Among all cyclic thermodynamic processes specific theoretical and practical application of a Carnot cycle.Often referred to as unbeatable, great, perfect, and so on. D. A lot he does seem to be something mysterious and incomprehensible.However, if the right place all the accents, then immediately open all the simplicity, beauty and genius of this invention, which was discovered by the French scientist and engineer Sadi Carnot.And it becomes clear that there is nothing supernatural in his proposed process, but there is only the most effective use of some of the laws of nature.
So what actually is a famous and mysterious Carnot cycle?It can be defined as a quasi-static process, based on the reduction of the thermodynamic system in thermal contact with a pair of tanks, thermostats, with permanent and stable temperatures.It is assumed that the temperature of the first (heater) higher than the second (refrigerator).The Carnot cycle is that the first thermodynamic system, originally having a specific heat value that comes into contact with the heater.Then, by an infinitely slow decrease in pressure in it is called a quasi-static expansion, followed by borrowing heat from the heater and resistance to external pressure.
The system is isolated, which again is in it for the quasi-static adiabatic expansion until its temperature reaches the similar indicators of the refrigerator.In this type of expansion of the thermodynamic system also performed some work resistance to external pressure.In this state, the system and brought into contact with the refrigerator, wherein by continuously increasing the pressure, it is compressed to a certain point, whereby then sends a full second reservoir heat energy from the heater borrowed.The Carnot cycle is unique because it is not accompanied by a loss of heat.Theoretically, such a scheme can be called a perpetual motion machine.This is because the thermal efficiency of the Carnot cycle, which depends solely on the temperature tank pair will always be the highest possible.However, so far no one has managed to create a machine thermal efficiency which would exceed thirty percent of the permissible cyclical process Sadi Carnot.
And this process is called ideal because it is much better than other cycles is capable of converting heat into useful work.On the other hand, due to the difficulties in organizing isothermal processes its use in actual engines extremely difficult.For maximum efficiency of heat transfer such a machine must be completely isolated from the external environment, which in reality is practically impossible.
reverse Carnot cycle is the basis of the principle of the heat pump, which, unlike the refrigerating machine must give as much power any hot object such as a heating system.Some of the heat is taken from the external environment, a lower temperature, the remaining fraction of the required energy is released when the mechanical work such as a compressor.
