Performance of a single slope solar still using different porous absorbing materials: an experimental approach.

Desalination is a critical process to address water scarcity in arid regions worldwide, and solar stills provide an economical solution despite their productivity limitations. This study aimed to enhance the performance and productivity of solar stills by constructing two stills with different natural and artificial absorbing materials such as black luffa, luffa, fine steel wool, and steel wool pads. The solar stills were tested in Egypt under comparable weather conditions, and their productivity, solar intensity, wind velocity, and temperature were measured to determine their thermal efficiency and exergo-economic analysis. Results showed that the choice of absorbing material significantly impacted solar still productivity, with steel wool pads achieving the highest yield of 4.384 l/m2. Moreover, steel wool pads also exhibited the highest thermal efficiency at 32.74%. The cost per liter (CPL) was the lowest with steel wool pads at 0.0034 $/l/m2. Finally, the payback period and exergo-economic analysis demonstrated that incorporating steel wool pads was the most promising modification for enhancing solar still performance compared to other modifications.

Performance investigation of a modified single-basin solar distiller by augmenting thermoelectric cooler as an external condenser.

Harvesting freshwater from saline and seawater using solar energy has proven a significant impact in recent times. The present study aims to investigate the performance of the solar desalination system by incorporating glass reflectors, heat storage media, and a thermoelectric cooling system with a single-basin-type distiller. Accordingly, the objective of the study is to improve the performance of the solar distiller in terms of freshwater production and efficiency compared to a conventional setup. Moreover, the designed unit was tested under the environment of the Western part of India (Mehsana-23.5880° N, 72.3693° E) for 19 days in the months of May and June 2022. The maximum daily productivity observed during the day was 2.5 l at an average solar radiation of 1200 W/m2, which was 1.23 times higher than its conventional counterpart. Similarly, the energy efficiency showed a maximum improvement of 23.73%. At the middle of the day, i.e., maximum performance condition, the exergy efficiency was doubled with current modifications. Solar radiation and ambient temperature were found to be the most critical parameters that influence performance. Modifications also increase the % off sunshine hour productivity compared to sunshine hour from ~ 10 to 11% to ~ 20.8 to 24%, respectively. The cost of water distillation for the proposed solar still was found as 0.037 $/l/m2,s and the payback period was estimated as 2.27 years. The overall results indicate the positive influence of the modifications; hence, this type of setup is feasible for implementation on the field in harsh and coastal line areas. However, modified single-basin solar still needs extended field study to realize the full potential of the modifications.

Hemispherical solar distiller with truncated circular cone-shaped reflector mirrors (TCC-RM): optimum inclination of reflector mirrors.

The present study aims to achieve the highest cumulative yield of the hemispherical distillers, by designing and constructing new reflector mirrors, which are truncated circular cone-shaped reflector mirrors (TCC-RM). To obtain the optimum inclination of TCC-RM that achieves the highest hemispherical distiller's performance, eight inclination angles (10°, 15°, 20°, 25°, 30°, 35°, 40°, and 45° with vertical) were experimentally studied. To achieve this, a series of experimental tests were carried out on the three hemispherical solar distillers: the first represents the reference distiller (traditional hemispherical solar distiller (THSD)) and the other two devices are the hemispherical solar distiller with truncated circular cone-shaped reflector mirrors (HSD-TCCRM) with different inclination angles. The experimental results indicate that utilizing TCC-RM with a 25° inclination angle achieves the maximum cumulative yield of 8.35 L/m2 with an improvement of 42.74% compared to THSD. While the utilization of TCC-RM with the inclination angles of 30°, 35°, 20°, 40°, and 15° achieves the cumulative yield of 7.9, 7.3, 7.05, 6.67, and 6.6 L/m2 compared with 5.85 L/m2 for THSD. On the contrary, adjusting the inclination angle of TCC-RM at 10° and 45° affects negatively the cumulative yield of the HSD with TCC-RM in comparison with THSD. Based on the data of cumulative yield, daily efficiency, and the economic analysis it is recommended to utilize TCC-RM with a 25° inclination angle to achieve the highest performance and minimum distillate cost of hemispherical solar distillers.

