Why the actual thermal efficiency is always less than the Carnot efficiency?
So if all the heat input was converted to useful work, the engine would have an efficiency of one (100% efficient). Thus, the efficiency is always less than one. Carnot showed that the maximum efficiency of a heat engine depends only on the temperatures between which the engine operates, not on the type of engine.
Is it possible to develop an actual heat engine cycle that is more efficient than a Carnot cycle operating between the same temperature limits?
No actual heat engine operating at same temperatures limits produces more efficiency than Carnot heat engine.
Is the Carnot cycle 100% efficient?
You are probably aware that in the Carnot reversible isothermal expansion the heat provided by the high temperature reservoir equals the work done in the expansion. That process converts heat to work at 100% efficiency.
Why Carnot cycle is most efficient?
The Carnot cycle can be thought of as the most efficient heat engine cycle allowed by physical laws. 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.
How efficient is a Carnot engine?
From the Carnot Efficiency formula, it can be inferred that a maximum of 64% of the fuel energy can go to generation. To make the Carnot efficiency as high as possible, either Thot should be increased or Tcold (temperature of heat rejection) should be decreased.
Why is the reversed Carnot cycle impractical?
An isothermal process is practically almost impossible. It can be achieved if the process is very slow(quasistatic) which is not feasible. Therefore, constant pressure heat exchange processes are used instead of isothermal processes and hence, Carnot cycle cannot be used.
What is reverse Carnot heat?
The reverse heat engine is a device that transfers energy from an object at a lower temperature to an object at a higher temperature by doing work on the system.
What is reversible heat?
If a system is in thermal contact with its surroundings, a reversible change can involve the exchange of heat between the system and the surroundings. A system can undergo a change in which it accepts (or liberates) heat while its temperature remains constant.
When heat is removed from a solid what happens?
Adding heat can cause ice (a solid) to melt to form water (a liquid). Removing heat causes water (a liquid) to freeze to form ice (a solid). When water changes to a solid or a gas, we say it changes to a different state of matter.
Is heat released during condensation?
The condensation is the opposite process of evaporation. Latent heat of condensation is energy released when water vapor condenses to form liquid droplets. The temperature does not change during this process, so heat released goes directly into changing the state of the substance. …
Is thermal energy added or removed in melting?
To change matter from a solid to a liquid, thermal energy must be added. The temperature stops rising when it reaches the melting point of the matter. The melting point is the temperature at which the solid changes to a liquid. As aluminum changes from solid to liquid, the temperature does not change.
What happens when you remove heat from a metal rod?
After the heat source is removed, the bar starts to cool down immediately. However, this only means the average temperature of the bar is decreasing. As long as there is a temperature difference, heat will continue to flow from the hotter to the colder regions.
When you heat a metal rod it will expand permanently?
When metal rod is heated it expands because as the temperature increases the atoms starts to vibrate. This vibration of atoms leads to the separation of atoms inside the metals. This separation is not enough to break the bonds between atoms but make them slightly apart. This is known as thermal expansion.
Does heat shrink or expand metal?
Metal arranged in a ring expands outward when heated. Imagine a ring of thin wire being heated–it expands primarily along its length, making both the inner and outer diameters larger. The same occurs with the material around a bolt hole.
What metal expands the most when heated?
potassium metal
Which metal expands least when heated?
Invar, also known as FeNi36, is an iron-nickel alloy notable for its lack of expansion or contraction with temperature changes.
Which expands more with heat aluminum or steel?
The thermally induced change in the length of a thin strip of metal differs for each material. For example, when heated, a strip of steel would expand by half as much as an equal length piece of aluminum.
Does titanium expand with heat?
Linear Coefficient of Expansion. Heating a metal to temperatures below its melting point causes it to expand or increase in length. Titanium has a low coefficient of linear expansion which is equal to 5.0×10-6 inch per inch/°F, whereas that of stainless steel is 7.8×10-6, copper 16.5×10-6, and aluminum 12.9×10-6.