May 29, 2017 - This project is focused on the simulation of solar still by using ANSYS FLUENT ... 4.2 Snapshot of Energy Equation of Single Slope Solar Still.
Thermal Simulation of Solar Distiller Units: Study of Heat & Mass Transfer Hrishi Jain (131786) Md. Nabeel Faruqui (131795) Nishant Kumar (131799)
Project Report submitted in partial fulfillment of the requirements for the degree of
Bachelor of technology In Mechanical Engineering Under the Guidance of Dr. Dhananjay R. Mishra Department of Mechanical Engineering Jaypee University of Engineering & Technology A.B. Road, Raghogarh, Guna - 473226 M.P. (India) May 2017
CERTIFICATE This is to certify that the work titled THERMAL SIMULATION OF SOLAR DISTILLAR UNITS: STUDY OF HEAT & MASS TRANSFER submitted by Hrishi Jain (131786), Md. Nabeel Faruqui (131795) and Nishant Kumar (131799) in partial fulfillment for the award of degree of Bachelor of Technology of Jaypee University of Engineering & Technology, Guna has been carried out under my supervision at JUET, Guna campus. This work has not been submitted partially or wholly to any other University or Institute for the award of this or any other degree.
Signature of Supervisor .
.
Name of Supervisor
Dr. Dhananjay R. Mishra
Designation
Assistant Professor (SG)
Date
29/05/2017
I
ACKNOWLEDGEMENT We would like to express our sincere gratitude to our supervisor Dr. Dhananjay R. Mishra for providing us with invaluable guidance, comments and suggestions throughout the course of the project. Also we wish to express our sincere gratitude to the entire staff of Mechanical Engineering Department for providing us with the opportunity to complete our project successfully.
Hrishi Jain (131786) Md. Nabeel Faruqui (131795) Nishant Kumar (131799)
II
EXECUTIVE SUMMARY The past few decades have seen outstanding improvement in Solar Still design and use due to low cost and easy handling. It gives us pure distilled water at very cheap rate. This project is an attempt to compare the theoretical and experimental data such that, our result and data can be used by anyone to get an exact idea of how one can build an optimum solar still. This project is focused on the simulation of solar still by using ANSYS FLUENT software to find out the heat and mass transfer rate. The project report also presents the review of various research papers mainly based on mathematical expression used to calculate the convective and evaporative heat transfer coefficient and the mass transfer rate. The objective to this project was to perform a CFD simulation of single slope solar still and to compare the theoretical and experimental data for optimum results.
III
TABLE OF CONTENTS PAGE CERTIFICATE
I
ACKNOWLEDGEMENT
II
EXECUTIVE SUMMARY
III
LIST OF FIGURES
V
CHAPTER
1. Introduction 1.1 Basic Principle of Solar Still
3
1.2 Principle of Solar Still
3
2. Theoretical Background 2.1 Radiative Heat Transfer Coefficient
5
2.2 Convective Heat Transfer Coefficient
5
2.3 Evaporative Heat Transfer Coefficient
6
2.4 Theoretical Amount of Condensate
6
2.5 Fraction of Heat Transfer
6
3. Thermal Simulation of Single Slope Solar Still 3.1 Modelling
8
3.2 Meshing
9
4. Influencing Input Parameters for Thermal Simulation Method 4.1 Simulation
16
4.2 Result
18
5. Conclusion and Future Scope References
IV
LIST OF FIGURES FIGURES
PAGE
1.1 Cross-sectional view of symmetric arrangement and various energy transfers
4
3.1 Snapshot of Mesh ISO of Single Slope Solar Still
8
3.2 Snapshot of Side View of Single Slope Solar Still
9
3.3 Snapshot of Mesh Closed View of Single Slope Solar Still
10
3.4 Snapshot of Back Plate and Absorber Plate of Single Slope Solar Still
11
4.1 Snapshot of Input Parameters of Single Slope Solar Still
12
4.2 Snapshot of Energy Equation of Single Slope Solar Still
13
4.3 Snapshot of Viscous Model of Single Slope Solar Still
13
4.4 Snapshot of Rosseland Model of Single Slope Solar Still
14
4.5 Snapshot of Boundary Conditions of Single Slope Solar Still
15
4.6 Snapshot of Glass Collector of Single Slope Solar Still
16
4.7 Snapshot of Vapour Fraction of Single Slope Solar Still
16
4.8 Variation of Temperature of Water and Glass with respect to Time
17
4.9 Variation of Temperature of Glass Actual and Glass with respect to Time
18
V
NOMENCLATURE •
he
-
evaporative heat transfer coefficient
•
hcv -
convective heat transfer coefficient
•
hfg -
heat of evaporation
•
Cpa -
specific heat capacity of air
•
Ra
-
Rayleigh number
•
R
-
gas constant
•
Po
-
Total pressure
•
Pvs -
Pressure of water vapour at the liquid surface
•
Pvg -
Pressure of water vapour at the condensing surface
•
mw -
mass flow rate
•
hcv -
Convective heat transfer
•
α
-
absorptivity
•
Q
-
heat transfer
•
I(t) -
solar flux on an inclined collector
•
hfg -
enthalpy of evaporation at Tw
•
cp
-
specific heat
•
q rw
-
radiative heat transfer
•
q cw
-
convective heat loss
.
