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Experimental investigation on the performance analysis of blue metal stones and pebble stones as thermal energy storage materials in single slope solar still
Abstract
Solar stills that use blue metal stones and Pebble stones to store heat are the subject of experimental studies and theoretical studies. Three identical solar stills measure 1 m² constructs for the analysis mentioned above. To avert water from evaporation and to maintain a consistent water level, each solar still has its glass cover with cooling and dripping mechanisms. Distillate yield from a solar still can be significantly increased by using blue metal stones in a cooling and dripping setup. Its purpose is to increase daily distillate output. It shows that theoretical predictions and experimental findings agree well. The blue metal stone in the solar still produced 1.5 times as much drinkable water as the pebble stone, while the combination of the two stones increased output by 18 % compared to a single still. The temperature was lowered to about 4 °C to 5 °C thanks to the cooling system on the glass cover.
... Over the past few years, many modifications have been made to SSs designs. It includes the single slope SS [5], double-slope SS [6], single and double effect SS [7], inclined SS [8], vertical SS [9], triangular SS [10], stepped SS [11], stepped with vertical wick SS [12], corrugated absorber SS [13], tubular SS [14], conical SS [15], spherical SS [16], rotating wick SS [17], corrugated wick SS [18], trapezoidal SS [19], and prism-shaped SS [20]. Other modifications have been conducted to the internal constituents' parts of the SS and some additives. ...
... Other modifications have been conducted to the internal constituents' parts of the SS and some additives. It includes using a sliced absorber plate with a new design of glass cover [21], using an external condenser [22], using the glass cover cooling technique [23], using a thermoelectric cooling system [24], using a PCM (Phase Change Material) [25,26] and a nano-based PCM [22], using sensible heat storage (SHS) materials [5], using an energy storage biomaterial [27], using boulders and fines in biodegradable organic materials [28], using different basin materials [29], using an evacuated flat-plate collector [30], using reflectors [26], using parabolic concentrators [31], using a nano-coated absorber [32], using fins [8] and wick finned absorber [33], using floating porous absorber with different shapes [34], using different materials of the transparent covers [24], using different materials of the absorber plate [35], using industrial wastewater as a basin feed water [36], using geothermal energy [37], and using Fe3O4, graphene oxide, and paraffin as nanofluids [38]. Mandev et al. [39] investigated the effect of using a Peltier cooling unit as well as using cellulose papers in the form of hemp and high absorber papers with dark colors on the productivity of the solar still. ...
In regions with a restricted availability of drinkable water, solar stills offer a solution for a passive solar desalination method. In this study, three designs for solar stills are examined: the conventional solar still (CSS), the hemispheric solar still (HSS), and the pyramidal solar still (PSS). The experimental investigations were conducted over three consecutive days, thereby varying the total dissolved solids (TDS) concentrations in the basin water at 1000, 2000, and 3000 ppm. A comparative analysis focused on the performance of the various solar stills and the impact of TDS variation. The results revealed that the PSS consistently outperformed the CSS and HSS across all TDS levels. Notably, the PSS exhibited superior daily energy and exergy efficiencies. Furthermore, the daily productivity and energy efficiencies displayed an inverse relationship with the TDS concentration. A cost analysis indicated that the PSS achieved the lowest distilled water price, reaching a value of 0.0151 $/L. Specifically, the PSS exhibited a 17.3% and 3.5% higher accumulated daily productivity compared to CSS and HSS, respectively, at TDS = 1000. However, at TDS = 3000, the daily productivity of the PSS decreased by 3.5% and 7.5% compared to TDS = 2000 and 1000, respectively. Similarly, the energy efficiency of the PSS decreased by 5.27% and 8.67% as the TDS increased from 1000 to 3000. Notably, across all solar still types, the lowest cost values were consistently associated with the lowest TDS concentrations, with the PSS yielding the lowest cost overall.
... Researchers conducted experimental analysis using concave stepped SS. According to the in overall increase 28.27% a that material study, employing SHS of results resulted in efficiency. utilizing concrete chunks increased the solar still's production by 11.6% and 7.37%, when related to utilizing sand and brick, according to the results. ...
... Equation (7) uses the system salvage amount, which is 20% of goods, as the variable S. Scientists determine the sinking fund component [28]. ...
Solar desalination efficiency can be significantly altered by combining several approaches to improve evaporation rate. The objective of this research is to find a way to make solar stills (SS) more efficient by combining evacuated tube solar collectors, blue metal stones, and corrugated fins. An investigation into a six-tube evacuated solar collector was conducted to increase the system's evaporation rate. Corrugated fins were thought of to rise the surface area of heat transfer between the water and absorber. Blue metal stone was proposed to keep the water at a maximum temperature even when solar radiation is minimal. Separate displays of the cumulative distillate output (DO) numbers and hourly values for each time period provide a comprehensive view. Based on the findings, the peak period for DO moves from 1 p.m. on a sample day in May 2024, which is six months into the project. In comparison to CSS, MSS temperature values are over 55 °C higher at the peak and nearly 26 °C higher on average. On top of that, the total DO during the day can reach 2.64 to 6.82 L, while at night it rises from 0.067 to 0.96 L. In addition, there is a 146.3% improvement in the average DO during the six months, going from 3.02 to 7.22 L. Additionally, MSS is 0.43₹ per liter and CSS is 0.47₹ per liter, in that order. The net amount of carbon dioxide reduction achieved by modified solar stills was approximately 2.44 times greater than that of conventional solar stills.
