As a result, entropy is usually expressed as a change in the entropy of the system indicated by ∆S. The entropy of a system is defined as the number of changes it has undergone from its prior condition to its current state. Let’s look at the definition of entropy and how it relates to the second rule of thermodynamics. Here, ΔS univ is a change in the universe’s entropy. The second law of thermodynamics is expressed mathematically as As a result, we may conclude that the two versions of the second law of thermodynamics are equivalent in every way. When the engine and the refrigerator operate together, they create a mechanism that absorbs all of the heat from the hot body and transforms it into work without sacrificing any of the cold body’s heat. The engine does not break the second law of thermodynamics on its own. Assume that an engine operating between the same hot and cold bodies absorbs heat from the hot body, transforms a portion W into work, and then transfers the remaining heat to the cold body. As a result, Clausius’ assertion is violated. Clausius’s assertion is used by heat pumps and refrigerators.Ī refrigerator, for example, can transfer a certain amount of heat from a cold body to a hot one without requiring any external energy. In other words, the refrigerator will not work unless the compressor is powered by an external source. It is impossible to build a technology that can transmit heat from a colder body to a warmer body without wasting any energy. This indicates that a sink is required to get continuous work. No engine can transform all of the heat from the source into work without wasting any heat. The working material of a heat engine absorbs heat from a hot body, transforms a portion of it into work, and returns the remainder to the cold body. It’s difficult to turn all of the heat emitted by a heated body into work. Different Statements for Second Law thermodynamics The Law of Increased Entropy is another name for the second law. The overall entropy of a system and its surroundings remains constant in some instances where the system is in thermodynamic equilibrium or going through a reversible process. In basic terms, the law states that the entropy of an isolated system will never decrease over time. This is why operating an air conditioner for an extended length of time is expensive.Īccording to the second rule of thermodynamics, any spontaneously occurring event will always result in an increase in the universe’s entropy. According to the second rule of thermodynamics, heat energy cannot be transferred from a lower temperature to a higher temperature without the addition of energy. If you’ve ever dropped a glass and watched it shatter, you know there’s no way of getting the unbroken glass back. But what exactly does it say? Let’s look at it more. The first and second principles of thermodynamics must be satisfied for a process to take place. The second law of thermodynamics is the criterion for determining if a process is feasible. Certain things only operate one way and not the other. We clean our rooms once and then they become filthy again in no time. The law can only declare that if the process occurs, there will always be an energy balance. The first law does not explain how a metallic bar of uniform temperature may grow warmer at one end and cooler at the other. While the first law of thermodynamics provides information on the quantity of energy transferred in a process, it does not provide any information about the direction of energy transfer or the quality of energy transferred. The first rule of thermodynamics says that the universe’s energy stays constant, even though energy may be transferred across systems and environments but not generated or destroyed. The direction of heat transmission and the efficiency of heat engines are constrained by the second law of thermodynamics.