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Perpetual motion machine of the second kind

Perpetual motion machine of the second kind


 Perpetual motion machine of the second kind is a machine which produces work from a single heat source. In this kind of perpetual motion machine, there is only one heat reservoir, and it is being spontaneously cooled generating work without heat transfer to a cooler reservoir. The prototype machine of this kind was the ammonia motor (called zeromotor) proposed in 1880s by John Gamgee. In ammonia motor, the heat reservoir is filled with ammonia. Ammonia boils at -33° C. It would be vaporized under ambient temperature, producing a vapor pressure of 4 atm that would drive a piston. As the vapor expanded it would also cool, condense and return to the reservoir for the next cycle. This kind of machine is impossible, since it violates the Second law of thermodynamics. Heat cannot be transferred from a colder to a hotter body. Therefore, it must be cooled by refrigeration for the ammonia to be condensed, which requires more energy than the energy produced by engine.

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This article is from the free online course:

Thermodynamics in Energy Engineering

Hanyang University