Comparative Experimental Analysis of Temperature Distribution in Mini Size Permeable and Non-Permeable Varying Salt Density Solar Pond

Ecological concerns have prompted the utilization of energy from the sun, which is increasingly plenteous and appropriate. It can utilize and store all the while during the daytime. Sunlight based lakes are one of the notable warmth stockpiling frameworks, which aggregate warm vitality utilizing sun oriented radiation. A solar pond is a very large, controllable body that contains water that can absorb and store solar energy. They never use tracking systems such as mirrors, nor do they concentrate the solar radiation as in many other sun’s energy technologies. There are two types of convective solar ponds one is the shallow solar pond and the deep saltless pond. Salinity gradient solar pond, membrane solar pond, and polymer gel layers solar pond are the major types of non-convective solar ponds.

The movement of heat energy can be characterized as the development or move of thermal energy starting with one thing then onto the next thing which at various temperatures. The heat is moved typically moved from an object of very high temperature to an object of very low temperature. The transfer of heat for the most part delivers a few changes in the inner vitality of both the frameworks which are associated with heat move. This is as indicated by the first law of thermodynamics.

Basically, there are three kinds of heat transfer namely conduction, convection, and radiation.

Conduction is one of the methods of heat transfer it is of by implies that the heat transfer happens because of the atomic commotion inside material with no movement of the material fully. For instance, on the off chance that one finish of a metal pole is at a higher temperature, at that point. the heat transfer will be moved to the opposite finish of the pole which is colder end because the particles move with higher speed and will crash into the slower ones with a complete exchange of energy to the slower ones.

Convection is one the mode of heat transfer occurs by the movement of any fluid (a liquid or a gas) between the objects or places of different temperature. It also can be termed as the bulk movement of liquid due to the density differences in the liquid. Generally, the warm air is less thick than the cold air, thus within the sight of a temperature angle convection flows can shape. Convection is of two types namely natural convection and forced convection. Natural convection is produced in the fluid when the currents are produced by the density differences which are temperature-derived. Forced convection is termed when the external factor such as a pump or fan induces convection currents. The rate of convection is directly proportional to the movement of the fluid.

Radiation is characterized as the exchange of heat from a body in high temperature to a body in a lower temperature, when bodies are not in direct physical contact with one another or when they are isolated in space, is called heat radiation.

Varying salt density solar ponds are one of the various sorts of solar ponds, which can be shaped by applying various kinds of salts. Varying salt density comprises of three layers. The main zone is the surface layer with the least salt and thickness, which alludes to the upper convective zone (UCZ). The UCZ is in atmospheric temperature and is the topmost layer in the solar ponds. The density of salt in this layer is very less when compared to other layers. At that point the subsequent zone, which is the center layer, and alludes to the non-convective zone (NCZ). Here, saturation increases by the depth and thickness being greater than UCZ. At last, the lowest layer alludes to the lower convective zone (LCZ), which is in a saturated condition. The Lower Convective Zone is present at the bottom of the solar pond. It has the most noteworthy saltiness among the three layers in the solar pond. The heat energy is stored in this layer. NCZ acts as thermal insulation for the bottom layer and aids in the prevention of heat loss. Despite the entrance of solar radiation into the profundity, it can't escape from the zone. Assari et al. [1], examined tentatively the exhibition of mixed medium in the lower convection zone of laboratory-scale solar pond. An expansion of 5.6% in temperature appears in the blended medium sun oriented lake. What's more, the variety of the most extreme temperature of the blended medium lake was not exactly the customary LCZ sun oriented lake. Progressively warm dependability and lower temperature drop are gotten by utilizing a blended medium in the LCZ. Additionally, the utilization of blended medium demonstrated higher warm obstruction and more stockpiling limit concerning the pond.

Hill and Carr [2], researched the straight insecurity of a sunlight-based lake containing permeable material in the lower convective zone (LCZ). It is discovered that, when all is said in done, sun oriented lakes that contain permeable material are progressively steady for truly sensible qualities.

Shi et al. [3] studied the impacts of permeable media on warm and salt dispersion of the solar ponds. It is shown that the heat insulation effect is enhanced by the expansion of permeable media to the base of a sun-based lake.

Silva and Almanza [4] researched the physical, substance, and water-powered properties of various soils tried mostly as compacted dirt liners. Because of the wide varieties in the materials utilized for sun-powered lake lining, studies ought to be routed to portray they're drawn-out exhibition within the sight of sweltering saline solutions.

Velmurugan et al. [5], tried the exhibition of balance type single bowl sunlight based still when it is altered with dark elastic, wipe, and sand, and the ventured sun oriented despite everything was changed with balance, rock, and wipe. The most extreme profitability of 100% was acquired when the blade type ventured sun based was incorporated with rock and wipe.

