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Performance evaluation of active solar distiller (double slope) in usual transmission method
Materials Today: Proceedings xxx (xxxx) xxx
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Performance evaluation of active solar distiller (double slope) in usual transmission method V.S. Gupta a, V.K. Dwivedi a, Preeti Gupta b, Ragini Singh a, Manohar Singh a a b
Galgotias College of Engineering and Technology, Greater Noida, India Inderprastha Engineering College, Ghaziabad, India
a r t i c l e
i n f o
Article history: Received 2 November 2019 Received in revised form 3 December 2019 Accepted 5 December 2019 Available online xxxx Keywords: Solar distillation Solar distiller unit Single slope Double slope
a b s t r a c t In this research paper design, fabrication and the performance evaluation of Double Slope Active Solar Distiller Unit under usual transmission method has been discussed for water purification. Extensive amount of research has been conducted for 24 h at the water depths of 0.01, 0.02, 0.03 m in various months of a year for this solar distiller unit. The performance of double slope active solar still has been compared with the performance of single and double slope passive solar still at the same water depth in the basin. It was observed that the double slope active solar still under natural mode produces approximately 614 kg of water per year which is almost 1.5 times higher than double slope passive solar still. Ó 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Mechanical and Energy Technologies.
1. Introduction History of solar distillation is very old. Della Porta used wide earthen pots, which were exposed to the intense heat of solar radiation to evaporate water and collect the condensate into vessels, placed underneath. Aristotle in fourth century B.C. invented a method to evaporate impure water and then condense it for potable use. Wilson, in 1872 was the first who designed conventional solar still for supplying fresh water to a nitrate mining community in Chile, which become quite popular and was in operation for more than 40 years. Various scientists and researchers have worked in the field of solar distillation to enhance its productivity). The total internal heat transfer coefficient is given by convective heat transfer coefficients from water surface to inner glass cover (hcwg ) which has been derived by Dunkle [4]. Malik et al. [7]analyzed solar distiller unit (passive). Study of active and passive solar stills till done by Tiwari [8]. A novelistic mathematical model to study the performance of a passive solar distiller unit (double slope) by taking the effect of heat capacity of condensing covers and insulation at bottom was carried out by Eduardo Rubio et al. [9].The performance and thermal modeling of passive solar distiller unit (single slope) condensing covers at different inclined position was carried out by Tiwari and Tiwari [10]. Dwivedi et al. (2008) proposed analysis of energy and exergy
of passive solar distiller unit (single slope) and passive solar distiller (double slope) based on yearly experimental statistics for 0.01, 0.02 and 0.03 m water depth. The performance of basin type solar distiller incorporated with FPC (flat plate collector) was investigated by Soliman [24]. Tripathi et al. (2005) carried out researches to examine the consequence of depth water on mass transfer and internal heat for solar distiller unit (active). A theoretical research was carried out by Tiwari and Tiwari [10] by incorporating solar distiller unit (active) combined with concentrating collector, Flat Plate Collector (FPC), evacuated tube collector with a heat pipe and without high temperature pipe. Many researchers reported that the solar distiller unit (passive) working process is slow for refinement of salty water. There are many choices for refinement of saline water like solar distiller incorporated with parabolic concentrator, plastic condensing covers, Evacuated Tube Collector and Flat Plate Collectors etc. that have been employed by numerous researchers to improve the day-to-day profit. Flat Plat Collector (FPC) is popular out of the possibilities. It is because of a simple design and not as much of maintenance cost required as in others. Tiwari and Tiwari [10] have studied the comparative thermal performance evaluation of an active solar distillation system. Literature review carried out by several researchers between year in 2006–2015 have been reviewed by Tiwari et al (2015). Sahota et al. [1] did a rigorous review on the energy economic analysis of both active as well as passive solar distillation system. Gupta et al. [2] and Singh et al. (2017) studied the active solar
E-mail address: [email protected] (P. Gupta) https://doi.org/10.1016/j.matpr.2019.12.052 2214-7853/Ó 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Mechanical and Energy Technologies.
Please cite this article as: V. S. Gupta, V. K. Dwivedi, P. Gupta et al., Performance evaluation of active solar distiller (double slope) in usual transmission method, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.052
2
V.S. Gupta et al. / Materials Today: Proceedings xxx (xxxx) xxx
distiller system by using photovoltaic thermal-compound parabolic concentrator collectors and they found that yield was more and also they developed a characteristic equation.
2. Active solar distiller unit (double slope) design and fabrication under usual transmission mode In Active Solar Distiller Unit (Double Slope), the Passive Solar Distiller Unit (Double Slope) is incorporated with FPC (Flat Plate Collector), the hot water from collecting plate come into the sink of solar distiller unit under usual transmission method. The incoming and outgoing water flow to the collecting plate comes from the bottommost of the sink as shown in Fig. 1. A gate valve has been
provided in the inlet pipe to control the circulation of water through the collector plate. When, the gate valve will be closed, the solar still will work under passive mode and with the gate valve opened, it will work as active solar still. The collector plate absorbs the solar energy and transfers that energy to water flowing through tubes (Fig. 2). In above Fig. 1 Active Solar Distiller (Double Slope) was placed in the direction East-West and collecting plate was placed at an angle of 30° fronting South direction to receive the maximum radiation from sun. Given below Table 1 shows the magnitudes of active solar distiller (double slope) (Fig. 3). The copper tube-aluminum absorber type collector plate has been used in double slope active solar still. An Aluminum sheet which is painted with black color acts as a gripping plate to engross
Fig. 1. Active Solar Distiller (Double Slope) under usual transmissionmethod.
Fig. 2. Various water depth (0.01, 0.02 and 0.03 m) for twelve months with respect to solar intensity(W/m2) has been for single slope Distiller.