VI
Chapter 1 Introduction Availability of fresh, clean water is still challenging to the many parts of the world. Distillation is one of the many processes available for obtaining fresh water from salty, brackish or contaminated water. Sunlight has an advantage of the zero fuel cost but requires large space area for the power generation. Despite a common belief, it is not necessary to boil water to distil it. Simply elevating its temperature below the boiling point adequately increases the evaporation rate. In fact, although vigorous boiling accelerates the distillation process, it can also force unwanted residue into the distillate defeating purification. Furthermore, to boil water with sunlight requires a more costly apparatus than the distiller units which operates at below boiling temperature. Generally, bulky and costly setups are required to generate high temperature. For people concerned with the quality of their municipally supplied drinking water and unhappy with other methods of purification available to them. In recent years, various studies (i.e. experimental and theoretical) have conducted on different configurations of solar stills to enhance the performance and productivity. Sampath Kumar and his associates
reported a detailed review of various
designs of active solar distillation [1]. In active mode, water in the basin was heated directly or indirectly (hot water available from solar collector or industries) for climatic conditions such as solar radiation, wind velocity, and ambient temperature has a direct effect on productivity. Although the initial water temperature and insulation thickness have direct effects, but the cover angle has an inverse effect in summer and direct effect in winter. A mathematical model to predict the effect of climatic condition and design parameters on the performance of a solar still were reported [2]. Better efficiency was obtained at the maximum temperature difference between water and glass cover [3]. Tiwari et al. [4] reported a comparative performance of three different designs of single basin solar stills. The better yield obtained using a single-slope, solar still made of fiber reinforcement plastic (FRP) than the double slope in winter, but in summer, the reverse results appeared. Al-Hayek and Badran [5] observed that using mirrors in asymmetric greenhouse type solar still, yield was recorded 20% higher than that of the symmetric greenhouse types. Mishra and Tiwari [6] reported the effect of coal powder and blackened metal chip on the single basin passive solar still were blanked metal chip containing in basin area of conventional solar still gives higher yield as compared to the still containing coal powder with the same height of 2.5cm. Mutasher et al. 1
[7] reports the enhancement in clean water productivity by using a combination of sun tracking system with solar still. Esfahani et al.[8] used thermoelectric technology to improve the productivity of solar stills. In addition to experimental researchers, there are many studies, which use mathematical modeling to estimate the productivity of solar stills. Experimental study of a solar still with sponge cubes in basin reported by Bassam et al. [9]. The basin water depth has a significant effect on the productivity of the basin. Investigations show that the water depth is inversely proportional to the productivity of still [10–12] Variation of the convective heat transfer coefficient and thermal modeling of solar stills have studied by many authors where the water depth parameter was incorporated as a major parameter that affects the still performance. The effect of using black rubber and black gravel for augmenting the productivity of the solar still is performed [10,11,13–15], these studies shows that black rubber, black gravel and floating perforated black aluminum plate in the solar still increases the solar still productivity by 20%, 19%, and 15%, respectively. Some authors worked on improving the performance of solar desalination systems by using modifications in the solar desalination systems [16]. The effect of water depth on heat and mass transfer in a passive solar still in summer climatic conditions has been studied [10]. In order to improve the performance of conventional solar stills, several other designs have been developed and proposed with their significance, such as the double-basin type [9,17], multibasin type [18,19], a wick basin type [20] and a multi-wick single slope solar still [21]. Integration of solar still in a multi-source and the multi-use environmental type was also studied [22]. The external reflector was inclined slightly forward to make the reflected sun rays hit the basin liner of the still effectively and daily productivity of a basin type still can be increased about 70% to 100% with a very simple modification using internal and external reflectors [23]. The experimental results and the theoretical predictions are in good agreement, especially on clear days [24].
