The solar thermal applications existing to investigative relationships of absorbing materials of water flowing over glass cover through the influence of PCM and nanoparticles for the enhancement of a single-slope single-basin solar still are presented and discussed. The results are compared with and without PCM and nanoparticles summer days for a conventional solar still. Numerically designed and experimental annotations have been written for the investigative solutions for the temperature of flowing water, glass cover, absorbing materials (FWCW and FWJW) and PCM and nanoparticles basin liner, respectively. The 24 h distillate manufacture rate of the solar still has been enhanced to usage of drip button through pure saline water to absorptive influence of FWCW capability is 70.02% and during (24 hours) daily distillate harvest of FWCW is 9.429 kg/m2 day, water flowing glass cover influence is 13.37%, respectively. A solar still analysis of Fourier coefficients with (6 to −6) harmonics Fourier series has been used for enhancement, and it is found to be a good representation of the observed variation. It is a good treaty among theoretical and experimental annotations of the structure.
- single-basin solar still
- PCM and nanoparticles
- fin wick
- drip button
- water flowing glass cover
- Fourier series
Water is mislaid every day through numerous physical processes and desired by each active cell; nearly all process that grosses place within the body is reliant on water. A solar energy using in application of thermal process to solar desalination is bid in which evaporative cooling to produce an enhanced for harvests to grow in clean water. Numerical modeling of water flowing over the glass cover in a solar still is actual substantial to design a frugally optimal still and to enhance the manufacture performance for a given cost. Prakash and Kavatherkar  have exposed the enactment of the regenerative still and its diurnal harvest is around 7.5 L/m2, associated to conventional solar stills. Singh and Tiwari  have approved out a passive regenerative solar still and the system is good agreement between theoretical and experimental results. An analytical expression for the thermal efficiency of an active regenerative solar still was observed by Singh and Tiwari . It found that to be heat transfer unit and the collector to overall thermal efficiency is 50%. The yield of concentrator assisted regenerative solar still is much higher than any other passive/active, regenerative/non regenerative stills and the overall efficiency increases with an increase in the flow rate of the cold water over the glass cover was suggested by Kumar and Sinha . Prasad et al.  reported that the regenerative active solar still harvests the thermal enactment increased. Suneja and Tiwari  have proposed that for a particular flow rate of water over the glass cover, the evaporative heat transfer coefficients decreases in increasing the water depth of the basin where as radiative and convective heat transfer coefficients does not very much. Zurigat and Abu-Arabi  analyzed a double-glass cover cooling desalination unit and inferred that the arrangement is double-fold which lowered the glass temperature and preheated the entering brine. Ultimately the stills efficiency was increased by over 25% than conventional single-basin single-glass solar stills. Zurigat and Abu-Arabi  had shown the performance of a regenerative solar still consisting of two basin effects (first effect and second effect) and the distillate yield is founded to be 20% higher than that of conventional solar stills. Janarthanan et al.  proposed the performance of a tilted wick-type solar still and concluded that the glass cover temperature decrease, water flow over the glass cover and the flow rate of 1.5 m/s has increased the production significantly. Murugavel et al.  had reviewed the productivity of single-basin solar still with different materials in the basin and inferred that rubber material in the basin improved the absorption, storage and evaporation effects. Boutebila  had shown that, the initial film thickness, plate inclination, the length of the still and the radiation reaching the flux plate are the factors affecting the still performance. Zeroual et al.  had investigated a double slope solar still with two effects and insisted that the productivity increased by 11.82% by cooling the condenser using flowing water over it (first effect) and 2.94% by shading the north wall from 12 to 14 hours (second effect). The performance of inverted absorber solar still by Dev et al.  and found that to be thermal efficiency of inverted absorber solar still is thrice than that of the normal solar still. Khalifa  had found that the effect of condensing cover tilt angle of simple solar still on the productivity in different seasons and latitudes. It has been found that the tilt angle should be large in winter and small in summer. Kumar and Dwivedi  anticipated the reformed single-slope single-basin active solar still with enhanced condensation procedure. It is found that the yield increment of 14.5% associated with the ordinary design. Shanmugan et al.  thermal model industrialized for an energy and exergy analysis of a single-slope single-basin solar still. Rahmani et al.  was urbanized for a natural circulation in a solar still and established the distillate yield of 3.72 L/m2/day by 45.15% efficiency. Ibrahim and Elshamarka  was amended basin type solar still and accomplished that the maximum freshwater productivity of 2.93 L/m2/day. Single-slope solar still was urbanized to integration for the systems to progress the efficiency.
