Daily Distillate Production Research Articles

Optimized irrigation through solar desalination: Exploring the impact of water temperature in wastewater treatment and phosphate fertilizer removal

Could rationalizing irrigation techniques be accomplished with solar desalination? This practical and theoretical study explores the optimization of a solar desalination unit employing the novel Humidification Dehumidification (HDH) method to evaluate its potential in irrigation to provide an answer to that topic. The performance of the system is examined in the first section of the research concerning raising the evaporator temperature and the ensuing temperature difference. The daily distillate production rate for the HDH system is 25 kg/m², and the results show that it has a global efficiency of 58 %. Using wastewater and saltwater polluted with phosphate fertilizers, the HDH system is evaluated in the second section of the study. The findings show that more than 98 % of ionic species were removed, besides presenting a potentially effective response to the complicated water treatment issues facing the agricultural industry.

Experimental Performance of Single-Slope Basin Solar Still Coupled with a Humidification–Dehumidification Cycle

Despite their low distillate yield, single-slope basin solar stills incorporate a simple and cheap technique to secure potable water in arid and rural areas away from fresh water resources and the power grid. Nevertheless, recovering a portion of the inevitable thermal losses from the still will significantly contribute to enhancing its daily distillate productivity and thermal performance. In this manuscript, the latent heat of condensation in single-slope basin solar still was partially recovered and utilized as the thermal energy source for an auxiliary humidification–dehumidification (HDH) distillation cycle. The thermal performance of the resultant SS-HDH distiller was experimentally tested side by side with a separate single-slope basin still of the same basin area. The results showed an increase of about 2 L/m2 in the daily distillate production of the SS-HDH distiller over that of the conventional single-slope basin still. In addition, the thermal efficiency of the SS-HDH distiller was 57% greater than that of the conventional single-slope basin still.

Pyramidal Solar Stills via Hollow Cylindrical Perforated Fins, Inclined Rectangular Perforated Fins, and Nanocomposites: An Experimental Investigation

A practical study was conducted to improve the performance of conventional pyramidal solar stills (CPSS) using two types of fins with differing geometries, as well as nanocomposites of TiO2 and graphene. The first fin was hollow, cylindrical, and perforated (HCPF), whereas the second fin was an inclined perforated rectangular fin (IPRF). The fins were integrated with the base of a solar still to evaluate their performance in comparison with a CPSS. The obtained experimental results demonstrated that the pyramidal solar still with hollow perforated cylindrical fins (PSS-HCPF) and the pyramidal solar still with inclined perforated rectangular fins (PSS-IPRF) produced more distillate than the PSS-HCPF and CPSS under all examined conditions. The daily productivities of the CPSS, PSS-HCPF, and PSS-IPRF were 3718, 4840, and 5750 mL/m2, respectively, with the PSS-HCPF and PSS-IPRF improving the productivity by 31.3% and 55.9%, respectively, compared to that of the CPSS. In addition, using nanocomposites with PSS-IPRF improved the daily distillate production by 82.1%.

Humidification dehumidification saline water desalination system utilizing high frequency ultrasonic humidifier and solar heated air stream

An experimental investigation on the solar desalination system was conducted according to humidification dehumidification methodology hybrid with hot air stream flow and vapor compression cycle as a condensation unit. A high-frequency ultrasonic atomizer (HFUA) was used as a humidifier which rapidly reaches 100% Relative Humidity. The tests were done during Aug. and Sept. 2020 under the climate of Suez city, Egypt 29.9668°N, 32.5498°E. The effect of high-frequency ultrasound atomizer situation, water height, and hot air stream flow rate on distillate yield were studied. The results illustrated that increasing atomizer number and decreasing water height increases the daily distillate production. The maximum daily freshwater productivity occurred at atomizer number N = 6, rising 38.6% and 115% compared with N = 4 and N = 2, respectively. Furthermore, water height at H = 1 cm is the most efficient with 16% and 28.6% increment compared with H = 2 cm and H = 3 cm, respectively. The optimum hot air stream flow rate ṁa = 0.01156 kg/s with an increment of 55.95%, 31%, 6.48%, 11.3%, and 38.5% compared with 0.0086, 0.01011, 0.013006, 0.0144, and 0.0173 kg/s, flow rates, respectively. The daily production reaches 7.72 kg\\day, the system efficiency 33.84 % and the estimated cost per unit liter is 0.03437 $/L.

