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.
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
.
Why can a Carnot’s engine not get 100% efficiency?
[100% ] efficiency is not possible because
some of the heat of the source will get used up for overcoming friction and other force and therefore full heat of source will not be transferred to the sink
and therefore there exists no ideal source.
Which engine gives 100% efficiency theoretically?
A Carnot engine
operating between two given temperatures has the greatest possible efficiency of any heat engine operating between these two temperatures. Furthermore, all engines employing only reversible processes have this same maximum efficiency when operating between the same given temperatures.
Are machines 100% efficient?
Machines are not 100% efficient
because some of the work done by a machine is used to overcome friction. So work output is always less than work input. 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.
Can devices be 100% efficient?
It
is not possible to have
an efficiency of greater than 1 or an efficiency percentage greater than 100%. … Mechanical devices can be made more efficient through lubrication to reduce the friction between moving parts of a machine and increase the amount of useful energy transferred.
Is Carnot engine 100 percent 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.
Is Carnot cycle 100 percent efficient?
No,, never
. It can be 100c/o only if the sink temperature is zero or the source temperature is infinite (very large value). Carnot is an ideal cycle is provides benchmark to compare efficiency of other cycles. Carnot efficiency is the maximum efficiency that can be achieved in a cycle.
How can we increase the efficiency of heat engine?
Therefore, the efficiency of the heat engine can be increased by
decreasing the temperature of the cold sink or increasing the temperature of the hot source
.
Why is Carnot engine Impossible?
No engine has been built using the cycle named in honor of Carnot
because two parts of the cycle require total insulation
. And two require conduction with one of either the hot or the cold sinks.
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
. Doing that removes energy from the gas so it cools and loses pressure. By repeating the compression of a hot gas and extracting energy using a piston, we can get continuous work.
Why Carnot engine is 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 there any real machine where its efficiency is 100% why?
Answer: In practice
no machine can achieve 100% efficiency
. When you mean 100% efficiency it means your input energy should be completely transformed to output energy. … Various mechanical and electrical losses like friction and eddy current losses are the reasons behind the energy dissipation.
What is the most efficient machine?
“
The bicycle
is the most efficient machine ever created. Converting calories into gas, a bicycle gets the equivalent of 3,000 miles per gallon.” —Bill Strickland Chart by Kirkpatrick Sale ranks energy efficiency from low end (mouse, plane, car) to supreme (human on bicycle).
Can a perfectly efficient system ever be created?
The fact is,
you can’t make a super-efficient system without any waste
. No matter how good of an engineer you are, you can’t invent a perfect engine. … Simply put, a heat engine is a machine or system that converts heat into other forms of energy.
Which device has more efficiency?
Experiments demonstrate a semiconductor device that emits more power as light than it takes in electrically. Physicists have known for decades that, in principle, a semiconductor device can emit more light power than it consumes electrically.