Please cite this article as: V. S. Gupta, V. K. Dwivedi, P. Gupta et al., Performance evaluation of active solar distiller (double slope) in usual transmission method, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.052
V.S. Gupta et al. / Materials Today: Proceedings xxx (xxxx) xxx
3.3. Measurement of solar radiation
Table 1 Dimensions of Active Solar Distiller (Double Slope). Constraints Area of basin Height of basin Area of condensing cover Thickness of condensing cover Angle of condensing cover Thickness of insulation
3
Double Slope 2
2.0 m 0.22 m, at sides, 0.48 m, at center 1.03 1.06 m2 0.004 m 15o 0.006 m
large amount of solar radiation. Glass of 4 cm thickness had been used over collector body. A Collecting plate comprises of 10 risers of copper element and is fixed with 2 headers. The distance between two copper tubes is 12 cm. The absorber plates made of aluminum are placed closely with the tubes made up of copper element. 3. Instrumentation 3.1 Temperature measurement Thermocouples made of Copper-constantan were used to measure the temperature of water and condensing cover. Digital temperature indicators were used to record the temperature accurately. Initially, the thermocouples are prepared by soldering the junctions of two dissimilar metals (copper and constantan). When the two ends of thermocouple wires are kept at different temperatures, electromagnetic force is generated, which is proportional to the temperature difference of two ends of thermocouple. The hot junction of thermocouple is kept in contact with the medium where temperature is to be measured and other end is connected to digital temperature indicator. In the experiment thermocouples are adjusted using typical thermometer. The surrounding heat present in the air is recorded with the help of a standardized instrument indicating temperature (mercury thermometer) having smallest count of 1 °C. The thermometer was hung at the height of solar still in a shaded post to ensure the accurate reading. 3.2. Measurement of distillate yield The distilled was collected in a flask and is checked by a gauging tube having a least count of 1 ml.
Calibrated Solarimeter was used to measure solar radiation. The least count of solarimeter used was 20 W/m2. The total solar radiation was measured by solarimeter. The diffuse solar radiation was measured by manually providing a shade over its photovoltaic sensor. The solarimeter works on the same principal as of pyranometer. Solar radiation is directly proportional to the current in the solarimeter. The deflection of the needle of solarimeter gives the solar intensity. 4. Experimental procedure The properly standardized thermocouples were fixed at the inner and outer surfaces of condensing covers and inside the water to measure the condensing cover and water temperature. One thermocouple is hung between water and condensing cover to measure vapor temperature. To attain steady state condition, the basin is filled with required quantity of water, one day before the start of experiment. The condensing surfaces are cleaned properly before the start of experiment. Experiments were conducted at the water depth of 0.03 m in the basin of solar still. Experiments are started at 7:00 a.m. in the morning and continued for 24 h. Water temperature, Vapor temperature, Inner and outer condensing cover temperatures, ambient air temperature, solar intensity and distillate yield are measured at an interval of one hour for double slope active solar still. 5. Observations The experiments on active solar distiller unit (double slope) under natural circulation mode were carried out in India” at 28o400 N, 77o250 E, altitude 216 m from mean sea level from January 2016 to June 2016 at the water depth of 3 cm. The observations of experimental data for the system under consideration as a sample are given in Table 2. The results of active solar still have also been compared with single and double slope solar still [12]. The daily yield, average ambient temperature, water temperature and total solar intensity for single and double slope passive solar still for different water depth in various months of a year have been given in Table 3. The details of number of clear days, monthly and annual yield obtained from single and double slope passive solar still with
Fig. 3. Various water depth (0.01, 0.02 and 0.03 m) for twelve months with respect to solar intensity(W/m2) has been for DoubleSlope Distiller.
Please cite this article as: V. S. Gupta, V. K. Dwivedi, P. Gupta et al., Performance evaluation of active solar distiller (double slope) in usual transmission method, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.052
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V.S. Gupta et al. / Materials Today: Proceedings xxx (xxxx) xxx
Table 2 Parameter of Active Solar Still (Double Slope) for a water depth in the sink of 0.03 m in the month of March 11, 2016. Double slope East side
West side
Time Hrs.
Ta. o C
IC W/m2
TcoE o C
TciE o C
Tw o C
ItE W/m2
mwE kg
TcoW o C
TciW o C
ItW W/m2
mwW kg
7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 24:00 1:00 2:00 3:00 4:00 5:00 6:00
18 19 22 23 24 27 28 26 25 25 23 23 22 22 22 21 21 20 20 20 19 19 19 18
0 100 280 360 500 660 660 600 480 260 180 0 0 0 0 0 0 0 0 0 0 0 0 0
21.2 22.4 26.6 33.6 37.8 43.5 49.8 51.3 46.5 41.3 37.8 31.7 28.9 26.6 23.7 23.9 23.4 23.1 22.8 22.4 21.5 21.0 20.8 20.6
21.3 22.7 27.1 34.2 39.1 46.8 51.4 54.6 49.8 45.2 40.6 33.5 29.4 27.1 23.9 23.4 23.5 23.3 23.0 22.8 21.8 20.9 21.0 21.1
21.6 23.3 31.5 37.5 47.9 54.3 59.7 68.9 73.6 66.2 58.2 49.2 41.6 37.2 33.6 31.4 30.1 29.2 28.5 27.7 27.6 27.3 27.0 26.8
0 120 320 400 520 640 600 540 420 300 160 0 0 0 0 0 0 0 0 0 0 0 0 0
0.000 0.016 0.026 0.006 0.104 0.265 0.448 0.470 0.388 0.286 0.175 0.164 0.092 0.068 0.062 0.055 0.048 0.042 0.040 0.033 0.022 0.015 0.013 0.009
21.0 21.9 24.7 30.6 35.7 43.8 50.1 52.3 51.1 49.8 43.3 37.8 34.2 31.2 28.6 26.7 24.8 23.8 23.0 22.2 21.4 21.1 20.8 20.4
21.1 22.2 24.9 31.0 36.2 44.4 50.8 52.4 51.6 50.1 45.4 40.5 36.3 31.9 29.1 27.0 25.3 24.1 23.5 22.9 21.7 22.0 21.1 20.7