Solar desalination unit coupled with a novel humidifier

The solar desalination system is experimentally investigated according to humidification dehumidification methodology (HDH) with hot air stream flow and heat pump as a condensation unit. The effects of high frequency ultrasound atomizer number, water height and hot air stream flow rate on distillate yield are studied. The results illustrated that increasing of atomizer number and decreasing water height increases the daily distillate production. The maximum daily freshwater productivity occurred at six atomizer number with an increase of 38.6% and 115% compared with atomizer number four and two, respectively. Furthermore, water height at 1 cm is the most efficient with an increment of 16% and 28.6% compared with 2 cm and 3 cm, respectively. The optimum hot air stream flow rate is 0.011 kg/s with an increment of 36.88%, 31.07%, 6.48%, 11.72%, 23.52% and 38.60% compared with 0.009, 0.010, 0.013, 0.014, 0.016, and 0.017 kg/s, flow rates, respectively. The air mass flow rate has a significant impact on system performance. The maximum gain output ratio (GOR) of the system is about 1.54. The daily production reaches 7.72 kg∖day, the system energy efficiency is 33.84% and 1.43% exergy efficiency the estimated cost is 0.0112 US$/L.

Improving the performance of stepped solar still using a graphite and PCM as hybrid store materials with internal reflectors coupled with evacuated tube solar collector

The present experimental study aims to improve the productivity of a stepped solar still. The stepped solar still using PCM as latent storage materials with stillinternal reflectors integrated with an evacuated tube collector (first case) and a stepped solar still using a graphite and PCM as hybrid storage materials with still internal reflectors integrated with an evacuated tube collector (second case) was designed, implemented and operated at Tanta University under the climatic conditions of Egypt to obtain the better configuration. This study illustrated to effects the graphite, PCM, still internal reflectors, and evacuated tube solar collector on the stepped solar still performance. The results show that the daily distillate productivity was varied between 11.24–11.29 and 13.6–13.62 L/m2 day for the first case and the second case, respectively. The daily efficiency was varied between 42.55–42.62% and 51.7–51.82% for the first case and the second case, respectively. These results indicated that the second case is more effecient than the first case. The percentage improved in the daily productivity for the second case as compared to thefirst case varied between 20.64 and 21.05%. Also, the percentage improved in the daily efficiency for thesecond case compared to the first case varied between 21.48 and 21.64%. Due to increase the hot brackish water flow rate from 15 to 35 ml/h, the daily productivity increases from10.54 to 12.08 l/m2and from 12.88 to 14.42 l/m2for the first case and the second case, respectively.

Effect of water flow in a solar still using novel materials

The effects of novel materials, viz. phase-change material and nanoparticles, and water flowing over a glass cover on the performance of a single-slope single-basin solar still for use in solar thermal applications are presented and discussed. The results obtained with and without PCM and nanoparticles are compared with those for a conventional solar still on summer days. Numerical simulations and experiments were carried out to provide solutions for the temperatures of the flowing water, glass cover, novel materials [i.e., fin with cotton wick (FWCW), fin with jute wick (FWJW), and PCM], and nanoparticle basin liner. The daily production rate of distillate from pure saline water by the solar still was enhanced by using a drip button due to the absorptive capability of FWCW of 70.02%, resulting in daily (24 h) distillate production of 9.429 kg m−2 day−1, while the effect of water flowing over the glass cover was 13.37%, being 25% higher than without PCM and nanoparticles, respectively. The enhanced performance of the solar still was investigated using Fourier analysis with harmonics from 6 to −6, revealing good agreement with the observations, validating the theoretical and experimental analysis of the system.

Enhancement of single solar still integrated with solar dishes: An experimental approach

The current experimental work targets to progress in the daily production of fresh water of a single solar still. Two identical solar parabolic dishes were equipped with two conical tanks were integrated with a single solar still and four modules of PV with total power output 1000 W. Each PV module is about 1650 mm × 992 mm × 46 mm dimensions. The proposed system was constructed and tested for three months under the weather conditions of Ismailia, Egypt. The area ratio of the receiver to the absorber is 100. The solar parabolic dish is of 2000 mm diameter. The modified system is used to increase the water basin temperature during the sunrise period. The basin water is recirculated to the cone tanks and sprayed in the solar still to increase the evaporation rate. The proposed system is controlled with a control unit which receives the input signals from various sensors and operates the output. The effect of basin water depths is studied at two values 10 and 20 mm. The experimental results were conducted in three cases that represent the conventional solar still, one solar parabolic dish, and two solar parabolic dishes. The experimental results showed that, the daily distillate productivity in case of one solar dish is 8.8 and 5.45 kg/day at the two water depths 10 and 20 mm, respectively. The usage of the two solar dishes integrates with the solar still increase the daily productivity to reach 13.63 and 7.69 kg/day at the two water depths 10 and 20 mm respectively.

