A, expression of the second law of thermodynamics
The first law of thermodynamics explains that energy can be neither created nor destroyed and energy transfer and conversion in the number of relations, therefore, the first class of water motivation is not possible. However, the first law of thermodynamics does not exclude the fantasy: the creation of a heat engine, it can absorb heat from a heat source, and for the broken out output mechanical power corresponding number, the engine is called the second kind of water motivation. If the second types of water motivation can be made, the earth does not exist on the energy issue. For example, we can take the ocean as a heat source, the ocean has a total of 6.88 × 10 "t water, if the water temperature is reduced by 1 C, can release 3.88 x 10" kJ heat. About 9.8 × Lo "t standard coal, equivalent to 100000 times the current annual energy consumption in the world. Also, any engine work done finally will be changed into heat energy, and this energy will remain in the earth, the water temperature in the ocean and also won't have what is reduced. Moreover, the sea also continue to absorb solar energy, the temperature even lower, the energy balance of earth, also will eventually rise to the reduction temperature. As the final total. Fruit, this engine is a no cost but can work constantly water motive. Of course the class motivation like water, no one can make out second types of water motivation.
The first law of thermodynamics to the factory energy phase mechanical equivalent relationship between, but did not explain the difference between the two, did not specify the direction of transformation, between the two phase depth. Furthermore, when the heat transfer between the two objects of different temperature, the first law of thermodynamics and points out a body loses energy be equal to another object to get energy, but did not specify the heat transfer direction. In addition, in practice, as we all know, the temperature and heat source, their value is also different, we call this the energy grade difference. The high temperature is called the high grade energy, low temperature is called the low grade energy. A heat carrier, if its temperature is equal to or near the factory environment temperature, regardless of whether it has heat much absolute value, there is no use value. Energy this temperature and taste, reflected not in the first law of thermodynamics in. These questions will be answered in the second law of thermodynamics and the related theorems.
The second law of thermodynamics has many expressions, here are two of them;
(1) Clausius (R.J.E.C1auslus, 1822 - 1888, the German physicist) first proposed in 1850 by the second law of thermodynamics complete: heat not spontaneously, without cost to the other high temperature object from a low-temperature objects.
(E) Tom (w.Thomson, 1824 - 1907, the British physicist, 2 years after 18G said Lord Kelvin (RD KclviE)) in 1851 proposed thermodynamic article:: another important expression of law: impossible -- from single heat source to absorb heat, to make it all into useful work, but don't cause other changes.
Clausius seems more intuitive * easy to accept. In daily life, if a glass of water on the interior, everyone can be observed in the surrounding air, water is exothermic, until the temperature and the temperature of the surrounding air are equal. Conversely, put a cup of ice water in the air, the water is always it is higher than the heat air from the temperature, its temperature will also gradually close to room temperature. Cold water into the air to become more and more cold or hot water to become more and more hot phenomenon has never happened before. Of course it is unthinkable to do
Tom students saying is clearly negative for second types of water motivation. Therefore, the second law of thermodynamics can also be expressed; second kinds of the motivation is not made.
This statement is not Clausius said then, in fact they are completely equivalent. If the argument can not field Musheng was established, that is to say, if we can slope to absorb heat from a single source, and make it into mechanical work without causing other changes, then we can heat by friction heat to mechanical power by heating a higher temperature, so the total effect of heat from a low temperature heat source to another high temperature heat source, without any impact on the outside, thus denying the view of Clausius. On the other hand, if the violation of the view of Clausius, also certainly contrary to Tom the claim. The above description is not proof of the second law of thermodynamics. In fact. The first and second law of thermodynamics is experience, not by macro
Method to prove it, but only by statistical method to explain.
No matter is the first law of thermodynamics and the second law of thermodynamics, are the basic constraint spanning not solve our energy problems, not to go to fantasy invented the first, second types of water motivation to solve the energy problem. |
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