0 80 180 240 380 580 640 640 540 360 220 0 0 0 0 0 0 0 0 0 0 0 0 0
0.000 0.018 0.042 0.007 0.118 0.286 0.418 0.455 0.364 0.258 0.163 0.128 0.080 0.062 0.052 0.050 0.046 0.043 0.038 0.034 0.028 0.018 0.012 0.007
Table 3 Passive solar distiller unit (double slope) observations for Average surrounding air temperature, average water temperature, total solar intensity and yield per day for passive solar distiller unit (single and double slope) for different depth of water in various months of a year. Months
November 2015
December 2015
January 2016
February 2016
March 2016
April 2016
May 2016
June 2016
July 2016
August 2016
September 2016
October 2016
Water depth
Ta
Single slope
Meter
o
It W/m2
Tw o C
Mw kg
It W/m2
Tw o C
Mw Kg
0.01 0.02 0.03 0.01 0.02 0.03 0.01 0.02 0.03 0.01 0.02 0.03 0.01 0.02 0.03 0.01 0.02 0.03 0.01 0.02 0.03 0.01 0.02 0.03 0.01 0.02 0.03 0.01 0.02 0.03 0.01 0.02 0.03 0.01 0.02 0.03
20.5 20.0 21.1 18.7 18.2 16.1 10.3 10.7 11.6 10.6 12.2 16.8 20.5 15.9 16.8 22.3 24.6 25.1 27.5 28.4 32.1 31.8 32.3 32.1 31.7 32.3 32.8 27.6 28.2 27.7 36.9 26.7 25.6 25.7 25.4 24.4
400 337 380 345 376 393 340 348 168 280 256 356 400 324 356 467 474 436 498 520 406 527 464 438 478 454 462 521 550 530 521 540 532 383 513 523
30.8 29.2 30.1 27.2 25.8 21.5 15.4 16.1 15.7 13.0 17.8 23.4 28.9 23.6 23.4 33.4 39.4 36.6 38.2 39.2 38.6 36.4 43.8 40.2 44.0 43.0 40.0 36.8 38.8 38.7 35.9 37.6 37.1 35.9 36.3 36.0
1.629 1.419 1.413 1.466 1.403 1.385 1.127 1.089 0.842 1.151 1.073 1.153 1.631 1.490 1.374 2.130 2.077 1.955 2.260 2.218 1.955 2.105 2.080 1.701 2.198 1.876 1.821 1.894 1.863 1.734 1.884 1.922 1.757 1.793 1.866 1.659
314 266 295 253 279 278 224 246 124 196 187 249 314 239 249 404 402 370 459 473 377 447 465 419 536 473 460 466 442 461 448 439 508 425 427 314
27.6 27.3 28.0 24.2 24.3 21.5 16.4 16.1 14.2 15.4 16.6 22.2 27.6 22.0 22.2 33.0 35.6 38.0 39.0 40.5 44.0 35.6 44.1 42.9 44.8 44.4 43.0 36.3 36.8 36.5 35.1 35.4 35.1 33.9 34.1 34.0
1.44 1.28 1.22 1.15 1.14 1.08 0.88 0.88 0.65 0.94 0.83 1.05 1.34 1.27 1.24 2.06 2.01 1.83 2.27 2.23 2.02 2.20 2.09 1.64 2.20 1.89 1.86 1.90 1.90 1.65 1.74 1.59 1.57 1.59 1.50 1.48
C
Double slope
Please cite this article as: V. S. Gupta, V. K. Dwivedi, P. Gupta et al., Performance evaluation of active solar distiller (double slope) in usual transmission method, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.052
5
V.S. Gupta et al. / Materials Today: Proceedings xxx (xxxx) xxx Table 4 Output on monthly and yearly basis obtained from passive solar distiller unit (single and double slope) using various water depths have tabulated below. Months
Number of clear days (N)
Monthly output for various water depths = Daily output number of clear days Solar Distiller Unit (Single Slope)
October 2015 November 2015 December 2015 January 2016 February 2016 March 2016 April 2016 May 2016 June 20,016 July 20,016 August 20,016 Sept 2016 Total
24 30 22 22 24 28 29 30 26 16 12 16 279
Solar Distiller Unit (Double Slope)
0.01 m kg/m2
0.02 m kg/m2
0.03 m kg/m2
0.01 m kg/m2
0.02 m kg/m2
0.03 m kg/m2
39.10 43.98 24.79 25.32 39.14 59.64 65.54 63.15 57.15 30.30 22.61 28.69 499.41
34.06 42.09 23.96 23.61 35.76 58.16 64.32 62.40 48.78 29.81 23.06 29.86 475.85
33.91 41.58 18.52 25.37 32.95 54.74 56.70 51.03 47.35 27.74 21.08 26.54 437.52
34.50 34.43 19.46 20.57 32.05 57.68 65.93 66.08 57.29 30.45 20.88 25.37 464.68
30.72 34.20 19.36 18.26 30.48 56.28 64.70 62.73 49.09 30.35 19.02 23.97 439.16
29.28 32.43 14.30 23.19 29.76 51.16 58.55 49.20 48.31 26.46 18.78 23.71 405.13
different water depths have been given in Table 4. The month of April observed the highest output among the monthly observed yield at the water depth of 0.01 m. It is because of the huge figure of clear days whereas the monthly output is lowest in the month of August due to lower number of clear days. It is also clear that the yields obtained from double slope solar still are higher only in summer months (April to July) in comparison to the yield from single slope solar still. The overall annual yield from single slope passive solar still is higher in comparison to the yield obtained from double slope passive solar still. The annual yield from single slope solar still at the water depth of 0.01 m is 4.95% and 14.14% higher in comparison with yield at 0.02 m and 0.03 m water depth respectively whereas the annual yield from double slope solar still at the water depth of 0.01 m is 5.81 and 14.69% higher in comparison with yield at 0.02 and 0.03 m water depth respectively. The Passive solar distiller unit (double slope) for a particular day in the month of March 2016 produces yield 1.838 kg per meter square while Active solar distiller unit (double slope) under usual method yields 2.791 kg per meter square which is fifty one percent more than the Passive solar distiller unit (double slope). For the better understanding of the data given in the Table 3 a graph comparing various water depth of 0.01, 0.02 and 0.03 m for twelve months and solar radiation (W/m2) has been drawn below. 6. Conclusion It has been concluded that output for active solar distiller unit (double slope) under usual method generates 51% more yield when compared with the passive solar distiller unit (double slope). The output on daily basis of passive solar distiller unit (double slope) for a specific day in the month of March 2016 was found 1.838 kg per meter square whereas the output on daily basis of active solar distiller unit (double slope) under usual circulation method was found 2.791 kg per meter square. References [1] L. Sahota, G.N. Tiwari, Review on the energy and economic efficiencies of passive and active solar distillation systems, Desalination (2017), 401151–179. [2] V.S. Gupta, DeshBandhu Singh, R.K. Mishra, Sanjeev Kumar Sharma, G.N. Tiwari, Development of characteristic equations for PVT-CPC active solar distillation system Desalination, Elsevier 266–279 (2018) 445. [4] R.V. Dunkle, Solar water distillation, the roof type solar still and a multi effect diffusion still, International developments in heat transfer, A.S.M.E, Proceedings of International Heat transfer, University of Colorado, 1961, 5895-902.
