Thermodynamics is concerned with the study of heat and energy. At its center, laws describing how the energy moves within the system is that it is an atom, a hurricane, or a black hole. The first law describes how energy can not be produced or destroyed, can only be transmitted from one form to another. The other law, though, is probably more familiar and even deeper because it describes the limits of the action of the universe. This law is about inefficiency, degeneration and decay. Tell us that everything we do is inherently frustrating and that there are irreverible processes in the universe. It gives us the time and tells us that our universe has an indescribably tense, desolate destiny.
Despite these somewhat defeating ideas, the ideas of thermodynamics were shaped at the time of the greatest technological optimism – the era of the industrial revolution. During the mid-19th century, physicists and engineers built steam engines for the mechanization of work and transportation, and thought to make them more powerful and more efficient.
Many scientists and engineers, including Rudolf Clasius, James Joule, and Lord Kelvin, contributed to the development of thermodynamics, but the father of discipline was French physicist Sadi Carnot. In 1824, he published a review of the “Rheflexions sur la puissance motrice du feu”, a work in which he laid down the basic principles he came to observe the movement of energy within the engine and the connection between the heat consumed and the usefulness work.
Another law can be explained in several ways, and the simplest is that the heat naturally goes from the warmer to the colder body. At the heart of this is the property of thermodynamics called entropy – in the equations in the figure the sign is “S” – the measure of the amount of disorder within the system. This can be demonstrated in several ways, for example in the arrangement of molecules of water molecules in ice cubes in a greater order than after heating in the gas. Water molecules in ice cubes are within a well-defined grate, while the gas floats unpredictable. Entropy of ice cubes is therefore less than gas entropy. Similarly, the entropy plate is larger when it is in pieces on the floor than when it is in the sink in one piece.
Formal definition of entropy for heat moving within the system is given in the first equation. The infinitesimal change in the entropy of the system (dS) is calculated by measuring the amount of heat entering the closed system (δQ), which is then divided by the common temperature (T) at the point where the heat transfer occurred
Another equation is the way of describing another law of thermodynamics in relation to entropy. The formula says that the entropy of an isolated natural system always tends to remain the same or increase – in other words, energy in the universe is gradually moving towards disorder. Our initial description of the second law is derived from this equation: heat can not spontaneously flow from a cold object (low entropy) to a warm object (high entropy) in a closed system because it would violate the equation. (The fridge seems to violate this rule because they can freeze things to a much lower air temperature around them.) But refrigerators do not violate another law because they are not isolated systems – they have a constant amount of electricity that exudes heat from their interior. would turn off the current, naturally return to the thermal equilibrium with the space.)
This formula sets the direction of time; while any other physical law we know was the same regardless of whether time goes in advance or backward, this is not exactly the second law of thermodynamics. A boiling water can hardly ever become an ice cube, as long as it is time to leave it on the source of heat. Broken plate will never be re-assembled because it would reduce the entropy of the system by breaking another thermodynamic law. Some processes are irreversible, Carnot noticed.
Carnot has been studying steam engines fueled by combustion to heat a cylinder containing vapor, which then spreads and compresses the clip, which then makes some useful. Part of the energy extracted from the fuel is doing something useful, what is called work, and the rest is the lost (and disordered) energy that we call heat. Carnot has shown that the theoretically maximum steam engine efficiency can be predicted by measuring the difference in the vapor temperature inside the cylinder and the air around it, which is termed in thermodynamics as the hot and cold reservoirs of the system
Heat engines work because the heat naturally goes from warm to cold places. When there was no cold tank to move, there would be no heat flow and the engine would not work. No heat engine can be 100% efficient because the cold tank is always above the absolute zero.
The best designed engines therefore heat the steam (or other gas) to the maximum possible temperature and then release the exhaust gas at the lowest possible temperature. The most modern steam engines deliver up to 60 percent of efficiency, and diesel engines in cars have an efficiency of around 50 percent. Gasoline internal combustion engines disperse much more fuel from fuel
Inefficiencies are part of every energy-efficient system and can be described thermodynamically. This lost energy means that the overall mess of the universe – its entropy – will eventually increase, but at some point will reach its maximum. At this point in an unimaginably distant future, the energy of the universe will be equally distributed and will, for all macroscopic purposes, be useless. Cosmologists call this “thermal death” of the universe, the inevitable consequence of an unstoppable entropy march.