effectiveness in energy absorption and the transfer of this energy to the working fluid. The efficiency of flat plate solar collectors can be increased by using nanofluids as the working fluid. Nanofluids are a relatively recent development which can greatly enhance the thermophysical properties of working fluids. In the present study, the effect of using Al2O3/Water nanofluid as the working fluid on the efficiency of a thermosyphon flat-plate solar collector was experimentally investigated. The results of this experiment show an increase in efficiency when using nanofluids as the working fluid compared to distilled water. It was found that Al2O3/water nanofluids are a viable enhancement for the efficiency of flat-plate solar collectors.

scholarly journals Numerical Investigation to Asses and Optimize Performance of Flat Plate Solar Collector by Using Different Working Fluid

2021 ◽  
Vol 87 (2) ◽  
pp. 44-55
Author(s):  
Yussra Malalah Abdula ◽  
Gadeer Salim ◽  
Salman K
Keyword(s):  
Numerical Model ◽  
Flat Plate ◽  
Solar Collector ◽  
Current Model ◽  
Effective Means ◽  
Industrial Applications ◽  
Working Fluid ◽  
Literature Study ◽  
Maximum Temperatures ◽  
Flat Plate Solar Collector

Sustainable energy becomes an optimal alternative to overcome environmental pollution economical cost of fossil fuel. One of the most effective means to invest solar radiation is flat plate solar collectors. A study carried out to optimize and assess the performance of flat plate solar collector (FPSC) for domestic and industrial applications in the Iraq climate. A 3D numerical model of FPSC has modeled by ANSYS19, CFD tool has been used to investigate thermal transfer through FPSC based on different working fluid. Water, and nanofluid of water/copper nanomaterials were used as working fluid with three different concentrations levels, 0.011 %, 0.055%, and 0,101 %. The velocity of water was 0.3, and 0.5 m/sec respectively. The result of the numerical model was compared with a literature study to prove the reliability of the current model. The result of the current study indicated that, adding Cu nanoparticular to the working fluid enhanced temperatures outlet of FPSC. Also, maximum temperatures can be achieved by reducing the velocity value.

scholarly journals Investigation of Performance of Solar Flat and Curved Plate Collectors through Numerical Simulations

2021 ◽  
Vol 40 (1) ◽  
pp. 66-74
Author(s):  
Luqman Ahmed Pirzada ◽  
Xiaoli Wu . ◽  
Qaiser Ali ◽  
Asif Khateeb .
Keyword(s):  
Solar Energy ◽  
Flat Plate ◽  
Solar Collector ◽  
Numerical Study ◽  
Hot Water ◽  
Working Fluid ◽  
Solar Panels ◽  
Modeling Tools ◽  
Design Work ◽  
Flat Plate Collector

Solar energy is radiant light as a form of thermal heat energy which can be obtained and used by means of a variety of solar apparatus. As apparatus the flat and curved plate solar collector is specifically designed for assembling solar energy as a solar water heater system. The designing potency of this collector lone can generate medium level hot water from radiant sunlight source via absorbed plates. Standard type flat and curved plates solar collector plates are mostly used in remote coldest regions of the world where hot water is consumed for commercial and domestic purposes. These types of solar collector Plates can cheaply be manufactured compared to other solar panels like solar Shingles, Polycrystalline Solar Panels, Mono-crystalline Solar Panels, and Thin Film Solar Panels. For future work, this proposed pre-design is recommended for fabrication. A numerical study was carried-out on eight city locations in China by tracing their horizontal and vertical longitudinal, latitudinal lines noting the date, time and sunlight feeding of temperatures in the Celsius scale with the help of simulation and modeling tools like CFD, ANSYS FLUENT software, mesh geometry tools, and by using the Navier-Stokes and Continuity equations by fluid flow discharge rate, mass flow, water temperature and dropping of temperature, radiation working mechanisms, dimensions of water flowing tubes and absorber plates, density, the velocity of water as the working fluid, the viscosity of water in a cold and hot state as a process of Pre-design. Work also focuses on the comparison between flat plate collector and curved plate collector radiant sunlight absorption, As end result it is found the Curved plate collector produces 22% more elevated heat of outgoing water than flat plate collector.

Sign in / Sign up

Export Citation Format

Share Document