This means that the Carnot cycle is an idealization, since
no real engine processes are reversible and all real physical processes involve some increase in entropy
. The conceptual value of the Carnot cycle is that it establishes the maximum possible efficiency for an engine cycle operating between T
H
and T
C
.
Why efficiency of Carnot engine is higher?
According to carnot’s theorem,
no heat engine is more efficient than a reversible engine within the same temperature limits
. So carnot engine’s efficiency is higher than all irreversible engines.
Why is Carnot cycle more efficient than Rankine?
Carnot cycle is a theoretical cycle whereas the Rankine cycle is a practical one.
Carnot cycle ensures the maximum efficiency under ideal conditions
, but the Rankine cycle ensures the operation in real conditions. The efficiency obtained by the Rankine cycle is always lower than that of the Carnot cycle.
Why is Carnot cycle more efficient than Otto?
The efficiency of Carnot and Stirling cycles
depends only on the ratio of the temperature extremes
whereas the efficiency of Otto and Brayton cycles depends only on the compression ratio.
What is the efficiency of Carnot cycle?
The efficiency of a Carnot cycle is determined only by the temperatures of the hot and cold reservoirs and is calculated using the Carnot efficiency equation:
η=1−TCTH
η = 1 − T C T H .
What is the maximum efficiency of Carnot cycle?
No real heat engine can do as well as the Carnot efficiency—an actual efficiency of
about 0.7
of this maximum is usually the best that can be accomplished. But the ideal Carnot engine, like the drinking bird above, while a fascinating novelty, has zero power.
Why is efficiency not more than 100?
It is not possible to have an efficiency of greater than 1 or an efficiency percentage greater than 100%. This would mean that
more energy is being transferred than is being supplied
, which would mean that energy is being created. This would break the law of conservation of energy.
Why is the efficiency of Carnot engine less than 100%?
The efficiency is 100% only when T
2
is zero or T
1
is infinite. This is not possible since
some amount of heat gets rejected to the sink
.
Why is the efficiency of Rankine cycle less than that of Carnot cycle Mcq?
The reason is that the average temperature at which heat is added in the Rankine cycle lies between T
2
and T
2
‘
and is thus less than the constant temperature T2′ at which heat is added to the Carnot cycle.
Why is Diesel cycle less efficient than Carnot cycle?
Since Carnot’s principle states that no engine can be more efficient than a reversible engine (a Carnot heat engine) operating between the same high temperature and low-temperature reservoirs
, the Diesel engine must have lower efficiency than the Carnot efficiency.
Why is the Brayton cycle less efficient than the Carnot cycle?
The reversible Otto and Brayton cycles
don’t operate between two fixed temperature reservoirs
as does the Carnot cycle. That makes them less efficient.
Which cycle is more efficient Otto or Diesel?
Although for a given compression ratio the
Otto cycle
has higher efficiency, because the Diesel engine can be operated to higher compression ratio, the engine can actually have higher efficiency than an Otto cycle when both are operated at compression ratios that might be achieved in practice.
Which is the more effective way to increase the thermal efficiency of a Carnot engine?
Detailed Solution
The efficiency of the Carnot engine is increased by
decreasing the lower temperature and increasing the higher temperature
but more effects on the efficiency of the Carnot cycle is by decreasing lower temperatures as compared to an increase in higher temperature.
Why is efficiency less than 1?
Since a machine does not contain a source of energy, nor can it store energy, from conservation of energy the power output of a machine can never be greater than its input
, so the efficiency can never be greater than 1.
Can we achieve 100% efficiency?
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.
Is any system 100% efficient?
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
.
How can you increase the efficiency of a Carnot cycle?
The efficiency of the carnot engine can be increased by either
increasing the sink temperature or by decreasing the reservoir temperature
.
On what factor does the efficiency of Carnot engine depends?
The efficiency of a Carnot engine depends solely on
the temperatures of the hot and cold reservoirs
. Carnot’s theorem states that all heat engines operating between two heat reservoirs are less efficient than a Carnot heat engine operating between the same reservoirs.