Sahota and Tiwari  were advanced for a double slope solar still used (Al2O3) nanoparticles in the basin. They clinched without and with nanofluids for three different concentrations are 0.04, 0.08 and 0.12%. Al2O3 nanoparticles efficiency in the system is 0.12%. It is the charity for the system in 35 and 80 kg base fluid equaled to the efficiency of 12.2 and 8.4% in the system. Shanmugan et al.  was premeditated in the experimental analysis of a double Slope—Tribasin solar still. It established that the associate with and without nanofluids enhanced the performance of first, second and third basin contributes were 35.71, 35.7 and 28.5%.
Sellamia et al.  have enriched in solar still exploration of altered thickness besmirched layers of sponge absorber in more energy saving to recover presentation. It is charity in altered sponge liner thickness like that on 0.5, 1.0 and 1.5 cm and harvest sponge liner are 58, 23.03 and 30%, respectively.
Sharshir et al.  was twisted in belongings of flake graphite nanoparticles, PCM and the film cooling on the solar still enactment. It is amended of a solar still in FGN and PCM, film cooling high yield on 73.8% and matched to conventional still, the upshot of intensifications on 13% and water depth are 2–0.5 cm. The classified a heat transfer if the structure is extensive time and extra energy rise to temperature formed at pick time.
Many researchers were designed of a single-slope single-basin solar still and have been emarginated to water flowing the glass cover with enormous scope of application developing PCM and nanoparticles by a system. It has twisted internal heat transfer mode scope of advance application in rules of functions. The internal heat transfer increase of a basin solar still is with new impression of harvest in expenditure of human nature foundation.
2. Materials and methods
2.1 Investigation of water flowing glass cover to evolvements absorbing materials by a solar still
An experimental analysis of a single-slope single-basin solar still with water flowing over the glass cover to performance of absorbing materials have been offered in Figure 1. The solar still comprises of outward and inward attachment made of plywood through element of 1.3 × 1.3 and 1.25 × 1.25 m. The fissure between the attachments is occupied with glass wool having the thermal conductivity of 0.0038 W/mK. The stature of the back wall is 0.03 m and front wall of 0.10 m. The glass cover of thinness 4 mm is secondhand as the condensing surface assistance to water flowing and the slope of the glass cover are immovable as 11° which is equivalent to the leeway of the position (Chennai). It is accomplished vapor tight through the benefit of metal putty. The j-shaped drainage channel is immobile nigh the front wall to accumulate the concentrate harvest and the output slobbered miserable to the gaging jar. The investigational engaged classical has been established for water flowing through a solar still follow the schematic plan Figure 2.
2.2 Heat transfer coefficient and productivity of a still
It have been finished in a basin area of copper leaf and black paint coating in a basin area, dye miscellaneous Al2O3 Nanoparticles coating through inner area with absorbing wick materials to absorb surplus solar radiation. The solar radiation communicated through the water flowing transfer to glass cover and fascinated by a wick and fin wick materials apparent—Al2O3 to comportment by the copper coil and then shadows the phase change materials—C18H36O2. The solar radiation is immersed through Al2O3 Nano particles soars esoteric the absorbing materials area intensification further heat transfer chic inside nigh to visible and IR spectrum. The saline water from side to side of an exceptional establishment has been finalized to pour saline water drop by drop over the absorbing material kept in the basin. The drip heat transfer pipes occupied coating Nano particles miscellaneous black paint to the lengthways dripping association is finished of drip button stationary at consistent intermissions of 0.10 m and heat pipe static in amidst the gap is 0.10 m horizontally in the basin.
The PCMs energy spread stabilities are melting in a wide temperature range . Various evaluations are escorted [24, 25] and a full association of the hottest progresses in PCMs with their thermo physical properties can be found that to be literature. Figure 3 current these progresses of the absorbing materials setting in basin to improve heat, based on the above reviews, with polymeric and solid-solid PCMs involved.
