Tuesday, September 23, 2008

Einsteinic Fridge Revolution

It's a pretty well known fact that modern fridges and refrigerators are very harmful to the environment. They don't do harm as long as they're functioning. No, the harm begins when they're disposed of, this because the substances that are used to cool the fridge are released into the atmosphere. These substances, freon, or CFC's (short for chloro-fluor-carbon) are terrible greenhouse gasses. Way worse then carbon dioxide!
I hear you ask: "Why don't we just leave them out of our fridges?" Ok here's fridge 101.

In order to cool the air inside your fridge down, heat energy that is contained within it has to be carried away. You may have spotted some sort of a curvy tube on the back of your fridge, this part is crucial to the cooling process (in fact it contains the freon). On the inside of your fridge there's a tube which is almost the same.
Now, there is something which is called a "refrigerator valve". This is a part that makes sure the pressure gets really low in half of the tube system. This results into direct evaporation of all the freon. The temperature almost immediately drops, thus enabling to take up the excess of heat inside the fridge. Then the freon warms up again, passes through a compressor which turns it into a liquid substance again, and the freon releases it's heat. Then it goes through the valve again and like this it goes round and round.

Now, what is this all about you'll be wondering. Back in the olden days Albert Einstein designed his own fridge. An alternative which uses less-harmful substances (ammonia, water and butane). The whole system is under low-pressure which lowers boiling points.

This is just a global sketch. In short there is a container with liquid butane (the one in the middle with the sprinkler above). Then the sprinkler introduces a non-butane vapor causing the butane to evaporate (this becaue the boiling point is lowered by the introduction of the vapor). Since evaporation takes up energy it becomes cold. And thus it's cooled.

For more in-depth information you should definitely check out the feature The Guardian posted about the "Einstein Refrigerator". It's very possible that within a few years everyone owns a fridge based upon Einsteinic ideas.


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