Performance correlation for single-basin double-slope solar still

Kandasamy et al. International Journal of Energy and Environmental Engineering 2013, 4:4 http://www.journal-ijeee.com/content/4/1/4 ORIGINAL RESEARCH Open Access Performance correlation for single-basin double-slope solar still Shanmugasundaram Kandasamy*, Manikandan Vellingiri, Shanmugan Sengottain and Janarthanan Balasundaram Abstract In this study, an attempt has been made to develop a new correlation for the productivity of a single-basin double-slope solar still using experimental results obtained for different brine depths (0.01, 0.02, 0.03, 0.04, 0.05, and 0.06 m) in the basin in Coimbatore, Tamilnadu, India. The proposed correlation has been validated with the experimental results for one of the typical days in Coimbatore, Tamilnadu, India. A concluding correlation has been developed by including the results mentioned in the literature regarding double-slope solar still alone and the proposed correlation. The concluding correlation is compared with the correlation developed by the researcher based on the results in the literature regarding both single- and double-slope solar stills. The results indicate that the correlation coefficient R2 is slightly higher as compared with that of previous results obtained for both single- and double-slope single-basin solar stills. Keywords: Distillation, Single-basin solar still, Brine water depths, Correlation Background Water is very much essential for human beings. Supplying drinkable water is one of the major problems in developing countries. A solar still is a simple device which is used in converting brackish/saline water into potable/drinkable water. Many researchers have found the productivity for different brine depths in the basin of a single-slope singlebasin solar still [1-15]. Further attempts have been made by researchers to investigate the effect of water depth in double-slope singlebasin solar still. A digital simulation method has been done for the productivity of a complicated still by Cooper [16], and the influence of more common variables such as water depth, wind velocity, still insulation, double glass cover, cover slope, and daily variability on the productivity has been investigated. Results of the simulation indicate that water depth and thermal insulation have little effect on the productivity at shallow water depth and that a double glass cover and high cover slopes are not justifiable. Garg and Mann [17] have investigated the effect of climatic, operational, and design parameters for singleand double-slope solar stills under the Indian arid zone regions and to find the effect of all possible variables on the performance of the single-effect solar still. Akash et al. [18] have studied the basin-type solar still under local climatic conditions and concluded that lower water depth and salinity of the brine produced higher distillate yields for the double-slope passive solar still. The effect of wind speed on daily productivity of some active and passive solar stills using computer simulation for different solar still designs has been studied by El-Sebaii [19]. It has been shown that for the active and multi-effective passive stills, daily productivity increases with the increase of wind velocity up to a typical velocity; beyond that, the productivity becomes insignificant for single-effect passive stills. AlHinani et al. [20] have studied the effect of climatic, design, and operational parameters such as solar intensity, wind velocity, ambient temperature, glass cover slope angle, feedwater temperature water depth on the basin, and basin material on the distillate output of the basintype solar still. They found that the 23° cover tilt angle, 0.1-m insulation thickness, and asphalt coating of solar still of the shallow water basin are the optimum parameters for producing higher yields. Al-Hayeka and Badran [21] have found the productivity of freshwater of two different designs of stills, which are asymmetric greenhouse with mirror and symmetric greenhouse solar stills, under * Correspondence: Department of Physics, Karpagam University, Coimbatore, Tamilnadu 641 021, India © 2013 Kandasamy et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Kandasamy et al. International Journal of Energy and Environmental Engineering 2013, 4:4 http://www.journal-ijeee.com/content/4/1/4 52 48 Ambient temperature (ºC) the climatic conditions of Jordan. It was inferred that the distilled water output of the asymmetric greenhouse type was 20% higher than that of the symmetric greenhouse type. Mowla and Karimi [22] have simulated a mathematical model for a solar still; the rate of production of freshwater has been calculated, and experiments have been carried out in Shiraz. It has been found that the experimental and calculated results are in good agreement. The effect of water depth on the transient performance of a double-basin solar still has been investigated by Tiwari and Tiwari [23]. Siddiqui and Bajpai [24] have made an attempt to develop a correlation between the thickness of dust collected and the difference in efficiencies for all seasons in Lucknow, India. The equation derived is very good for the measurement of correlation with experimental results for all the months. Pragya et al. [25] have made an attempt to investigate the advantages of a two-layer solar panel for the enhancement of solar energy absorption. Results have shown an increase of 70% in the output. Hitesh and Shah [26] have aimed to evaluate the effect of various energyabsorbing plates in solar still to increase the daily distillate Page 2 of 6 44 40 36 Ta-10.4.2012(1cm) Ta-12.4.2012(3cm) Ta-18.4.2012(5cm) 32 Ta-11.4.2012(2cm) Ta-17.4.2012(4cm) Ta-19.4.2012(6cm) 28 8 10 12 14 Time of the day (hrs) 16 18 Figure 2 Variation of ambient temperature for experimental days with different brine depths. yield. It has been concluded that the utilization of aluminium floating plate has a significant impact on the productivity of the still. The main objective of this work is to propose a correlation to find the productivity of the still based on the experimental results for different brine depth in the basin of the double-slope solar still. Experimental studies were carried out to validate the developed correlation. The correlation has been compared with the correlation developed by Khalifa and Hamood [27]. The decrease in productivity depends on the design parameter, location, and range of depth of brine water in the basin. Moreover, the existing models lack the inclusion of factors influencing the working of the still. These inconveniences paved the way for the present investigation to propose a correlation for a double-slope singlebasin solar still alone. 1400 1300 Slar radi (...truncated)