Wang et al. [6], studied the temperature improvement of including coal soot at the base of SGSP has been tentatively and hypothetically. The outcomes show that contrasted with the conventional base treatment the expansion of coal soot at the base of SGSP prompts a higher LCZ temperature.

Wang et al. [7], studied the impact of the porosity permeable material on the saltiness dissemination under the consistent Lower Convective Zone (LCZ) temperature is tentatively by including permeable material. It tends to be derived that the impact of the permeable medium on salt dispersion will be likewise affected by the expansion of the temperature.

Assari et al. [8], studied the presentation of including stage change material (PCM) to little saltiness inclination sun-powered lake tentatively. Contrasting tentatively the sun-powered lake and without PCM, the most extreme normal temperature for the lake without PCM was higher than the lake with PCM.

Sarathkumar et al. [9], studied the execution of Al₂O₃ nanoparticles are included with PCM in the sun oriented lake. For the manufactured pilot sun-powered lake, the warmth balance investigation was controlled by performing heat move examination. It was discovered that the greatest measure of accessible helpful warmth vitality is 167 W.

Agha [10], talked about the improvement of the size of the lake and the number of stages for three diverse stockpiling zone temperatures taking into accounts the enormous variety in the middle of summer and winter. He finished up the outcome is that prompting some dismissal of the warmth gathered throughout the mid-year will bring about a higher usage factor of the desalination plant and a decrease in the late spring/winter yield proportion.

Andrews and Akbarzadeh [11], explored with the point of opening the general energy proficiency of collecting sun based radiation, putting away heat, and conveying this heat to an application. It is reasoned that contrasted and the ordinary strategy for heat extraction the warmth extraction from the slope layer can expand the general vitality effectiveness of sun oriented lake conveying heat at a moderately high temperature by up to half, exclusively from the LCZ.

Appadurai and Velmurugan [12], researched the hypothetical execution and test investigation of a traditional sun-powered despite everything, balance type sun based despite everything, balance type sun based lake incorporated with blade type sun oriented still. The water assortment gain for the Fin type little sun-powered lake with customary sunlight based despite everything is 47%, blade type single bowl sun based despite everything is 45.5% and balance type smaller than usual sun based lake coordinated with balance type single bowl sun-powered despite everything is half.

Berkani et al. [13], examined the warm conduct of three test little sun oriented lakes (1 m ×1 m × 1 m). One of the accompanying salts, to be specific Sodium Chloride, Na₂CO₃, and CaCl₂ are contained in every one of the lakes. From the investigation, it is presumed that the lake with CaCl₂ is thermally faster than the two different lakes without arriving at immersion.

Busquets et al. [14], considered the different saltiness inclinations that were performed dependent on the Stability Margin Number (SMN) standard, which is utilized to fulfill the dynamic steadiness measure. Because of convection in the LCZ and mass dissemination, there is an increasing speed of the NCZ. The thickness of the NCZ is significantly influenced as the SMN arrives at 1.5 was the resolution.

El-Sebaii et al. [15], played out the investigative model for the different components of the framework (the lake the still). Up to common estimations of 0.030 m and 0.015 kg/s, there is a lessening in the everyday profitability P_d and effectiveness η_d with expanding the thickness d_w and mass stream rate m˙.

El-Sebaii et al. [16], researched the warm presence of a shallow sun-powered lake (SSP) under the open and shut cycle nonstop stream warming methods of warmth extraction were found hypothetically and tentatively. The day by day efficiencies for shut cycle mode is 59% and open cycle mode is 33%. The STZ temperature can be increased by maintaining stable NCZ [17]. The multi-cell structure in the UCZ and the LCZ, is generated by increasing of the aspect ratio further improves the fluid mixing in these two zones [18].

The temperature at the LCZ is higher in the unburied ponds [19]. The exergetic efficiencies are dependant on the turbidities of the zones [20].

Valderrama et al. [21], conducted an experiment using a salt-gradient solar pond and observed the maximum temperature at the NCZ and 10% of total solar radiation was quantified as heat loss. Goldoust et al. [22], the thermal characteristics of two-phased closed thermosyphon were experimentally studied. The maximum output is achieved for all the filling ratios at 60^°.Alwan et al. [23], experimentally investigated the modified solar still and found that at low relative humidity when the solar irradiance is increased, the productivity of the solar still is in turn increased. La Rocca et al. [24], studied a solar pond for feeding a thermoelectric generator. The combination of SGSP and ORC gave higher efficiencies. Norozi et al. [25], studied the improvement of the solar radiation sing hourly sun-tracking solar still. The efficiency of solar irradiance is increased by 10-15%.

A solar pond is a regular case of such a sort of warm gadget among different existed frameworks. Along these lines, it is critical to look into additional on the impact of this unique condition on solar pond execution. Thus, in the current examination, the temperature gradient, temperature conduct, and execution of permeable and non-permeable solar ponds explored. Two comparable solar ponds secured with meager plastic material with blended medium and regular in the lower convection zone (LCZ) were utilized in the LCZ.