The water collection area was improved by
connecting the stepped trays of 12 numbers, Different water depths of 2 cm, 3 cm, 4 cm were used in the conventional basin while a constant 2 cm water depth was maintained in the stepped tray type basin and Maximum productivity of 1.468 kg/m2 was recorded for 2 cm water depth and lowest production of 1.150 kg/m2is obtained for 4 cm water depth [25]. Sponges are added to improve the capillary action [9]. For 2 cm water depth with wick and sponge combination, the maximum output of 1.305 kg/m2was obtained [26]. The lowest productivity was recorded for 4 cm water depth with sponge's combination (1.280 kg/m2). Packing materials such as wooden chips, sand, coal, coconut coir, were added in the inclined 2
flat plate collector to increase the area of exposure [27]. Different packing material analyzed, rock, sponge and wick combination gain the maximum productivity of 1.745 kg/m2and lowest productivity is for sand and wick combination (1.200 kg/m2) [28]. The daily efficiency of various combinations was calculated for the coconut coir and wick combination produced 16.36%, nearly 3% increase in efficiency when compared to be conventional still [29]. A theoretical analysis was also performed and compared with experimental results, At maximum deviation of less than 10% between theoretical and experimental analysis was obtained [29]. A theoretical analysis of a tilted wick solar still with an external flat plate reflector which was able to incline in forwards as well as backward according to the seasons [30,31]. The analyses of observed data that the variation of the mean temperature of the earth was explained by the variation of short-wave radiation, arriving at the surface of the Earth [32]. In connection with this, the influence of long-term changes of radiation, caused by variations of atmospheric transparency on the thermal regime reported [33]. A comparison between fixed and the sun tracked solar stills showed that the use of sun tracking increased the productivity for around 22%, due to the increase of overall efficiency by 2%, It was concluded that the sun tracking was more effective than the system and it was capable of enhancing the productivity [34]. Mathematical modeling of lond solar still reported by Mishra et al.[39].Mishra and Tiwari [40- 43] also reported the way to utilize ground rnrgy for enhancing the productivity of single slope solar still. 1.1 Basic principle of a solar still The basic principle of distillation is simple and it replicates the way of nature made rain. Sun energy increases the temperature of water, which causes the increase in the surface evaporation rate, results in formation of water vapors and condensate at the inner cover of glass as a cool surface. This process removes heavier metals, salts as well as microbiological organisms from water and provides the purest form of water as rainwater.
1.2 Principles of solar still Increasing the area of water in contact with the air to enhance the rate of water evaporation, which can lead to the higher yield of the solar still. Basin area of the still painted with the black color to maximize the coefficient of absorption of the basin. Evaporated water vapors are trapped with the help glass cover, which should be several degrees at a lower temperature than the water. Water from solar still should be quite pure. The slow process of distillation allows a pure form of water to evaporate from the surface and condensate at the lower surface 3
of the inner glass surface. A careful design, constructional material, and operation of a solar still will give pure water free from the harmful materials and cancer-causing substance, colorless, odorless and unfortunately tasteless also, so it has recommended that to add a small quantity of salt for the test to the distilled water obtained from the still. Various energy transfer within the single slope solar still shown in Fig.1.1[35].
Fig. 1.1 Cross-sectional view of schematic arrangement and various energy transfers[35]. The objective of this study is to develop a 3D CFD model of Single slope Solar Still to understand the evaporation and condensation phenomena in solar still. The model has been developed with the help of ANSYS Workbench and then simulated with Fluent. Water temperature and production rate of fresh water from the simulation results compared with the actual results. Further comparison has been made between simulation result and experimental results of water temperature, glass cover temperature. Parametric analyses have been done to enhance the productivity of Solar Still. F R P m a t e r i a l were used in basin to improve the heat and absorption capacity to increase the evaporation rate. We also calculate the yield and to study the heat and mass transfer rate of the still. In the next chapter, various factors affecting the performance of the solar still including solar intensity, ambient temperature, water glass temperature difference and free surface area of water, absorber plate area, temperatures of inlet water, glass angle and depth of water have been examined. On the basis of study of various research papers, a number of numerical expressions were noted which were useful for the theoretical calculations including energy balance equations and the expression to find the evaporative heat transfer coefficient, convective heat transfer coefficient, the mass outflow and total condensation rate.