... This translates into an approximate 102.64% boost in production. In SSSSs, Kumaravel et al. [44] studied the performance of pebble stones and blue metal stones as thermal energy storage materials. For this experimental research, three identical solar stills were fitted with dripping and cooling systems to keep the water level steady. ...
One exciting method to enhance solar stills' efficiency is incorporating additives with high thermal storage materials. Material science and engineering advances are expanding the possibilities, making solar stills a more appealing solution for global water scarcity issues. Ongoing research and development are expected to address current challenges and pave the way for more efficient and durable solar desalination technologies. This paper is a comprehensive resource for researchers and practitioners aiming to advance sustainable water purification technologies by compiling and analyzing data on high thermal storage material additions in solar stills. Combining additives with other enhancements such as reflectors, absorbers, or multi-effect distillation systems has demonstrated that combining additives can create synergistic effects that further boost performance. Studies evaluating the cost–benefit ratio of adding high thermal storage materials to solar stills indicate that, despite potentially higher initial costs, the long-term benefits of increased water output and efficiency justify the investment.
... Kabeel et al. [46] they combined the CPC with a tubular distiller with graphite-paraffin wax mix to enhance the distillate production by 65.4 %. Kumaravel et al. [47] empirically enhanced the distiller yield by 18 % using combined pebble stones and metal stones. Sharshir et al. [48] empirically enhanced the hemisphere production by 39.6 % using wick corrugated trough and PCM under trough. ...
... Combining external reflectors (top and bottom) with external condenser, and PCM improved the SS productivity by about 42%, 57%, and 41%, respectively. Kumaravel et al. (2022) investigated the performance analysis of a single slope SS integrated with thermal energy storage with blue metal stones and pebble stones. The findings showed that combining the two types of rocks and their integration with the SS increased productivity by 18% relative to conventional SS. ...
In the present study, the thermal performance of a modified solar still (MSS) system coupled with hybrid nanofluid (HNF) of titanium oxide (TiO2) and silicon oxide (SiO2) has been investigated theoretically based on energetic, exergetic, economic, and enviroeconomic assessment. The model of the MSS has been introduced using a new numerical technique of the Atangana-Baleanu fractional derivative. The fractional model of the MSS system is presented under various weather circumstances (winter and summer seasons) in Egypt to show the impact of HNF on the MSS output: temperatures, freshwater productivity, exergy, and energy efficiencies. The outcomes of the fractional model are contrasted to those derived from actual experimental data collected under varying climatic conditions in Upper Egypt. Numerical findings demonstrate specific consistency between the experimental results and the proposed model of the solar still (SS), with a percentage of error of 4.65% in freshwater productivity. Moreover, using hybrid nano enhances daily productivity in the summertime by 27.2% and in the wintertime by 21.7%, increasing efficiencies. Additionally, a comparative economic and environmental assessment has been investigated for all the proposed desalination systems without and with HNF. The findings found that the cost per liter of MSS was 44% lower than that of the conventional solar still (CSS) during the summer season. Using exergy and energy approaches, MSS reduced CO2 by 22% and 29.6% more during the winter.
... Panchal et al. [11] Used various materials for thermal energy storage, including blackboard, black granite steel, and concrete with a high distillate production. Kumaravel et al. [12] attempted to store thermal energy using blue metal stones. Its objective was to capture solar energy during the day and efficiently use it at night. ...
This research investigates the impact of different energy storage materials on the efficiency of a pyramid solar still (PSS) for producing drinkable water in Pongalur, Tamil Nadu, India (10.9729° N, 77.3698° E). The study compares the performance of PSS using kanche marbles, natural banana fibers, and a reference solar still with only black paint at the basin. Results indicate that kanche marbles yield the highest distillate output, producing 2.94 kg daily, followed by banana fibers at 2.85 kg, and the reference still at 2.20 kg. Notably, kanche marbles and banana fibers enhance day and night distillate production by 36% and 21%, respectively, over the reference solar still. These findings highlight the significant potential of kanche marbles and natural banana fibers in improving solar still efficiency.
... They conducted that the gain in the yield reached 41.95% for utilizing the external condenser and pin fins absorber. Kumaravel, Nagaraj, and Bharathiraja (2023) improved the yield of solar distiller by 18% using the combination of Pebble stones and blue metal stones as energy storage materials. Vigneswaran et al. (2021) improved the yield of solar distiller by 19.1% using acrylic absorber with PCM as storage materials ) experimentally conducted the influences of utilizing black receiver tubes as collectors and condensers on the yield of solar distillers. ...
... In this equation, the wet weight refers to the weight of the product or material when it is in its moist or hydrated state, while the dry weight refers to the weight of the product after it has been completely dried to remove all moisture [42,43]. ...
