A practical comparative study of the performance of a single siope solar still with a new design

doi:10.21203/rs.3.rs-4373323/v1

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A practical comparative study of the performance of a single siope solar still with a new design

https://doi.org/10.21203/rs.3.rs-4373323/v1

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Water distillation systems using free solar energy are known to be easy to install, low-cost, and environmentally friendly. However, due to the low productivity of fresh water for solar stills of all types, many practical and theoretical studies have been presented to enhance the productivity of solar stills using different engineering designs and improvement techniques. The overall productivity of the model is affected by several factors, the most important of which are the design, the nature of operating conditions, and environmental conditions. The current study aims to determine the effect of changing the geometric shape of the absorber plate on the cumulative productivity of a single-slope-single-basin solar still. A single-slope solar still with a different design and a specially shaped absorption basin was studied, and the proposed model was compared with the traditional model for the same manufacturing specifications and under the same test conditions. The traditional square shape has been modified so that it begins with a three-sided polygon and ends with an arc, while maintaining the same total area of the absorption plate. In this modification, the shadow areas are reduced and the solar radiation generated on the base is blocked by the walls, in addition to benefiting from using the back wall to act as a reflective arch for solar radiation. The new design, with and without an internal reflector, is examined and compared with the traditional model under the weather conditions of the Iraqi city of Najaf. Using the new-design solar still increased daily productivity by about 47.96%, while the cost will decrease to about $0.023 per liter/0.25 m².

Single slope solar still

New design absorption basin

Desalination

Reflectors

Renewable energy

The water problem has emerged as one of the most significant issues facing humanity as a result of the phenomena of global warming, ice melting, and desertification that is becoming more and more prevalent in many parts of the world. These factors, along with the high cost of fossil fuels, inadequate infrastructure, growing population, and other factors, have caused a shortage of drinking water supplies for many people worldwide [1][2]. The desalination process requires the use of an energy source that heats water to vaporize it and then condenses that vapor to create healthy water. Given the high costs of using fossil fuels, in addition to the fact that they do not directly cause environmental pollution, other technologies and other energy sources must be used, such as the use of solar energy that is freely and safely available [3][4]. Desalination methods can be divided into two categories: Membrane technologiesinclude reverse osmosis and electrolysis desalination[5][6]. The other type is called flash desalination or phase change processes[7], desalination via boiling [8], vapour compression[9], freezing distillation[10], humidification dehumidification desalination[11], Integrating the distillation device with a primary water heating device [12] [13], Store heat using phase-change materials such as paraffin wax[14]. Solar distillation devices can be divided into two groups, negative and positive, according to the way each works, provided that the positive one is connected to or dependent on an external power source [15] [16]. In the case of positive distillation solar stills, external equipment is used, such as primary heaters, pumps, fans, vibration generators, etc.[17] [18]. In simple terms, the solar radiation falling on the absorption plate of the distillation device increases the temperature of the plate and thus heats the water in contact with it until it evaporates. Then the steam is condensed on a transparent upper layer to produce drinking water. In this way, healthy, fresh water free of salts is produced. And dust, metals, and other pollutants [19] [20]. Due to the limited overall yields of distilled water from solar distillation plants, there have been many studies that have attempted to enhance the overall productivity by controlling the basic design or operating parameters to obtain the best production without adding additional components or other costs. One of the criteria that had a clear impact on the volume of production without adding other components was changing the design or geometric shape of the distillation device. Practical and experimental studies were conducted to determine the effect of the geometric shape of the device on the evaporative mass and the amount of total production. Solar stills are designed in cylindrical [21], spherical[22], prismatic [23], semi-tubular [24], and multi-slope shapes[25], in addition to the traditional shape [26]. The current study describes the possibility of designing and implementing a single-slope solar still with a different geometric shape to ensure reduced cost, increased efficiency, and ease of installation and use.

