Date of Award

6-9-2014

Document Type

Thesis - SCU Access Only

Publisher

Santa Clara: Santa Clara University, 2014.

Department

Mechanical Engineering

First Advisor

Abdlmonem Beitelmal

Second Advisor

Drazen Fabris

Abstract

Current potable water demands in developing nations exceed existing water delivery infrastructure, increasing the prevalence of waterborne diseases. This thesis describes a standalone off-grid water purification system designed to produce clean drinking water in an economically viable manner. The system utilizes concentrated solar-thermal energy generated by reflective parabolic troughs to boil sea, brackish, or contaminated water for distillation. The resulting water vapor is condensed into clean water and stored in a collection tank. System optimization and design (heat exchanger, boiler, parabolic troughs, tracking and control system, photovoltaic panels and vapor and heat transfer fluid pumps) and specifically parabolic trough fabrication are discussed in detail. Two troughs were designed and constructed each with an area of 3.07 m2 (33 ft2). Duratherm 450, a non-toxic, non-hazardous heat transfer fluid (HTF) is selected as the working fluid for the solar trough hot loop. System performance analysis was conducted through a combination of experimental testing and through a virtual system model utilizing Engineering Equation Solver (EES). EES is used to model the heat transfer process of the overall distillation system, optimal HTF flow rates, and future system scalability. Experimental results show a maximum system operating temperature of 124oC and maximum performance for the numerically determined optimal HTF flow rate. Furthermore, results show that parabolic troughs are suitable for distillation and are less expensive to manufacture, operate at a higher temperature, and provide higher performance when compared to a distillation system that utilizes flat thermal panels. The overall manufacturing cost is approximately $5000, which includes tracking, a control system, and all other components related to distillation. This system is designed to fit into a standard 20-foot shipping container for ease of transportation worldwide.

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