4
Chapter 2 Theoretical Background There are three modes possible for heat transfer from water surface to condensing cover these are radiative, convective and evaporative heat transfer. 2.1 Radiative heat transfer coefficient
The rate of radiative heat transfer ( q rw ) from water surface to the condensing cover can be obtained as[36];
q rw T14 T2 4
(1)
Where, T1 (Tw 273) K , T2 (Tg 273) K ,
1 1 1 w g
Eq. 1 can be rewritten as q rw hrw (T1 T2 )
(2)
(Tw 273)4 (Tg 273) 4 h Where, rw Tw Tg
(3)
1
5.67 108W / m2 K 4
and
radiative heat transfer coefficient can be
calculated. 2.2 Convective heat transfer coefficient The convective heat transfer coefficient ( hcw ) can be obtain from 1
3 ( Pw Pg ) (Tw 273) hcw 0.884 (Tw Tg ) 2.689 105 Pw
The volume of
Pw
and
Pg (for
(4)
the range of temperature 10oC to 90oC) can be obtained at
water and inner condensing cover temperature from the relation considering
Pw
and
Pg as
a
function of temperature.
5144 P(T ) exp 25.317 T 273
5
(5)
The rate of convective heat loss q cw in W / m2 from water surface to the inner condensing
cover can be obtained.
qcw hcw (Tw Tg )
(6)
2.3 Evaporative heat transfer coefficient
The rate of evaporative heat loss q ew from water to inner condensing cover is given by
qew 0.0166 hcw Pw Pg
(7)
Eq.7 may be rearranged as,
qew hew (Tw Tg )
(8)
q ew Or hew Tw Tg
(9)
And this evaporative heat transfer coefficient can be rearranged as,
Pw Pg hew 0.016 hcw Tw Tg Using Eqs. 1, 2 and 3, total heat transfer coefficient
(10) h1
can be written as,
h1 hrw hcw hew
(11)
The rate of heat transfer from water surface to the inner condensing cover one can obtained as,
q h1 Tw Tg
(12)
2.4 Theoretical Amount of Condensate The yield in Kg can be calculated as
M ew
q A t ew t L L 3.1615 106 1 7.6160 104 Tw
Where For temperature higher than 70℃, and
L 2.4935 106 1 9.4779 104 Tw 1.3132 107 Tw2 4.7974 109 Tw3
6
(13)
for operating temperature less than 70℃ [36–38]. At is basin area of distiller unit , t = time interval of the experiment . 2.5 Fraction of Heat Transfer The fraction of heat transfer due to the radiation, convection, and radiation can be evaluated as Frw
q rw
q cw
q ew
; Fcw
q
q
; Few
(14)
q
In the next chapter, each and every step of the simulation performed has been briefly explained to provide a general idea. The modelling is shown in different views and the procedure of modelling is also discussed. Along with modelling, meshing is also shown with proper element size and name selection is also done in this step. The view of meshing is also discussed in the following chapters.
7
Chapter 3 Thermal Simulation of single slope solar still 3.1 Modeling A model of solar still in the ANSYS design modular window was made as shown in Fig. 2. The basic commands used in making this model are extrude, Boolean, cut etc.
Fig. 3.1 Snapshot of Mesh ISO of Single Slope Solar Still 8
And its side view is shown in Fig. 3.2,
Fig. 3.2 Snapshot of Side View of Single Slope Solar Still 3.2 Meshing In order to analyze fluid flows, flow domains are split into smaller subdomains (made up of geometric primitives like hexahedra and tetrahedral in 3D and quadrilaterals and triangles in 2D). The governing equations are then discretized and solved inside each of these subdomains. Typically, one of three methods is used to solve the approximate version of the system of equations: finite volumes, finite elements, or finite differences. The subdomains are often called elements or cells, and the collection of all elements or cells is called a mesh or grid. The process of obtaining an appropriate mesh (or grid) is termed mesh generation (or grid generation), and has long been considered a bottleneck in the analysis process due to the lack of a fully automatic mesh generation procedure. Access to a good software package and expertise in using this software are vital to the success of a modelling effort. So an attempt was made to try meshing by first dividing this
9
model into 3 parts basin, collector & still. A cut cell type method was used which gave the brick type 3D structure as element as shown in Fig. 3.3 and 3.4.For the basin of Single Slope Solar Still, 1 cm element size was used, for still and collector also 1 cm element size was used and for rest of the solar still, 1.2 cm size was used. The motive for using such element size was to minimize computational time without compromising the actual results.
