Parametric Study of an Evacuated Multi-Stage Solar Still

Solar Energy ◽  
2004 ◽  
Author(s):  
Yousif A. Abakr ◽  
Ahmad F. Ismail ◽  
Mirghani I. Ahmed
Keyword(s):  
Mathematical Model ◽  
Solar Radiation ◽  
Parametric Study ◽  
Solar Still ◽  
Balance Equations ◽  
Multi Stage ◽  
System Components ◽  
Practical Design ◽  
Radiation Conditions ◽  
The Mathematical Model

On this work a practical design to utilize the multistage evacuated solar still concept was developed. The mathematical model of the system was developed based on the energy and mass balance equations of the system. The system components were fabricated and the overall system was assembled. A prototype was constructed and tested at outdoor real solar radiation conditions. The experimental results show a significant improvement of the overall productivity relative to other systems.

Enhancement the Solar Still Performance Using Chimney Exhaust Gases

2021 ◽  
Author(s):  
Hamdy Hassan
Keyword(s):  
Mathematical Model ◽  
Theoretical Study ◽  
Saline Water ◽  
Kutta Method ◽  
Solar Still ◽  
Climate Conditions ◽  
Exhaust Gases ◽  
Runge Kutta Method ◽  
The Impact ◽  
The Mathematical Model

Abstract In this paper, a theoretical study is presented on enhancement of the solar still performance by using the exhaust gases passing inside a chimney under the still basin. The impact of the exhaust gases temperature on the solar still temperature, productivity, and efficiency are considered. The performance of solar still with chimney is compared with that of conventional solar still. The study is carried out under the hot and climate conditions of Upper Egypt. A complete transient mathematical model of the physical model including the solar still regions temperatures, productivity, and heat transfer between the solar still and the exhaust gases are constructed. The mathematical model is solved numerically by using fourth-order Runge-Kutta method and is programmed by using MATLAB. The mathematical model is validated using an experimental work. The results show that the solar still saline water temperature increases and productivity with using and rising the exhaust gases. Furthermore, the impact of using exhaust gases on the still performance in winter is greater than in summer. using chimney exhaust gases at 75 °C and 125 °C enhances the daily freshwater yield of the conventional still by more than three times and about six times in winter, respectively, and about two and half times and more than three times in summer, respectively.

Experimental and Theoretical Investigation of Performance of a Solar Chimney Model Part II: Model Development and Validation

2021 ◽  
Vol 5 (2) ◽  
Author(s):  
Ibrahim A Abuashe ◽  
Bashir H Arebi ◽  
Essaied M Shuia
Keyword(s):  
Mathematical Model ◽  
Power Output ◽  
Model Development ◽  
Geometrical Parameters ◽  
Balance Equations ◽  
Solar Chimney ◽  
And Performance ◽  
Development And Validation ◽  
The Mathematical Model ◽  
Good Agreement

A mathematical model based on the momentum, continuity and energy balance equations was developed to simulate the behavior of the air flow inside the solar chimney system. The model can estimate the power output and performance of solar chimney systems. The developed mathematical model is validated by the experimental data that were collected from small pilot solar chimney; (experiment was presented in part I). Good agreement was obtained between the experimental results and that from the mathematical model. The model can be used to analyze the solar chimney systems and to determine the effect of geometrical parameters such as chimney height and collector diameter on the power output and the efficiency of the system

Chaotic Phenomena Induced by the Fast Plastic Deformation of Metals During Cutting

2005 ◽  
Vol 73 (2) ◽  
pp. 240-245 ◽  
Author(s):  
Zoltan Palmai
Keyword(s):  
Mathematical Model ◽  
Plastic Deformation ◽  
Shear Stress ◽  
General Structure ◽  
Equation System ◽  
Qualitative Description ◽  
Balance Equations ◽  
Different Types ◽  
Energy Equations ◽  
The Mathematical Model

In the present study the examination of chip formation is focused on the primary shear zone, which is divided into two layers, and the variation of shear stress and temperature in time are given by two mechanical balance equations and three energy equations. All the five evolution differential equations are autonomous and nonlinear. The material characteristics are determined by an exponential constitutive equation. The mathematical model is suitable for the qualitative description of different types of chips, such as continuous chips and periodic or aperiodic shear localized chips, which is demonstrated by the general structure and typical solutions of the equation system.

scholarly journals Mathematical modeling of plastic deformation of a tube from dispersion-hardened aluminum alloy

2018 ◽  
Vol 243 ◽  
pp. 00008 ◽  
Author(s):  
Oleg Matvienko ◽  
Olga Daneyko ◽  
Tatyana Kovalevskaya
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Plastic Deformation ◽  
External Pressure ◽  
Dislocation Loops ◽  
Balance Equations ◽  
Deformable Solid ◽  
Deformation Defects ◽  
Resistance Decrease ◽  
The Mathematical Model

