Table of Contents
- 1 Is it possible to have 100 efficiency for an engine?
- 2 Under what condition the efficiency of a reversible heat engine is 100 \%?
- 3 What is reversible heat engine?
- 4 Which of the following engines have 100 efficiency?
- 5 What is the reversibility of Carnot engine?
- 6 How do you calculate work done by a reversible heat engine?
Is it possible to have 100 efficiency for an engine?
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.
Under what condition the efficiency of a reversible heat engine is 100 \%?
For engine to be 100\% efficient, all input energy would need to be converted into useful output energy.
Can you develop a heat engine with 100\% efficiency?
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\%. The modern heat engines built with further improved designs have 40\% efficiency.
Can a Carnot engine be 100 efficient?
In order to achieve 100\% efficiency (η=1), Q2 must be equal to 0 which means that all the heat form the source is converted to work. Hence negative temperature of absolute scale is impossible and we cannot reach absolute 0 temperature. …
What is reversible heat engine?
Answer. The engine, in which the process can be retraced at any stage of its operation by reversing the boundary conditions, is called a reversible heat engine. Its efficiency is maximum, as no dissipation of energy takes place against friction, etc in such a heat engine.
Which of the following engines have 100 efficiency?
Carnot engine
The Carnot engine is the most efficient engine in converting heat energy to work done in a system but no practical Carnot engine can be 100\% efficient in reality.
Which of the following have 100 efficiency?
A simple machine, such as a lever, pulley, or gear train, is “ideal” if the power input is equal to the power output of the device, which means there are no losses. In this case, the mechanical efficiency is 100\%.
Why is a reversible car engine called reversible?
Carnot engine is called reversible because there is no change during compression and expansion and there is an isothermal process that occurs a problem in real life.
What is the reversibility of Carnot engine?
Reversibility is a condition imposed on “Carnot Engine”, which is a theoretical engine, that will not exists in real life. Reason is because the engine is assumed not to lose any of its energy in anyway.
How do you calculate work done by a reversible heat engine?
Over a cycle, this work, δW, is exactly equal to the heat input, δQ, to the cyclic engine, i.e. The work done by the reversible heat engine is equal to the heat input minus the heat output, i.e. Now we can express the total work done by the system, as follows
Can a reversible heat engine work on the environment?
Nikolaos D. Katopodes, in Free-Surface Flow, 2019 Next, consider a reversible heat engine that absorbs heat, δQ0, from a reservoir held at constant temperature, T0, as shown in Fig. 2.33. The engine is assumed to do work, δW0, on the environment.