The shelf life of food products can be increased by reducing their moisture content with the aid of solar dryers. However, the poor efficiency of solar collectors increases the time and energy required for drying the food crops. Hence, the present work aims to overcome the above bottleneck by employing corrugated shot-blasted absorbers in solar air heaters and comparing their performance with flat plate solar air heaters. Subsequently, the drying kinetics of bitter gourd and tapioca cassava were subject to experimental investigation using indirect solar dryers in their natural mode, aiming to assess the dryers' overall performance. The experiments revealed that the average thermal efficiencies of the SAHs equipped with flat plate absorber plates and corrugation with shot-blasted absorber plate treatment displayed variations ranging from 39.05 to 53.12 % while maintaining a constant MFR of 0.02 kg/s. The average exergy efficiency of the FPAP is 1.103 % and the CSB absorber plate is 1.755 % with a constant flow rate of 0.02 kg/s. The research findings indicate that the CSBAP (surface-improved SAH) demonstrates a higher heat-absorbing capacity when compared to the FPAP SAH. The utilization of the CSBAP design along with the incorporation of pebble stone results in a greater ability to efficiently absorb and retain heat when compared to the traditional FPAP design with a shot-blasted surface. The inclusion of pebble stones in the drying process, as observed in Case II for Tapioca cassava, led to a remarkable improvement in drying efficiency by approximately 36 % when compared to Case I. Furthermore, the drying efficiency for bitter gourd in Case IV experienced a notable improvement of around 30 % when pebble stones were integrated into the drying process, in contrast to Case III. Eventually, the experimental results specified that the carbon credits accrued for the CO 2 mitigated by the FPAP and CSBAP systems in the natural convection mode were calculated to be approximately 226.48 and 308.11 Rate $/year, respectively. These alterations synergistically contribute to enhancing the SAH's effectiveness and effectively utilizing solar heat directly contributes to reducing greenhouse gas emissions and, subsequently, the carbon footprint.
The main goal of this study is to investigate the performance, energy, exergy, economic, environmental, and
sustainability analyses of single-slope solar still using different sensible storage materials. Three different storage
materials were used: pebbles and basalt, which are common storage materials, and aluminum dross, which is a
new storage material. The performance of still with storage material was compared to that of the traditional solar
still. The study findings indicated that, compared to a conventional solar still, using pebbles, basalt, and
aluminum dross increased water productivity by 7 %, 11.4 %, and 21.2 %, respectively. The thermal efficiency
increased by 5.4 %, 15.7 %, and 22 % for pebbles, basalt, and aluminum dross, respectively. The increase in
exergy efficiency was 43 %, 15.3 %, and 22 % for pebbles, basalt, and aluminum dross, respectively. Based on
sustainability analysis, aluminum dross achieved the lowest payback time based on energy which was lower than
three years, followed by basalt and pebbles. Also, aluminum dross achieved the highest energy production factor,
followed by basalt and pebbles. The total annual cost was 22.73, 25.4, and $26.91 for pebbles, basalt, and
aluminum dross, respectively. The exergo-economic based on energy and exergy was the highest for aluminum
dross followed by basalt and pebbles. The environmental analysis revealed that the mitigated carbon dioxide by
pebbles, basalt, and aluminum dross was 5.59 tons, 7.23 tons, and 8.21 tons, respectively. In conclusion,
regardless of aluminum dross having the highest annual cost, it achieved the highest water productivity and
efficient operation based on environmental and sustainability levels.
This research work intends to enhance the stepped double-slope solar still performance through an experimental assessment of combining linen wicks and cobalt oxide nanoparticles to the stepped double-slope solar still to improve the water evaporation and water production. The results illustrated that the cotton wicks and cobalt oxide (Co 3 O 4 ) nanofluid with 1wt% increased the hourly freshwater output (HP) and instantaneous thermal efficiency (ITE). On the other hand, this study compares four machine learning methods to create a prediction model of tubular solar still performance. The methods developed and compared are support vector regressor (SVR), decision tree regressor, neural network, and deep neural network based on experimental data. This problem is a multi-output prediction problem which is HP and ITE. The prediction performance for the SVR was the lowest, with 70 (ml/m ² h) mean absolute error (MAE) for HP and 4.5% for ITE. Decision tree regressor has a better prediction for HP with 33 (ml/m ² h) MAE and almost the same MAE for ITE. Neural network has a better prediction for HP with 28 (ml/m ² h) MAE and a bit worse prediction for ITE with 5.7%. The best model used the deep neural network with 1.94 (ml/m ² h) MAE for HP and 0.67% MAE for ITE.
Productivity improvement is one of the high-priority areas in the development of solar stills. The present work describes the use of some low-cost energy storage materials such as sand, gravels, and black granite as potential candidates to improve the productivity of the tubular solar still (TSS). The experimental studies have been carried out at Nagpur (21.1241° N, 79.0023° E) to investigate the effects of these materials on the productivity of the TSS. Three separate TSS experimental setups have been made for each energy storage materials. These include (a) 5 kg of fine sand (0.125–0.25-mm grain size), (b) small gravels (20–30 mm), and (c) black granite (5-mm thickness) placed in the absorber basin of individual TSS setup, separately. The experiments have been performed by varying basin water depth at 0.5 cm, 1 cm, and 2 cm, for each case. The results show that for water depth of 0.5 cm, productivity of TSS-Black granite is enhanced by 10.5% and 34.88% as compared to TSS-Gravel case and TSS-Sand case, respectively. Thermal efficiency and exergy efficiency of TSS-Black granite at 0.5-cm water depth is enhanced by (32.4%, 9.8%) and (92.1%, 21.9%) as compared to TSS-Sand case and TSS-Gravel case, respectively. Furthermore, it has been estimated that the cost of production of freshwater using TSS-Black granite is lowest among all selected combinations.
