The Otto cycle is more complicated than a Carnot cycle, in a number of ways: ... This makes the engine less efficient that a Carnot engine, because heat is being discharged at a temperature that is not as cool as the environment .
What is the most efficient thermodynamic cycle and why?
Classical thermodynamics indicates that the most efficient thermodynamic cycle operating between two heat reservoirs is the Carnot engine [1] , and a basic theorem expresses that any reversible cycle working between two constant temperature levels should have the same efficiency as a Carnot cycle [2].
Which is the most efficient cycle?
The most efficient heat engine
Why is Carnot cycle most efficient?
The Efficiency of Carnot’s Cycle
Practical engine cycles are irreversible and thus have inherently lower efficiency than the Carnot efficiency when operating at the same temperatures. ... The Carnot cycle achieves maximum efficiency because all the heat is added to the working fluid at the maximum temperature .
Is any cycle possible 100% efficiency?
But that work equals the heat into the system minus heat rejected, for an efficiency of less than 100% . All heat engine cycles must reject some heat for an efficiency of less than 100%.
Is Carnot engine 100 efficient?
In order to achieve 100% efficiency (η=1), Q 2 must be equal to 0 which means that all the heat form the source is converted to work. The temperature of sink means a negative temperature on the absolute scale at which the temperature is greater than unity.
What is K in Otto cycle?
Thermal Efficiency Derivation
A typical value for an air/fuel mixture is k = 1.35 .
Why is Carnot cycle Impossible?
In real engines, the heat transfers at a sudden change in temperature whereas in a Carnot engine, the temperature remains constant. In our day to day lives, reversible processes can’t be carried out and there is no such engine with 100 % efficiency. Thus, the Carnot cycle is practically not possible .
Why is a heat engine not 100% efficient?
A heat engine is considered to be 100% efficient if only all the heat is converted into useful work or mechanical energy . Since heat engines cannot convert all the heat energy into mechanical energy, their efficiency can never be 100%.
Is Carnot cycle reversible?
The Carnot heat-engine cycle described is a totally reversible cycle . That is all the processes that compose it can be reversed, in which case it becomes the Carnot refrigeration cycle. This time, the cycle remains exactly the same except that the directions of any heat and work interactions are reversed.
Which heat engine is the most efficient?
The most efficient heat engine cycle is the Carnot cycle , consisting of two isothermal processes and two adiabatic processes. The Carnot cycle can be thought of as the most efficient heat engine cycle allowed by physical laws.
What is Carnot principle?
Carnot’s theorem, developed in 1824 by Nicolas Léonard Sadi Carnot, also called Carnot’s rule, is a principle that specifies limits on the maximum efficiency any heat engine can obtain . The efficiency of a Carnot engine depends solely on the temperatures of the hot and cold reservoirs.
Can we make Carnot heat engine in real?
A Carnot engine has to be perfectly reversible . This means zero friction, and perfect thermal conductivity between reservoirs * . In practice neither of these things are possible so you will only ever get “close”.
Can we consider heat engine 100% efficient?
It is impossible for heat engines to achieve 100% thermal efficiency () according to the Second law of thermodynamics. This is impossible because some waste heat is always produced produced in a heat engine, shown in Figure 1 by the term.
Are the engines 100% efficient if not what happens to the remaining percent?
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.
What is the maximum efficiency?
uncountable noun. Efficiency is the quality of being able to do a task successfully, without wasting time or energy.
