- #1
AAMAIK
- 47
- 0
Carnot's postulate: one cannot build an engine whose sole effect is to transfer heat from a cold body to a hot body. How granted this postulate can I prove that no engine beats Carnot's engine?
From this postulate, I can conclude that work must be done from the surroundings and that Carnot's hypothetical device can run as both an engine/refrigerator.
I have a Carnot engine which takes QH calories, delivers W1 calories in work, and rejects QL1. Someone claims to have an engine with better efficiency than that of Carnot's engine, this implies that for the same heat input
W2>W1 and QL2<QL1
If I run Carnot's' engine backward, the refrigerator requires W1 calories of work input, to reject QH Calories to the high-temperature reservoir. The two devices are connected such that the work input to Carnot's refrigerator is satisfied. But in doing so I am violating the first law If I define my system to be Carnot's' refrigerator because I am supplying more work than it needs. Also If I define my system to be the two devices altogether excluding the temperature I will violate both the 1st law of thermodynamics and the postulate.
So is my analysis generic and correct?
From this postulate, I can conclude that work must be done from the surroundings and that Carnot's hypothetical device can run as both an engine/refrigerator.
I have a Carnot engine which takes QH calories, delivers W1 calories in work, and rejects QL1. Someone claims to have an engine with better efficiency than that of Carnot's engine, this implies that for the same heat input
W2>W1 and QL2<QL1
If I run Carnot's' engine backward, the refrigerator requires W1 calories of work input, to reject QH Calories to the high-temperature reservoir. The two devices are connected such that the work input to Carnot's refrigerator is satisfied. But in doing so I am violating the first law If I define my system to be Carnot's' refrigerator because I am supplying more work than it needs. Also If I define my system to be the two devices altogether excluding the temperature I will violate both the 1st law of thermodynamics and the postulate.
So is my analysis generic and correct?