Fig. 3.3 Snapshot of Mesh Closed View of Single Slope Solar Still
10
Fig. 3.4 Snapshot of back plate aw2d5nd absorber plate of Single Slope Solar Still In the next chapter, the entire process of simulation of Single Slope Solar Still are explained. The various models used are discussed along, with the image which clearly explains everything. Also various boundary conditions are discussed which were used for getting optimum results. Various graphs have been plotted for the clear understanding of the output results obtained from simulation along with their comparison with the actual results obtained from experiments.
11
Chapter 4 Influencing input parameters for the Thermal Simulation Method To perform this simulation, a series of steps which starts from the first step of launch of ANSYS fluent window were followed systematically. Figure 4.1 shows the window in which transient simulation and correct gravitation of the model is specified from below.
Fig. 4.1 Snapshot of input parameters of Single Slope Solar Still Under models option, 3 phases, liquid, vapour and air were declared. Then the energy equation box was checked in order to use energy equation in the setup as shown in Fig. 4.2.
12
Fig. 4.2 Snapshot of Energy Equation of Single Slope Solar Still Now in viscous model, k-epsilon (2 equation) with RNG model was used as shown in Fig. 4.3 because it is assumed to be best for simulation of evaporation and condensation type problems. Also, enhanced wall treatment with thermal effects was provided. K-epsilon (k-ε) turbulence model is the most common model used in Computational Fluid Dynamics (CFD) to simulate mean flow characteristics for turbulent flow conditions. It is a two equation model which gives a general description of turbulence by means of two transport equations (PDEs). The original impetus for the K-epsilon model was to improve the mixing-length model, as well as to find an alternative to algebraically prescribing turbulent length scales in moderate to high complexity flows.
The first transported variable determines the energy in the turbulence and is called turbulent kinetic energy (k). The second transported variable is the turbulent dissipation (ε) which determines the rate
of dissipation of the turbulent kinetic energy. The exact k-ε equations contain many unknown and unmeasurable terms. For a much more practical approach, the standard k-ε turbulence model is used which is based on our best understanding of the relevant processes, thus minimizing unknowns and presenting a set of equations which can be applied to a large number of turbulent applications.
For turbulent kinetic energy k
13
For dissipation e
Fig. 4.3 Snapshot of Viscous model of Single Slope Solar Still Now, Rosseland model (Fig. 4.4) was used because of its simplicity to work with less complications and less time. The main input on which maximum parameters depend is radiation or irradiation. So radiation has been directed in piecewise linear manner.
14
Fig. 4.4 Snapshot of Rosseland model of Single Slope Solar Still Now for materials, in fluid, both water vapour and water liquid were provided, and in solid, both glass and fibre reinforced plastic (FRP) were provided. Now boundary conditions which are given according to the body as shown in Fig. 4.5.
15
Fig. 4.5 Snapshot of Boundary Condition of Single Slope Solar Still Now this included providing different physical conditions such as specifying black body to absorber plate. Providing convection with the heat transfer coefficient 1.2 to all the walls of solar still that basically is providing loss on different walls. In case of glass, in this step, its absorptivity and transmissivity were specified. Also, convection from glass takes place, as a result of which, convection was specified. After doing this, the basin requires to be patched. Here patching basically means that the body which is acting as water must be specified. Thermal analysis part is performed with the help of core i5, 5th generation system. Iterations were performed, with step size of 150 sec. 4.1 Simulation After providing the equations and model, contour for the temperature of glass was obtained as shown in 4.6.
16
Fig. 4.6 Snapshot of Glass collector of Single Slope Solar Still And also at the end of simulation the vapour fraction was obtained as shown in Fig. 4.7.
