A novel approach to augment stepped solar still productivity using the heat storage characteristics of water

Year 2025, Volume: 11 Issue: 5, 1355 - 1373, 21.10.2025

J.s D’cotha P. R. Suresh P. Sajeesh

Abstract

Improvement in freshwater productivity by minimizing the carbon footprint is the main goal paving way to the development and modification of solar stills. The primary objective of this study is to enhance the productivity of the solar still while optimizing construction and main-tenance costs. In contrast to other phase change materials and heat storage materials, this study utilizes water as the sensible heat storage medium. This investigation deviates from established protocols by implementing a feed water addition strategy that exceeds evaporated water quan-tities. The still’s performance was enhanced by using a dynamic water depth strategy, where lower depths during morning hours boosted daytime yield, and higher depths later in the day improved night-time output. This process optimizes the use of incident energy, converting it into specific heat energy while minimizing the impact on temperature increase. Experiments in Ko-chi, India, revealed that the solar still’s overall yield, without feed water addition, decreased with increasing initial water depth, yielding 5290 ml/m², 5140 ml/m², and 4800 ml/m² at depths of 0.5 cm, 1.0 cm, and 1.5 cm, respectively. Adding 100 ml of feed water to each tray at the three initial water depths resulted in productivity increases of 2.3%, 2.5%, and 2.9%, respectively, compared to no feed water additions. Furthermore, adding 200 ml of feed water led to more significant improvements in productivity, with increases of 5.9%, 8.2%, and 7.5%, respectively. A solar still with an initial water depth of 0.5 cm and a feed water inlet of 400 ml per tray achieved the highest distillate output of 6330 ml/m²/day, corresponding to a maximum daily efficiency of 66.45%. Ex-perimental values were validated against theoretical energy balance equations, with a deviation of less than 6%. The cost of distillate produced was $0.03, which is approximately one-tenth the price of water available in the regional market. Solar stills offer a viable solution for producing potable water, addressing the drinking water needs of communities and urban areas facing water scarcity. The low cost, simplicity, and eco-friendliness of this desalination process make it ideal for household use. Future research should focus on developing intelligent feed water systems that adapt to solar radiation and ambient temperature fluctuations, optimizing feed water quantity and maximizing daily still output.