Experimental study on the single basin solar still integrated with shell and spiral finned tube latent heat storage system enhanced by copper oxide nanoparticles.

In this work, a latent heat storage system was designed, installed, and tested when it was integrated with a single basin solar still. The latent heat storage system is a shell and spiral finned tubes, where 20 kg of a paraffin-CuO nanocomposite with a weight fraction concentration of 1% was poured into the shell while hot water from the solar collector was being pumped through the spiral finned tubes. In order to identify the effect of implementing the storage system on the performance of the solar still, two experiments were conducted, with and without storage, under approximatelysimilar weather conditions. The proposed design of the storage system succeeded to overcome all challenges associated with using paraffin wax as storage material with the solar still. The obtained results revealed that an improvement in fresh water daily productivity of 4.54% was achieved when the storage system was integrated with the solar still. The economic analysis showed that the cost per 1 L of fresh water was 0.25 $/L when the storage unit was used. This high cost will be significantly reduced when a large-scale system is installed.

Application of heat sinks inside the pyramid solar distiller: experimental study on distiller performance under various operating conditions.

Solar still is a cheap decentralized mode for obtaining potable water from saline water using solar energy, but it has low productivity. Previous studies showed that using pin fins in the absorber can increase the solar still efficiency and yield. The heat sink has better heat transfer properties than those of the pin fin because it has a higher surface area to volume ratio than that of the pin fin. The current study investigates the effect of heat sinks in passive pyramid solar still under two water depths (11 and 30 mm) on the hourly yield, accumulated yield, and efficiency of the distiller. Three cases were compared: conventional solar still (CSS), regular distribution of heat sinks (DHS), and grouped heat sinks in the middle of the solar still basin (GHS). In addition, the effect of atmospheric parameters such as solar radiation, UV index, humidity, dry bulb temperature, and ambient temperature on the solar still parameters such as water, vapor, cover, and feedwater temperature is investigated. Unexpectedly, heat sinks weakly affect the performance of solar still. Therefore, the conclusion of the previous studies that the finned absorber has a favorable impact on the solar still performance is not general and needs further investigation. The highest thermal efficiency was observed for the DHS and GHS at 30-mm water depth, where the efficiency was 35%.

Performance evaluation of using evacuated tubes solar collector, perforated fins, and pebbles in a solar still - experimental study and CO2 mitigation analysis.

The combination of various methods of increasing evaporation rate can highly impact the performance of solar desalination. This investigation aims to find the impact of using evacuated tubes solar collector, perforated fins, and pebbles on the performance enhancement of a solar still. Simultaneously six-evacuated-tube solar collector to raise the evaporation rate of the system, the perforated fins to increase the heat transfer surface between water and absorber, and the immersed pebbles stone in the water to keep the high water temperature at low solar radiation were considered. The hourly and cumulative distillate output (DO) values are presented separately for the daytime and nighttime to provide extensive insight. The results indicate that on a sample day from the six months of experiments, which was in February 2019, the time for DO peak shifts from 1 to 3 p.m. Moreover, the temperature values for MSS experience almost 43 ℃ jumps on the peak and almost 19 ℃ increase on average compared to CSS. Furthermore, the cumulative DO in the daytime reaches from 2.515 to 6.662 L, while during the nighttime, an increase from 0.057 to 0.872 L is observed. Additionally, during the six months, the average DO jumps from 2.88 to 7.03 L, which means a significant enhancement of 144.1%. Moreover, the costs per liter of MSS and CSS are 0.0051 and 0.0056 dollars per liter, respectively. The net amount of CO2 reduction of MSS was improved by about 2.44 times higher than CSS.

Concentrator-assisted solar still for improving freshwater yield: an experimental approach.

