Let's start with a more detailed description:
The solar desalination system has three main components: the solar collector assembly, the salt water container and the condenser. Air is heated up in the collector assembly, then bubbled through the salt water where it becomes saturated with water. In the condenser, most of the water vapor in the air stream is condensed out to recover the fresh water.
Collector Assembly: This consists of an an array of coke/pepsi cans with holes at the the top and bottom and joined end to end. The cans absorb solar radiation and become hot, thereby heating up the air inside them. When the air gets hot, it becomes less dense and starts flowing upwards through the collector channel. This type of flow is know as buoyancy induced flow because it results from density difference created by heating up air.
Salt water container: This is simply a container, for example, a bucket, where you pour the salt water. The hot air from the collector assembly flows through the water, absorbing some of it and becomes humid. The humidity increases until it gets saturated. Saturation is the limit of the water carrying capacity of air. And the hotter the air, the more water vapor it can carry, i.e., the higher the saturation limit.
Condenser: This is where you collect the fresh water vapor in the humid air. The idea is to lower the temperature and increase the amount of ‘cool’ solid surface the humid air comes in contact with in order to condense as much water as possible.
Solar radiation, buoyancy induced flow, air saturation, absorption and reflection of solar radiation, emmissivity.
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Now, let's start building.
Define the size of your system
The larger the collector assembly, the hotter the air gets, and the higher the freshwater yield. The size will also be limited by the number of coke cans you have at your disposal and the amount of space you have. For now let us build a small assembly that is 5 pepsi cans long and 4 pepsi cans wide!
Of course if you prefer coca cola, you could use coke cans . . . or beer cans . . . or several combinations