Thermal Modeling, Experimental Validation, and Comparative Analysis of Modified Solar Stills

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Piyush Pal ◽  
Rahul Dev
Keyword(s):  
Comparative Analysis ◽  
Thermal Modeling ◽  
Uttar Pradesh ◽  
Solar Still ◽  
Solar Desalination ◽  
Low Efficiency ◽  
Basin Area ◽  
Evaluation Parameters ◽  
Theoretical Results ◽  
Good Agreement

AbstractIn the present work, an effort is carried out to enhance the distillate yield of a single-slope basin-type solar still by increasing the heat input through its transparent walls and providing hanging wicks to increase the evaporation–condensation rates. A modified basin-type single-slope multi-wick solar still (MBSSMWSS) was proposed and fabricated to increase the productivity and improve the low efficiency of the recently designed modified basin-type single-slope solar still (MBSSSS). Experiments were conducted on both the solar stills to assess their performance, productivity, and efficiency (thermal and exergy) for the same basin area and water depth for the climatic condition of Prayagraj, Uttar Pradesh (U.P.), India. Results showed that the productivity, overall energy (thermal) efficiency, and maximum values of measured instantaneous exergy efficiency of the MBSSSS and MBSSMWSS systems were found to be 3.2 l/m2 day and 4.22 l/m2 day, 18.16% and 26.89%, and 4.28% and 5.31%, respectively. Furthermore, thermal modeling was also done using the energy balance equations, and then, a theoretical analysis was carried out to validate with the respective experimental observations. A good agreement was found between experimental and theoretical results. Finally, based on the results of the evaluation parameters and comparative analysis, the modified solar still with wick was found to be a better system compared with that of the system without wick and might be a good option as a solar desalination system.

Comparative analysis of the use of flash evaporator and solar still with a solar desalination system

2020 ◽  
pp. 1-8
Author(s):  
Hemin Thakkar ◽  
Kishor kumar Sadasivuni ◽  
P. V. Ramana ◽  
Hitesh Panchal ◽  
M. Suresh ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Solar Still ◽  
Solar Desalination

Mathematical modelling and experimental study of a solar distillation system

2011 ◽  
Vol 225 (5) ◽  
pp. 1203-1212 ◽  
Author(s):  
O Mahian ◽  
A Kianifar
Keyword(s):  
Mathematical Model ◽  
Wind Velocity ◽  
Low Cost ◽  
Solar Still ◽  
Solar Distillation ◽  
Distillation System ◽  
Insulation Thickness ◽  
The Mathematical Model ◽  
Basin Area ◽  
Good Agreement

The production of potable water from saltwater or brackish water using solar distillation has been practised for many years in different parts of the world. However, little attention has been paid to the feasibility of this technique in Iran. In this work, a solar still with a basin area of 0.9 m2 and a glass cover in the form of a pyramid has been designed and constructed, and its performance is studied experimentally in Mashhad, Iran. Also, the performance of the solar still is modelled where a small fan was utilized to enhance the daily productivity of freshwater. In addition to the effect of forced convection caused by a fan, the effects of the water depth, the insulation thickness of the basin base, and the wind velocity have been investigated. The empirical results have been compared with the results obtained from the mathematical model and good agreement has been obtained. The results show that the use of a low-cost fan with negligible power can be an effective and economical way of enhancing the evaporation rate and hence freshwater production. Based on the mathematical model, the daily productivity of freshwater increases up to ∼ 56 per cent at a Reynolds number of 35 000. Finally, an effective range for the wind velocity as well as insulation thickness is presented in order to optimize the production rate of freshwater.

Theoretical and Experimental Investigation of a Novel Multistage Evacuated Solar Still

2005 ◽  
Vol 127 (3) ◽  
pp. 381-385 ◽  
Author(s):  
Yousif A. Abakr ◽  
Ahmad F. Ismail
Keyword(s):  
Cfd Simulation ◽  
Condensation Process ◽  
Solar Still ◽  
Ambient Conditions ◽  
Element Analysis ◽  
Solar Desalination ◽  
Multi Stage ◽  
Low Efficiency ◽  
The Cost ◽  
New System