The influence of the internal and external pressure subjected to the tube from dispersion-hardened aluminium alloy was investigated. The approach which combines methods of crystal plasticity and mechanics of deformable solid was used to explore the limits of elastic and plastic resistance. The mathematical model of plastic deformation includes balance equations for deformation defects with regard to the generation and annihilation of shear dislocations, vacancy and interstitial prismatic dislocation loops, and dislocations in dipole configurations of vacancy and interstitial types and also equilibrium equation, geometrical and physical relations between the deformations, displacements and stresses. It has been established that as the temperature increases, the limits of the elastic and plastic resistance decrease. Results of investigation demonstrate that the hardening the alloy by nanoparticles significantly improves the strength characteristics of the material.

scholarly journals Estimating the Optimum Tilt Angles for South-Facing Surfaces in Palestine

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 623 ◽  
Author(s):  
Ramez Abdallah ◽  
Adel Juaidi ◽  
Salameh Abdel-Fattah ◽  
Francisco Manzano-Agugliaro
Keyword(s):  
Mathematical Model ◽  
Solar Radiation ◽  
Tilt Angle ◽  
Peak Power ◽  
Horizontal Surface ◽  
Geographical Information ◽  
Solar Panels ◽  
Energy Gains ◽  
The Mathematical Model

The optimum tilt angle of solar panels or collectors is crucial when determining parameters that affect the performance of those panels. A mathematical model is used for determining the optimum tilt angle and for calculating the solar radiation on a south-facing surface on a daily, monthly, seasonal, semi-annual, and annual basis. Photovoltaic Geographical Information System (PVGIS) and Photovoltaic Software (PVWatts) is developed by the NREL (US National Renewable Energy Laboratory) are also used to calculate the optimum monthly, seasonal, semi-annual, and annual tilt angles and to compare these results with the results obtained from the mathematical model. The results are very similar. PVGIS and PVWatts are used to estimate the solar radiation on south-facing surfaces with different tilt angles. A case study of a mono-crystalline module with 5 kWP of peak power is used to find out the amount of increased energy (gains) obtained by adjusting the Photovoltaic (PV) tilt angles based on yearly, semi-annual, seasonal, and monthly tilt angles. The results show that monthly adjustments of the solar panels in the main Palestinian cities can generate about 17% more solar energy than the case of solar panels fixed on a horizontal surface. Seasonal and semi-annual adjustments can generate about 15% more energy (i.e., it is worth changing the solar panels 12 times a year (monthly) or at least 2 times a year (semi-annually). The yearly optimum tilt angle for most Palestinian cities is about 29°, which yields an increase of about 10% energy gain compared to a solar panel fixed on a horizontal surface.

Development of a Mathematical Model to Forecast Solar Radiation and Validating Results Using Machine Learning Technique

2021 ◽  
Author(s):  
H.M.K.K.M.B. Herath ◽  
S.V.A.S.H. Ariyathunge ◽  
G.M.K.B. Karunasena
Keyword(s):  
Neural Network ◽  
Mathematical Model ◽  
Linear Regression ◽  
Solar Radiation ◽  
Multiple Linear Regression ◽  
Rural Areas ◽  
Meteorological Data ◽  
Measuring Instruments ◽  
Linear Regression Method ◽  
The Mathematical Model

Abstract Solar radiation or also referred to as solar power is the general expression for electromagnetic radiation emitted by the Sun. Direct solar radiation is an important factor in global solar radiation and is very influential in the efficiency evaluation of various applications for solar energy. For countries like Sri Lanka, installing a solar radiation instrument in rural areas is a challenge. Thus, both scientific and economically, measuring solar radiation without installing measuring instruments is an advantage. The aim of this study is to development of a mathematical model to predict solar radiation where solar radiation measurement instruments are not installed. The Artificial Neural Network (ANN) was used to verify the predictions of the mathematical model. Multiple Linear Regression (MLR) analysis was used for the development of a mathematical model to predict solar radiation. The model with the highest R2 value (0.5973) was chosen from the 127 equations as the best model that describes the solar radiation that reaches the surface of the earth. The dataset used for this study was meteorological data from the four month HI-SEAS weather station and are composed of ten attributes including date, time, radiation (H), temperature (Tair), pressure (P), humidity (φ), sunrise time, sunset time, wind direction (D), and speed (S). The angle of declination (δ) and sunshine hours (N) were calculated using the dataset. For the training of the neural network, 80 % of the data from the HI-SEAS dataset was used. The remaining data were used for testing both mathematical and ANN models. Results obtained from the multiple linear regression method and the ANN method was compared with the measured values. The experimental results suggested that the mathematical model was predicted the solar radiation with ±100 Wm-2 tolerance for both measured and ANN values.