As needs are, the impact of the permeable medium on the productivity of a sun-powered lake was concentrated tentatively. At last, an endeavor was made to get a hypothetical rule for evaluating the viability of utilizing blended mediums.

The total heat storage in the mixed medium solar pond is given as [1].

E_MMSP=E_br+E_gp+E_ws    (5)

Here E_br, E_gp, E_ws are heat storage (kJ) in the brine, granite pieces, and welding spatter.

E_MMSP = C_brm_br∆T+ C_gpm_gp∆T+ C_wsm_ws∆T    (6)

C_br, C_gp, C_ws are heat capacity (kJ/kg ℃) in the brine, granite pieces and welding spatter, respectively and m_br, m_gp, m_ws are mass (kg) in the brine, granite pieces, and welding spatter, respectively, and ∆T is the temperature difference (℃).

$\mathrm{E}_{\mathrm{MMGP}}=\mathrm{V} \Delta \mathrm{T}\left[(1-\mathrm{x}-\mathrm{y}) \mathrm{C}_{\mathrm{br}} \rho_{\mathrm{br}}+\mathrm{x} \mathrm{C}_{\mathrm{pb}} \rho_{\mathrm{pb}} \mid+\mathrm{yC}_{\mathrm{bb}} \rho_{\mathrm{bb}}\right]$    (7)

$E_{M M S P}=V \Delta T(\rho C)_{b r}\left[(1-x-y)+x \frac{C_{p b}}{C_{b r}} \frac{\rho_{p b}}{\rho_{b r}}+y \frac{C_{b b}}{C_{b r}} \frac{\rho_{b b}}{\rho_{b r}}\right]$    (8)

$\beta_{\mathrm{elk}}=\left[\left(1-\frac{\mathrm{C}_{\mathrm{pb}}}{\mathrm{C}_{\mathrm{br}}} \frac{\rho_{\mathrm{pb}}}{\rho_{\mathrm{br}}}\right)+\mathrm{a}\left(1-\frac{\mathrm{C}_{\mathrm{bb}}}{\mathrm{C}_{\mathrm{br}}} \frac{\rho_{\mathrm{bb}}}{\rho_{\mathrm{br}}}\right)\right]$    (9)

Here, $\beta_{\text {elk }}$  is a criterion parameter to indicate which permeable material is optimal for saving energy and to use economically. Significantly, $\beta_{\text {elk }}$ is used to call this criterion. Even though more energy will be stored by increasing the depth of LCZ, the depth of LCZ in MMSP is restricted from the economical point of view caused by the cost of salt, etc. Hence, it can be adequate to utilize low-cost permeable medium with $\beta_{\text {elk }}$≤ 0.

There is a plentiful measure of solar radiation in the southern district of India. So, it is right to store solar energy in this area. Also, it is of less windy area, so it is a much-suited place to perform this experiment. The southern region of India is located in the tropical region of the Earth were a large amount of solar radiation. In this study, two comparable solar ponds with a similar cross-segment and amount of water with the permeable medium in one solar pond and another non-permeable solar pond are explored tentatively. The conveyance of temperature, temperature contrast, and salt gradient, on the activity of changing salt thickness solar ponds, is incorporated for a time of 30 days. To indicate the effect of the permeable medium in storing the heat energy, dimensionless numbers are used. A criterion parameter was given to for showing which permeable material is appropriate for saving energy. From the literature survey, it is known that more amount of energy will be stored by increasing the depth of LCZ. Perfect suitable permeable material is chosen after laboratory testing was conducted. Also, from the economic point of view the permeable materials were chosen.

More amount of energy can be stored with increased depth in the LCZ, but considering the economic point of view that might be caused due to the cost of salt the depth of the LCZ is limited.

Hence it is better to use the cheaper mixed medium solar pond. The temperatures at the lower convective zones are 42.30℃ and 40.60℃ in the solar ponds with permeable medium and non- permeable solar pond respectively.

Thus, the temperature obtained from the permeable medium solar pond is higher than the non-permeable solar pond. Therefore, the solar pond with a permeable medium indicated an increase of 4.18% in temperature.

The results obtained in this experiment were similar to the previous work did by other researchers [1]. The mixed medium solar pond indicated an increase of 5.6% in temperature due to a very large volume of the solar pond it shows a higher increase in temperature.

Due to the usage of more amount of thermal insulation materials, the variation of temperature (1.7℃) in the solar ponds indicated that these variations are less compared to the ambient temperature values.

It is better to use a solar pond $\beta_{\text {elk }}$≤0 to reduce the economic cost.

Also, it was found that the dust accumulation over the glass plate on the solar pond has some negative effects on storing thermal energy. The contrast between the measures of heat transfer is 4.54 kJ.

Henceforth the solar ponds with the permeable medium are favored the best to use.