Thermodynamic performance analysis is carried out on a flat plate solar thermal collector utilizing single and hybrid nanofluids. Fe2O4/water, Zn-Fe2O4/water hybrid nanofluids, and water are used as heat transfer fluids, and their performance is compared based on the energy and exergy transfer rate. The thermo-physical properties are evaluated by regression polynomial model for all the working fluids. Developed codes in MATLAB are created to solve the collector’s thermal model iteratively, energy, and exergetic performance. The system is then subjected to parametric investigation and optimization for variations in fluid flow rate, temperatures, and concentrations of nanoparticles. The findings show that utilizing Zn-Fe2O4/water hybrid nanofluids with a particle concentration of 0.5% enhanced the solar collector’s thermal performance by 6.6% while using Fe2O4/water nanofluids raised the collector’s thermal performance by 7.83% when compared to water as the working fluid. The maximum energy efficiency of 80.1% is attained at the mass flow rate of 0.1 kg/s. The hybrid nanofluids have also given a maximum exergetic efficiency of 5.36% and an enhancement of 8.24% compared to Fe2O4/water nanofluids. It evidences that the hybrid nanofluids would become a better thermal alternative for water as well as single nanofluids.
The paucity of freshwater is very dangerous in the coming years. Many coastal countries suffer from a scarcity of freshwater. Solar desalination is the cheapest way to produce freshwater from any type of non-drinkable water (brackish water and seawater). In this work, single-slope single-basin solar still for seawater desalination was examined under Upper Egyptian weather conditions of Qena City (latitude 26.16°, longitude 32.71°). The main goal of the work is to compare the performance of conventional solar still, solar still supported with PCM, and solar still supported with local clay material to augment the solar still yield during both daytime and nighttime periods of operation. The results demonstrated that the total production of desalinated water from the simple conventional solar still, the solar still with PCM, and the solar still with local clay reached about 3885, 4704, and 5388.6 ml/m ² , respectively. Moreover, compared to the conventional solar still, the yield was increased by about 21% when using the PCM, and about 38.7% when using the local clay material. Furthermore, it can be observed that the daytime productivity in the case of solar still supported with local clay was higher than that for the solar still supported with PCM, while the nighttime productivity was higher in the case of solar still supported with PCM compared with solar still supported with local clay. Moreover, the average daily efficiency of conventional solar still, solar still with PCM, and solar still with local clay reached about 34, 41.2, and 47%, respectively. Therefore, it is recommended to use the solar still with local clay for seawater desalination in such arid and hot climate of Qena City.
Water scarcity necessitates a cost-effective and productive solution. This study focused to enhance the productivity of single slope solar still by incorporating the better weight of palm flower powder (micro-sized) in the basin and micro phase change material heat storage bed under the basin. In this aspect, the different quantity of palm powder weights such as 10, 30, 50, 70, 100, 120 and 150 g in the basin was experimentally examined. The absorber basin containing 50 g of palm powder has better productivity of 37.25%, whereas for 10, 30, 70, 100, 120 and 150 g, they were 11.85, 24.78, 36.8, 33.05, 10.25 and − 20.22% respectively. The influence of palm powder with different weight% impregnated in the paraffin wax was analysed. The maximum thermal conductivity of 0.33 W/m K was obtained in the sample containing palm flower powder of 20 wt%. The experimental investigation was carried out with 50 g of micro-sized palm powder in the basin and thermal storage bed under the basin containing 20 wt% of micro phase change material (PCMPFP-SS) and conventional solar still (CSS). The overall distillate output of PCMPFP-SS was 4670 and 4250 mL/m² on day 1 and day 2 respectively. On the other hand, the overall distillate output for CSS was 3030 and 2800 mL/m² on day 1 and day 2. From the economic analysis, it was found that the cost per litre (CPL) of PCMPFP-SS and CSS was 0.032 respectively. Moreover, the payback period of PCMPFP-SS was lowered from 5.1 to 4.1 months compared to CSS.
The present work aims to investigate the effects of various additives on the stability of graphene nanoplatelet (GnP)–based nanofluid phase change material (NFPCM) for cold thermal energy storage (CTES). The NFPCMs are prepared by dispersing six different types of surfactants (anionic, cationic, and non-ionic types) in deionized (DI) water at a mass ratio of 1:0.5 GnP to surfactant. NFPCMs can be found to be stable with a suitable surfactant even after 30 days using zeta-potential distribution, UV–vis absorption, visual inspection, and sedimentation tests at low temperature. The maximum enhancement in thermal conductivity of 8.3% and 48.3% is recorded in both liquid and solid states for the NFPCM with gum arabic (GA) respectively. The viscosity was enhanced by the dispersion of non-ionic surfactants, where the anionic surfactant (sodium dodecylbenzene sulfonate (SDBS)) NFPCM had a 29.9% lower augmentation compared to DI water. Furthermore, differential scanning calorimetry (DSC) results demonstrate that the phase change properties of the NFPCM are significantly affected depending on the surfactant type. The maximum phase change enthalpy is lowered (10.6%) in the Tween 80 NFPCM as compared to the base PCM. The long-term stability with the highest thermal transport property of the NFPCM storage unit integrated with the chiller is capable of achieving environmental pollution remediation by minimising the time it takes to charge the PCM.
