ABSTRACT
This chapter introduces the second law of thermodynamics from the perspective of the performance of devices that execute a cyclic process. It discusses different statements of the law. The chapter examines their equivalence, and describes limits imposed by the second law on how best the devices can perform. It deals with the development of the second law with a description of cyclic devices. Right from the beginning, inventors focused on developing engines that operate in a cycle and convert heat into work. The emphasis on cyclic operation stemmed from the fact that, such engines can operate continuously and forever. Since the Kelvin-Planck statement is applicable to direct heat engines and the Clausius statement is applicable to reverse heat engines, the possibility that a device may violate one but not the other, if real, would be a vexing dilemma.
