Final Solution Rationale Report

  Re-introduction of Solutions:

Alternate Solution 1 features a desalination cone followed by 9 chambers of thermal distillation, powered by an array of solar panels on the "roof". The water travels in a circular path from chamber to chamber and eventually drips into a collection basin attached to the bottom of the unit, where UV lights can sanitize it. Water is dispensed through a faucet on the side, perhaps with an attached pitcher.

All of the moving parts are consolidated into one box,  which is good for streamlining the process and for improving aesthetics. The nine chambers of desalination are what is recommended by large-scale facilities, but at our price point, one has to wonder if we can really afford to power all of those

Alternate Solution 2 is basically the same as AS1, except that its storage receptacle is separate from the unit itself, which allows for an indoor storage unit and outdoor desalination unit, connected by a hose. This would make it easier for families to gain access to their fresh water.

Alternate Solution 3 utilized the property of parabolas to focus light at a point to speed up the solar desalination of a desalination cone. A parabola of mirrors would be constructed around an elevated desalination cone, and the rapidly evaporating water would be carried by gravity to a storage receptacle. This configuration had very little power needs but would be difficult to assemble perfectly for maximum efficiency.

Alternate Solution 4 also uses the sun as the direct power for the distillation of the seawater. The traditional desalination cone is placed on top of a chambered receptacle, which holds the saltwater (to be evaporated) in an inner chamber, and after it evaporates and condenses, it is allowed to run down the sides of the cone into an outer chamber, and thence through a tube into a storage unit where UV light awaits it. The water in the outer chamber is protected from further evaporation by two slanted flaps that allow water to flow past, but block almost all light. The unit would be placed outside and elevated, so that gravity could carry the freshwater down to a storage unit inside the house. The UV lights are the only things that need power.

Selection
  Our group decided to use Alternate Solution 4 for our final product, based on analysis of several factors, including power availability and uptake. This solution drastically decreases the energy used by relying solely on solar distillation, rather than boiling the water many times in many different chambers (AS 1 and 2). The cylindrical, cone-topped shape is compact, with few moving parts for easy installation and maintenance. Also helping with ease of user interface is the screw-off top, making the inside easy to clean of salt residue.

        Since the sun directly desalinates the water from the inner reservoir and the desalination unit will be elevating, utilizing gravity to transfer the freshwater to the storage unit inside, the solar panels will only be needed to power the UV lights that disinfect the water in the storage reservoir. This drastically reduces the number of solar panels needed, which will lower our manufacturing costs and installation difficulty.

    None of our alternate solutions could produce 40 litres solo, so no matter which design we chose, multiple units would need to be assigned to each household. With AS 4, however, the construction of multiple units would be easier, cheaper, and overall more feasible than with the other solutions, which involved many small chambers and moving parts. With AS 4, each small barrel can be hooked up to the same indoor reservoir, and families would not have to worry about a multitude of heat plates or membrane systems outside their house. Overall, this solution is markedly simpler and more efficient, not only for us, the manufacturer, but for the eventual customer.
To see more imagery of our final solution, (WITH EDITS), click here, HERE or here. For an explanation of the edits you see in the additional drawings, click here - 

Below is the Design Matrix used to choose the Final Solution.
Though one of our top specifications is "desalinates and purifies water", all of the Alternate Solutions would accomplish that task, so that specification was divided into Volume and Speed of desalination (Columns 1 and 2). Thus, we can better see which design would be the most practical. 

	Productive (Volume)	Efficient (Speed)	Streamlined (Aesthetics)	Sturdy  (Materials)
AS1	2 Once the center cone is full, volume is set at that small number, unless it is refilled.	3 Though the water might boil faster, it would still have to travel through 9 chambers.	3 With all moving parts hidden inside the box, the machine looks quite streamlined and aesthetically pleasing, barring the sharp corners and/or size	2 Boxes are quite sturdy, but since everything is outside, it is more susceptible to breakage.
AS2	2 Once the center cone is full, volume is set at that small number, unless it is refilled.	2 Though the water might boil faster, it would still have to travel through 9 chambers and a tube.	2 Each component of the device is streamlined, but spreading it from outside to inside makes it less aesthetically pleasing, involves more tubing and such.	3 Keeping the main storage unit inside reduces risk. The box left outside is still quite sturdy.
AS3	1 Only a thin layer of water can be added at a time.	1 With only the sun for heat, water would evaporate slowly, and still have to travel through the tube	1 This requires a lot of outside land area for the mirror array, and the desal component looks like a demented birdbath. No one wants this in their yard.	1  That one pillar on which the desal component stands is absurd. Also, the mirrors will constantly break or go out of alignment.
AS4	4 The double-walled cylinder shape offers high input volume.	4 Heat is more focused, so evaporation will be faster, and there is only one chamber to deal with.	4 Two streamlined cylinders are highly aesthetically pleasing. Maintenance should be a breeze. Highly desirable.	4 Cylinders are good at being outside (ie garbage cans, flagpoles, etc). If weighted properly, this should be perfect.

Total: AS1=9, AS2=10, AS3=4, AS4=16