Is it possible to attain an efficiency of 100 percent in heat engines?

Answer 1

The maximum efficiency of the carnot engine only depends on two factors:

1 - The temperature of the hot reservoir (TH)

2 - The temperature of the cold reservoir (TC)

And is given by (TH - TC) / TH « or » 1 - TC / TH So by that we can see the maximum efficiency (100%) would be when the difference of temperatures between the two reservoirs is infinite.

Answer 2

now the Carnot efficiency or in other words one defines efficiency as heat given the system from which the maximum work is extracted since heat transfer takes place from a body at high temperature to the body comparatively at lower one and hence there is no engine which does the opposite thing unless and until the ambient temperature is at a lower temperature.

the efficiency depends on the ambient temperature whether it being lower or higher .............

Answer 3

heat engine can never attain 100% efficiency or other wise it will not work. According to second law of thermodynamics.

explanation: suppose a heat reservoir at higher temperature acting as source and an heat reservoir at lower temperature acting as a sink and a heat engine is operating between them. And heat q1 flows to heat engine and reject heat q2 (which is reason for not having 100% efficiency) and produces work w.

But to have 100 percent efficiency q2 must be zero, so let us make it zero. Now what happens??

Note: Now we can remove sink at lower temperature because there is no use of sink AND ONLY SOURCE AND ENGINE ARE THERE AND NOTHING ELSE.

Now what is the temperature of the engine?? The temperature of engine is same as of source. AND NOW SOURCE AND SINK ARE AT SAME TEMPERATURE SO HEAT CAN'T FLOW TO ENGINE AND ENGINE WILL NOT WORK.

That is why q2 must be released to sink to link the engine to the lower temperature so that there would be temperature difference between engine and source and heat can flow.

NOTE: Friction or other dissipative effects are not the reason for not having 100% efficiency theoretically. Many people have this confusion. This law is not so simple.

Answer 4

The Carnot's heat engine is a ideal heat engine.In this process the source has infinite heat capacity and the temperature of the source is constant( when we take large amount of heat from the source but it has same temperature ) .This is one assumption. The sink is also this condition means if it gain heat energy from the source the temperature of the sink is also constant . this is another assumption. Ideal gas works as working substance(system).

enclose in a cylinder whose walls and piston are perfectly adiabatic and base is perfectly diathermic.conversion of heat to work is an irriversible process but in carnot's heat engine it is possible.the initial temparature of system is infinite it is depend on temparature of the system.

the perfect ideal gas and the perfect insulators are not exist so this process is only assumption.

Answer 5

Efficiency is defined as output power divided by input power.The efficiency of a heat engine - for specific temperatures - cannot be greater than the efficiency of the theoretical Carnot engine.

Answer 6

Anywhere from 0% to 99%+. Below 0% is impossible; there is no such thing as negative work. 100% and above is impossible by the 1st and 2nd laws of thermodynamics.

Answer 7

Depends on the ration between the exhaust and intake temperatures

Answer 8

I read a scientific article by Ormat (Israeli company) who claim they reached 20%.

Answer 9

No, it is not possible