2.1 Installation and manufacturing solar still

The single-slope solar still is designed with a different geometry, keeping in mind cost stability compared to the conventional model, i.e., without changing the absorption area and without using additional expensive materials. Figure 1 shows a realistic drawing and a detailed diagram of the model used in the practical experiment. The base was designed to be made of a 1 mm thick iron plate painted matte black with a new and different geometric shape in terms of design and geometric dimensions, as shown in Fig. 2, where the front edge was formed in the form of an open polygon with three sides to ensure the benefit of incident solar radiation from any direction while reducing shadow areas resulting from the use of right-angled sides. The arc-shaped back is also designed to install an indoor solar inverter. The black iron base, with a total area of 0.25 square meters, is inserted into a high-pressure cork structure that has the same shape as the base. This structure has walls and a base thickness of 6 cm; the height of its small front facade is 10 cm; and its inclination angle is 32.1 degrees. A PVC freshwater collection tube with a diameter of 2.5 cm is installed at the end of the low edge of the glass, adjacent to the face of the frame, which is directly connected to the product collection flask. As for the back wall of the structure, reflective aluminum foil is installed on it to direct and increase the intensity of solar radiation on the absorption panel. A 4 mm-thick transparent glass sheet with an inclination angle of 32.1° is glued to the open top face of the cork body using transparent thermal silicone glue. The salty well water is introduced into the black absorption basin using a clear plastic pipe connected directly to a side distribution tank equipped with a mechanical float, ensuring that the water level in the black basin is 1 cm. The black tank is cleaned of salt and dust periodically by pumping and withdrawing water through the salt water entry port. This new model was designed from very cheap materials and is easy to install and use, allowing it to be manufactured and used at home and in remote and agricultural areas. A practical test comparison was carried out to show the productivity of the newly designed solar still with a conventional solar still with a base length of 0.5 m and made of exactly the same materials as shown in Fig. 3.

2.2 Test procedure

A practical comparative study was conducted between the newly designed solar still and the traditional solar still on April 13, 2024, under the climatic conditions of the city of Najaf in Iraq, from eight in the morning until ten at night. The following is the parameters recorded every hour:

Temperatures for : Glass Cover(1), Water basin(2), Basin plate(3), Steam (4) and Ambient (5).

Wind speed and Solar radiation.

Hourly Productivity and cumulative yield.

Type K thermocouples were installed inside the model to measure various temperatures and outside the model to measure the ambient air temperature. These thermocouples are connected to an HTI (HT-9815) four-channel digital temperature reader (6). The intensity of solar radiation was measured using the Metravi 207 device (7). While air speed was measured using a GM816 Proster digital anemometer,(8) as show in Fig. 4.

The comparative experimental test was carried out on April 13, 2024, in the Iraqi city of Najaf, under the local climate. Figure 5 displays the air temperature, solar radiation, and wind speed data that varies during the time of the experiment. Figure 5-a shows the gradual increase in solar radiation intensity and air temperature starting at 7 am until the intensity of solar radiation reaches its highest value at 12 pm, which is estimated at about 981 watts/m2, then gradually decreases until it reaches its lowest value at the end of sunrise at 18:30, while the maximum temperature is approximately 36°C. While the wind speed fluctuated significantly over time, with its maximum value estimated at about 13.5 m/s at 7 a.m., as shown in Fig. 5-B,.

Through Fig. 6, we notice the change in temperature of the absorption plate, the salt water layer, and the glass cover layer with time for both modern and traditional models because they are affected by the nature of environmental conditions such as air temperature, the amount of incident solar radiation, and wind speed.

Figure 6 shows an increase in the temperature of the water layer as a result of an increase in the temperature of the black absorption layer in contact with it, which is very close to its temperature. From the results, the maximum temperature was 77.8°C and 61.3°C for the new and conventional still, respectively, and the results showed that the new design of the distillation device had a positive effect on raising the temperature of the water layer for two basic reasons: The first is choosing the polygonal shape face for the device, which reduced the amount of shadow generated on the dark base. As for the other and more important reason, it is to exploit the curved back side to paste internal reflective aluminum foil on it, which works to increase the concentration of solar radiation on the dark base, which leads to an increase in its temperature and thus an increase in the temperature of the turbid water layer.

It is noted that increasing the value of incoming solar radiation passing through the glass layer, then the water layer, and reaching the black absorption plate leads to an increase in the temperature of the absorption plate. Through conduction, the temperature of the water layer gradually rises due to its direct contact with the dark absorption plate, which leads to the formation of a mass of vapor, and then the formed vapor rises to the top due to its light weight. The temperature difference between the resulting mass of steam and the upper glass surface causes the steam to adapt at the glass layer, then the condensed steam slides down the inclined part of the glass and collects in the collection channel connected to the outer part of the device, where it is transferred via a hose to the included collection bottle.

Figure 7 shows that the productivity of the new and traditional models reaches its maximum value of about 135 and 102ml/0.25m².hr respectively, affected by the high turbid water temperature at 1pm.