Keywords

Feed Water , Heat Storage , Nocturnal Yield , Stepped Still

References

• [1] Sadigov R. Rapid growth of the world population and its socioeconomic results. Sci World J 2022;2022:8110229. [CrossRef]
• [2] Cruz-Pérez N, Santamarta JC, Gamallo-Paz I, Rodríguez-Martín J, García-Gil A. A comparison between carbon footprint of water production facilities in the Canary Islands: groundwater resources vs seawater desalination. Sustain Water Resour Manag 2022;8:1–9. [CrossRef]
• [3] Heihsel M, Lenzen M, Malik A, Geschke A. The carbon footprint of desalination: An input-output analysis of seawater reverse osmosis desalination in Australia for 2005–2015. Desalination 2019;454:71–81. [CrossRef]
• [4] Nassrullah H, Anis SF, Hashaikeh R, Hilal N. Energy for desalination: A state-of-the-art review. Desalination 2020;491:114569. [CrossRef]
• [5] Hussen HM, Younes MM, Alawee WH, Abdullah AS, Mohammed SA, Atteya TEM, et al. An experimental comparison study between four different designs of solar stills. Case Stud Therm Eng 2023;44:102841. [CrossRef]
• [6] Atteya TEM, Abbas F. Testing a stepped solar still with different sand beds and reflectors. Case Stud Therm Eng 2023;43:102782. [CrossRef]
• [7] Jathar LD, Ganesan S. Assessing the performance of concave type stepped solar still with brick, sand, and concrete pieces. Int J Ambient Energy 2020;43:1–36. [CrossRef]
• [8] Chauhan MK, Chauhan AK, Khan Y, Singh AP. Experimental and theoretical investigation of thermal efficiency and productivity of single slope basin type solar distillation system using honey-comb. J Therm Eng 2023;9:1559–1571. [CrossRef]
• [9] Dhivagar R, Shoeibi S, Parsa SM, Hoseinzadeh S, Kargarsharifabad H, Khiadani M. Performance evaluation of solar still using energy storage biomaterial with porous surface: An experimental study and environmental analysis. Renew Energy 2023;206:879–889. [CrossRef]
• [10] Ramalingam VK, Karthick A, Jeyalekshmi MPV, Decruz AMMAJ, Manokar AM, Sathyamurthy R. Enhancing the fresh water produced from inclined cover stepped absorber solar still using wick and energy storage materials. Environ Sci Pollut Res 2021;28:18146–18162. [CrossRef]
• [11] Abdullah AS. Improving the performance of stepped solar still. Desalination 2013;319:60–65. [CrossRef]
• [12] Ali C, Rabhi K, Nciri R, Nasri F, Attyaoui S. Theoretical and experimental analysis of pin fins absorber solar still. Desalin Water Treat 2015;56:1705–1711. [CrossRef]
• [13] Muftah AF, Sopian K, Alghoul MA. Performance of basin type stepped solar still enhanced with superior design concepts. Desalination 2018;435:198–209. [CrossRef]
• [14] Lilley D, Yu P, Ma J, Jain A, Prasher R. Thermal fluids with high specific heat capacity through reversible Diels–Alder reactions. IScience 2022;25:103540. [CrossRef]
• [15] Arunkumar T, Wang J, Dsilva Winfred Rufuss D, Denkenberger D, Kabeel AE. Sensible desalting: Investigation of sensible thermal storage materials in solar stills. J Energy Storage 2020;32:1–27. [CrossRef]
• [16] Siddula S, Stalin N, Mahesha CR, Dattu VSNCH, S H, Singh DP, et al. Triangular and single slope solar stills: Performance and yield studies with different water mass. Energy Reports 2022;8:480–488. [CrossRef]
• [17] Kabeel AE, El-Agouz SA, Sathyamurthy R, Arunkumar T. Augmenting the productivity of solar still using jute cloth knitted with sand heat energy storage. Desalination 2018;443:122–129. [CrossRef]
• [18] Hammoodi KA, Dhahad HA, Alawee WH, Omara ZM. A detailed review of the factors impacting pyramid type solar still performance. Alexandria Eng J 2023;66:123–154. [CrossRef]
• [19] Hoque A, Abir AH, Paul Shourov K. Solar still for saline water desalination for low-income coastal areas. Appl Water Sci 2019;9:104. [CrossRef]
• [20] Zanganeh P, Soltani A, Ayatollahi S, Feilizadeh M. Efficiency improvement of solar stills through wettability alteration of the condensation surface: An experimental study. Appl Energy 2020;268:1–11. [CrossRef]
• [21] D’Cotha JS, Sajeesh P, Suresh PR. Influence of initial water depth of extended stepped tray on the productivity while working beyond sunshine hours. Mater Today Proc 2023;217:267−275. [CrossRef]
• [22] Saadi Z, Rahmani A, Lachtar S, Soualmi H. Performance evaluation of a new stepped solar still under the desert climatic conditions. Energy Convers Manag 2018;171:1749–1760. [CrossRef]
• [23] Abdullah AS, Younes MM, Omara ZM, Essa FA. New design of trays solar still with enhanced evaporation methods – Comprehensive study. Sol Energy 2020;203:164–174. [CrossRef]
• [24] Abujazar MSS, Fatihah S, Lotfy ER, Kabeel AE, Sharil S. Performance evaluation of inclined copper-stepped solar still in a wet tropical climate. Desalination 2018;425:94–103. [CrossRef]
• [25] Kabeel AE, Khalil A, Omara ZM, Younes MM. Theoretical and experimental parametric study of modified stepped solar still. Desalination 2012;289:12–20. [CrossRef]
