You can take heat energy and convert it to work energy and vice versa, and it doesn't say anything about that you have to waste heat if you're going to transform heat into work.

你可以把热能便成功,也可以反过来,但它对于如果你要把热变成功,就必须浪费热量这件事只字未提,它只是说这是能量。

麻省理工公开课 - 热力学与动力学课程节选