[7] M.A.S. Malik, G.N. Tiwari, A. Kumar, M.S. Sodha, Solar distillation, Pregamon Press, Istedn. UK, 1982. [8] G.N. Tiwari, Recent advances in solar distillation. Contemporary Physics-Solar Energy and Energy Conservation, Wiley Eastern Ltd, New Delhi, India, 1992, Chapter II. [9] Eduardo Rubio, José L. Fernández, Miguel A. Porta-Gándara, Modeling thermal asymmetries in double slope solar stills, Renew. Energy 29 (6) (2004) 895–906. [10] A.K. Tiwari, G.N. Tiwari, Annual performance analysis and thermal modeling of passive solar still for different inclination of condensing cover, IJER 31 (14) (2007) 1358–1382. [12] V.K. Dwivedi, G.N. Tiwari, Energy and exergy analysis of single and double slope passive solar still, Trend. Appl. Sci. Res. 3 (3) (2008) 225–241. [24] H.S. Soliman, Solar Still Coupled with a Solar Water Heater, Mosul University, Mosul, Iraq, 1976.
Further reading [3] D.B. Singh, G.N. Tiwari, Exergoeconomic, enviroeconomic and productivity analyses of basin type solar stills by incorporating N identical PVT compound parabolicconcentrator collectors: a comparative study, Energy Convers. Manage. 135 (2017) 129–147. [5] Z.S. Abdel-Rehim, A. Lasheen, Experimental and theoretical study of a solar desalination system located in Cairo, Egypt, Desalination 217 (2007) 52–64. [6] S.D. Hendrie, Evaluation of combined photovoltaic/thermal collectors, In: Proceedings of international conference ISES, vol. 3. Atlanta, GA, USA, pp. 1865–1869, 1979. [11] H.S. Aybar, Mathematical modeling of an inclined solar water distillation system, Desalination 190 (2006) 63–70. [13] D. Atheaya, A. Tiwari, G.N. Tiwari, I.M. Al-Helal, Analytical characteristic equation for partially covered photovoltaic thermal (PVT) - compound parabolic concentrator (CPC), Sol. Energy 111 (2015) 176–185. [14] A.A. Badran, A.A. Al-Hallaq, I.A. Eyal Salman, M.Z. Odat, A solar still augmented with a flat-plate collector, Desalination 172 (2005) 227–234. [15] F. Calise, M.D. d’Accadia, A. Piacentino, A novel solar trigeneration system integrating PVT (photovoltaic/thermal collectors) and SW (seawater) desalination: dynamic simulation and economic assessment’, Energy 67 (2014) 129–148. [16] S. Dubey, G.S. Sandhu, G.N. Tiwari, Analytical expression for electrical efficiency of PVT hybrid air collector, Appl. Energy 86 (5) (2009) 697–705. [17] M.A. Eltawil, Z.M. Omara, Enhancing the solar still performance using solar photovoltaic, flat plate collector and hot air, Desalination 349 (2014) 1–9. [18] D.L. Evans, Simplified method for predicting PV array output. Solar Energy 27, 555–560. In: Schott, T., (Ed.) (1985), Operational temperatures of PV modules, In: Proceedings of 6th PVSolar Energy Conference, 1981, pp. 392–396. [19] M.K. Gaur, G.N. Tiwari, Optimization of number of collectors for integrated PV/ T hybrid active solar still, Appl. Energy 87 (2010) 1763–1772. [20] J.A. Eibling, S.G. Talbert, G.O.G. Lof, Solar stills for community use- digest of technology, Solar Energy 13 (1971) 263–276. [21] S.S. Park, N.J. Kim, A study on the characteristics of carbon nanofluid for heat transfer enhancement of heat pipe, Renew. Energy 65 (2014) 123–129. [22] T.P. Otanicar, P.E. Phelan, J.S. Golden, Optical properties of liquids for direct absorption solar thermal energy systems, Solar Energy 83 (2009) 969–977. [23] O.A. Hamadou, K. Abdellatif, modeling an active solar still for sea water desalination process optimization, Desalination 354 (2014) 1–8.
