Research Article Effect of Tin Oxide/Black Paint Coating on Absorber Plate Temperature for Improved Solar Still Production: A Controlled Indoor and Outdoor Investigation Sayfar Rasachak, 1 Rana Sami Ullah Khan, 2 Laveet Kumar, 1 Taiba Zahid, 3 Usman Ghafoor , 4 Jeyraj Selvaraj, 1 Rehena Nasrin , 5 and Muhammad Shakeel Ahmad 1 1 Higher Institution Centre of Excellence (HICoE), UM Power Energy Dedicated Advanced Centre (UMPEDAC), Level 4, Wisma R&D, University of Malaya, JalanPantai Baharu, 59990 Kuala Lumpur, Malaysia 2 Department of Mechatronics and Biomedical Engineering, Air University, Islamabad, Pakistan 3 NUST Business School, National University of Science and Technology, Islamabad, Pakistan 4 Department of Mechanical Engineering, Institute of Space Technology, Islamabad, Pakistan 5 Department of Mathematics, Faculty of Science, Bangladesh University of Engineering and Technology, Dhaka 1000, Bangladesh Correspondence should be addressed to Rehena Nasrin; rehena@math.buet.ac.bd and Muhammad Shakeel Ahmad; shakeelalpha@gmail.com Received 3 August 2021; Revised 27 September 2021; Accepted 4 December 2021; Published 22 January 2022 Academic Editor: Mamdouh El Haj Assad Copyright © 2022 Sayfar Rasachak et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The ever-increasing water stress and availability of fresh drinking water are becoming a major challenge in rural and urban communities. The current high-end and large-scale technologies are becoming way more expensive and not friendly to the environment. In this regard, solar still is becoming a prominent and promising future technology due to its environment- friendly nature, less maintenance and operational costs, and simple design. The technological challenge regarding solar still is its low distillate yield. In this study, an attempt has been made to investigate the effect of tin oxide (SnO 2 ) on the absorption surface of solar still towards improvement in sunlight absorption, which would lead to high distillate production rates. Various concentrations of SnO 2, i.e., 0.5wt%, 1 wt%, 3 wt%, 5 wt%, 7 wt%, 10 wt%, 15 wt%, and 20 wt%, have been mixed in black and applied on the absorber plate to further optimize the suitable concentration. The experiments have been performed in both indoor (simulated) and outdoor conditions. An increase in surface temperature of absorber plate has been observed with increasing concentration of SnO 2 under both the indoor and outdoor conditions, which is due to high solar spectrum absorption properties of SnO 2 in the ultraviolet (UV) and near to far-infrared (IR) regions. The highest surface temperature of 101.61 ° C has been observed for specimens containing 15 wt% SnO 2 in black paint under indoor conditions at 1000W/m 2 irradiation levels, which is 53.67% higher compared to bare aluminum plate and 16.91% higher compared to only black paint coated aluminum plate. On the other hand, the maximum temperature of 74.96 ° C has been recorded for the identical specimens containing 15 wt% SnO 2 under uncontrolled outdoor conditions. The recorded temperature is 47.96% higher than the bare aluminum plate and 14.88% higher than the black paint-coated aluminum plate. The difference of maximum temperatures under indoor and outdoor conditions is due to uncontrolled outdoor conditions and convective losses. 1. Introduction Fresh drinking water is an essential need for human survival, and it plays a vital role in environmental sustainability. Due to the increase in population, the demand for fresh drinking water is also increasing. Even though the earth is 70% cov- ered with water, 97% is saline water. Only 3% is remaining as freshwater, and out of this, 2% is inaccessible because of frozen icy masses [1]. Therefore, solar energy is a practical and feasible approach for properly utilizing seawater and Hindawi International Journal of Photoenergy Volume 2022, Article ID 6902783, 12 pages https://doi.org/10.1155/2022/6902783