On the Characteristics of a Novel Floating Sub-Atmospheric Solar Water Desalination System

2011 ◽  
Vol 110-116 ◽  
pp. 2139-2147
Author(s):  
Hooman Mohammad Pour ◽  
Mehdi Ashjaee
Keyword(s):  
Mathematical Model ◽  
Solar Radiation ◽  
Water Temperature ◽  
Water Resource ◽  
Atmospheric Condition ◽  
Water Desalination ◽  
Incident Solar Radiation ◽  
Solar Water ◽  
Significant Parameter ◽  
The Mathematical Model

This paper proposes a new floating sub-atmospheric solar water desalination system to provide the water resource for domestic to industrial usage. In addition to conventional solar stills (CSS) which only utilize incident solar radiation, the sub-atmospheric condition of this system greatly increases the productivity of the system. The mathematical model of the system is developed and the performance of the still is evaluated. The overall productivity of the still is shown to be sensitive to evaporator pressure as the most significant parameter of the system. Other parameters affecting the performance include cover transmissivity and input water temperature.

A Mathematical Model for the Performance of a Horizontal Convective Solar Still

2005 ◽  
Author(s):  
M. Feng ◽  
Y.-X. Tao
Keyword(s):  
Mathematical Model ◽  
Solar Radiation ◽  
Flow Direction ◽  
Vertical Direction ◽  
Operating Conditions ◽  
Radiation Absorption ◽  
Solar Still ◽  
Materials Used ◽  
The One ◽  
Physical Phenomena

A mathematical model is developed to predict the rate of distilled water production for a solar still with convective, double-deck configuration. The model is based on the one-dimensionally distributed formulation in the flow direction and two media treatment in the vertical direction. Different operating conditions are investigated to include different airflow rates, variable rates of solar radiation and ambient temperature. The effects of materials used in the still canopy and physical phenomena such as solar radiation absorption of liquid film on the performance are also investigated. The comparisons between the model results and fully two-dimensional CFD model results are presented.

scholarly journals Experimental and Theoretical Analysis of a Mono PV Cell with Five Parameters, Simulation Model Compatible with Iraqi Climate

2020 ◽  
Vol 27 (1) ◽  
pp. 54-64
Author(s):  
Bdoor Majed Ahmed ◽  
Nibal Fadel Farman Alhialy
Keyword(s):  
Mathematical Model ◽  
Solar Radiation ◽  
Ambient Temperature ◽  
Weather Conditions ◽  
Included Study ◽  
Standard Test ◽  
Solar Panel ◽  
Solar Panels ◽  
Proposed Model ◽  
The Mathematical Model

The present work included study of the effects of weather conditions such as solar radiation and  ambient temperature on solar panels (monocrystalline 30 Watts) via proposed mathematical model, MATLAB_Simulation was used by scripts file to create a special code to solve the mathematical model , The latter is single –diode model (Five parameter) ,Where the effect of ambient temperature and solar radiation on the output of the solar panel was studied, the Newton Raphson method was used to find the  output current of the solar panel and plot P-V ,I-V curves, the performance of the PV was determined at Standard Test Condition (STC) (1000W/m2)and a comparison between theoretical and experimental results were done .The best efficiency  ranging from 0.15 to 0.16. With a particularly, error about (-0.333) for experimental power (30 Watt) comparing with theoretical power (30.1), through these results it is concluded the validity of the proposed model. This model can be used for all types of photovoltaic panels and also with larger output power.

scholarly journals MODELING OF SOLAR RADIATION FOR USE IN RENEWABLE ENERGY AND IN CONSTRUCTION THERMAL PHYSICS

2018 ◽  
Vol 40 (1) ◽  
pp. 44-50
Author(s):  
B.I. Basok ◽  
B.V. Davydenko ◽  
V.G. Novikov ◽  
R.Ya. Sorokovoy
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Renewable Energy ◽  
Solar Radiation ◽  
Experimental Studies ◽  
Program Code ◽  
Solar Insolation ◽  
Thermal Physics ◽  
The Mathematical Model ◽  
Design And Construction

The work is devoted to the estimation of the intensity and energy of solar radiation at the earth's surface. The aim of the research is to develop a mathematical model of solar radiation, necessary for the design of devices for renewable energy, as well as in the design and construction of buildings and structures. The mathematical model of solar radiation is realized in the Python code. The program code allows you to calculate the intensity of solar radiation and solar insolation on any day of the year. The model is verified by the results of experimental studies of solar radiation in the Odessa region and by the results of our own experimental data.

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