Experimental investigation and economic assessment of a solar still performance using high-frequency ultrasound waves atomizer

In this paper, an experimental study is performed to investigate the influence of utilizing high frequency ultrasound atomizer (HFU) on augmenting the performance of a solar still (SS). Atomized saline water has been utilized as a motivator to enhance the humidification process inside the SS cavity. Due to the negative influence of fogging on heat transfer by radiation, an on-off timer is utilized to control the HFU atomizer on-time and off-time which helps to avoid this influence. The different parameters such as the atomizer number, water height, feed water salinity and on-time and off-time were studied with two operating modes; HFU-SS (SS with atomizers) and C-SS (conventional design). It has been found that the saline water atomizing by ultrasound waves significantly augments the evaporation performance inside the SS cavity. Results depict that the increasing of the atomizer number has a positive influence on the system efficiency and productivity. Results show that the C-SS and HFU-SS daily productivity were about 3.58 L/m(2) and 4.41 L/m(2) respectively. The average thermal efficiency of the HFU-SS atomizer was augmented by about 28.75%-55.75% compared to C-SS. The thermal efficiency of HFU-SS affect the atomizer number and reaches the maximum value 40.21% at two atomizer. The thermal efficiency of HFU-SS decreased with the increment of the water height and varied between 35.61% and 40.5%. The thermal efficiency of HFU-SS was augmented by about 72% for on-time = 25 min and off-time = 25 min compared to the continuous operation. Also, an economic analysis was performed and illustrated that the cost of distillate water from HFU-SS reduced by about 12.94%-14.54% less than C-SS. (C) 2020 Elsevier Ltd. All rights reserved.