Please cite this article as: V. S. Gupta, V. K. Dwivedi, P. Gupta et al., Performance evaluation of active solar distiller (double slope) in usual transmission method, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.052
Contents lists available at ScienceDirect
Materials Today: Proceedings journal homepage: www.elsevier.com/locate/matpr
Performance evaluation of active solar distiller (double slope) in usual transmission method V.S. Gupta a, V.K. Dwivedi a, Preeti Gupta b, Ragini Singh a, Manohar Singh a a b
Galgotias College of Engineering and Technology, Greater Noida, India Inderprastha Engineering College, Ghaziabad, India
a r t i c l e
i n f o
Article history: Received 2 November 2019 Received in revised form 3 December 2019 Accepted 5 December 2019 Available online xxxx Keywords: Solar distillation Solar distiller unit Single slope Double slope
a b s t r a c t In this research paper design, fabrication and the performance evaluation of Double Slope Active Solar Distiller Unit under usual transmission method has been discussed for water purification. Extensive amount of research has been conducted for 24 h at the water depths of 0.01, 0.02, 0.03 m in various months of a year for this solar distiller unit. The performance of double slope active solar still has been compared with the performance of single and double slope passive solar still at the same water depth in the basin. It was observed that the double slope active solar still under natural mode produces approximately 614 kg of water per year which is almost 1.5 times higher than double slope passive solar still. Ó 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Mechanical and Energy Technologies.
1. Introduction History of solar distillation is very old. Della Porta used wide earthen pots, which were exposed to the intense heat of solar radiation to evaporate water and collect the condensate into vessels, placed underneath. Aristotle in fourth century B.C. invented a method to evaporate impure water and then condense it for potable use. Wilson, in 1872 was the first who designed conventional solar still for supplying fresh water to a nitrate mining community in Chile, which become quite popular and was in operation for more than 40 years. Various scientists and researchers have worked in the field of solar distillation to enhance its productivity). The total internal heat transfer coefficient is given by convective heat transfer coefficients from water surface to inner glass cover (hcwg ) which has been derived by Dunkle [4]. Malik et al. [7]analyzed solar distiller unit (passive). Study of active and passive solar stills till done by Tiwari [8]. A novelistic mathematical model to study the performance of a passive solar distiller unit (double slope) by taking the effect of heat capacity of condensing covers and insulation at bottom was carried out by Eduardo Rubio et al. [9].The performance and thermal modeling of passive solar distiller unit (single slope) condensing covers at different inclined position was carried out by Tiwari and Tiwari [10]. Dwivedi et al. (2008) proposed analysis of energy and exergy
of passive solar distiller unit (single slope) and passive solar distiller (double slope) based on yearly experimental statistics for 0.01, 0.02 and 0.03 m water depth. The performance of basin type solar distiller incorporated with FPC (flat plate collector) was investigated by Soliman [24]. Tripathi et al. (2005) carried out researches to examine the consequence of depth water on mass transfer and internal heat for solar distiller unit (active). A theoretical research was carried out by Tiwari and Tiwari [10] by incorporating solar distiller unit (active) combined with concentrating collector, Flat Plate Collector (FPC), evacuated tube collector with a heat pipe and without high temperature pipe. Many researchers reported that the solar distiller unit (passive) working process is slow for refinement of salty water. There are many choices for refinement of saline water like solar distiller incorporated with parabolic concentrator, plastic condensing covers, Evacuated Tube Collector and Flat Plate Collectors etc. that have been employed by numerous researchers to improve the day-to-day profit. Flat Plat Collector (FPC) is popular out of the possibilities. It is because of a simple design and not as much of maintenance cost required as in others. Tiwari and Tiwari [10] have studied the comparative thermal performance evaluation of an active solar distillation system. Literature review carried out by several researchers between year in 2006–2015 have been reviewed by Tiwari et al (2015). Sahota et al. [1] did a rigorous review on the energy economic analysis of both active as well as passive solar distillation system. Gupta et al. [2] and Singh et al. (2017) studied the active solar
E-mail address: [email protected] (P. Gupta) https://doi.org/10.1016/j.matpr.2019.12.052 2214-7853/Ó 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Mechanical and Energy Technologies.
Please cite this article as: V. S. Gupta, V. K. Dwivedi, P. Gupta et al., Performance evaluation of active solar distiller (double slope) in usual transmission method, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.052
2
V.S. Gupta et al. / Materials Today: Proceedings xxx (xxxx) xxx
distiller system by using photovoltaic thermal-compound parabolic concentrator collectors and they found that yield was more and also they developed a characteristic equation.
2. Active solar distiller unit (double slope) design and fabrication under usual transmission mode In Active Solar Distiller Unit (Double Slope), the Passive Solar Distiller Unit (Double Slope) is incorporated with FPC (Flat Plate Collector), the hot water from collecting plate come into the sink of solar distiller unit under usual transmission method. The incoming and outgoing water flow to the collecting plate comes from the bottommost of the sink as shown in Fig. 1. A gate valve has been
provided in the inlet pipe to control the circulation of water through the collector plate. When, the gate valve will be closed, the solar still will work under passive mode and with the gate valve opened, it will work as active solar still. The collector plate absorbs the solar energy and transfers that energy to water flowing through tubes (Fig. 2). In above Fig. 1 Active Solar Distiller (Double Slope) was placed in the direction East-West and collecting plate was placed at an angle of 30° fronting South direction to receive the maximum radiation from sun. Given below Table 1 shows the magnitudes of active solar distiller (double slope) (Fig. 3). The copper tube-aluminum absorber type collector plate has been used in double slope active solar still. An Aluminum sheet which is painted with black color acts as a gripping plate to engross
Fig. 1. Active Solar Distiller (Double Slope) under usual transmissionmethod.
Fig. 2. Various water depth (0.01, 0.02 and 0.03 m) for twelve months with respect to solar intensity(W/m2) has been for single slope Distiller.
