热力学第二定律 Hot source T H t source Heat Flow of +20 energy +5 -15 Engine Work T 第二类动机 Cold sink 2. Lord Kelvin(1824-1907)In a cycle of processes, it is impossible to transfer heat from a heat reservoir and convert it all into work without at the same time transferring a certain amount of heat from a hotter to a colder body The Second Law第二类永动机 The Second Law 热力学第二定律