• [26] Omara ZM, Kabeel AE, Younes MM. Enhancing the stepped solar still performance using internal reflectors. Desalination 2013;314:67–72. [CrossRef]
• [27] D’Cotha JS, Sajeesh P, Suresh PR, Jithu J. Inherent configuration characteristics altering the distillate enhancement of passive stepped solar still: A review. J King Saud Univ Eng Sci 2021;8:684−693. [CrossRef]
• [28] Thakur VK, Gaur MK, Sagar MK, Tiwari GN. A study on heat and mass transfer analysis of solar distillation system. J Therm Eng 2021;7:1184–1205. [CrossRef]
• [29] Rani A, Kant R, Suresh S, Kumar A. Experimental investigation on thermal behavior of hybrid single slope solar still. J Therm Eng 2021;7:677–689. [CrossRef]
• [30] Abdullah AS, Alawee WH, Shanmugan S, Omara ZM. Techniques used to maintain minimum water depth of solar stills for water desalination – A comparative review. Results Eng 2023;19:101301. [CrossRef]
• [31] Alwan NT, Ali BM, Alomar OR, Abdulrazzaq NM, Ali OM, Abed RM. Performance of solar still units and enhancement techniques: A review investigation. Heliyon 2024;10:e37693. [CrossRef]
• [32] Nougriaya SK, Chopra MK, Gupta B, Baredar P, Parmar H. Influence of basin water depth and energy storage materials on productivity of solar still: A review. Mater Today Proc 2021;44:1589–1603. [CrossRef]
• [33] Agrawal A, Rana RS, Srivastava PK. Heat transfer coefficients and productivity of a single slope single basin solar still in Indian climatic condition: Experimental and theoretical comparison. Resour Technol 2017;3:466–482. [CrossRef]
• [34] Gawande JS, Bhuyar LB. Effect of shape of the absorber surface on the performance of stepped type solar still. Energy Power Eng 2013;5:489–497. [CrossRef]
• [35] Omara ZM, Abdullah AS, Kabeel AE, Essa FA. The cooling techniques of the solar stills’ glass covers – A review. Renew Sustain Energy Rev 2017;78:176–193. [CrossRef]
• [36] Dunkle R. Solar water distillation; the roof type still and a multiple effect diffusion still. Dev Heat Transf ASME Proc Heat Transf Part V 1961;:895.
• [37] Jamil B, Akhtar N. Effect of gap between absorber plate and condenser cover on the performance of a solar still. Green Energy Technol 2016;PartF2:161–173. [CrossRef]
• [38] Jamil B, Akhtar N. Effect of specific height on the performance of a single slope solar still: An experimental study. Desalination 2017;414:73–88. [CrossRef]
• [39] Dhivagar R, Mohanraj M, Hidouri K, Belyayev Y. Energy, exergy, economic and enviro-economic (4E) analysis of gravel coarse aggregate sensible heat storage-assisted single-slope solar still. J Therm Anal Calorim 2021;145:475–494. [CrossRef]
• [40] Abujazar MSS, Fatihah S, Kabeel AE. Seawater desalination using inclined stepped solar still with copper trays in a wet tropical climate. Desalination 2017;423:141–148. [CrossRef]
• [41] Agrawal A, Rana RS. Theoretical and experimental performance evaluation of single-slope single-basin solar still with multiple V-shaped floating wicks. Heliyon 2019;5:e01525. [CrossRef]
• [42] El-Sebaii AA. Effect of wind speed on active and passive solar stills. Energy Convers Manag 2004;45:1187–1204. [CrossRef]
• [43] Alshqirate AA, Awad AS, Al Alawin A, Essa MA. Experimental investigation of solar still productivity enhancement of distilled water by using natural fibers. Desalination 2023;553:116487. [CrossRef]
• [44] Sharshir SW, Eltawil MA, Algazzar AM, Sathyamurthy R, Kandeal AW. Performance enhancement of stepped double slope solar still by using nanoparticles and linen wicks: Energy, exergy and economic analysis. Appl Therm Eng 2020;174:115278. [CrossRef]
• [45] Hadj-Taieb L, Abdullah AS, Aljaghtham M, Alkhudhiri A, Omara ZM, Essa FA. Improving the performance of trays solar still by using sand beds and reflectors. Alexandria Eng J 2023;71:659–668. [CrossRef]
• [46] Mohamed AF, Hegazi AA, Sultan GI, El-Said EMS. Enhancement of a solar still performance by inclusion of basalt stones as a porous sensible absorber: Experimental study and thermo-economic analysis. Sol Energy Mater Sol Cells 2019;200:109958. [CrossRef]
• [47] Bilal A, Jamil B, Haque NU, Ansari MA. Investigating the effect of pumice stones sensible heat storage on the performance of a solar still. Groundw Sustain Dev 2019;9:100228. [CrossRef]
• [48] El-Bialy E, Shalaby SM, Kabeel AE, Fathy AM. Cost analysis for several solar desalination systems. Desalination 2016;384:12–30. [CrossRef]
• [49] Velmurugan V, Naveen Kumar KJ, Noorul Haq T, Srithar K. Performance analysis in stepped solar still for effluent desalination. Energy 2009;34:1179–1186. [CrossRef]
• [50] Panchal HN. Life cycle cost analysis of a double-effect solar still. Int J Ambient Energy 2017;38:395–399. [CrossRef]
• [51] Rahbar N, Gharaiian A, Rashidi S. Exergy and economic analysis for a double slope solar still equipped by thermoelectric heating modules – An experimental investigation. Desalination 2017;420:106–113. [CrossRef]
• [52] Furbo S. Using water for heat storage in thermal energy storage (TES) systems. Cambridge, UK: Woodhead Publ Ltd; 2015. [CrossRef]