Fig. 4.7 Snapshot of Vapour fraction of Single Slope Solar Still
17
4.2 Result The variation of temperature between water and glass was plotted as shown in Fig. 4.8. 370 Temp of water
360
Temp of glass
Temperature (k)
350 340 330 320 310 300 290
Time (h)
Fig. 4.8 Variation of temperature of water and glass with respect to time The graph was obtained as expected. The temperature difference initially was less as it was seen at around 7:00 AM the temperature of water was 322.201 K and the temperature of glass was 313.35 K showing a difference of 8.84 K and percentage difference of 2.74 % with respect to water .At 10:00 AM the temperature of water was recorded 338.419 K and the temperature of glass was 318.948 K showing a difference of 19.47 K and percentage difference of 5.75 % with respect to water. But from 11:00 AM it was found that temperature of water was 351.518 K and the temperature of glass was 325.017 K making increase in difference temperature with value around 26.501 K and percentage difference of 7.53 % with respect to water. At 1:00 PM temperature of water was highest with 359.551 K and temperature of glass was 330.555 K showing highest temperature difference of 28.996 K and highest percentage difference of 8.064 % with respect to water. At 3:00 PM there was decrease in temperature and it was found to be 351.326 K and temperature of glass was 328.826 K. At evening time 5:00 PM temperature of water was low around 328.634 K and temperature of glass was 320.2729 K making a difference of 8.3611 K and percentage
18
difference of 2.54% with respect to water. This simulated model was in good agreement with experimental result. Another variation was plotted between temperature of glass actual and temperature of glass simulated and the result obtained is as shown in Fig. 4.9: 340 Temp of glass
Temp of glass simulation
330
Temperature
320 310 300 290 280 270 260
Time
Fig. 4.9 Variation of temperature of glass actual and glass simulation vs time Now initially, the error is large as at 7:00 AM it shows temperature of glass by simulation to be around 313.352 K instead of 284.1 K which was actual glass temperature. But at around 12:00 AM the simulated temperature was 328.628 K and actual glass temperature was 320.6 K which was roughly closer with difference of 8.028 K and close percentage difference of 2.44 % with respect glass simulated temperature. But at around 1:30 PM temperature of simulation was 330.579 K which was nearly close to actual glass temperature of 327.4 K with just difference of 3.179 K and nearly close percentage difference of 0.961% with respect to glass simulated. And at 5:00 PM the temperature by simulation was 320.2729 K and actual glass temperature was 314.7 K making difference of 5.5729 K and percentage difference of 1.74 % with respect to glass simulated. This shows that the simulation performed was in agreement with the actual results.
19
Chapter 5 Conclusion and Future Scope The results obtained from simulation were found to be of correct order when compared with the actual data. The difference in temperature of glass and water was found to be maximum at 1:00 PM with value of 28.996 K. This order of difference matches with the actual experimental results. Also the temperature of glass obtained through CFD simulation was of the same order that is at around 1:30 PM the temperature by simulation was 330.579 K which was nearly close to the actual glass temperature. By the analysis performed, it was shown that near actual results are obtained from these analyses. Although the results were not accurate but they draw a clear picture of the trend that follows. From the analysis performed, very close values of temperature of glass compared to actual temperature of glass were obtained. Also, temperature of water obtained was very close. These results and steps could be used to get an exact idea of how one can build an optimum solar still. The simulation was performed on small scale Single Slope Solar water still for experimental purposes but this could be extended to more accurate results by refining mesh and including higher level equations. This simulation was a step towards obtaining the near perfect result of experiment. The step and result obtained could be used in making a large scale desalination plant for minimizing the need of potable water in the countries like India, Sri lanka and less developed countries of Africa.
20
References [1]
Sampathkumar K, Arjunan T V., Pitchandi P, Senthilkumar P. Active solar distillationA detailed review. Renew Sustain Energy Rev 2010;14:1503–26. doi:10.1016 .
[2]
Jubran B a. Effect of climatic, design and operational parameters on the yield of a simple solar still Al-Hinai, H. et al. Energy Conversion and Management, 2002, 43, (13), 1639–1650. Fuel Energy Abstr 2003;44:87. doi:10.1016/S0140-6701(03)90659X.
[3]
Abdenacer PK, Nafila S. Impact of temperature difference ( water-solar collector ) on solar-still global efficiency 2007;209:298–305. doi:10.1016/j.desal.2007.04.043.
[4]
Tiwari GN, Mukherjee K, Ashok KR, Yadav YP. Comparison of various designs of solar stills. Desalination 1986;60:191–202. doi:10.1016/0011-9164(86)90008-1.