Figure 3, new solar still have been manufactured in the basin area static a copper coil arrangement and is immovable drip heat pipes. The influence of the solar still is immovable in 10 drip heat pipes and buttons are each a distance of 0.10 × 0.10 m by a placed horizontally in the basin with south to north orientation. It have been prepared in the basin vulnerable copper coil in 1 diameter, intervals of 0.10 m and total coil 10 m fixed in the basin. The coil occupied mad black painted and mixed Al2O3—nano particles more absorb solar radiation and heat extraction supplementary progress the still is the charity for C18H36O2—PCM for 8 kg inside the coil secure basin area. The PCM melting point increase has been debauched evaporation of the solar still. The saline water tank is providing with a gate valve and is associated with the fjord of the dripping organization.
A provisional organization of water flowing over the glass cover of a single-slope single-basin solar still have been finished with the help of PVC pipe of ½ inch diameter. The length of the pipe is taken precisely equal to the width of the still so that the water would not flow in the lengthwise direction. A number of holes are made in the pipe by equal spacing to maintain the uniform flow over the glass cover. The PVC pipe is clipped at the top of the glass cover. The water at the lower end of the glass cover was collected in a small plastic bucket. Due to the water flow over the glass cover, most of the heat was utilized for evaporation during the day, uptown mid night in this process. There existed fast evaporation due to the large temperature difference between the glass cover and the water surface as expected shown that the Figure 4 water flowing the experimental glass cover cooling effect.
The water temperature in the absorbing materials is to condensing water flowing cover temperature quantity by fixing copper-constantan thermocouples which have been calibrated originally. Solar radiation intensity and ambient temperature have been restrained with solar radiation monitor and digital thermometer. Experimental work analysis of a solar still have been carried out from 6 to 6 am of 24 hours duration with water flowing over the glass cover by absorbing materials deliverable during 2017 at Research Center of Physics, Veltech Multitech Engineering College, Avadi, Chennai—600062 [Latitude 13.1067°N, 80.0970°E], Tamilnadu, India.
2.3 Investigation of thermal modeling by a solar still with effect of absorbing materials
The solar radiation is absorbing to water flowing by glass cover transported over the absorbing materials with working of inside heat ability accessible in the organization as shown in Figures 1 and 4. The novel design made of fin wick absorbing materials following the flowchart Figure 5.
Figure 6 the water flowing over the glass cover influence of absorbing materials surface to harvest by a solar still with succeeding suppositions have been prepared to different parameters script the energy equilibrium equations.
The solar still (PCM and nanoparticles) performance of the water flowing over the glass cover during absorbing materials surface of heat ability have been organized full tight of insulation in the scheme and glass cover is negligible.
There is no hotness escape of vapor surface in the scheme.
A single-slope single-basin solar still is water flowing over the glass cover, absorbing materials surface and distillate water fragment.
Vapor pressure of water have been made full tight of experimental assumed to be linear with temperature work proof of (P = R1T + R2) single-slope single-basin solar still is given as:
Flowing water with absorbing materials by a solar still
Glass cover with absorbing materials by a solar still
Basin liner with absorbing materials by a solar still
Water mass with absorbing materials by a solar still
where are demarcated in the Appendix
The explanation of the Eq. (5) can be written as
The explanation of Eq. (6) exposed to the initial conditions by a still
for all value of t at x = 0
Substituting the equation for c in Eq. (6), we get
Equation (8) is the obligatory explicit expressions for the temperatures with fin wick materials and flowing over the glass cover by a still, respectively.
Solar radiation and ambient temperature are episodic in environment these can be Fourier series in the form
The flowing water over glass cover with influence of fin wick materials by a solar still of variation with time can be articulated by
Since, solar radiation and ambient temperature are periodic nature can be Fourier analyzed in the form of the solar still
where is the time independent component of b (t); is the coefficient of the time dependent component of b (t), and they are in the form
The values of TFw (t) are designed at intervals of ½ hour starting from sun rise by Equation (15), and Tg (t) is calculated from the following relation
During off-sunshine hours, solar intensity and ambient temperature terms will evaporate, then the analysis will be the same.
The instantaneous hourly distillate output per unit with absorbing materials area of the still is premeditated by
The efficiency of the proposed structure may be articulated as
where mentions to the time interval over which the solar intensity is measured.
3. Result and discussion
Numerical calculations have been made in instruction to escalate the fin with cotton wick (FWCW) and fin with jute wick (FWJW) in the basin surface area. Expending of a still is hourly variations of the data in summer days through the solar intensity and ambient temperature measurement of monitors for two of the typical days in 2017 at Chennai weather conditions, the Fourier coefficients of solar intensity and ambient temperature have been evaluated to (6 to −6) harmonics of the Fourier series. The water flowing over the glass cover with influence of FWCW and FWJW of the solar still following parameters have been evaluated the instantaneous thermal efficiency of the suggested solar still.
