Carnot’s interesting result implies that 100% efficiency would be possible only if Tc = 0 K—that is, only if the cold reservoir were at absolute zero, a practical and theoretical impossibility.
In which condition the efficiency of Carnot engine is 100%?
The efficiency of a Carnot’s engine at a particular source and sink temperature is 12 . When the sink temperature is reduced by 100∘C, the engine efficiency, becomes 23.
Can a heat engine be 100 efficient?
Heat engines often operate at around 30% to 50% efficiency, due to practical limitations. It is impossible for heat engines to achieve 100% thermal efficiency () according to the Second law of thermodynamics.
What is the efficiency of a Carnot engine?
The Carnot Efficiency is the theoretical maximum efficiency one can get when the heat engine is operating between two temperatures: The temperature at which the high temperature reservoir operates ( THot ). The temperature at which the low temperature reservoir operates ( TCold ).
Why can’t we have 100 efficiency?
Explanation: No machine is free from the effects of gravity, and even with wonderful lubrication, friction always exists. The energy a machine produces is always less than the energy put into it (energy input). … That is why 100% efficiency in machines shall not be possible.
What is Newton’s second law of thermodynamics?
The Second Law of Thermodynamics is about the quality of energy. It states that as energy is transferred or transformed, more and more of it is wasted. The Second Law also states that there is a natural tendency of any isolated system to degenerate into a more disordered state.
Can a Carnot heat engine attain 100% efficiency justify your answer?
The efficiency of a heat engine can be 100% only if all the heat energy gets converted into work (or mechanical energy). … Since heat energy can never be transformed completely into mechanical energy, so the efficiency of a heat engine can never be 100 per cent.
Which Stirling engine is the most powerful?
One of the most efficient Stirling engines ever made was the MOD II automotive engine, produced in the 1980′s. It reached a peak thermal efficiency of 38.5%. Compare this to a modern spark-ignition (gasoline) engine, which has a peak efficiency of 20-25%.
Can we consider heat engine 100% efficient Why Why not?
100 percent efficient engine is not possible. In reality, heat engines are inefficient systems. The input is not equivalent to the output of the system. This is because engine efficiency is reduced by friction.
Why are heat engines so terribly inefficient?
But yes, heat engines are generally quite inefficient. Ultimately, it’s because heat itself is a fairly inaccessible form of energy. It’s just the random motion and vibration of molecules, and because it’s random, the overall direction of that motion is just a statistical average.
Is Carnot engine possible?
While Carnot engines are ideal engines, in reality, no engine achieves Carnot’s theoretical maximum efficiency, since dissipative processes, such as friction, play a role. Carnot cycles without heat loss may be possible at absolute zero, but this has never been seen in nature.
Which cycle has highest efficiency?
Explanation: Otto cycle is more efficient than Diesel cycle for a given compression ratio. 6. For constant maximum pressure and heat input, the air standard efficiency of the gas power cycle is in the order.
Why is efficiency less than 1?
It is usually the ratio of the power delivered by a mechanical system to the power supplied to it, and, because of friction, this efficiency is always less than one. For simple machines, such as the lever and the jackscrew, the efficiency is the actual load lifted divided by the theoretical force delivered.
Can a machine be 100% efficient?
In other words, no machine can be more than 100% efficient. Machines cannot multiply energy or work input. … If a machine were 100% efficient then it can’t have any energy losses to friction, so no friction can be present.
How can you be 100% efficient?
Heat, sound, and mechanical energy are all unwanted byproducts. So if you put in 100 watts of power and get 50 watts of light the system is 100% efficient. There is a principle called “unity efficiency” that can allow you to produce MORE than 100% of the input.
Is 100 percent efficiency possible?
Efficiency is the percent of work put into a machine by the user (input work) that becomes work done by the machine (output work). The output work is always less than the input work because some of the input work is used to overcome friction. Therefore, efficiency is always less than 100 percent.