Question

steam engine boiler is maintained
250°C and water is converted into stream. This steam is used to do work and heat is ejected to the surrounding
air at temperature 300K. Calculate the
maximum efficiency it can have?
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Answer 1

Answer:

The novelty toy known as the drinking bird (seen in Figure 1) is an example of Carnot’s engine. It contains methylene chloride (mixed with a dye) in the abdomen, which boils at a very low temperature—about 100ºF . To operate, one gets the bird’s head wet. As the water evaporates, fluid moves up into the head, causing the bird to become top-heavy and dip forward back into the water. This cools down the methylene chloride in the head, and it moves back into the abdomen, causing the bird to become bottom heavy and tip up. Except for a very small input of energy—the original head-wetting—the bird becomes a perpetual motion machine of sorts.