Please cite this article as: V. S. Gupta, V. K. Dwivedi, P. Gupta et al., Performance evaluation of active solar distiller (double slope) in usual transmission method, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.052
V.S. Gupta et al. / Materials Today: Proceedings xxx (xxxx) xxx
3.3. Measurement of solar radiation
Table 1 Dimensions of Active Solar Distiller (Double Slope). Constraints Area of basin Height of basin Area of condensing cover Thickness of condensing cover Angle of condensing cover Thickness of insulation
3
Double Slope 2
2.0 m 0.22 m, at sides, 0.48 m, at center 1.03 1.06 m2 0.004 m 15o 0.006 m
large amount of solar radiation. Glass of 4 cm thickness had been used over collector body. A Collecting plate comprises of 10 risers of copper element and is fixed with 2 headers. The distance between two copper tubes is 12 cm. The absorber plates made of aluminum are placed closely with the tubes made up of copper element. 3. Instrumentation 3.1 Temperature measurement Thermocouples made of Copper-constantan were used to measure the temperature of water and condensing cover. Digital temperature indicators were used to record the temperature accurately. Initially, the thermocouples are prepared by soldering the junctions of two dissimilar metals (copper and constantan). When the two ends of thermocouple wires are kept at different temperatures, electromagnetic force is generated, which is proportional to the temperature difference of two ends of thermocouple. The hot junction of thermocouple is kept in contact with the medium where temperature is to be measured and other end is connected to digital temperature indicator. In the experiment thermocouples are adjusted using typical thermometer. The surrounding heat present in the air is recorded with the help of a standardized instrument indicating temperature (mercury thermometer) having smallest count of 1 °C. The thermometer was hung at the height of solar still in a shaded post to ensure the accurate reading. 3.2. Measurement of distillate yield The distilled was collected in a flask and is checked by a gauging tube having a least count of 1 ml.
Calibrated Solarimeter was used to measure solar radiation. The least count of solarimeter used was 20 W/m2. The total solar radiation was measured by solarimeter. The diffuse solar radiation was measured by manually providing a shade over its photovoltaic sensor. The solarimeter works on the same principal as of pyranometer. Solar radiation is directly proportional to the current in the solarimeter. The deflection of the needle of solarimeter gives the solar intensity. 4. Experimental procedure The properly standardized thermocouples were fixed at the inner and outer surfaces of condensing covers and inside the water to measure the condensing cover and water temperature. One thermocouple is hung between water and condensing cover to measure vapor temperature. To attain steady state condition, the basin is filled with required quantity of water, one day before the start of experiment. The condensing surfaces are cleaned properly before the start of experiment. Experiments were conducted at the water depth of 0.03 m in the basin of solar still. Experiments are started at 7:00 a.m. in the morning and continued for 24 h. Water temperature, Vapor temperature, Inner and outer condensing cover temperatures, ambient air temperature, solar intensity and distillate yield are measured at an interval of one hour for double slope active solar still. 5. Observations The experiments on active solar distiller unit (double slope) under natural circulation mode were carried out in India” at 28o400 N, 77o250 E, altitude 216 m from mean sea level from January 2016 to June 2016 at the water depth of 3 cm. The observations of experimental data for the system under consideration as a sample are given in Table 2. The results of active solar still have also been compared with single and double slope solar still [12]. The daily yield, average ambient temperature, water temperature and total solar intensity for single and double slope passive solar still for different water depth in various months of a year have been given in Table 3. The details of number of clear days, monthly and annual yield obtained from single and double slope passive solar still with
Fig. 3. Various water depth (0.01, 0.02 and 0.03 m) for twelve months with respect to solar intensity(W/m2) has been for DoubleSlope Distiller.
Please cite this article as: V. S. Gupta, V. K. Dwivedi, P. Gupta et al., Performance evaluation of active solar distiller (double slope) in usual transmission method, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.052
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Table 2 Parameter of Active Solar Still (Double Slope) for a water depth in the sink of 0.03 m in the month of March 11, 2016. Double slope East side
West side
Time Hrs.
Ta. o C
IC W/m2
TcoE o C
TciE o C
Tw o C
ItE W/m2
mwE kg
TcoW o C
TciW o C
ItW W/m2
mwW kg
7:00 8:00 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18:00 19:00 20:00 21:00 22:00 23:00 24:00 1:00 2:00 3:00 4:00 5:00 6:00
18 19 22 23 24 27 28 26 25 25 23 23 22 22 22 21 21 20 20 20 19 19 19 18
0 100 280 360 500 660 660 600 480 260 180 0 0 0 0 0 0 0 0 0 0 0 0 0
21.2 22.4 26.6 33.6 37.8 43.5 49.8 51.3 46.5 41.3 37.8 31.7 28.9 26.6 23.7 23.9 23.4 23.1 22.8 22.4 21.5 21.0 20.8 20.6
21.3 22.7 27.1 34.2 39.1 46.8 51.4 54.6 49.8 45.2 40.6 33.5 29.4 27.1 23.9 23.4 23.5 23.3 23.0 22.8 21.8 20.9 21.0 21.1
21.6 23.3 31.5 37.5 47.9 54.3 59.7 68.9 73.6 66.2 58.2 49.2 41.6 37.2 33.6 31.4 30.1 29.2 28.5 27.7 27.6 27.3 27.0 26.8
0 120 320 400 520 640 600 540 420 300 160 0 0 0 0 0 0 0 0 0 0 0 0 0
0.000 0.016 0.026 0.006 0.104 0.265 0.448 0.470 0.388 0.286 0.175 0.164 0.092 0.068 0.062 0.055 0.048 0.042 0.040 0.033 0.022 0.015 0.013 0.009
21.0 21.9 24.7 30.6 35.7 43.8 50.1 52.3 51.1 49.8 43.3 37.8 34.2 31.2 28.6 26.7 24.8 23.8 23.0 22.2 21.4 21.1 20.8 20.4
21.1 22.2 24.9 31.0 36.2 44.4 50.8 52.4 51.6 50.1 45.4 40.5 36.3 31.9 29.1 27.0 25.3 24.1 23.5 22.9 21.7 22.0 21.1 20.7
0 80 180 240 380 580 640 640 540 360 220 0 0 0 0 0 0 0 0 0 0 0 0 0