Although the solar distillers are one of the economic solutions for addressing the freshwater shortage problem around the world, these devices suffer from low productivity. In this paper, a simple and inexpensive modification was made in the tubular solar still (TSS) to improve its productivity. The adjustment is to tilt the glass cylinder, something to help the droplets move down and collect them as a distillate. The modified inclined TSS was abbreviated by ITSS. Then, three different inclination angles were investigated (2°, 4°, and 6°), and the performance of ITSS with these inclination angles was compared with that of TSS without inclination angle (0°). Moreover, to obtain additional productivity for ITSS, the basin was painted with a mixture of matte black paint with nanomaterials. Three types of nanomaterials were studied (copper oxide nanoparticles, titanium oxide nanoparticles, and silver nanoparticles). For further improvement in ITSS productivity, Ag nanoparticles mixed with phase change material (PCM) were employed beneath the ITSS base to work as thermal energy storage material. Experimental results revealed that the highest average daily productivity rise for ITSS over TSS was observed when tilting ITSS by 6°, where the daily productivity rise and thermal efficiency reached 24% and 37.6%, respectively. Besides, the average increase in daily distillate of ITSS was 34%, 30%, and 28.5% when using Ag, CuO, and TiO2, respectively, compared to that of TSS. Moreover, ITSS with Ag provided the best thermal efficiency compared to the other operating cases, where it was 39.1%. In addition, ITSS-PCM-Ag showed a daily productivity of 62.5% more than that of TSS and a thermal efficiency of 43.5%.
Nanofluids are great heat transfer carriers for collecting thermal energy in solar thermal applications. In the present study, a theoretical study of single‐slope solar still (passive type) has been carried out by incorporating CuO, Al2O3, Ag, Fe2O3, and SiC‐water nanofluids at different volume concentrations (0.02, 0.05, 0.08, 0.12, and 0.2). This analysis has been carried out with an optimum water depth of 0.02m as obtained from the experimental and theoretical studies. In order to validate the model, the experiments were conducted on solar still and then performance of still was compared. The analytical expression of the characteristic equation using Runga‐Kutta ODE, for passive single slope solar still was found to be in good agreement with experiments carried out in Patiala, India. The total deviation for both experimental and theoretical distillate output of a still for a day was found to be 12.24%. Daily production for Al2O3‐water‐based nanofluid was found to be (14.22%) higher than simple solar still without nanofluid, followed by CuO (10.82%), Ag (8.11%), Fe2O3 (7.63%) and SiC (7.61%).
The need for fresh drinking water is increasing rapidly, and drinking water availability reduces day by day. Solar desalination is a viable option to change saltwater to fresh drinkable water. Solar still used for desalination includes processes like heating, evaporation, and condensation. The major problem faced by solar stills is that they have low productivity. Therefore, high demand for freshwater cannot be met. The present review aims to provide the researchers with an idea to select suitable methods for enhancing solar stills' performance. This article mainly focuses on the climatic, design, and operational parameters affecting the performance of solar stills. Results reveal that a combination of the incredible intensity of solar radiations, solar still type, and regions with optimum temperature can provide higher daily distillate output. Further, high productivity can be achieved with inclined solar stills by making an inclination angle equivalent to the location's latitude. A water depth of around 1 cm can provide the best output in terms of productivity for conventional solar stills. A combination of V-corrugated absorber plate with fins and energy storing materials coupled with external reflector plates can provide optimized conditions to enhance productivity. The performance of solar still can be improved by minimizing the gap between absorber plates and condensing cover. Finally, the sun tracking system, either single or dual axis in solar still, can enhance productivity.
In this work, a new attempt was made to study the behavior of the Conventional Solar Still (CSS) by adding a black-painted copper plate and phosphate pellets. Therefore, the performance of the three solar stills has been studied and compared. The first is the CSS and the second is the modified solar still (MSS). The MSS performance was tested using black coated copper plate (measuring 49 x 49 cm and 0.2 cm thick) with and without phosphate pellets and compared to the CSS in the similar climatic conditions. The results showed that the combination of black coated copper plate and the inclusion of phosphate pellets improved the evaporation rate and daily productivity. During the experiments, yields using black coated copper plate without and with phosphate pellets were 14.96% and 29.53% greater than the CSS. The effectiveness of the CSS, MSS with copper metal plate (MSS-CP), and MSS with copper metal plate with phosphate pellets (MSS-CP & PP) are around 30.23 35.3 and 41.44%, respectively.
Coating on the surface of the material create impact on their property especially emissivity is desirable property for the radiation absorbing part in solar related projects and equipments. In this experimental investigation discussed about the emissivity of the aluminium which is coated with black Nickel. This coating has the thickness of 0.2 mm on the surface. Emissivity of the coated surface obtained through traditional relation of black body and polished body surface temperatures measurements. Temperature measurements completed by the thermocouples connected through corresponding surfaces total setup placed in closed chamber for accurate outcome of experimental conditions.
The present research paper deals with the theoretical and experimental investigation of solar stills with two different thermal energy storage materials, namely, marble pieces and sandstones. To carry out this research, three solar stills of 1 m square area have been made. All solar stills have been provided with a glass cover and a cooling and dripping arrangement for reducing top heat loss and maintaining a constant level of water. It has been found that the use of sandstones as storage materials and the cooling and dripping arrangement have a remarkable effect on the distillate output of a solar still. The set-up has been used to augment the distillate output throughout the day. Theoretical results have also been compared with the experimental results and have been found to be in good agreement.