[5]
Al-Hayeka I, Badran OO. The effect of using different designs of solar stills on water distillation. Desalination 2004;169:121–7. doi:10.1016/j.desal.2004.08.013.
[6]
D. R. Mishra, A.K. Tiwari, Effect of coal and metal chip on the solar still. Journal of Scientific and Technical Research, 2013; 3 (1) :1–6.
[7]
Mutasher SA, Mir-Nasiri N, Wong SY, Ngoo KC, Wong LY. Improving a conventional greenhouse solar still using sun tracking system to increase clean water yield. Desalin Water Treat 2010;24:140–9. doi:10.5004/dwt.2010.1473.
[8]
Abolfazli J, Rahbar N, Lavvaf M. Utilization of thermoelectric cooling in a portable active solar still — An experimental study on winter days. DES 2011;269:198–205. doi:10.1016/j.desal.2010.10.062.
[9]
Abu-Hijleh B, Rababa’h HM. Experimental study of a solar still with sponge cubes in basin. Energy Convers Manag 2003;44:1411–8. doi:10.1016/S0196-8904(02)00162-0.
[10] Tiwari AK, Tiwari GN. Effect of water depths on heat and mass transfer in a passive solar still: in summer climatic condition. Desalination 2006;195:78–94. doi:10.1016 . [11] Tripathi R, Tiwari GN. Effect of water depth on internal heat and mass transfer for active
solar
distillation.
Desalination
2005;173:187–200.
doi:10.1016/j.desal.2004.08.032. [12] Dev R, Abdul-wahab SA, Tiwari GN. Performance study of the inverted absorber solar 21
still with water depth and total dissolved solid. Appl Energy 2011;88:252–64. doi:10.1016/j.apenergy.2010.08.001. [13] Nafey AS, Abdelkader M, Abdelmotalip A, Mabrouk AA. Solar still productivity enhancement. Energy Convers Manag 2001;42:1401–8. doi:10.1016/S0196-8904. [14] Nafey AS, Abdelkader M, Abdelmotalip A, Mabrouk AA. Enhancement of solar still productivity using floating perforated black plate. Energy Convers Manag 2002;43:937–46. doi:http://dx.doi.org/10.1016/S0196-8904(01)00079-6. [15] Dimri V, Sarkar B, Singh U, Tiwari GN. Effect of condensing cover material on yield of an active solar still: an experimental validation. Desalination 2008;227:178–89. doi:10.1016/j.desal.2007.06.024. [16] Abdel-rehim ZS, Lasheen A. Improving the performance of solar desalination systems 2005;30:1955–71. doi:10.1016/j.renene.2005.01.008. [17] Tiwari GN, Singh SK, Bhatnagar VP. Analytical thermal modelling of multi-basin solar still. Energy Convers Manag 1993;34:1261–6. doi:10.1016/0196-8904(93)90122Q. [18] Al-Karaghouli AA, Alnaser WE. Experimental comparative study of the performances of
single
and
double
basin
solar-stills.
Appl
Energy
2004;77:317–25.