0.000 0.018 0.042 0.007 0.118 0.286 0.418 0.455 0.364 0.258 0.163 0.128 0.080 0.062 0.052 0.050 0.046 0.043 0.038 0.034 0.028 0.018 0.012 0.007
Table 3 Passive solar distiller unit (double slope) observations for Average surrounding air temperature, average water temperature, total solar intensity and yield per day for passive solar distiller unit (single and double slope) for different depth of water in various months of a year. Months
November 2015
December 2015
January 2016
February 2016
March 2016
April 2016
May 2016
June 2016
July 2016
August 2016
September 2016
October 2016
Water depth
Ta
Single slope
Meter
o
It W/m2
Tw o C
Mw kg
It W/m2
Tw o C
Mw Kg
0.01 0.02 0.03 0.01 0.02 0.03 0.01 0.02 0.03 0.01 0.02 0.03 0.01 0.02 0.03 0.01 0.02 0.03 0.01 0.02 0.03 0.01 0.02 0.03 0.01 0.02 0.03 0.01 0.02 0.03 0.01 0.02 0.03 0.01 0.02 0.03
20.5 20.0 21.1 18.7 18.2 16.1 10.3 10.7 11.6 10.6 12.2 16.8 20.5 15.9 16.8 22.3 24.6 25.1 27.5 28.4 32.1 31.8 32.3 32.1 31.7 32.3 32.8 27.6 28.2 27.7 36.9 26.7 25.6 25.7 25.4 24.4
400 337 380 345 376 393 340 348 168 280 256 356 400 324 356 467 474 436 498 520 406 527 464 438 478 454 462 521 550 530 521 540 532 383 513 523
30.8 29.2 30.1 27.2 25.8 21.5 15.4 16.1 15.7 13.0 17.8 23.4 28.9 23.6 23.4 33.4 39.4 36.6 38.2 39.2 38.6 36.4 43.8 40.2 44.0 43.0 40.0 36.8 38.8 38.7 35.9 37.6 37.1 35.9 36.3 36.0
1.629 1.419 1.413 1.466 1.403 1.385 1.127 1.089 0.842 1.151 1.073 1.153 1.631 1.490 1.374 2.130 2.077 1.955 2.260 2.218 1.955 2.105 2.080 1.701 2.198 1.876 1.821 1.894 1.863 1.734 1.884 1.922 1.757 1.793 1.866 1.659
314 266 295 253 279 278 224 246 124 196 187 249 314 239 249 404 402 370 459 473 377 447 465 419 536 473 460 466 442 461 448 439 508 425 427 314
27.6 27.3 28.0 24.2 24.3 21.5 16.4 16.1 14.2 15.4 16.6 22.2 27.6 22.0 22.2 33.0 35.6 38.0 39.0 40.5 44.0 35.6 44.1 42.9 44.8 44.4 43.0 36.3 36.8 36.5 35.1 35.4 35.1 33.9 34.1 34.0
1.44 1.28 1.22 1.15 1.14 1.08 0.88 0.88 0.65 0.94 0.83 1.05 1.34 1.27 1.24 2.06 2.01 1.83 2.27 2.23 2.02 2.20 2.09 1.64 2.20 1.89 1.86 1.90 1.90 1.65 1.74 1.59 1.57 1.59 1.50 1.48
C
Double slope
Please cite this article as: V. S. Gupta, V. K. Dwivedi, P. Gupta et al., Performance evaluation of active solar distiller (double slope) in usual transmission method, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.052
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V.S. Gupta et al. / Materials Today: Proceedings xxx (xxxx) xxx Table 4 Output on monthly and yearly basis obtained from passive solar distiller unit (single and double slope) using various water depths have tabulated below. Months
Number of clear days (N)
Monthly output for various water depths = Daily output number of clear days Solar Distiller Unit (Single Slope)
October 2015 November 2015 December 2015 January 2016 February 2016 March 2016 April 2016 May 2016 June 20,016 July 20,016 August 20,016 Sept 2016 Total
24 30 22 22 24 28 29 30 26 16 12 16 279
Solar Distiller Unit (Double Slope)
0.01 m kg/m2
0.02 m kg/m2
0.03 m kg/m2
0.01 m kg/m2
0.02 m kg/m2
0.03 m kg/m2
39.10 43.98 24.79 25.32 39.14 59.64 65.54 63.15 57.15 30.30 22.61 28.69 499.41
34.06 42.09 23.96 23.61 35.76 58.16 64.32 62.40 48.78 29.81 23.06 29.86 475.85
33.91 41.58 18.52 25.37 32.95 54.74 56.70 51.03 47.35 27.74 21.08 26.54 437.52
34.50 34.43 19.46 20.57 32.05 57.68 65.93 66.08 57.29 30.45 20.88 25.37 464.68
30.72 34.20 19.36 18.26 30.48 56.28 64.70 62.73 49.09 30.35 19.02 23.97 439.16
29.28 32.43 14.30 23.19 29.76 51.16 58.55 49.20 48.31 26.46 18.78 23.71 405.13
different water depths have been given in Table 4. The month of April observed the highest output among the monthly observed yield at the water depth of 0.01 m. It is because of the huge figure of clear days whereas the monthly output is lowest in the month of August due to lower number of clear days. It is also clear that the yields obtained from double slope solar still are higher only in summer months (April to July) in comparison to the yield from single slope solar still. The overall annual yield from single slope passive solar still is higher in comparison to the yield obtained from double slope passive solar still. The annual yield from single slope solar still at the water depth of 0.01 m is 4.95% and 14.14% higher in comparison with yield at 0.02 m and 0.03 m water depth respectively whereas the annual yield from double slope solar still at the water depth of 0.01 m is 5.81 and 14.69% higher in comparison with yield at 0.02 and 0.03 m water depth respectively. The Passive solar distiller unit (double slope) for a particular day in the month of March 2016 produces yield 1.838 kg per meter square while Active solar distiller unit (double slope) under usual method yields 2.791 kg per meter square which is fifty one percent more than the Passive solar distiller unit (double slope). For the better understanding of the data given in the Table 3 a graph comparing various water depth of 0.01, 0.02 and 0.03 m for twelve months and solar radiation (W/m2) has been drawn below. 6. Conclusion It has been concluded that output for active solar distiller unit (double slope) under usual method generates 51% more yield when compared with the passive solar distiller unit (double slope). The output on daily basis of passive solar distiller unit (double slope) for a specific day in the month of March 2016 was found 1.838 kg per meter square whereas the output on daily basis of active solar distiller unit (double slope) under usual circulation method was found 2.791 kg per meter square. References [1] L. Sahota, G.N. Tiwari, Review on the energy and economic efficiencies of passive and active solar distillation systems, Desalination (2017), 401151–179. [2] V.S. Gupta, DeshBandhu Singh, R.K. Mishra, Sanjeev Kumar Sharma, G.N. Tiwari, Development of characteristic equations for PVT-CPC active solar distillation system Desalination, Elsevier 266–279 (2018) 445. [4] R.V. Dunkle, Solar water distillation, the roof type solar still and a multi effect diffusion still, International developments in heat transfer, A.S.M.E, Proceedings of International Heat transfer, University of Colorado, 1961, 5895-902.