The present experimental study aims to make advancements in the daily production of freshwater by a single solar still, with the ultimate goal of increasing its efficiency. The experiment was carried out in the solar still with and without integration at four different water masses within the basin, and metrics such as water, glass, basin temperature, and drinkable water generated were measured. The results showed that the daily distillate collected from the integrated system using 2.5 kg/h of mass flow in the parabolic concentrator produced 2.99 kg at the minimum water mass of 20 kg placed in the basin. When the flow velocity of water in the parabolic concentrator is raised from 2.5 to 5 kg/h, the amount of freshwater generated decreases from 2.99 to 2.66 kg. Compared to traditional single slope solar still, the potable water generated increases by roughly 18.24, 18.29, and 18.33% for water mass of 30, 40, and 50 kg, respectively, with the mass flow rate of water in the serpentine tubes as 2.5 kg/h. The results also reveals that, in addition to the PTC collector, the mass flowrate of fluid in the serpentine tube arrangement submerged in the basin affects daily solar efficiency. There is a significant reduction of about 1-2.3% in the daily efficiency of the system with increased mass flow rate of fluid in the serpentine tube arrangement. Similarly, the daily efficiency in all the cases reduces with increased water depth.

Performance improvement and advancement studies of mixed-mode solar thermal dryers: a review.

Solar thermal dryers are solar-operated gadgets utilized to dehumidify various products, especially food items and rubber sheets. This article provides detailed design, parametric studies, and an in-depth review of mixed-mode solar dryers (MMSD) with a case study of fish drying near coastal lines. Due to several advantages compared to open sun drying and prominent performance index compared to indirect and direct type solar dryers, mixed-mode solar dryers have large adaptability on the field. Moreover, mixed-mode solar thermal dryers with different augmentations are reviewed, for instance, mixed-mode solar dryers with evacuated tube collectors, phase change materials, ultraviolet rays stabilized housing, and dehumidifiers. The case study of fish drying near the coastal line of Gujarat, India has been carried out to study the present scenario of the drying activities. Hence, the objective of this review is to identify the capable mixed-mode solar dryer with heat recovery systems. Substantial reviews within the article suggest an essential need to implement the hybrid mixed-mode solar dryer cum distiller technology for small-scale enterprises that can simultaneously provide potable water near coastal lines along with drying of fishes from the solar dryer. Furthermore, future research demands such hybrid mixed-mode solar drying systems that strongly fulfill the requirements of local communities near coastal lines involved in fish drying activities.

Deep neural network prediction of modified stepped double-slope solar still with a cotton wick and cobalt oxide nanofluid.

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 (Co3O4) 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/m2 h) mean absolute error (MAE) for HP and 4.5% for ITE. Decision tree regressor has a better prediction for HP with 33 (ml/m2 h) MAE and almost the same MAE for ITE. Neural network has a better prediction for HP with 28 (ml/m2 h) MAE and a bit worse prediction for ITE with 5.7%. The best model used the deep neural network with 1.94 (ml/m2 h) MAE for HP and 0.67% MAE for ITE.

An experimental approach on the utilization of palm oil biodiesel with higher concentration of Al2O3 nanoadditive for performance enhancement and emission reduction.

Demand for energy is one of the crises that the whole world is now facing as a direct result of the rapid depletion of fossil resources. Because of the many positive effects that biodiesel may have on both the economy and the environment, a significant amount of study has been conducted on the topic in recent years. In order to improve the physiochemical qualities, a number of researchers have been conducting studies to determine whether or not biodiesel can be used effectively as a renewable fuel in diesel engines. This research report presents the findings of an experimental investigation into the use of aluminium oxide nanoparticles as an additive in alternative fuel made from palm oil biodiesel. The investigation was carried out in the context of a nanoparticle mix. The method of transesterification is used in the manufacturing of biodiesel. The properties of the tested using American Society of Testing Methods (ASTM). The results showed that there is a significant increase in the brake thermal efficiency and a reduction of the brake-specific fuel consumption from the engine using biodiesel blends. When compared to the diesel fuel in the engine, the brake thermal efficiency of the engine fuelled using POBD20 with 50 ppm Al2O3 nanoadditive and POBD20 is found to be 11.78 and 4.76% respectively, while the engine is operated at peak load. However, the BTE is improved by about 14.16, 15.69, 20.55 and 18.39% using POBD20 and POBD20 with 25, 50 and 75 ppm Al2O3 nanoadditive respectively compared to neat palm oil biodiesel. The improvement in the BTE of the engine would be completely due to the existence of higher thermal conductivity nanoparticle which enhanced the surface to volume ratio with in the fuel. This acts as a chemical catalyst during the combustion and thereby increases the burning rate of fuel inside the combustion chamber. Furthermore, the analysis revealed that the NOx formation increased with other emissions such as carbon monoxide (CO) and unburnt hydrocarbons (UBHC) which are reduced.

