Economic feasibility of a solar still desalination system with enhanced productivity

Solar still desalination systems offer sustainable tools for fresh water production. However, their widespread application is often hindered by their relatively low production rates compared to other desalination methods. In this study, a simple amendment, in the form of a slowly-rotating hollow cylinder, was introduced within the solar still, significantly increasing the evaporative surface area. This new modified still was analyzed in terms of both operation and economic feasibility. The introduced cylinder resulted in a 200–300% increase in water output relative to a control, which did not include the cylinder. The resulting percent improvement far exceeds that obtained by other modifications. Unit production cost estimates varied between 6 and 60 $/m3 depending on discount rates, productivity, service lifetime and initial capital costs. These projections are well within reported cost ranges for renewable-based technologies. In order to evaluate the system's feasibility in real market value, different scenarios that introduce carbon-trading schemes and environmental degradation costs for fuel-based desalination, were performed. Reported costs for fuel-based brackish water and seawater desalination were thus adjusted to include unaccounted-for costs related to environmental damage. This analysis yielded results that further justify the economic feasibility of the new modified solar still, particularly for seawater desalination. © 2013 Elsevier B.V. All rights reserved.

In this study a new design of solar still is proposed which significantly increases the water output without forsaking the key advantages of the still. Based on the experimental study and the cost analysis conducted, the following conclusions are deduced: ▪ The introduced rotating cylinder significantly accelerates the evaporation process and results in a 200–300% enhancement in productivity compared to the control. The enhancement in productivity due to this low-cost amendment exceeds that of many of the complex modifications introduced to the solar still before. ▪ An economic assessment of the proposed system reveals that the cost per unit water produced is comparable to that reported in the literature for other renewable-based desalination methods. ▪ Cost values for fuel-based desalination are adjusted to include externalities due to CO2, SO2, NOx and particulate matter and different carbon-trading cost scenarios. This analysis shows that the economic feasibility of desalination systems based on renewable energy becomes more justified if environmental degradation costs associated with fuel-based-desalination are acknowledged. Acknowledgments The authors would like to acknowledge the Lebanese National Council for Scientific Research and the Middle East Desalination Research Center, Oman for financially supporting this work.