Solar desalination is an ideal source of fresh water for both drinking and agriculture. A lot of research was conducted on solar desalination systems, but most of the available systems have low production, are expensive, and are not reliable for long term use. In this work a new multistage evacuated solar desalination system was proposed and designed. The objective of this work is to increase the productivity and improve the low efficiency of the traditional solar desalination systems. The new system works by virtue of the higher evaporation rate under vacuum condition inside the solar still. A model for the system was developed and used to optimize the system design. The new model was subjected to a Finite Element Analysis (FEA) structural analysis using MSC/NASTRAN™ FEA software. A Computational Fluid Dynamics (CFD) simulation of the evaporation and condensation process inside one stage of the new solar still was conducted using FLUENT™ software. The system prototype was fabricated and tested at the actual outdoor ambient conditions for a period of 3 months. The productivity of this new system was found to be 14.2kg/m2/day, which is about threefold of the maximum productivity of the basin type solar still. The cost of produced still water is estimated as 0.20 US$/gal. The results show that the multi-stage evacuated solar still might be a good option as a solar desalination system.

Investigating the Nonlinear Optical Response of Pepper Oil under Low Power Irradiation with Continuous Wave Visible Laser Beam

2020 ◽  
pp. 131-138
Keyword(s):  
Refractive Index ◽  
Nonlinear Refractive Index ◽  
Nonlinear Optical ◽  
Continuous Wave ◽  
Diffraction Integral ◽  
Visible Laser ◽  
Limiting Property ◽  
Kirchhoff Diffraction Integral ◽  
Theoretical Results ◽  
Good Agreement

The nonlinear optical properties of pepper oil are studied by diffraction ring patterns and Z-scan techniques with continuous wave beam from solid state laser at 473 nm wavelength. The nonlinear refractive index of the sample is calculated by both techniques. The sample show high nonlinear refractive index. Based on Fresnel-Kirchhoff diffraction integral, the far-field intensity distributions of ring patterns have been calculated. It is found that the experimental results are in good agreement with the theoretical results. Also the optical limiting property of pepper oil is reported. The results obtained in this study prove that the pepper oil has applications in nonlinear optical devices.

Solar desalination using solar still enhanced by PCM and nano fluid

2020 ◽  
Author(s):  
Karthikeyan Alagu ◽  
M. Siva Reddy ◽  
M. Narendra Kumar ◽  
Anderson Arul Gnana Dhas
Keyword(s):  
Solar Still ◽  
Nano Fluid ◽  
Solar Desalination

Studies of local structures for Cu2+ centers in M2Zn(SO4)2·6H2O (M = NH4 and Rb) crystals

2021 ◽  
Vol 76 (4) ◽  
pp. 299-304
Author(s):  
Fu Chen ◽  
Jian-Rong Yang ◽  
Zi-Fa Zhou
Keyword(s):  
Crystal Field ◽  
Elongation Ratio ◽  
Paramagnetic Resonance ◽  
Local Structures ◽  
Epr Parameters ◽  
Structure Constants ◽  
Crystal Field Parameters ◽  
Electron Paramagnetic ◽  
Theoretical Results ◽  
Good Agreement

Abstract The electron paramagnetic resonance (EPR) parameters (g factor g i , and hyperfine structure constants A i , with i = x, y, z) and local structures for Cu2+ centers in M2Zn(SO4)2·6H2O (M = NH4 and Rb) are theoretically investigated using the high order perturbation formulas of these EPR parameters for a 3d 9 ion under orthorhombically elongated octahedra. In the calculations, contribution to these EPR parameters due to the admixture of d-orbitals in the ground state wave function of the Cu2+ ion are taken into account based on the cluster approach, and the required crystal-field parameters are estimated from the superposition model which enables correlation of the crystal-field parameters and hence the studied EPR parameters with the local structures of the Cu2+ centers. Based on the calculations, the Cu–H2O bonds are found to suffer the axial elongation ratio δ of about 3 and 2.9% along the z-axis, meanwhile, the planar bond lengths may experience variation ratio τ (≈3.8 and 1%) along x- and y-axis for Cu2+ center in (NH4)2Zn(SO4)2·6H2O and Rb2Zn(SO4)2·6H2O, respectively. The theoretical results show good agreement with the observed values.

