 Welcome back Mechanical AI. The Carnot cycle is the most efficient heat engine and the Rankine cycle is what powered the steam engines of the past and the thermal power plants of the present. This makes us wonder, what are Carnot and Rankine cycles? Before we jump in, check out the previous part of this series to learn about what steam tables are. Now, a Carnot cycle is an ideal hypothetical cycle in which all the processes are reversible. The cycle consists of four processes, two reversible isotherms and two reversible adiabatics. First, a reversible constant temperature process called as an isotherm in which heat enters increases the internal energy of the system. Second is a reversible constant entropy process called as a reversible adiabatic process where work is done by the system at the expense of internal energy and the temperature is increased. The third process is a constant temperature process in which heat leaves the system and the internal energy of the system further decreases. The final process is a reversible constant entropy process in which work is done on the system and the internal energy of the system is increased and restored to point one and the temperature rises from T2 to T1. Next comes the Rankine cycle. There are four processes in the Rankine cycle, two of them are isobaric that is constant pressure and two of them are isentropic that is constant entropy. First, the working fluid is pumped at constant entropy from low to high pressure at constant temperature. Second, the high pressure liquid enters a boiler where it is heated at constant pressure by an external heat source to become a dry saturated vapor. Third, the dry saturated vapor expands through a turbine generating power. This decreases the temperature and pressure of the vapor. Fourth, the wet vapor then enters a condenser where it is condensed at a constant pressure to become a saturated liquid. Hence, we first saw what the Carnot cycle is and then saw what the Rankine cycle is. So, here are the top mechanical EIs of our last videos. In the next episode of Mechanical EI, find out what cogeneration is.