In a reversible thermodynamic process, such as a Carnot engine, the change in entropy over a full cycle must be equal to zero. It can be seen that heat has a lower energy quality than mechanical energy or electricity, so this can be used to understand why an amount of heat cannot be converted completely into the same amount of these higher quality forms of energy. Shown in Figure 1, this is represented as the "energy quality", which decreases as the entropy of a system increases. Therefore entropy can be regarded as a measure of the effectiveness of a specific amount of energy. Įntropy can also be described as a system's thermal energy per unit temperature that is unavailable for doing useful work. The maximum disorder of a system occurs when it is at thermal equilibrium, therefore, this is what all isolated systems will tend to over time. This means that the "multiplicity", or number of ways a system can be arranged will never decrease, and that the system will naturally tend to higher disorder. This concept is fundamental to physics and chemistry, and is used in the Second law of thermodynamics, which states that the entropy of a closed system (meaning it doesn't exchange matter or energy with its surroundings) may never decrease. Įntropy is a measure of the number of ways a thermodynamic system can be arranged, commonly described as the "disorder" of a system. This is why low quality heat cannot be transferred completely into useful work. Figure 1: With entropy of a closed system naturally increasing, this means that the energy quality will decrease.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |