A parametric investigation was performed theoretically for a solar still consisting of a vertical multiple-effect unit (MEU) and a tilted wick unit (TWU). Thermal input to MEU is the latent heat of vapor from TWO and solar radiation directly incident on MEU. Parameters analyzed in this study were the inclination angle of TWO, the ratio of the height of MEU to the length of TWU, air gap sizes in double glass covers Of MEU and TWO, and the distance between the plates and number of plates used in MEU. Each parameter was analyzed to find the optimum value to produce the maximum daily production of distilled Water. With optimum conditions, the total daily production of the still would be competitive with other types of multiple-effect stills. Outdoor experiment with 4-effect MEU was also performed, and it was found that the discrepancy between experimental and theoretical results was about 10%. (C) 2017 Elsevier B.V. All rights reserved.