Ag = 1.69 m2, τg = 0.75, Aw = 1.69 m2, Mw = Mfw = 12 kg, εg = 0.88, σ = 5.66 × 10−8 W/m2K4, αg = 0.05, Cw = 4190 J/kg, V = 1.4 m/K = 0.038 W/mK, 22.52 W/m2 ; 15.64 W/m2 ; 137.05 W/m2 ; 135.5 W/m2 ; 0.7686 W/m2 ; 14.01 W/m2 ; 6.27 W/m2 ; 0.04 W/m; L = 2372.52 kJ/kg; = 0.05 m; = 7.2722 10−5 s−1; ; ; ; = 0.88; = 1000.0 kg/m3; 4190 J/kg .
The solar still have been implemented for high thermal energy accumulation through benefit of PCM and nanoparticles immersed by solar intensity and ambient temperature for 2 days with absorbing wick materials, i.e., FWCW and FWJW in summer typical days have been shown in the Figure 7. Expending of the absorbing materials has been implemented for Fourier coefficients in in 2017 at Chennai in Tamilnadu, India. It is traceable that the (6 to −6) harmonics used in design is adequate for the convergence of the Fourier series. The hourly variation of solar still have same trend for all the days and solar radiation appears to be supreme among 12–2 pm.
Numerically designed and experimental annotations of with and without PCM and nanoparticles using in the basin liner to more increases of FWCW, FWJW temperature, glass cover temperature and flowing over the water temperature of the optional solar still have been expected in Figures 8A and 9. It is clear that the merchandise of FWCW, FWJW temperature through experimental and theoretical consequences have the equivalent tendency. The innovative solar still has been manufactured through a thermal application of internal heat transfer modes to construction of numerous parameters enhancement occupation to originate of basin liner stable of PCM temperature (copper coils) and black paint dye miscellaneous nanoparticles (basin) temperature and more engross solar radiation in the organization to hourly variation of temperature to established in exposed Figure 8B, through of PCM and nanoparticles using in the basin liner.
The hourly variation to manufacture rate of FWCW and FWJW temperature, glass cover temperature, flowing over the water temperature for the basin liner to use in PCM and nanoparticles preparation of absorbing materials through dripping pure saline water to continue least water depth has been compared to with and without PCM and nanoparticles of expressions in Figure 10. From the diagram it is clear that with PCM and nanoparticles of saline water in the absorbing materials illustrations augmented rate of evaporation due to the large temperature difference between absorbing materials and glass cover temperature. The temperature variance among the absorbing materials and glass cover temperature without PCM and nanoparticles are small due to huge thermal ability and the amount of evaporation is moderate. The supreme FWCW and FWJW distillate harvest of the structure is 0.469 and 0.415 kg/m2 30 minutes during 12.30–2 pm and without PCM and nanoparticles 0.250 and 0.244 kg/m2 30 minutes. The whole FWCW and FWJW distillate harvest during 9 am–17 pm is found to 6.699 and 5.659 kg/m2 and without PCM and nanoparticles 3.343 and 3.014 kg/m2. Hence, peak luminous during of the solar still through PCM and nanoparticles except to FWCW and FWJW has been distributed with a progressive sunshine distillate harvest as well as nocturnal output in 2.730 and 2.130 kg/m2 nightly concentrate produce. Over 24 hours cycle, the overall FWCW and FWJW manufacture of the anticipated structure is found to be 9.429 and 7.789 kg/m2 day and without PCM and nanoparticles is found to be 5.234 and 4.434 kg/m2 day. Numerical results from FWCW, FWJW, glass cover, flowing over the water, basin liner temperature are in neighboring agreement through the experimental observations.
The absorbing materials instantaneous efficiency of the suggested structure has been established for exposed in the Figure 11. The absorptive of the wick surface are noteworthy working parameter of the solar still and should be inactive optimal to provide enhanced efficiency. The water flowing over the glass cover to influence of instantaneous overall efficiency in FWCW, FWJW with and without PCM and nanoparticles to varies of absorbing materials from 70.02 to 46.69% and 31.19 to 24.62%, respectively. It has clearly reflected that the instantaneous distillate harvest with PCM and nanoparticles to water flowing over the glass cover influence solar still is found to be 25% higher than the without PCM and nanoparticles of the solar still. Furthermore the theoretical results authenticated through the experimental explanations are rather good as there is no aberration in the tendency.
