scholarly journals Heat transfer coefficients and productivity of a single slope single basin solar still in Indian climatic condition: Experimental and theoretical comparison

2017 ◽  
Vol 3 (4) ◽  
pp. 466-482 ◽  
Author(s):  
Abhay Agrawal ◽  
R.S. Rana ◽  
Pankaj K. Srivastava
Keyword(s):  
Heat Transfer ◽  
Climatic Condition ◽  
Solar Still ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Theoretical Comparison ◽  
Indian Climatic ◽  
Indian Climatic Condition

Influence of fully submerged permanent magnets in the evaluation of heat transfer and performance analysis of single slope glass solar still

2021 ◽  
pp. 095765092110310
Author(s):  
Ajay Kumar Kaviti ◽  
Akkala Siva Ram ◽  
Amit Kumar Thakur
Keyword(s):  
Heat Transfer ◽  
Permanent Magnets ◽  
Outer Diameter ◽  
Solar Still ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Inner Diameter ◽  
Evaporative Heat Transfer ◽  
And Performance ◽  
Depth Water

In this experimental study, permanent magnets with three different sizes (M-1: 32 mm inner diameter, 70 mm outer diameter and 15 mm thick, M-2: 25 mm inner diameter, 60 mm outer diameter and 10 mm thick, M-3: 22 mm inner diameter, 45 mm outer diameter and 9 mm thick) are fully submerged in the single-slope glass solar still. The performance of magnetic solar stills (MSS) with three different sizes at 2 cm depth water to ensure that magnets are fully submerged is compared with conventional solar still (CSS) at the location 17.3850°N, 78.4867°E. Tiwari model is adapted to calculate the heat transfer coefficients (HTC), internal and exergy efficiencies. MSS with M-1, M-2 and M-3 significantly enhanced the convective, radiative, and evaporative heat transfer rate for the 2 cm depth of water. This is due to the desired magnetic treatment of water, which reduces the surface tension and increases the hydrogen bonds. The MSS's total internal HTC, instantaneous efficiencies led CSS by 25.52%, 28.8%, respectively, with M-1. Having various magnetic fields due to different magnets sizes increases MSS's exergetic efficiency by 33.61% with M-1, 33.76% with M-2, and 42.25% with M-3. Cumulative yield output for MSS with M-1, M-2, and M-3 is 21.66%, 17.64%, 15.78% higher than CSS. The use of permanent magnets of different sizes in the MSS is a viable, economical and straight forward technique to enhance productivity.

Calculation of Hourly Output of a Solar Still

1993 ◽  
Vol 115 (4) ◽  
pp. 231-236 ◽  
Author(s):  
V. B. Sharma ◽  
S. C. Mullick
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Heat Balance ◽  
Solar Still ◽  
Balance Equations ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Hourly Output ◽  
The Heat Balance

An approximate method for calculation of the hourly output of a solar still over a 24-hour cycle has been studied. The hourly performance of a solar still is predicted given the values of the insolation, ambient temperature, wind heat-transfer coefficient, water depth, and the heat-transfer coefficient through base and sides. The proposed method does not require graphical constructions and does not assume constant heat-transfer coefficients as in the previous methods. The possibility of using the values of the heat-transfer coefficients for the preceding time interval in the heat balance equations is examined. In fact, two variants of the basic method of calculation are examined. The hourly rate of evaporation is obtained. The results are compared to those obtained by numerical solution of the complete set of heat balance equations. The errors from the approximate method in prediction of the 24-hour output are within ±1.5 percent of the values from the numerical solution using the heat balance equations. The range of variables covered is 5 to 15 cms in water depth, 0 to 3 W/m2K in a heat-transfer coefficient through base and sides, and 5 to 40 W/m2K in a wind heat-transfer coefficient.

scholarly journals Analytical thermal modeling of double slope solar still by using inner glass cover temperature

2008 ◽  
Vol 12 (3) ◽  
pp. 139-152 ◽  
Author(s):  
Kumar Shukla ◽  
Ajeet Rai
Keyword(s):  
Internal Heat ◽  
Climatic Conditions ◽  
Solar Still ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Glass Cover ◽  
Solar Distillation ◽  
Indian Climatic ◽  
C And N ◽  
Internal Heat Transfer

In this paper, expressions for water and glass temperatures, hourly yield and instantaneous efficiency for double slope solar distillation systems have been derived analytically. The analysis is based on the basic energy balance for the systems. A thermal model has been developed to predict the performance of the still based on both, the inner and the outer glass temperatures of the solar still. In the present work two sets of values of C and n of internal heat and mass transfer coefficients, obtained from the experimental data under Indian climatic conditions, have been used. It is concluded that (1) there is a significant effect of operating temperature range on the internal heat transfer coefficients and (2) by considering the inner glass cover temperature there is reasonable agreement between the experimental and predicted theoretical results.

Estimation of Heat-Transfer Coefficients, the Upward Heat Flow, and Evaporation in a Solar Still

1991 ◽  
Vol 113 (1) ◽  
pp. 36-41 ◽  
Author(s):  
V. B. Sharma ◽  
S. C. Mullick
Keyword(s):  
Heat Transfer ◽  
Heat Flow ◽  
Empirical Relation ◽  
Absolute Error ◽  
Solar Still ◽  
Transfer Coefficients ◽  
Maximum Absolute Error ◽  
Heat Transfer Coefficients ◽  
Glass Cover ◽  
The Heat Balance

The present work enables prediction of the performance of a solar still through simple calculations. Estimation of the temperature of the glass cover by an empirical relation developed in this work permits calculation of the heat-transfer coefficients, the upward heat flow, and evaporation. Since some of the heat-transfer coefficients vary substantially and nonlinearly with temperature, the empirical relation developed for glass cover temperature is based on an approximate solution of the heat balance equation. Hence, the overall upward heat flow factor is obtained with a maximum absolute error of three percent compared to the value obtained through a numerical solution of the heat balance equation along with the relations for vapor pressure and latent heat. The fraction of upward heat flow utilized for evaporation is determined with a maximum absolute error of 0.5 percent. The range of variables covered is 30°C to 80°C in water temperature, 5W/m2K to 40W/m2K in wind heat-transfer coefficient, and 5°C to 40°C in ambient temperature.

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