The difference in temperature rise of the absorbing plate and the turbid water layer of the new-designed solar still compared to the traditional solar still appears clearly from 9 a.m. to 4 p.m. This occurs as a result of reducing the blocking of solar radiation by the walls of the device and increasing the intensity of the radiation exploited from the base as a result of using the reflector, which leads to increased production of the new model.

The cumulative production of yields reached approximately 907 ml/0.25 m².hr and 613 ml/0.25 m².hr for the two rigs with the new design and the traditional solar still, respectively. The percentage increase in productivity for the new model was about 47.96% compared to the traditional model.

The total cost of manufacturing solar still ( C ) is calculated from the following equation[27] [28]:

$$C=Fixed Cost\left(F\right)+Variable Cost\left(V\right)$$

$$\text{V}=\text{n}\times 0.2\times \text{F}$$

Where;

$$n= The expected lifespan of the solar unit is approximately 10 years.$$

The total cost of the solar still is calculated using the data shown in Table 1, as the flowing:

$$C=21+\left(10\times 0.2\times 21\right)=63\$$$

The total daily yield of the new-design solar still was approximately 907 ml/0.25 m². If we assume that the total working days of the device per year are 300 days, this means that the total production rate of the device during its life span (10 years) will be 2721 L/0.25m² .

From here, the total cost of producing one liter of fresh water can be calculated as follows:

63/2721 = 0.023$\$$ for each L//0.25m².

Table 1

Materials and their costs to manufacture the new-design solar still.
No.	Material type	Specifications	Cost ($\varvec{\$}$)
1	Cork structure.	0.1m³	6.5
2	Glass cover with a 4mm thick.	0.33m²	3
3	Basin made of iron plate 0.1mm thick.	0.2916m²	7
4	Strips of aluminum foil, 0.2 mm thick	0.4m²	0.5
5	Heat-resistant matte black dye.	1 spray piece.	1
6	Heat-resistant silicone adhesive.	1 piece.	1
7	Plastic collection and connection pipes.	3 pieces.	2
	Total Cost .		21

1- The increase in the temperature of turbid water is the result of an increase in the value of the intensity of solar radiation falling on the absorption plate, so that it can be noted that the maximum value of the temperature of turbid water reaches 77.8 C. after 12 p.m., and the value of solar radiation is close to its maximum value, which is 981 w/m².

2- The new design of the solar still reduces the blocking of incoming solar radiation as a result of the use of the polygonal shape design at the front of the solar still. The use of a solar reflector installed on the inner rear surface also increases the concentration of solar radiation on the base and returns the direction of solar radiation on the black plate at sunrise and sunset.

3- The daily productivity of the new-design solar still was about 907ml/0.25m², while the daily productivity of the traditional solar still was about 613 ml/0.25m², meaning that the new design increased the productivity of the solar still by about 47.96% compared to the traditional model.

4- By calculating the production cost, it was found that using the new-design solar still reduced the total cost per liter of fresh water to about $0.023 per liter/0.25 m² compared to the traditional distillation device that uses $0.0385 to product each liter/0.25m² of fresh water.