Experimental investigation on a modified design of hemispherical solar distiller with v-corrugated iron trays and wick materials for improving freshwater production.

The low energy efficiency of the solar distillers is one of the key barriers to their effectual usage in the desalination domain. Hence, this work introduces an experimental investigation to enhance the freshwater productivity of the hemispherical solar distiller with different trays' configurations and utilizing wick materials. This was achieved by utilizing iron trays and wicks in the circular basin of hemispherical solar still in order to increase the vaporization surface area for better heat transfer of saline water. The performance of the hemispherical solar distiller was investigated with flat and v-corrugated iron trays configurations. Three distillers were designed and examined, namely, conventional hemispherical solar distiller, hemispherical solar distillery with flat iron trays, and hemispherical solar distiller with v-corrugated iron trays. Moreover, the combined effects of using wick materials with flat and v-corrugated iron trays in the basin of hemispherical distiller have been also investigated. Experiments were carried out at the desert climate conditions of El-Oued (33°27'N, 7°11'E), Algeria. The results showed that the productivity improvement is 42.85% and 14.30% over the conventional hemispherical distiller for v-corrugated and flat trays hemispherical solar still (HSD), respectively. While the inclusion of wick materials with v-corrugated iron trays further increases the productivity by about 83.12% over the reference distiller. Moreover, the energy efficiency of the flat trays HSD, v-corrugated trays HSD, HSD flat trays and wicks, and HSD v-corrugated trays and wicks is 38.72%, 48.28%, 52.16%, and 61.67%, respectively. Additionally, the .cost of freshwater production of HSD v-corrugated trays and wicks was 41.72% lower than that of a traditional hemispherical distiller.

Analysis of a solar still with photovoltaic modules and electrical heater - Energy and exergy approach.

The availability of drinkable water, along with food and air, is a fundamental human necessity. Because of the presence of higher amounts of salt and pollution, direct use of water from sources such as lakes, sea, rivers, and subsurface water reservoirs is not normally suggested. Solar is still a basic technology that can use solar energy to transform accessible waste or brackish water into drinkable water. Exergy analysis is a strong inferential technique for evaluating the performance of thermal systems. Exergy is becoming more popular as a predictive tool for analysis, and there is a rising interest in using it. In this paper, performance analysis on the aspect of energy and exergy from the proposed solar still (PSS) (conventional solar still with the photovoltaic modules-AC heater) was analyzed on three different water depths (Wd) conditions (1, 2, and 3 cm). Using a solar still with an electric heater, the daily potable water production was found as 8.54, 6.37, and 4.43 kg, for the variations in water depth (Wd) of 1, 2, and 3 cm respectively. The energy and exergy efficiency of the PSS at the Wd of 1, 2, and 3 cm were 75.67, 51.45, and 37.21% and 5.08, 2.29, and 1.03%, respectively. At 1 cm Wd, PSS produced the maximum freshwater yield as compared to the other two water depths. When the Wd is increased from 1 to 2 cm and from 1 to 3 cm, the yield is decreased up to 27.3 and 52.7%, respectively. Similarly, the energy and exergy efficiency is decreased up to 36.8 and 53.2% and 50.4 and 80.6%, respectively. The water cost of the modified solar still is calculated as 0.028 $/kg for the least water thickness.

Optimization of the hemispherical solar distiller performance assisted by high thermal conductivity metal trays incorporated with reflective mirrors.