Comparative Experimental Study Between Conventional Stepped Solar Still and an Active Stepped Solar Still Incorporated with a Water Circulation System

In the following experimental study modifications were carried out into a stepped solar still, considerably increasing the distilled water productivity. Objective function in present study is the comparison between of an active stepped solar still provided with modifications in a new water cooling circulation depending upon an active mode by means of a PV cell incorporated for a stepped solar still, with a conventional solar still without water circulation. In the study the results of glass cover temperature, basin temperature, and fresh water productivity are collected for both stepped solar stills. Also, the solar radiation rate for a period of June 2018 to November 2018 have been carried out in order to optimize the stepped still performance and its yield as well. It was found that, these additions and modifications highly enhance the evaporation and condensation, so distillate yield was augmented. It was found that, daily distilled water productivity reached about 7.21 l/m2 day for the stepped solar still with water circulation. While corresponding value was 4.45 l/m2 day for the conventional stepped solar still at the same water depth (2) cm at summer times and 6.41 l/m2 day for the stepped solar still with water circulation and 3.5 l/m2 day for the conventional stepped solar still at winter times also at the same water depth. The increase in daily distillate water productivity for a stepped solar still with a PV and water circulation is about 78.24 % higher than that of a conventional stepped solar still. Moreover, the average efficiency of daily freshwater productivity is 42.84 % for a stepped solar still with water circulation, while it was 37 % for a conventional stepped solar still, at the same water depth 2 cm at summer and 40.5 % for a stepped solar still with water circulation and 34 % for a conventional stepped solar still at winter times. The present study held under the climate conditions of Egypt at Faculty of Engineering-Tanta University, Egypt.

Performance of a pyramid solar still with stepped trays: Experimental approach

The present experimental work aims to enhance the daily productivity of solar stills. A stepped pyramidal still with three trays was fabricated and tested under Tanta conditions, Egypt in September 2016. The still was tested with the brine feed being uninterrupted in one experiment, and with intermittent brine supply in another experiment. For continuous brine supply, the accumulated distillate was 4.95 L. For intermittent brine supply, the accumulated distillate was 4.6 L. Per unit total area, the average daily distillate water productivity is 5.5 and 5.11 L/m2 for the continuous and the intermittent feed stills, respectively. In the two ways, the still yielded a greater productivity than that of conventional pyramid solar still which is 4.4 L/m2 .

Analyzing the effect of an enlarged flat plate reflector (FPR) on a vertical multiple-effect diffusion solar still’s (VMEDS) performance

The vertical multiple-effect diffusion solar still (VMEDS) has a great design advantage in that the narrow gaps between partitions allow it to stand tall and be space-efficient. Unfortunately, VMEDS require additional equipment for absorbing sufficient solar energy. One with the simplest configurations is the flat plate reflector (FPR) which is essentially a fixed angle mirror. However, previous studies have pointed out that the direction of VMEDS with FPR needs to be adjusted relative to the sun’s position once a day. To eliminate this troublesome rotation of VMEDS, as well as to compensate for the decrease of daily distillate productivity ∑md,total caused by fixing VMEDS, a VMEDS with an enlarged FPR is introduced. Also, a new graphical model -- to calculate reflected radiation from FPR and absorbed on VMEDS for the case that width of FPR is not equal to that of VMEDS -- is introduced. The results show that the ∑md,total of the fixed VMEDS with an enlarged FPR area is less than that of a rotated VMEDS whose FPR area is equal to VMEDS. However, ∑md,total can be increased by enlarging FPR for fixed VMEDS, making it a better choice to eliminate the troublesome rotation of VMEDS with FPR.