doi:10.1016/S0306-2619(03)00124-7. [19] El-Sebaii AA. Thermal performance of a triple-basin solar still. Desalination 2005;174:23–37. doi:10.1016/j.desal.2004.08.038. [20] Sodha MS, Kumar A, Tiwari GN, Tyagi RC. Simple multiple wick solar still: Analysis and performance. Sol Energy 1981;26:127–31. doi:10.1016/0038-092X(81)90075-X. [21] Tiwari GN. Demonstration plant of a multi wick solar still. Energy Convers Manag 1984;24:313–6. doi:10.1016/0196-8904(84)90011-6. [22] Mathioulakis E, Belessiotis V. Integration of solar still in a multi-source , multi-use environment. Sol Energy 2003;75:403–11. doi:10.1016/j.solener.2003.07.006. [23] Tanaka H. Tilted wick solar still with external flat plate reflector: Optimum inclination of still and reflector. Desalination 2009;249:411–5. doi:10.1016/j.desal.2009.06.048. [24] Tanaka H, Nakatake Y. One step azimuth tracking tilted-wick solar still with a vertical flat plate reflector. DES 2009;235:1–8. doi:10.1016/j.desal.2008.01.011. [25] Tiwari AK, Tiwari GN. Effect of water depths on heat and mass transfer in a passive solar still: in summer climatic condition. Desalination 2006;195:78–94. doi:10.1016 . [26] Abu-Hijleh B, Rababa’h HM. Experimental study of a solar still with sponge cubes in basin. Energy Convers Manag 2003;44:1411–8. doi:10.1016/S0196-8904(02)00162-0. 22
[27] Arjunan T V., Aybar H, Neelakrishnan S, Sampathkumar K, Amjad S, Subramanian R, et al. The Effect of Sponge Liner Colors on the Performance of Simple Solar Stills. Energy Sources, Part A Recover Util Environ Eff 2012;34:1984–94. doi:10.1080 . [28] Alaudeen A, Johnson K, Ganasundar P, Syed Abuthahir A, Srithar K. Study on stepped type basin in a solar still. J King Saud Univ - Eng Sci 2014;26:176–83. doi:10.1016/j.jksues.2013.05.002. [29] Kalidasa Murugavel K, Srithar K. Performance study on basin type double slope solar still with different wick materials and minimum mass of water. Renew Energy 2011;36:612–20. doi:10.1016/j.renene.2010.08.009. [30] Tanaka H. Tilted wick solar still with external flat plate reflector: Optimum inclination of still and reflector. Desalination 2009;249:411–5. doi:10.1016/j.desal.2009.06.048. [31] Tanaka H, Nakatake Y. Effect of inclination of external flat plate reflector of basin type still in winter 2007;81:1035–42. doi:10.1016/j.solener.2006.11.006. [32] Budyko MI. The effect of solar radiation variations on the climate of the Earth. Tellus A 1969. [33] Wild M, Folini D, Henschel F, Fischer N. ScienceDirect Projections of long-term changes in solar radiation based on CMIP5 climate models and their influence on energy
yields
of
photovoltaic
systems
2015;116:12–24.
doi:10.1016/j.solener.2015.03.039. [34] Abdallah S, Badran OO. Sun tracking system for productivity enhancement of solar still. Desalination 2008;220:669–76. doi:10.1016/j.desal.2007.02.047. [35] Tiwari AK, Tiwari GN. Thermal modeling based on solar fraction and experimental study of the annual and seasonal performance of a single slope passive solar still: The effect of water depths. Desalination 2007;207:184–204. doi:10.1016/j.desal.2006. [36] M.S Sodha, D.R Mishra,., A.K. Tiwari, Solar Earth Water Still for Highly Wet Ground. Journal of
Fundamental Renew Energy Applications 2014;4:1–2.
doi:10.4172/2090-4541.1000e103. [37] Abutayeh M, Yogi Goswami D, Stefanakos EK. Theoretical and Experimental Simulation of Passive Vacuum Solar Flash Desalination. J Sol Energy Eng 2013;135. [38] Tiwari AK, Tiwari GN. Evaluating the Performance of Single Slope Passive Solar Still for Different Slope of Cover and Water Depths by Thermal Modeling: In Moderate Climatic Condition. Sol. Energy, vol. 2006, ASME; 2006, p. 545–53. doi:10.1115 . [39] Dhananjay R. Mishra, Anil Kr. Tiwari, Mahendra Singh Sodha, Mathematical modeling and evaluation of new long single slope still for utilizing of hot water, Appl. Therm. Eng. 108 23
(2016) 353–357. [40] Dhananjay R. Mishra, Anil Kr. Tiwari, Productivity enhancement of single slope solar still using ground energy, J. Sci. Tech. Res. 6(2) (2017) 28-34.
[41] Dhananjay R Mishra Mayank Sharma, Anil Kr. Tiwari, Experimental evaluation of single basin solar still coupled with the ground earth surface using artificial neural network, Solaris 2017
[42] Dhananjay R Mishra, Anil Kr. Tiwari, Performance evaluation of conventional and sand bed ground solar still and effect of covering by black polythene sheet and coal powder on nearby surfaces of sand bed solar still, 3rd International Conference on Recent Trend in Science and Technology (IC-RTST 2015) 27-28 Feb., 2015. SVNU, Sagar
[43] Anil Kr. Tiwari, Dhananjay R. Mishra, Effect of covering by black polythene sheet and coal powder on nearby surfaces of sand bed solar still: Studying heat and mass transfer, 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, (2014) 514-521.
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