On the Flow Fields of Inertial Impactors

1974 ◽  
Vol 96 (4) ◽  
pp. 394-400 ◽  
Author(s):  
V. A. Marple ◽  
B. Y. H. Liu ◽  
K. T. Whitby
Keyword(s):  
Flow Field ◽  
Stokes Equations ◽  
Relaxation Method ◽  
Water Model ◽  
Navier Stokes ◽  
Visualization Technique ◽  
Navier Stokes Equations ◽  
Theoretical Results ◽  
Plate Distance ◽  
Good Agreement

The flow field in an inertial impactor was studied experimentally with a water model by means of a flow visualization technique. The influence of such parameters as Reynolds number and jet-to-plate distance on the flow field was determined. The Navier-Stokes equations describing the laminar flow field in the impactor were solved numerically by means of a finite difference relaxation method. The theoretical results were found to be in good agreement with the empirical observations made with the water model.

Explanation of the Influence of Inflow Air Content on the Lift of Cavitating Hydrofoils

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Eduard Amromin
Keyword(s):  
Experimental Data ◽  
Theoretical Study ◽  
Lift Coefficient ◽  
Cavity Surface ◽  
Air Bubbles ◽  
Incoming Flow ◽  
Fluid Density ◽  
Air Content ◽  
Theoretical Results ◽  
Good Agreement

According to several known experiments, an increase of the incoming flow air content can increase the hydrofoil lift coefficient. The presented theoretical study shows that such increase is associated with the decrease of the fluid density at the cavity surface. This decrease is caused by entrainment of air bubbles to the cavity from the surrounding flow. The theoretical results based on such explanation are in a good agreement with the earlier published experimental data for NACA0015.

Models for New Corrugated and Porous Solar Air Collectors under Transient Operation

2017 ◽  
Vol 42 (1) ◽  
Author(s):  
Qahtan Adnan Abed ◽  
Viorel Badescu ◽  
Adrian Ciocanea ◽  
Iuliana Soriga ◽  
Dorin Bureţea
Keyword(s):  
Climatic Conditions ◽  
Meteorological Conditions ◽  
Bias Error ◽  
First Order ◽  
Solar Air Collector ◽  
Section Surface ◽  
South Eastern Europe ◽  
Main Components ◽  
Theoretical Results ◽  
Good Agreement

AbstractMathematical models have been developed to evaluate the dynamic behavior of two solar air collectors: the first one is equipped with a V-porous absorber and the second one with a U-corrugated absorber. The collectors have the same geometry, cross-section surface area and are built from the same materials, the only difference between them being the absorbers. V-corrugated absorbers have been treated in literature but the V-porous absorbers modeled here have not been very often considered. The models are based on first-order differential equations which describe the heat exchange between the main components of the two types of solar air heaters. Both collectors were exposed to the sun in the same meteorological conditions, at identical tilt angle and they operated at the same air mass flow rate. The tests were carried out in the climatic conditions of Bucharest (Romania, South Eastern Europe). There is good agreement between the theoretical results and experiments. The average bias error was about 7.75 % and 10.55 % for the solar air collector with “V”-porous absorber and with “U”-corrugated absorber, respectively. The collector based on V-porous absorber has higher efficiency than the collector with U-corrugated absorber around the noon of clear days. Around sunrise and sunset, the collector with U-corrugated absorber is more effective.

Cancelling of Self-Excited Vibrations by Means of Parametric Excitation

1999 ◽  
Author(s):  
Aleš Tondl ◽  
Horst Ecker
Keyword(s):  
Numerical Simulation ◽  
Harmonic Function ◽  
Parametric Excitation ◽  
Exciting Force ◽  
Mass System ◽  
Parameter Variations ◽  
Simulation Parameter ◽  
Top Mass ◽  
Theoretical Results ◽  
Good Agreement

Abstract The possibility of cancelling self-excited vibrations of a mechanical system using parametric excitation is discussed. A two-mass system is considered, with the top mass excited by a flow-generated self-exciting force. The parameter of the connecting stiffness between the base mass and the foundation is a harmonic function of time and represents a parametric excitation. For such a system general conditions for full vibration cancelling are derived and presented. By means of numerical simulation the system is investigated for several sets of parameters. The theoretical results are found to be in very good agreement with the results obtained by simulation. Parameter variations show the extent of the parameter space where significant vibration cancelling can be achieved and illustrate possible applications.

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