Determination of optimal inclination function for external reflector of basin type still for maximum distillate productivity

Abstract A basin type solar still design problem is examined in the present work and the Levenberg-Marquardt Method is utilized to estimate the optimal inclination function for external reflector to obtain maximum daily distillate productivity. The design algorithm is to estimate the optimal design variables of inclination function for external reflector. Four different designs for time-dependent inclined angle of external reflector from vertical will be considered in the present study, and the resultant daily amount of distillate of the solar still for each design will be examined. Results indicate that using case 1 design the daily amount of distillate of the still would be about 27.8% greater than that with the vertical external reflector, and about 2.38 times as large as that of the still without the reflectors on a winter solstice day. The daily amount of distillate with case 2 design would be about 1.72% greater than that with case 1 design on a winter solstice day and the productivity of distillate is almost the same for case 2, case 3 and case 4 designs. The fact indicates that case 2 design should be recommended for use to produce the distillate of the solar still.

Energy-environment-economic investigations on evacuated active multiple stage series flow solar distillation unit for potable water production

Multi stage solar distillation units are well known for their higher distillate productivity and are capable of fulfilling the potable water requirements of families in remote, rural, and coastal regions. In this article, active multiple stage series flow solar distillation unit has been proposed for desalting saline water and its performance, environmental benefits and economic feasibility were assessed by carrying out 3E (Energy-Environment-Economic) analyses using the developed mathematical model. Better performance was observed for the distillation unit with five distillation stages, two solar collectors connected in parallel configuration and saline water mass flow rate of 135.0kg/d and 75.0kg/d, during summer and winter seasons. Low-pressure operation in combination with evaporative cooling of condenser of last stage has enhanced the annual average daily distillate productivity from 12.60kg/d to 48.80kg/d. Distillate production was found to drop from 48.80kg/d to 38.90kg/d with the increase in salt concentration of saline water from 0wt% to 10wt%. Energy payback time of the unit desalting saline water with 5wt% salt concentration was within 1.0yr and the unit can mitigate nearly 221.80 tons of CO2 emission, 1594.73kg of SO2 emission and 651.37kg of NO emission from Indian coal based power plants during its 20yrs lifespan under 250 clear day operation. Increased salt concentration in saline water reduces the emission mitigation potential and increases the energy payback time of the proposed distillation unit. Distillate production cost was increased by 16.0% for every 5wt% increase in salt concentration. Amount invested in the unit can be regained with in 3.56yr irrespective of interest rate for distilled water selling price of 0.06USD/L (Rs. 3.91/L).

Assessing the performance of solar thermal driven membrane distillation for seawater desalination by computer simulation

A computer model was developed to simulate the performance of an integrated solar thermal driven direct contact membrane distillation (DCMD) system for seawater desalination using recorded weather data. The results highlight the importance of simulating the DCMD process together with the energy source. Indeed, when considered in isolation from the thermal energy source, increasing water cross flow velocities in the feed and distillate channels results in an increase in water flux and thermal efficiency of the DCMD module. By contrast, when coupling the DCMD module with the solar thermal collector, increasing water cross flow velocities reduces both the process water flux and thermal efficiency. This is because of the limited supply of solar thermal at any given time, and hence the feed temperature decreases when cross flow velocities increase. Thus, any benefits in the reduction of temperature polarisation due to increasing cross flow velocities are overwhelmed by the effects of feed temperature decrease on water flux and thermal efficiency. Results from our simulation also demonstrate the viability of the solar thermal driven DCMD process for small-scale seawater desalination applications. Distillate production is dependent on the availability of solar radiation during the day; nevertheless, a small system with a 7.2m2 spiral-wound DCMD module and a 22.6m2 flat plate solar thermal collector can produce over 140kg of distillate each day under real weather conditions. This is equivalent to a daily distillate production rate of 19.7kg per m2 of membrane or 6.3kg per m2 of solar thermal collector.

Theoretical analysis of a vertical multiple-effect diffusion solar still coupled with a tilted wick still

In this study, a combination of vertical multiple-effect diffusion solar still and tilted wick still is proposed and theoretically analyzed. The vertical multiple-effect diffusion still consists of a double glass cover and a number of vertical and parallel partitions in contact with saline-soaked wicks with narrow air gaps between the partitions. The moisture-rich layers of air in the tilted wick still and the multiple-effect still are connected so that the vapor evaporated from the wick of the tilted wick still can be transported to the humid air layer between the inner glass cover and the first partition of the multiple-effect still by natural convection. The latent heat of condensation of the vapor on the front surface of the first partition can be utilized as an added heat source for the multiple-effect still. It was found that solar energy utilized in the multiple-effect still would be adequate year-round. The total daily distillate production was predicted to be about 19.2, 16.0 and 15.9kg/m2day on the spring equinox and summer and winter solstices, respectively, when the diffusion gaps between partitions is 5mm and the number of partitions is 10.