In this work pyramid-shaped two solar still units were tested experimentally, one of them is a traditional unit and the other is a modified pyramid solar still unit with wick material, reflectors, glass cover cooling, and adding nano-TiO2 particles. Five cases for modified pyramid solar still were considered, MPSS-Case 1 (modified pyramid solar still with hanging wick), MPSS-Case 2 (modified pyramid solar still with hanging wick and glass cooling), MPSS-Case 3 (modified pyramid solar still with hanging wick and reflectors), MPSS-Case 4 (modified pyramid solar still with hanging wick, glass cooling, and reflectors), and Case 5 (modified pyramid solar still with hanging wick, glass cooling, reflectors, and nano-Tio2 particles). The performance of MPSS-Case 5 was the best when compared with the other cases. The total productivity during the day for the Traditional Solar Still (TSS) was 3080 ml/m²/day and for the Modified Pyramid Solar Still Case 5 (MPSS-Case 5) was 7000 ml/m²/day, which means that the yield of the modified unit enhanced by 127.27 % over TSS. Additionally, the daily thermal efficiency was 83.8 %, 37.87 % for MPSS-Case 5 and TSS, respectively. The cost per liter for MPSS-Case 5 was 0.021$ which is lower than that for TSS by about 52.38 %.
The current work shows the results of an experimental assessment into the performance of a baffled solar based air heater (SAH-BP) with the organic phase changing material (OPCM) backup. The experiments were conducted in two modes of operation during two identical solar days in the month of February 2021 at 11.0168°North, 76.9558°East. They were SAH having baffled absorber without any PCM (SAH-BP), and baffled SAH with OPCM (SAH-BP-OPCM). The baffle plates were attached over the absorber surface in alternative sequential way and OPCM was stored beneath the absorber. The normal commercial grade paraffin was employed as OPCM and the experimentations were carried-out at the constant flow rate of 0.18 kg/s. The results substantiated that the amalgamation of OPCM within the baffled SAH enhanced its performance in terms of energy efficiency. The OPCM improved the energy efficiency of the SAH-BP by 11.25%.
The current work examines the enactment of a traditional single sloped type of solar still in the presence of crude wax as an organic phase changing material (PCM) and a low mass of nano-zinc oxide (ZnO) particles disbanded crude wax as NDPCM in terms of daily potable water output. To accomplish this goal, three identical solar stills were planned and constructed. Among these, one was an unchanged traditional still (Normal Still), another still was combined with crude wax based PCM (CW Still), and a third still was amalgamated with NDPCM (NDPCM Still). Earlier, the NDPCM was formed by combining 1.0 percent mass of zinc oxide nanoparticles with enough quantity of crude wax. The tests were carried-out in March 2021 at 11.0168°N, 76.9558°E. The results indicated that the addition of crude wax and specifically , the NDPCM increased the output of clean water by 50.24 percent and 65.17 percent, respectively.
In this work, an effort has taken to improve the thermal storage capacity of the evacuated tube solar water heating (SWH) system by means of a new kind of twin-nano/paraffin as a thermal storage medium. Beforehand, the twin-nano/paraffin has been prepared by amalgamating 1% mass of twin-nanoparticles (comprising an equal quantity of SiO2 and CuO nanoparticles) within the paraffin. The experiments were performed in three cases, viz., without paraffin, with paraffin, and with twin-nano/paraffin under the real-time solar conditions on the clear sunny days. The thermal storage characteristics had been measured in terms of the hotness of available hot water in the storage tank during the second day morning. The experiment for the each case was performed for twenty four hours continuously from the first day morning to next morning. During the experiment, the water was drawn-off after twelve hours, i.e., at 6 p.m in the evening, so as to replicate the real-time hot water demand in households. The experiments proved that the integration of paraffin and further, twin-nano/paraffin enhanced the thermal storage capacity of the evacuated tube SWH, by improving the temperature of available hot water during the next morning. The results substantiated that the water temperature was augmented by 8.8 °C and 11.7 °C, respectively with paraffin and twin-nano/paraffin. The enhancement was noticed to be significantly higher for the case with twin-nano/paraffin.
The study aims to predict the internal heat transfer coefficient (HTC) and distillate output of single slope solar still with and without nanoparticles for 41° tilt angle of glass cover with 4 cm water depth using various existing thermal models. The experiment is conducted in the winter season at the Solar Lab of MITS, Gwalior campus, M.P., India. After experiment on SSs at three different tilt angles (11°, 26°, and 41°) and three different water depths (4 cm, 5 cm, and 10 cm) it is observed that for winter season, the optimum tilt angle of glass cover is 41° and optimum water depth is 4 cm. Therefore, in this paper, six different thermal models have been validated at optimal parameters. The yield predicted using different thermal models is validated with the experimental yield. Statistical tool correlation coefficient (r) and root mean square percentage deviation (e) are calculated to show the error between experimental and predicted values. It is noticed that the value of correlation coefficient (r) is almost 0.99 for all models and for all cases. Kumar and Tiwari model shows the better agreement with the experimental value, with the lowest yield percentage deviation of 8.41%, 9.52%, and 9.89% for solar still with ZnO nanofluids, CuO nanofluids, and without nanoparticles, respectively. The distillate obtained through the CuO nanofluids and ZnO nanofluids is about 41.11% and 9.75% higher than the water without nanoparticles for 41° tilt angle of glass cover and 4 cm of water depth.