The present comprehensive study aims to achieve the highest freshwater productivity of hemispherical solar distillers which are characterized by having a large condensing and receiving surface area. This was done by incorporating two effective modifications to the design of the hemispherical solar distiller, namely the use of metal trays with high thermal conductivity and reflective mirrors. In the present experimental work, three different high thermal conductivity metal trays (steel, zinc, and copper) incorporated with the reflective mirrors were tested under the same climate conditions, in order to determine the optimum selection of metal trays that are incorporated with the reflective mirrors that achieve the highest performance of the hemispherical distillers. To realize this objective, four distillers were fabricated and tested at the same climate condition namely: Hemispherical solar Distiller with Black Silicone Walls (HSD-BSW) which represent the reference case, Hemispherical Solar Distiller with Steel Trays and Reflective Mirrors (HSD-ST&RM), Hemispherical Solar Distiller with Zinc Trays and Reflective Mirrors (HSD-ZT&RM), and Hemispherical Solar Distiller with Copper Trays and Reflective Mirrors (HSD-CT&RM). The experimental results presented that the utilization of copper trays incorporated with reflective mirrors (HSD-CT&RM) represents the very effective option to achieve the highest performance of the hemispherical solar distillers. The cumulative production achieve by the reference HSD-BSW reached 4.65 l/m2day, while utilization of copper trays incorporated with reflective mirrors (HSD-CT&RM) increases the cumulative production to 9.5 l/m2day, with an improvement of 104.3%. Also, utilization of copper trays incorporated with reflective mirrors (HSD-CT&RM) improves the daily thermal and exergy efficiencies by 102.4% and 194.9%, respectively compared to HSD-BSW. Additionally, the economic feasibility showed that the use of copper trays incorporated with reflective mirrors (HSD-CT&RM) is a very effective option as it reduces the cost of distilled water by 44.1%.

Optimization of thermal efficiency on solar parabolic collectors using phase change materials - experimental and numerical study.

Solar energy is a one-of-a-kind renewable energy source that has many uses, and in the thermal applications, it is receiving more attention and is becoming more feasible. The present work presents numerical and experimental studies to investigate the performance of a parabolic trough solar concentrator (PTC) integrated with a thermal energy storage system. A new receiver design is built that stores thermal energy using phase change material (PCM). A concentric absorber tube with two different kinds of PCM - MgCl2·6H2O and erythritol (filling the annular-space of absorber tube) - were used to construct a PTC, and its thermal performance and thermal efficiency were investigated under two different HTF flow rates of 0.005 kg/s and 0.033 kg/s. Solar energy is transformed into heat, which is then used to store in the PCM before being discharged to cold water, which is the final heat transfer fluid in the receiver's inner pipe. The simultaneous studies of the PTC with and without PCM are investigated. A commercial Mat Lab's operating model through an imperialist competitive algorithm of the entire PTC system is presented, and the numerical results were compared to the experimental results, which were carried out with and without PCM in PTC. With the PCM in PTC (0.005 kg/s and 0.033kg/s), the HTF exhibited gain in peak temperatures of 11°C (erythritol) and 9°C (MgCl2·6H2O) at 0.05 kg/s, whereas the peak temperatures further increase to 14°C (erythritol) and 12°C (MgCl2·6H2O) respectively at 0.033 kg/s, as compared to HTF without PCM. Average thermal efficiency of PTC with HTF flow rate of 0.033 kg/s was highest with usage of erythritol (40.6%), among all the cases. The experimental and predicted thermal efficiency performance indices for different flow rates and PCM are found to be with a deviation of around ± 1.9%, demonstrating the accuracy of the developed numerical model.

Experimental investigation of an active inclined solar panel absorber solar still-energy and exergy analysis.