[7] M.A.S. Malik, G.N. Tiwari, A. Kumar, M.S. Sodha, Solar distillation, Pregamon Press, Istedn. UK, 1982. [8] G.N. Tiwari, Recent advances in solar distillation. Contemporary Physics-Solar Energy and Energy Conservation, Wiley Eastern Ltd, New Delhi, India, 1992, Chapter II. [9] Eduardo Rubio, José L. Fernández, Miguel A. Porta-Gándara, Modeling thermal asymmetries in double slope solar stills, Renew. Energy 29 (6) (2004) 895–906. [10] A.K. Tiwari, G.N. Tiwari, Annual performance analysis and thermal modeling of passive solar still for different inclination of condensing cover, IJER 31 (14) (2007) 1358–1382. [12] V.K. Dwivedi, G.N. Tiwari, Energy and exergy analysis of single and double slope passive solar still, Trend. Appl. Sci. Res. 3 (3) (2008) 225–241. [24] H.S. Soliman, Solar Still Coupled with a Solar Water Heater, Mosul University, Mosul, Iraq, 1976.
Further reading [3] D.B. Singh, G.N. Tiwari, Exergoeconomic, enviroeconomic and productivity analyses of basin type solar stills by incorporating N identical PVT compound parabolicconcentrator collectors: a comparative study, Energy Convers. Manage. 135 (2017) 129–147. [5] Z.S. Abdel-Rehim, A. Lasheen, Experimental and theoretical study of a solar desalination system located in Cairo, Egypt, Desalination 217 (2007) 52–64. [6] S.D. Hendrie, Evaluation of combined photovoltaic/thermal collectors, In: Proceedings of international conference ISES, vol. 3. Atlanta, GA, USA, pp. 1865–1869, 1979. [11] H.S. Aybar, Mathematical modeling of an inclined solar water distillation system, Desalination 190 (2006) 63–70. [13] D. Atheaya, A. Tiwari, G.N. Tiwari, I.M. Al-Helal, Analytical characteristic equation for partially covered photovoltaic thermal (PVT) - compound parabolic concentrator (CPC), Sol. Energy 111 (2015) 176–185. [14] A.A. Badran, A.A. Al-Hallaq, I.A. Eyal Salman, M.Z. Odat, A solar still augmented with a flat-plate collector, Desalination 172 (2005) 227–234. [15] F. Calise, M.D. d’Accadia, A. Piacentino, A novel solar trigeneration system integrating PVT (photovoltaic/thermal collectors) and SW (seawater) desalination: dynamic simulation and economic assessment’, Energy 67 (2014) 129–148. [16] S. Dubey, G.S. Sandhu, G.N. Tiwari, Analytical expression for electrical efficiency of PVT hybrid air collector, Appl. Energy 86 (5) (2009) 697–705. [17] M.A. Eltawil, Z.M. Omara, Enhancing the solar still performance using solar photovoltaic, flat plate collector and hot air, Desalination 349 (2014) 1–9. [18] D.L. Evans, Simplified method for predicting PV array output. Solar Energy 27, 555–560. In: Schott, T., (Ed.) (1985), Operational temperatures of PV modules, In: Proceedings of 6th PVSolar Energy Conference, 1981, pp. 392–396. [19] M.K. Gaur, G.N. Tiwari, Optimization of number of collectors for integrated PV/ T hybrid active solar still, Appl. Energy 87 (2010) 1763–1772. [20] J.A. Eibling, S.G. Talbert, G.O.G. Lof, Solar stills for community use- digest of technology, Solar Energy 13 (1971) 263–276. [21] S.S. Park, N.J. Kim, A study on the characteristics of carbon nanofluid for heat transfer enhancement of heat pipe, Renew. Energy 65 (2014) 123–129. [22] T.P. Otanicar, P.E. Phelan, J.S. Golden, Optical properties of liquids for direct absorption solar thermal energy systems, Solar Energy 83 (2009) 969–977. [23] O.A. Hamadou, K. Abdellatif, modeling an active solar still for sea water desalination process optimization, Desalination 354 (2014) 1–8.
Please cite this article as: V. S. Gupta, V. K. Dwivedi, P. Gupta et al., Performance evaluation of active solar distiller (double slope) in usual transmission method, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.12.052