Author Contribution

All figures Muntadher mohammed aliall write muntadher, hassanian and asssad

Hameed H, Diabil H, Saeed M (2021) Performance of a new model of air heating system: experimental investigation. J Mech Eng Res Dev 44:420–432
Samimi M, Moghadam H (2024) Investigation of structural parameters for inclined weir-type solar stills. Renew Sustain Energy Rev 190:113969
Essa FA (2024) Aspects of energy, exergy, economy, and environment for performance evaluation of modified spherical solar still with rotating ball and phase change material. J Energy Storage 81:110500
Noman S, Manokar AM (2024) Experimental investigation of pistachio shell powder (bio-waste) to augment the performance of tubular solar still: Energy, exergy, and environmental analysis. Desalination 576:117317
Harby K et al (2024) Reverse osmosis hybridization with other desalination techniques: An overview and opportunities. Desalination, p. 117600
Kabir MM et al (2024) Electrodialysis desalination, resource and energy recovery from water industries for a circular economy. Desalination 569:117041
Xu B, Zhao X, Zuo X, Yang H (2024) Progress of phase change materials in solar water desalination system: A review. Sol Energy Mater Sol Cells 271:112874
Iskander J, Shihimi O, Mahallawy NE, Abd-Elhady MS (2024) Water desalination using PV panels based on boiling and evaporation. Discov Water 4(1):3
Shahzamanian B, Varga S, Soares J, Palmero-Marrero AI, Oliveira AC (2024) Theoretical performance assessment of a multi-effect distillation system integrated with thermal vapour compression unit running on solar energy. Int J Low-Carbon Technol 19:908–921
Tang X, Jia S, Tang W, Wang J, Gong J (2024) Highly efficient freezing desalination technology: Parameters optimization and model configuration. Desalination 576:117331
Alsaman AS, Ghazy M, Ali ES, Askalany AA, Farid AM, Tawfik MHM (2024) Solar-powered adsorption desalination utilizing composite silica gel with a humidification-dehumidification desalination system. Desalination, p. 117663
Dongare SD, Somani SK, Patil HS (2024) Implementation and Analysis of Novel Standalone Compact Solar Still Using Heat Augmentation Techniques Integration. Nat Camp 28(1):2173–2184
Abdullah AS, Alawee WH, Mohammed SA, Majdi A, Omara ZM, Younes MM (2023) Utilizing a single slope solar still with copper heating coil, external condenser, phase change material, along with internal and external reflectors—experimental study. J Energy Storage 63:106899
Saeed MMA, Hachim DM, Hameed HG (2019) Numerical investigation for single slope solar still performance with optimal amount of nano-PCM. J Adv Res Fluid Mech Therm Sci 63(2):302–316
Lin Y-C, Wyżga P, Macyk J, Macyk W, Guzik MN (2024) Solar-driven (photo) electrochemical devices for green hydrogen production and storage: Working principles and design. J Energy Storage 82:110484
Amiri H (2024) Development and application of a thermal model for the improved stepped solar still with a built-in passive condenser. Sol Energy 270:112378
Chaichan MT, Kazem HA, Al-Waeli AHA, Elawee WH, Fayad MA, Sopian K (2024) Advanced techniques for enhancing solar distiller productivity: a review. Energy Sources Part Recover Util Environ Eff 46(1):736–772
Maurya A, Kumar R, Gupta A, Ahmadi MH, Al-Bahrani M (2024) Energy, exergy, economic, exergoeconomic, exergoenvironment, and enviroeconomic (6E) analysis of solar stills—A critical review. Energy Sci Eng 12(1):267–283
Sathyamurthy R et al (2024) Enhancing solar still thermal performance: The role of surface coating and thermal energy storage in repurposed soda cans. J Energy Storage 77:109807
Davra D, Mehta P, Patel N, Markam B (2024) Solar-enhanced freshwater generation in arid coastal environments: A double basin stepped solar still with vertical wick assistance study in northern Gujarat. Sol Energy 268:112297
Sharma P, Birla SK (2024) Improving solar still efficiency with nanoparticles–Infused copper cylinders and latent heat storage: An experimental and simulation study. Appl Therm Eng, p. 122650
Essa FA (2024) Innovative integration: Enhancing solar distillation efficiency with modified spherical solar stills. Desalination 576:117388
Bait O (2024) A critical review on triangular pyramid, weir–type, spherical, and hemispherical solar water distiller conceptions. Sol Energy 269:112322
Sharon H, Srinivas Reddy K (2024) Multi-effect Tubular Solar Thermal Desalination Systems. in Solar Thermal Desalination Technologies for Potable Water: Exploring Viable Options for Reliable and Sustainable Water Production. Springer, pp 185–202
Isah AS, Bint Takaijudin H, Singh BSM, Abimbola TO, Muhammad MM, Sani SB (2024) Photovoltaic-integrated advancements for sustainable water production: Developing and evaluating an enhanced hybrid solar desalination system. Desalination, p. 117453
Omara ZM, Alawee WH, Basem A, Al-Bayati ADJ (2024) Heat loss reduction techniques for walls in solar stills: A review. Results Eng, p. 101996
Anika UA, Kibria MG, Kanka SD, Mohtasim MS, Paul UK, Das BK (2024) Exergy, exergo-economic, environmental and sustainability analysis of pyramid solar still integrated hybrid nano-PCM, black sand, and sponge. Sol Energy 274:112559
Noman S, Kabeel AE, Manokar AM (2024) Performance improvement of tubular solar still with pistachios shell materials: Energy, exergy, economic, and sustainability analysis. J Energy Storage 78:110132

No competing interests reported.

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A practical comparative study of the performance of a single siope solar still with a new design

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Version 1

Abstract

Figures

1. Introduction

2. Experimental Methodology

2.1 Installation and manufacturing solar still

2.2 Test procedure

3. Results and discussion

4. Calculated cost of productivity

5. Conclusion

Declarations

Author Contribution

References

Additional Declarations

Status:

Version 1