1 Effect of collector area and forced circulation on the solar still system at Nasiriya city Rafid M. Hannun rafid.alsaleh@gmail.com Mechanical Eng. Dept., College of Engineering, Thi-Qar University Mushtaq I.Hasan Mechanical Eng. Dept., College of Engineering, Thi-Qar University Mohammed H. Khalaf Elect. Distr. Directory of Thi-Qar ABSTRACT: The solar distillation system is one of the important fields to be studied on the world which transform the sun arrays energy to heat the water liquid to steam. The present paper demonstrates combined system of multi solar collectors connected to water pump and solar basin that accumulate the warm saline water after passing through out the pipes to pump and similar solar collectors at Nasiriya city (Iraq). The benefit of collectors is to absorb the solar energy with different area and the pump to force the convective heat transfer between the water pipes inside the collector and the water. Many parameters were calculated by using the theoretical equations in these systems such as: average temperature of water, glass and basin; convective, radiative and evaporative heat transfer coefficient inside the basin; hourly output distillated water; overall hourly thermal efficiency; average water and glass temperature and output distillated water along the day with different three heights of basin. The validity of this work was done by comparing the output distillated water with other researches to be compatible results approximately. Increase the collectors number should increase the distillated water output and efficiency (0.86 kg/m 2 .h and 31% respectively.). ËÅģÄ ÌÅ×ěÄ ÄĤ ěïÄ åÏÄ ĘÅ :ËßÄ ءÅěÄ ßÏ ěïÄ ËÄ ËÅÄ Ĕ ÏÄ ÅÄ ÅģÏÄäà Ï ÏÄ ÅÄ Ĥ ôĤ ĠÅ Ëß÷ě ËėóÏ ÊàÏ ÌÅě× ØÄÄ ËÄ ËěïÄ ËÅÄ ě×Ï ËÉå Ëğ ÉÄ Äã .äÅß ħ ËåÅğÄ Ëğ ËěïÄ ËÅÄ ě×Ĥ ÷ Å ÔĤåßÄ Ĕ ÅäĤå ËÃÄÄ ËÅěÄ ĠÅěÄ ÄåÏ ĨãÄ ě ě×ěÄ ÊÅ .)ČÄåÄ( ËěïÄ ËÅÄ ðÅóÏ ě×ěÄ Äà ĠÅěÄ Å ěÅ ÊäÄåÄ ĔÅÏÄ äÅÉ Ëß÷Ĥ ËċėÏß ÌÅÅě Ï :Ó ËěÄ Ġã ËåğÄ ÌàÅěÄ ĘÄßÏÅ ÌÅėěÄ Ä ÆÅ .ءÅěÄĤ ؛ôÄĤ ÔÅÄĤ ءÅěÄ ÊäÄå Ëäà ěÅ ÊäÄåÄ ĔÅÏÄ Å .ËÅÅ ËėēÄ ËäÄåÄ ÊءÅċēÄ ؛ÊåěÄ ĠÅěė ËÅÄ ÌÅåßěÄ ؛ôÄ Äà åßÉÏÄĤ ÅÄ ،ĨäÄåÄ Ï ÔÅÏÄĤ ÔÅÄĤ ءÅěÄ ÊäÄå Ëäà ءÅěÄ Äã ËàĤ ÏÄ Ĥ .ôÄ ËċėÏß ÌÅÏ Ë ĘÄ Ĕø ħė åěÄ ËäÅ Ĕ ěÄ ÔÅÏÄ ĜÄ × ÌÅě×ěÄ à ÊàÅæ ĜÄ .ÅÉå ËÄÏ ÅÏğÄ ĜēÏ ÐÅÄ Åå åěÅ ÅğÄ ءÅěÄ ( ÊءÅċēÄĤ ÊåěÄ ĠÅěÄ ˹;X6 Ę/ ˻ ËÅ . Ĥ ˼˺ .)ÄÏÄ ħė 1 INTRODUCTION Solar still is a process where solar energy is used to distill water from saltwater to pure water. The different methods used in desalination are based on thermal or membrane principles. Among the thermal methods used is solar desalination. There are a lot of research conducted for the development of distilled solar and increasing productivity , as the distillation solar energy is not new has begun since Malik (1872) when the construction of the first plant distillation sun productivity 4.255 L / m 2 day and an area of 4700 m , and continued to researchers in the development of this technique in much of the research conducted in this area. Soliman (1972) , Hanson (1973), Howe (1974) presented for the study of atmospheric effects of various productivity of wind speed, solar radiation, air temperature and slope angle of cover transparent thermal insulation dripped factors operating different such as the depth of the pond and the feeding way on the performance of distilled water. Satcunanathan (1973) presented that there is an ideal the temperature for the condensation surface to the highest productivity of distilled depend on variables and what surrounds it did not mention the amount of increase in productivity in this case. The researcher (Hanson1973) studied the impact of vacuum distance between distilled Basin and the transparent cover , as well as Milan lid on the performance of distilled water , has been found to reduce the size into the pelvis improves performance as well as make distilled Milan cover perpendicular to the path of the fall of the sun to reduce the reflection of solar radiation falling on distilled water (Hansen 1973). Kamaraj (1978) has studied the effects of linking reflector to the sun as much as basin area distilled at an angle and is unlike rays additional to the inside of the base Basin distilled has increased productivity by 50 – 60% when using the reflective mirror and an increase of 25 when using a reflector of aluminum, but the efficiency will be reduced. At the exhibition