Solar desalination system using spray evaporation S.A. El-Agouz a, * , G.B. Abd El-Aziz b , A.M. Awad b a Mech. Eng. Dep., Faculty of Eng., Tanta Univ., Egypt b Mech. Dept., Faculty of Industrial Education, Suez University, Egypt article info Article history: Received 31 January 2014 Received in revised form 1 August 2014 Accepted 3 August 2014 Available online 26 September 2014 Keywords: Solar desalination system Spray evaporation Salty water Experimentally abstract This paper evaluates a one-stage technique to improve fresh water production from salty water by enhancing the evaporation and condensation. A pilot plant is designed and constructed in an arid area with 1 m 2 solar water collector area to evaluate the one-stage process. The effect of main parameters on fresh water production of the unit is studied. The results show that, the productivity, efficiency, pro- ductivity rate, and Gained Output Ratio of the desalination unit are strongly affected by the inlet hot water temperature and flow rate. Within the studied ranges, the maximum daily productivity reached to 9 l/m 2 . According to these results, fresher water production of the present system is higher than that solar humidificationedehumidification desalination system in the previous studies. The maximum daily efficiency in the desalination system is about 87%. A TDS (total dissolved solids) of fresher water is 40 ppm. Finally, the cost of distilled water per liter is $0.029. © 2014 Elsevier Ltd. All rights reserved. 1. Introduction Desalination based on renewable energy such as solar energy, presents a sustainable and a zero-polluting alternative to fossil fuel based desalination, which aggravates environmental pollution problems. It is cheap, allows energy diversification, available for predictable periods of time, and helps avoid dependence on external energy supplies (Garcia-Rodriguez [1]). Solar still desali- nation uses a sustainable and pollution-free source to produce high-quality water. Fresh water could be obtained from salty water through the solar HDH (humidificationedehumidification) cycle. In this pro- cess, hot air supplied from a solar collector was circulated either by a natural or a forced convection process over the water where it becomes humid. The humid air was then passed through a condenser or de-humidifier system where the desalinated water was obtained. Multi-effect humidification plants were the most effective units among solar desalination plants (Farid et al. [2]). Many researchers have conducted studies on process and the equipment's related to the (HDH) systems for water desalination. Abdelkader [3] studied the solar desalination system with multi- effect humidificationedehumidification cycles with couples cen- tral solar receiver. In this system, saline water was warmed through the solar central receiver and it was then entered into a desalina- tion chamber. The air circulation in the humidification chamber was provided by natural convection. The amount of distillate water produced by the unit depends on the solar collector size. The performance of the collector depends mainly on the weather conditions, design and operating parame- ters. However, to estimate the optimum values of these parameters in different weather conditions using full experiment was costly and time-consuming. Therefore, the development of a simulation model offers a better alternative and has proven to be a powerful tool in the evaluation of the performance of the system. Both air and water, solar collectors were the main components of a solar desalination unit and any improvement in their efficiency will have a direct bearing on the water production rate and the product cost (Al-Hallaj and Selman [4]). The solar collectors that were used to heat water and/or air were expensive and can reach in some cases from 25 to 30% of the total desalination unit cost by Ben Bacha et al. [5]. The best known thermal processes for the desalination of seawater, namely MED (multi-effect desalination) and MSF (multistage flash), make an efficient use of energy because the heat released in each stage or effect was used in the next one, making multiple use of energy. However, these processes require a very precise control of temperature and pressure in each stage, which must be constant in time in order to keep the conditions needed for the boiling process (El-Dessouky and Ettouney [6]). This poses a problem when coupling desalination with solar energy, due to the intrinsic variability of insolation, thus requiring a thermal storage * Corresponding author. E-mail addresses: elagouz2002@yahoo.com, elagouz2011a@yahoo.com, elagouz2011@yahoo.com (S.A. El-Agouz). Contents lists available at ScienceDirect Energy journal homepage: www.elsevier.com/locate/energy http://dx.doi.org/10.1016/j.energy.2014.08.009 0360-5442/© 2014 Elsevier Ltd. All rights reserved. Energy 76 (2014) 276e283