This work investigates and compares the yield of distillate water and economic feasibility of two types of solar stills, namely the conventional solar still (CSS) and the suggested solar still (SSS). Both the solar stills (CSS and MSS) were identical in dimensions and under the same operating conditions to facilitate comparison of the thermal performance. An hourly daily production analysis was performed for both models together with the detailed analysis to assess the annual cost of producing a liter of distilled water. The purpose of the present work is to overcome the relatively low productivity issues of conventional solar stills and excessive fog from humidifiers ultrasonic during low solar radiation intensity hours. Therefore, the suggested solar still (SSS) was augmented by humidifiers ultrasonic devices inside the basin water solar still, and covering it with a cotton cloth cover, to increases the evaporation surface area, reducing the distinctive dimension and not allowing the generated fog to spread even in cases of low solar radiation and the most important is increased the distilled daily water productivity in comparison with conventional solar still. The results reveal that the suggested solar still (SSS) has a daily yield higher than of CSS by 68%, SSS thermal efficiency reached 1.1 times (110%) in comparison with CSS at 4:00 pm. The proposed improvement has reduced the cost of producing a liter of distillate water by 34.9% compared to CSS. To verify the importance of the suggested solar still, a comparison was conducted with the previous studies in terms of the cost of producing a liter of distilled water. The analysis of the results revealed that there is an appropriate agreement between the previous works and the suggested solar still in the current work.
Solar still has been proposed as a potential solution to tap potable water from the brackish water in recent times. The absorber of the solar still is playing a pivotal role on the performance of the solar still. This paper presents the outcome of an experimental work, which was carried to improve the performance of a conventional solar still by coating its absorber with a nano-doped black paint (NDBP). Two solar stills with similar dimensions were used in this work. One solar still was fabricated by coating the black paint on the absorber and labelled as conventional still with black paint (CS-BP). The second still was fabricated by coating the absorber with nano-doped black paint and labelled as conventional still with nano-doped black paint (CS-NDBP). The experiments were conducted on two consecutive days by maintaining 15 mm and 25 mm water depths in both solar stills, respectively. Before hand, nano-SiO2 particles (0.5% mass) were thoroughly mixed with the black paint for fabricating CS-NDBP. The results provided the evidence that the yield of the solar still was augmented by 8.78% and 7.83% for 15 mm and 25 mm water depths, respectively, with the coating of NDBP as compared to the plain black paint.
The present paper investigates the performance of a conventional single slope passive solar still (CSS) under the influence of a paraffin based phase change material (PCM) and a nano-PCM (n-PCM) in terms of the fresh water production per day. To achieve this objective, three solar stills with the same dimensions were designed and fabricated. Among them, one still was left without any modification (CSS), another one was incorporated with paraffin as PCM (PCMSS), and third one was assimilated with an n-PCM (NPCMSS). Previously, the n-PCM was prepared by adding 0.5% mass of silica nanoparticles in paraffin. The experiments had steered on a hot and humid weather at Coimbatore, India during the month of April 2020. The results evidenced that the incorporation of PCM and n-PCM improved the fresh water production by 51.22% and 67.07%, respectively.
Drinking water scarcity becomes the alarming issue in recent days. On the other way, the atmospheric air carries a huge amount of water content in the form of water vapour. The suitable harvesting method can appositely address the water scarcity issue to a certain extent. This paper investigates a method of recovering potable water from the atmospheric air with the help of a desiccant based solar recuperation system. The orange silica gel was used as the desiccant by which the water molecules from the atmospheric air were adsorbed during the night time. The water from the laden silica gel was recuperated using a solar recuperation system during the day time. The experiments were conducted for three similar solar days during the month of April 2020 in Coimbatore, India, and the average results are presented. It was observed that the system produced 0.98 L of potable water per day, economically.
The present research paper shows the use of Titanium oxide nanoparticle to enhance the yield of Solar still. Titanium Oxide and black die mixture used as a base paint and find out the performance of the solar still at 20% and 40% weight by weight in a combination of titanium oxide materials and a black die. To check the consequences of water depth on productivity yield, readings were taken at different depth of water like 10 mm, 15 mm, 20 mm. The reading of these experiments has compared with a conventional solar still (CSS) in the same location (Gandhinagar, India, 23.2156° N, 72.6369° E) at the same ambient conditions. The outcome of the experiment shows, at higher water depth productivity of solar still increases up to a certain limit. We find that in comparison with conventional solar still 11-18% and 20- 23% increment in productivity with 20% and 40% mixture.
Highlight:
• Performance of Passive Solar still, active Solar still and phase change material is studied.
• Nanomaterials are studied, and Titanium oxide (TiO2) used as a phase change material in Distilling system.
• Effect of variable water depth and concentration of nanomaterial with paint on productivity yield has been studied.
The concentration of 40% (w/v) of TiO2 and black paint offer 23% addition efficiency at a water depth of 10 mm concerning conventional solar still.
Composite materials have been in use since ages. The introduction of chemical revolution changed the face of composite development. However, the environmental impact of polymer composites is becoming a problem that needs to be addressed properly. This brings the situation to revive the natural composites back to day to day use by replacing them in place of synthetic composites. An attempt has been made to study about the behavior of natural composites namely aloe vera and Jute. The following mechanical properties namely ultimate tensile strength, flexural strength and impact strength as well as thermal properties namely thermal conductivity and heat deflection temperature are calculated for jute as well as aloe vera. Water absorption test is carried out to study the effect of exposure of natural composites to water. Thermogravimetric analysis is done to understand the weight loss due to temperature. Finally, all the properties are to be compared with jute and aloe vera hybrid composites.