The objective of the current study is to investigate the performance of the inclined solar panel basin still (ISPBS) incorporated with a spiral tube collector (STC) for various mass flow rates of water (mf). The maximum potable water yield of 8.1, 6.9, and 6.1 kg is obtained for different mass flow rates of 1.8, 3.2, and 4.7 kg/h in each instance. Also, for mf of 1.8, 3.2, and 4.7 kg per hour, the daily average energy and exergy efficiency of the ISPBS is recorded to be 47.9, 39.3, and 31.02 % and 9.8, 7.9, and 5.6 %, in each instance. The average electrical, thermal, and exergy efficiency of the PV panel is noted to be 6.5, 7.1, and 7.5 %; 15.67, 17.1, and 18.04 %; and 20.03, 22.21, and 23.36 % for mf of 1.8, 3.2, and 4.7 kg/h in each instance. The rise in mf causes a drop in the fresh water production yield; thermal, exergy, and overall thermal effectiveness; and an enhancement in the power production of the panel, electrical, thermal, exergy, and overall exergy efficiency of the system. Also, the cost of yield production is noted to be low-cost in AISS at minimum mf of 1.8 kg per hour (0.019 $/l) when compared to the other two mf of 3.2 and 4.7 kg per hour (0.022 and 0.025 $/l).

Experimental studies on natural convection open and closed solar drying using external reflector.

For low temperature agricultural crop and meat drying, dryers utilizing the renewable energy source (solar energy) appear to be an efficient technique as it is ecofriendly, energy efficient, and available in free of cost. This work presents the experimental investigation on a solar food dryer equipped with external reflectors to enhance the rate of drying efficiency by removing the moisture content available in the anchovy fish. A comparison of conventional open solar drying is carried out to assess the parameters such as drying efficiency, moisture removal rate, and heat energy required for drying the anchovy fish using the modified solar dryer using the natural convection technique. From the experimental results it is observed that the relative humidity greatly influence the rate of drying. The average relative humidity during the experiments using open solar drying is found as 50-65% whereas, the using solar dryer the average relative humidity inside the chamber is found as 20-35%. The relative humidity of the fish using open solar drying is higher as compared to solar dryer drying as the drying products are kept in open atmosphere. The physical examination results on the dried products proved that using a modified solar dryers, the dried product is free from insects, and dust. Also, it is found that the loss of color from the product is a minimum while compared to conventional open solar drying. The results showed that the thermal efficiency of top tray (dryer 1) and bottom tray (dryer 2) is comparatively higher as compared to that of conventional open solar drying and found as 16.73 and 19.34 %, respectively. Results also showed that nearly 20.05% of the energy could be saved using the modified solar dryer as compared to the open solar drying technique.

Exergy and energy analysis of a tubular solar still with and without fins: a comparative theoretical and experimental approach.

One of the major challenges faced by human society is the freshwater crisis and shortage of conventional energy. Solar still is considered as one of the promising sources for the production of freshwater from saline water by desalination method. This paper represents the theoretical and experimental study of tubular solar still with and without fins. In this experimental study, the readings were recorded from 8:00 AM to 6:00 PM. The results of this experiment show that the efficiency of tubular solar still (TSS) with fins and without fins is found as 23.39 and 13.76% respectively. The rate of irreversibility from the basin of TSS with flat is higher than TSS with finned absorber and also the rate of irreversibility from water is significantly reduced by TSS with the finned absorber. The exergy analysis showed the maximum exergy efficiency of about 11.8% from the TSS with fins and about 10.6% from the TSS with a flat absorber.

Enhancing the hemispherical solar distiller performance using internal reflectors and El Oued sand grains as energy storage mediums.

