You have surely heard of the dippy bird, right? This is a contraption that looks like a bird that is drinking from a cup of water. But have you heard of the dippy bird power? Probably not.
There had been some speculation, for a long time now, about generating power based on the concept of the dippy bird. Nobody has made this idea into reality – or at least, we have not heard of it yet. But is it possible to use the dippy bird to create a large scale power source? Let us explore what makes this bird move.
This drinking bird is basically a simple heat engine. It is able to use the difference in temperature to convert heat energy into pressure. This conversion makes the mechanical work happen – which is manifested in the movement of the drinking bird. The whole concept works around a thermodynamic cycle.
Here’s how the dippy bird power is manifested. The bird is in a vertical position with a wet beak. As the water evaporates, it lowers the temperature on the head of the bird. The decrease in temperature causes the condensation of the dichloromethane vapor in the head. When the change in temperature and the condensation happens, it causes the drop of pressure in the head. The higher vapor pressure that happens in the warmer base causes the liquid to be pushed up the neck of the bird.
When the liquid goes up the neck, the upper portion of the bird becomes heavy – causing it to tip over. When this happens, the bottom end of the neck tube is brought higher than the surface of the liquid. As this motion happens, the bubble of warm vapor goes up the tube , and it displaces the liquid in the process. This causes the liquid to flow back to the bottom bulb. The pressure is then equalized between the top and bottom bulb. Since the bottom bulb is now heavier, the bird goes back to its original vertical position. The ambient air causes the liquid at the bottom bulb to heat up – which is slightly higher than the temperature in the bird head.
This process is repeated when a cup of water is placed in front of the bird so the beak is constantly wet as the head goes down. As long as the beak of the bird is wet, this motion will keep on happening.
It has to be understood that the source of energy that makes this bird move is in the temperature changes between the head and base of the toy. It is said that the evaporative heat flux that is causing the small bird to move is around half a watt. The mechanical power exhibited by the bird’s motion is said to be 1/20,000 of a watt.
So the question remains: can the dippy bird power be replicated to provide power on a large scale?
Possibly. However, you have to realize that the more energy you want to extract from the system, the bigger the difference in temperature needs to be.
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