Simple Guide On Carnot Cycle

The Carnot cycle (also known as the Carnot heat engine) is one of the most important concepts in thermodynamics. While it may seem complex and abstract at first, this guide will make things simple by breaking down the components of the Carnot cycle, walking you through how they operate together, and exploring their significance in terms of adiabatic processes, otto cycles, and efficiency of Carnot engines. By the end of this article, you’ll understand everything you need to know about the Carnot cycle to apply it to your career or hobby.

What exactly is the Carnot cycle? In its most basic form, it’s an idealized process that describes how to convert heat into work. The Carnot cycle was developed by Nicolas Léonard Sadi Carnot in 1824 when he was trying to develop an engine that could produce more power than the steam engines of his day.

Adiabatic process

In a thermodynamic system that is undergoing an adiabatic process, no heat enters or leaves it. If a change in entropy occurs, it is due only to work done on or by the system (in contrast to other kinds of processes, where heat and work are different forms of energy transferred into or out of a system). 

A modern example is air conditioning (see air conditioner), which employs adiabatic expansion for cooling. Other common occurrences are pressure-volume work and compression-volume work. Adiabatic heating occurs when no external work is performed on a system; instead, its thermal energy is raised through non-mechanical means such as insulation, internal reflection, and absorption.

Otto cycle

In a Carnot engine, an otto cycle occurs when there is a return stroke. The engine absorbs heat from its surroundings on both sides of a piston—as well as through radiation—but it releases only during a power stroke. The efficiency of the Carnot engine is improved by ensuring that all heat energy absorbed goes toward work to reduce waste energy. 

Since we want any remaining heat energy to go towards work in our Carnot engine, efficiency increases with smaller gas volume and shorter gas expansion time due to low pressure; therefore, as pressure rises along with temperature at constant volume, efficiency falls. In other words, limiting expansion reduces wasted energy and thereby increases network efficiency.

The efficiency of Carnot engine

Carnot cycle efficiency, named after its inventor Nicolas Léonard Sadi Carnot, is concerned with how much energy can be converted from heat to work. In contrast to other thermodynamic cycles such as Otto or Diesel, which rely on a mixture of heat and pressure to transfer energy from fuel to vehicle, a Carnot engine requires only temperature differences. 

Low entropy in hot sources allows for high efficiency through greater expansion of gases into colder sinks. Reversing operation of the Carnot cycle is also more efficient than Otto and Diesel cycles. To return all liquid in the system back to its original state, (reversing any adiabatic process), 100% of heat content must be extracted.

Limitations of the Carnot cycle

The Carnot cycle is an efficient approach that can’t be used in real engines. It only works if the actual temperatures of the cold reservoir (T1) and hot reservoir (T2) are equal or within a small range of each other. You need to burn methane and it needs to be confined to a closed cylinder for the cycle to work optimally. 

Also, the adiabatic process (which the engine goes through for the Carnot cycle to happen) would take an infinite amount of time outside the world of thermodynamics. That said, it does give us insights into how real-world cars operate, what makes them more efficient than others, and why most production cars are still so much less efficient than they could be using modern technology.

Conclusion

The Carnot cycle describes an idealized thermodynamic system in which heat does not enter or leave the system during its cycles of operation, the two processes of which are described as the high-temperature process and the low-temperature process. The Carnot cycle is named after Nicolas Léonard Sadi Carnot, who was one of the founders of thermodynamics.