Simulation study of a capillary film solar still coupled with a conventional solar still in south Algeria

This work presents a numerical simulation of capillary film solar still (distiller) coupled in series with another conventional solar still. Different transfer phenomena of heat and mass are considered to evaluate the daily distillate production. The study takes into account the quality of brackish water with moderate salinity in Adrar city (south of Algeria). The performance of the system is evaluated and compared with that of conventional solar still under the same meteorological conditions. A numerical simulation is carried out to appreciate the developed model and to optimize the relationship between both distillers collecting surfaces. The obtained results show that the system daily production is at 54–83% higher than that of the conventional one. In addition, some parameters influences are studied to define the optimal operating conditions for the present system. For the first solar still, the inclination angle and surfaces ratio have a significant effect on distillate production. Brine flow rate and wind speed have slight effect on still production.

Theoretical estimation of the optimum glass cover water film cooling parameters combinations of a stepped solar still

In the present work, theoretical performance evaluation of a stepped solar still using water film cooling over the glass cover is investigated. The effect of film cooling thickness, flow rate, inlet temperature, and air wind speed on the stepped solar still daily productivity is studied. To increase the performance of the stepped solar still outlet water film cooling is recycled as a makeup water. It was found that film cooling thickness, volumetric flow rate, and water film inlet temperature have a significant effect on the daily distillate productivity. The presence of the glass cover water film cooling may increase the stepped still daily productivity by about 8.2% but the value of this percentage mainly depends on the combinations of film cooling parameters. On the other hand, the presence of the film cooling neutralized the effect of air wind speed on the still distillate productivity. Moreover, it was found that the proper combinations of film cooling parameters have a great influence on stepped still productivity and the best combination was: film thickness from 2.5 × 10−4 to 5.5 × 10−4 m, cooling water volumetric flow rate from 4 × 10−5 to 8.5 × 10−5 m3/s, and glass cover length from 2 to 2.8 m. Finally a good agreement between the present theoretical work and previous experimental result has been obtained.

Water Distillation Using Solar Energy System with Lauric Acid as Storage Medium

An experimental investigation on a solar still with lauric acid as phase change material (PCM) is carried out to examine the effect of both the mass of PCM and basin water on the daily distillate productivity and efficiency of the system under outdoor condition. Basic energy balance equations are written to predict the water and glass temperatures, daily distillate productivity and instantaneous efficiency of the single slope solar distillation system with PCM. It is found that the higher mass of PCM with lower mass of water in solar still basin significantly increases the daily productivity and the efficiency. Therefore, the distillate productivity at night and on day for solar still with PCM increased by 127% and 30-35% respectively than without PCM one. Shukla et al. approach of the use of inner glass cover temperature for productivity prediction which has also been investigated, and the prediction shows relatively better agreement with the experimental data than outer glass cover temperature.

Optimizing the operating parameters of a solar desalination plant

A simulation program developed for predicting the performance of solar desalination plants was used to optimize the operating conditions of the solar plant at Abu Dhabi. The program was validated against actual operating results from the plant and agreement was satisfactory even under unsettled weather conditions. This program was used to optimize three major operating parameters that affect the performance and distillate output, namely, the collector area in service, the high-temperature collector setpoint, and the heating water flow rate. Typical weather conditions for Abu Dhabi have been used as input to the simulation program. A number of computer runs were made using values for the operating parameters that may easily be achieved at the plant by simply changing the setpoints or adjusting a manual valve. The aim of this work is to look for the optimum values for the operating parameters that result in maximizing the evaporator distillate production for every month of the year. The maximum daily distillate production corresponding to the optimum operating parameters was found to be 120 m 3/day (full load) for eight months of the year, namely, February, March, April, May, June, August, September, and October. The production level during the other months is somewhat lower, reaching its lowest value of 90 m 3/day in December.

Thermal modelling of high temperature distillation

This communication presents a comparative study of a single basin solar still under various modes of operation. A simple transient analysis of all the modes under the same meteorological conditions has been presented. The water depth in the solar still and the absorptivity of the basin liner along with the water flow over the glass cover of the still has been found to affect the daily distillate production of the system considerably. The thermosyphon mode enhances the daily distillate production. It has also been observed that the evaporative heat transfer coefficient is a very strong function of temperature.