22. (II) It is not necessary that a heat engine's hot
Chapter 15, Problem 22(choose chapter or problem)
22. (II) It is not necessary that a heat engine's hot environment be hotter than ambient temperature. Liquid nitrogen (77 K) is about as cheap as bottled water. What would be the efficiency of an engine that made use of heat transferred from air at room temperature (293 K) to the liquid nitrogen fuel (Fig. 15-25)?
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