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Accessibility to clean water which is necessary for a healthy lifestyle is a problem that spans the globe. Many societies that lack clean water are also without the energy resources such as electricity or gas that are used for purification. This project is on the development of a solar powered water purification system with Phase Change Material (PCM) energy storage and experimental studies on the system. Water distillation was achieved and analyses were performed on the effects of weather conditions on the distillate production. Solar systems are affected by limited sunshine which occurs only during daylight hours. A second part of the research involved adding a PCM heat exchanger to the system to extend distillation beyond the daylight hours. The analyses evaluated distillate production against outdoor conditions such as temperature, wind speed, and use of the PCM heat exchanger, to determine how they affect the performance of the system. Results show that increased outdoor temperature and clear atmospheric conditions yield greater distillate production. The effects of wind speed were less conclusive. Use of the PCM heat exchanger shifted production to later in the day, but overall, resulted in lower daily production than when the heat exchanger was bypassed. The most definite indicator of distillate production was the temperature differential between the water entering the still and the outdoor temperature.

This thesis project investigates the configuration of an enclosed evaporation chamber with the intention of converting seawater into potable freshwater. The evaporation chamber's sole heat source is provided by a Fresnel lens, located above the chamber, which concentrates sunlight onto a 3-inch diameter focal plate built into the core of the chamber. The design of the evaporation chamber is modeled after a solar still and is coupled with a heat exchanger to boost efficiency of the system. The chamber was designed with the objectives of being portable, lightweight, low cost, corrosion resistant, interchangeable, and size convenient with the goal of producing 1 Liter of freshwater per hour of operation. The evaporation chamber consists of two primary components, a core and an attached arrangement of fins, all of which are heated via the Fresnel lens. A consistent intake of 2 grams/second of saltwater enters from the top of the chamber and is then gravity fed across the fins. Fin orientation has been designed to inhibit the flow rate of water within the chamber, maximizing the surface area of contact with the heated fins. The evaporation chamber was modeled through SOLIDWORKS and underwent a physical optimization study to reduce material usage while maximizing potential for heat transfer and minimizing fluid flow rate. A symmetric profile of one quarter of the chamber was then simulated in COMSOL Multiphysics. Concentrated solar heat flux through a Fresnel lens was applied to the receiver on the top of the core. The simulation was split into a preheating and an evaporation phase. A profile approximation for the fluid flow was modeled by the CFD module. Following computer simulations, the evaporation chamber was constructed and tested.

Yes / The desalination of saltwater is a viable option to produce freshwater. All the desalination processes are energy-intensive and can be carried out on a large scale. Therefore, producing freshwater using renewable energy sources is the most desirable option considering the current energy crisis and the effect that fossil-fuel-based energy has on our carbon footprint. In this respect, the tray-type still, one of several solar power desalination still varieties, is popular owing to its straightforward design, economic materials of construction, and minimal maintenance requirements, especially in isolated island regions with restricted energy and natural water supplies. The traditional tray-type solar power has a few drawbacks, such as the inability to recover latent heat from condensation, reduced thermal convection, a large heat capacity, and comparatively minimal driving power through evaporation. Therefore, the improvement of heat and mass transfer capabilities in tray-type stills has been the subject of many studies. However, there is a lack of a comprehensive review in the open literature that covers the design and operational details of multistage solar stills. The purpose of this paper is to present a thorough overview of the past research on multistage solar stills, in terms of configurations, capabilities, and cutting-edge options. In comparison to a unit without a salt-blocking formation, the review indicates that a multistage distillation unit may run continuously at high radiation and generate pure water that is around 1.7 times higher than a unit without a salt-blocking formation. The most effective deign is found to be “V”-shaped solar still trays that attach to four-stage stills, since they are less expensive and more economical than the “floor” (Λ-shape) design, which requires two collectors. Additionally, it can be stated that the unit thermal efficiency, solar percentage, and collected solar energy (over the course of a year) increase by 23%, 18%, and 24%, respectively, when the solar collectors are increased by 26% (at the constant inflow velocity of the water).