This paper presents a comprehensive experimental study of the some effective modifications which aim to improve the cumulative productivity of solar distillers, in order to reach the best modification that achieves the highest cumulative productivity of hemispherical distillates. The experimentations were carried on the hemispherical distillers which are characterized by a large area of receiving and condensation. To obtain the best modification that achieves the highest cumulative productivity, the present comprehensive studies were conducted on two experimental scenarios. In the first scenario, the influences of internal reflective (Reflective Mirrors and Reflective Aluminum Foil) on hemispherical distillers performance was studied. In the second scenario, the influences of internal reflective with El-Oued sand grains as the energy store mediums on hemispherical distiller performances was studied. To achieve this goal, we designed and fabricated three hemispherical distillers, the first distiller represents the reference case (Conventional Hemispherical Solar Still-CHSS), the second is the Hemispherical Solar Still with Internal Reflective Mirrors (HSS-IRM), and a third is the Hemispherical Solar Still with Internal Reflective Aluminum Foil (HSS-IRAF). In the second experimental scenario, the El-Oued sand grains were added to the basin of the second and third distillers as follows; where the second distiller became a Hemispherical Solar Still with Internal Reflective Mirrors and El-Oued sand grains (HSS-IRM & SG), and a third distiller became a Hemispherical Solar Still with Internal Reflective Aluminum Foil and El-Oued sand grains (HSS-IRAF & SG). The results presented that the cumulative production of reference distiller (CHSS) up to 4750 mL/m2, while use of internal reflective mirrors and El-Oued sand grains (HSS-IRM & SG) increases the production to 9400 mL/m2 day. The maximum improvement in cumulative distillate production, exergy efficiency, and thermal efficiency was recorded for utilization of internal reflective mirrors and El-Oued sand grains (HSS-IRM & SG) which reached 98, 200.9, and 96%, respectively, compared to reference case (CHSS). The economic feasibility indicated that the utilization of HSS-IRM & SG represent the good modification which reduced the cost of freshwater productivity by 49.1% compared to CHSS.

Performance assessment of conventional solar desalination system in Northern part of Gujarat.

Water distillation by utilising free energy from the sun is one of the significant techniques for getting freshwater from salty and seawater. For the remote areas and small societies where freshwater is distant, solar distillation is one of the best explanations for freshwater creation. The main objective of this study is to evaluate the performance of the flat plate collector-assisted conventional solar still incorporating mirror wall and heat storage material, which was tested at Anchor institute of solar energy studies, Mehsana (23.5275311° latitude and 72.3881041° longitude), Gujarat. Moreover, the study captures average productivity with and without FPC which was 1.5 L and 1.0 L respectively during the day time for the entire period of experiments. In this study, the water depth is varied from 1 to 5 cm inside the single basin solar still to obtain the optimum depth. It was observed that when mirror augmented still was operated with the FPC, 3.6L/day productivity was achieved with 30% instantaneous efficiency, at solar radiation of 1122 W/m2 and ambient temperature of 24 °C. Also, the maximum productivity was observed at a water depth of 3 cm and 4 cm. Moreover, improvements in daily and yearly productivity were observed to be 51.515% and 56.6474% respectively, which were estimated on the basis of with and without FPC. An experiment was performed at Anchor Institute of Solar Energy, Mehsana located at the north part of Gujarat where the average annual rain was comparatively less compared to other regions, so this type of solar still can provide potable water to daily workers who work on site. Furthermore, economic study reveals 0.577 INR/litre cost of distiller output for conventional set-up and 0.477 INR/litre for the FPC assisted set-up.

Effects of solar geometry and operation period on stability of solar desalination systems: a review.

The sun is the primary source of life on the earth. The heating effect of the sun provides a more fruitful environment for mankind. In addition, solar energy in the form of thermal radiation has been utilized for solar thermal applications and space heating. With abundant solar radiation, the emergence of the solar desalination has been emerged as a viable solution for water purification by utilizing solar stills. However, solar-powered distillation is relatively a slow process due to the requirement of bulk heating. To suppress thermal conduction to bulk water, various photothermal materials were employed. However, there are many governing parameters which influence the productivity, including solar intensity, cloud, wind, ambient air temperature, humidity, solar absorption of blackened surface, depth of bulk water, feed water type, angle of condensation surface, water film thickness, underneath the condensing surface, and experiment period. Further, systematic and continuous experiments for extended periods are essential for determining the stability and durability of a solar desalination system. The main objective of this article is to review all the experimental studies conducted for two months at minimum up to 1-year duration. In addition, all the SDSs handled in this study further were examined by solar geometrical factors, including day length (DL) and position of the sun or zenith angle (θz). As a result, the sunshine hours, day length, and the solar zenith angle play an important role in the water evaporation rate. Lower solar zenith angle and longer day length (more sunshine hours) are desirable for higher water productivity.