Application of Thermodynamics

In summary, the Carnot cycle is a theoretical cycle that is not possible in reality. It represents the most efficient cyclical process possible and only involves reversible processes that are adiabatic and isothermal. Any engine that could do this would be called the Carnot engine. Carnot engines, should they exist, have the maximal possible efficiency. Friction and other dissipative processes naturally reduce the efficiency of an engine.

APPLICATION OF THERMODYNAMICS

There are so-called engines, like refrigerators, air conditioners, and heat pumps that are basically heat engines run backwards but not in reverse. Heat transfer runs from a cold reservoir into a hot one, requiring the input of work, which is also going to be converted into heat transfer. This means that the heat transfer cooling the refrigerator will be equal to the heat output plus the work done. The goal is to have the heat transfer to occur from a cool environment into a warm environment, such as a refrigerator in a warm room. Figure 90 shows what this looks like schematically:

Figure 90.