Enhancement of solar still performance using a reciprocating spray feeding system—An experimental approach

It is well-established that minimizing water depth is one of the most vital key features to enhance the performance of solar stills. Accordingly, the performance of most recent attempts and proposed ideas tackling this point is limited. Thus, this work introduces a new approach that permits governing the water depth as desired and simultaneously evades all previous experienced interrelated implications through creating a thin re-established film of saline water on a particular manner in the solar still. This has been performed by feeding the saline water into the still through a controlled transverse reciprocating spraying system on the form of fine droplets to spread on the top surface of a corrugated steeped shape absorber of solar still. The application of the saline water thin film with the very low warming up period on this way has numerous significant advantages on the still performance. Consequently, the present approach has undergone a systematic study to examine its anticipated validity in real practice and to optimize its performance at various varying operating conditions. The performance results at any operating conditions reveal extraordinary superiority over those obtained from other recent stills by other investigators. Instead, an optimum operating condition could be identified. At then, an accumulated productivity of 6.355 l/m2 over only 10 working hours at high efficiency of 77.35% was gained. Similarly, the hourly productivity profiles exhibited good uniformity along the representative testing hours of the daytime with relatively high average values. These findings are a result of improving the performance along the whole daytime and, particularly, on the morning hours. This indicates the high response of the still to the increase of the solar radiation leading to the rapid heating up on launching phases. In addition, the performance distributions at various operating conditions showed slight deviations. This emphasizes the flexible, consistent and robust characteristics encountered with this approach that fold on many practical benefits.

Research Highlights
► The study presented a new design of a stepped solar desalination with flashing chamber.
► The work studied the performance of stepped solar coupled with a spray water system.
► The effect of water flow rate and speed of spray system is studied experimentally.
► The system accumulated productivity and efficiency are 6.355 l/m2 and 77.4% over only 10 h.