The scarcity of potable water for drinking purpose is everywhere in the world. The solar still can be used to provide potable water for the drinking purpose, but it has a daily yield of 3 litres/day. The experimental examination has been conducted on Modified solar still during March 2019 for climate condition of Patan district, Gujarat, India during morning 09 am to evening 06 pm. The performance enhancement of the Modified Solar still (MSS) has been carried out by the use of Zinc Oxide as nanoparticle and dripping arrangement of water compared with the Conventional Solar still (CSS). From the experiments, it has been observed that the yield of MSS and CSS found 3.04 l/m² and 1.887 l/m². The thermal efficiency of the MSS and CSS also determined and found 30% and 21%, respectively. It has also been observed that the modifications applied to the MSS obtained overall efficiency of 52.5%. The economic analysis of the MSS and CSS found the cost of water is, respectively, 0.95 INR/l and 0.75 INR/l. It is concluded that the solar still with nanomaterials and dripping arrangement improved the yield.
Desalination with solar powered air heating and packed bed humidification is designed and fabricated using locally available materials. The system with fined type dehumidifier is designed using LMTD method. There are different solar desalination techniques like solar still, solar air humidification dehumidification and solar water flash evaporation. Among these desalination techniques solar air humidification dehumidification was already successfully used in very large scale desalination but, not effectively tried for small scale desalination. Desalination system with HDH was designed and fabricated during this research project for small scale output. There are three main components of the system: Solar air heater, humidifier and dehumidifier. The packed bed was used in the design of humidifier for increasing the surface contact area of air with water. Psychrometric properties are recorded with use of sensors DHT11 and ESP8266 micro-controller wifi board. The water temperatures are recorded with PT100 sensors and 8 channels data logger.
This paper presents an overview on the performance improvement of trough concentrating photovoltaic thermal system by optimizing different components and operating parameters of the system and has been put forwarded. Initially, the performance of four types of solar cell arrays was studied, in that triple junction GaAs cells possessed good performance characteristics. Subsequently the importance of increasing the concentrator reflectivity for improving the performance of TCPV/T system is presented by increasing the mirror reflectivity from 0.69 to 0.92 and consequently the maximum power of the cell array got increased. Then, the role of receiver shape like rectangle and triangle for the maximum utilization of solar radiation is also presented.
Generally, photovoltaic (PV) solar cell generates electricity by receiving solar irradiance in the forms of photons. When the heat induced in the panel exceeds the operating temperature, there is drop in electrical efficiency. The objective of this project is to design the system to increase the electrical efficiency of solar cell by cooling the cell with the help of various heat sinks and wick structure with copper and aluminum fins. The heat removed from the back surface of the panel with the help of fins that absorb heat generated by the cells during the day. Therefore, the decreased temperature of PV panel increases the electrical efficiency of solar cell. When the solar cells receive more solar radiations, it generates more electricity. At the same time, the efficiency drops when the temperature of solar cell increases. It can be concluded that the efficiency and electrical characteristics of the copper fins are higher than the aluminum by 4% and 6%, respectively.
This work presents the theoretical analysis on the effect of mass flow, feed water temperature, internal heat transfer coefficient and the absorber plate temperature of an improved inclined solar still for producing fresh water. The solar intensity and other environmental parameters are considered for simulating the solar still in order to examine the effect of mass flow; feed water temperature; internal heat and mass transfer parameters; basin temperature on yield and effect of air gap distance between plates. The results show that, at a minimum mass flow rate, yield was increased by 57.14% and the maximum average water temperature for the flow rates of 0.0833, 0.1666, 0.3222 and 0.4166 kg/min are found to be 62, 45, 40 and 38oC respectively. The average temperature of hot water collected in the lower storage was 47.9oC. The effect of inlet feed water temperature shows that, there is an increase in yield by 65% with a flow rate of 0.0833 kg/min and the inlet temperature 60oC respectively. Also, introducing baffle plates in the basin absorbs some of the intensities which will heat up the flowing water for achieving higher brine temperature. The present RHN (Ravi-Harris-Nagarajan) model can be applied to stepped and weir cascaded solar still for determining the average water temperature in the solar still.
The aims of this paper is to investigate the effects of various materials inside the solar still on the increase of the productivity of potable water. Here, blue metal stones and cow dung cakes were used as materials. To investigate their effect, three identical solar stills with an effective area of 1 m square made from locally available materials were tested in climate conditions of Mehsana (23°50′ N 72° 23′). The first and second solar stills were filled with blue metal, stones and cow dung cakes, while the third one was taken as a reference which consisted of only blue paint at the basin. The experiments show that blue metal stones have the highest distillate output at daytime, followed by cow dung cakes solar still and reference solar still. On the other hand, the overall distillate output of blue metal stones and cow dung cakes at daytime as well as at night were 35% and 20% compared with that of reference solar still.
Experimental investigation and parameter analysis of solar still with the different wick materials
- Elangovan
Teaching learning optimization and neural network for the effective prediction of heat transfer rates in tube heat exchangers
- Thanikodi