Global Journal of Researches in Engineering, A: Mechanical & Mechanics, Volume 22 Issue 1

turn increases the productivity rate. Ambient air temperature proportionately increased with increase of solar intensity and decreasing trends were noticed during off-sunshine hours. Maximum ambient temperature was found at 36.2°C at 12:10 PM whereas lowest ambient temperature reached up to 27°C at 07:00 AM. In addition From Figure 3 it can be observed that the maximum basin water temperature of modified stepped solar still and conventional solar still was about 73.7°C and 54.6°C. The maximum value of glass temperature of modified stepped solar still and conventional solar still was about 69°C and 49.1°C, respectively. The solar still performance was improved at mid-noon, and this due to the increase of solar radiation which leads to higher ambient temperature and higher solar still temperature. From Figure 3, it can be indicated that the saline water temperature and glass temperature of modified stepped solar still are higher than that of conventional solar still by about 14.1°C, 19.9°C respectively. This is because adding reflector of the stepped still. This reflector reflects a fraction of the radiation onto the water surface, thus consequently increase the water and glass temperatures of the stepped solar still. So, the evaporation condensation rates in stepped solar stills were higher than that of conventional still. Figure 3: The hourly temperature variation and solar radiation for modified stepped solar still, stepped solar still without modification, and conventional solar still 0 200 400 600 800 1000 1200 20 30 40 50 60 70 80 07:00:00 10:00:00 01:00:00 04:00:00 07:00:00 Tw ( modified stepped still) Tw(conv. Still) Tg(modified still) Tg(covv.still) Ta solar radiation Solar Radiation (W/m ²) Temperature (Cº) Time (hours) Performance of a Modified Stepped Solar Still Global Journal of Researches in Engineering (A ) Volume XxXII Issue I Version I 15 Year 2022 © 2022 Global Journals