Numerical results from FWCW, FWJW, glass cover, flowing over the water, basin liner temperature in neighboring agreement through of the solar still have been observed energy to form into heat to force of a higher efficiency and compare to the upsurge in saturated vapor pressure is substantiated by Huang et al. and Shanmugan et al. [26, 27] augmentation is pretentious for a nanoparticle and found that to be hydrophobic nanoparticles and PCM assistance to the fast evaporation to vapor heaviness of productivity water to the enhancement.
Figure 12, modulation of flowing water over the glass to high enhancement of FWCM in basin solar still have been compared to with and without PCM and nanoparticles total productivity (24 hours) on 9.429 kg/m2 day. Figure 13 is the photograph of comparison of flowing water over the glass, drip, PCM and nanoparticles of overall high efficiency of the solar still.
3.1 Analysis of water quality by a solar still
A new solar still have been established in natural purification (H2O) standard water in produce and contaminants are removed. The aim of this reduction in elevations of pH, EC, TDS and total hardness is due to solar desalination process.
The solar thermal applications exhibiting and investigative relationships for the instantaneous energy productivity is done and substantiated. The subsequent assumptions have been haggard in the existing investigation of absorbing materials to water flowing glass cover with influence of PCM and nanoparticles for enhancement of a solar still [28, 29, 30, 31, 32, 33].
The influence of flowing water over the glass cover has been absorbed role on the enactment and is good treaty among theoretical and experimental annotations of the structure.
During the effective of hours in the structure is improvement of PCM and nanoparticles for different heat movements of storage density and the isothermal nature extension of intact productivity of the solar still.
The daily distillate manufacture rate of the still has been enhanced to usage of drip button through pure saline water to absorptive influence of FWCW capability is 70.02%. FWCW surface should be upheld by several eliminations of salt deposition.
The significance absolute produce superior of the solar still is entire daily distillate harvest in through 24 hours for FWCW is 9.429 kg/m2 day, respectively.
The investigation of absorbing materials to water flowing glass cover with influence of PCM and nanoparticles for enhancement of a solar still analyses of solar intensity and ambient temperature with 6 to −6 harmonics are used and found to be a good representation of the observed variation.
breadth of the solar still (m)
specific heat of fin wick and flowing water (J/kg °C)
solar radiation (W/m2)
overall bottom heat loss coefficient from basin liner improve heat use of PCM and nanoparticles to ambient through bottom insulation (W/m2 °C)
total heat transfer coefficient from fin wick water surface to glass cover (W/m2 °C)
convective and radiative heat transfer coefficient from water flow cooling glass cover to ambient (W/m2 °C)
convective heat transfer coefficient from PCM and nanoparticles by basin liner to water mass (W/m2 °C)
convective heat transfer coefficient from glass cover to flowing water (W/m2 °C)
the thickness of flowing water over the glass covers (m)
fin wick mass in the basin surface area (kg)
mass of flowing water rate (kg/m2h)
heat flux of the still
evaporative heat transfer rate
two constants obtained from saturation vapor data (°C)
temperature of the ambient (°C)
temperature of the PCM and nanoparticles basin surface area (°C)
temperature of the glass covers (°C)
flowing water temperature (°C)
temperature of the fin wick water surface (°C)
surface temperature of the sun (
energy absorptivity of PCM and nanoparticles basin surface area
energy absorptivity of glass cover
energy absorptivity of fin wick water mass
energy absorptivity of flowing water
energy efficiency of the still
The experimental work analysis of a solar still have been approved out from 6 to 6 am of 24 hours duration the collective evaporative, convective and radiative heat transfer coefficient with water flowing over the glass cover by absorbing materials deliverable during 2017 at Research Center of Physics, Veltech Multitech Engineering College, Avadi, Chennai—600062 [Latitude 13.1067°N, 80.0970°E], Tamilnadu, India to the atmosphere can be written as
where is the thickness of flowing water over the glass cover
where the water, flowing water temperature at x = 0; and glass cover is instantaneous glass temperature for each hour.
|FWCW||fin with cotton wick|