Category:First Law and Its Applications

From ThermoWiki

In many processes, work can make a significant contribution to the total energy requirement. We extract work from systems to drive turbines, water wheels, and propellers on ships; in such cases, we want to maximize the amount of work extracted. We do work on systems to drive compressors, pumps, and blowers; in these cases, we aim to minimize the amount of work that must be supplied. However, work is a process variable, so its magnitude generally depends on how the process is performed. But in calculating energy requirements, we prefer to deal with system properties rather than process variables.

The First Law connects the change in a system property to the amounts of heat and work (troublesome path functions) involved in a process. More remarkably, the First Law asserts that the total energy of system plus surroundings is conserved for any process. This fact guides every analysis and every design of any process in which energy is transformed from one form to another.