How do you calculate second law efficiency?

Asked By: Artemi Zubilaga | Last Updated: 10th May, 2020
Category: science physics
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The temperatures here should be in Kelvin → K = ºC + 273.15 or Rankin = 460 + ºF. 2. Second Law Efficiency Second Law efficiency is a measure of how much of the theoretical maximum (Carnot) you achieve, or in other words, a comparison of the system's thermal efficiency to the maximum possible efficiency.

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Consequently, what do you mean by second law efficiency?

Exergy efficiency (also known as the second-law efficiency or rational efficiency) computes the effectiveness of a system relative to its performance in reversible conditions. It can also be described as the ratio of the useful work output of the system to the reversible work output for work-consuming systems.

Also, what is First Law efficiency? FIRST LAW EFFICIENCY. The first law states that energy cannot be created or destroyed, but can be converted from one form. to another.

Besides, what is the difference between 1st and 2nd Law Efficiency?

The basic difference between both concepts is that while first law efficiency solely relates to the specific technology applied in order to satisfy certain tasks, for example, illumination and space heating, the concept of second law efficiency takes into account both the actual technology employed and the technology

What is Carnot efficiency?

The Carnot Efficiency is the theoretical maximum efficiency one can get when the heat engine is operating between two temperatures: The temperature at which the high temperature reservoir operates ( THot ).

35 Related Question Answers Found

What is Exergy destruction?

The exergy destruction of a cycle is the sum of the exergy destruction of the processes that compose that cycle. The exergy destruction of a cycle can also be determined without tracing the individual processes by considering the entire cycle as a single process and using one of the exergy destruction equations.

What symbol represents internal energy in the first law of thermodynamics?

Then the first law of thermodynamics (ΔU = Q − W) can be used to find the change in internal energy.

What is irreversibility in thermodynamics?

An irreversible process is a process that cannot return both the system and the surroundings to their original conditions. That is, the system and the surroundings would not return to their original conditions if the process was reversed.

What is Exergy balance?


Exergy balance consists of internal exergy loss, and represents the results of exergy analysis. In accordance with the second law, the exergy destruction is positive in an irreversible process and vanishes in a reversible process. The change in exergy of a system can be positive, negative, or zero.

What is refrigerator in thermodynamics?

A refrigerator is a device which is designed to remove heat from a space that is at lower temperature than its surroundings. Effectively any heat engine cycle, when reversed, becomes a refrigeration cycle. The vapor compression cycle is the most commonly used in refrigeration and air condition applications.

What is the First Law and Second Law of Thermodynamics?

Key Points. The first law, also known as Law of Conservation of Energy, states that energy cannot be created or destroyed in an isolated system. The second law of thermodynamics states that the entropy of any isolated system always increases.

What does the second law of thermodynamics mean?

The First Law of Thermodynamics states that energy cannot be created or destroyed; the total quantity of energy in the universe stays the same. The Second Law of Thermodynamics is about the quality of energy. It states that as energy is transferred or transformed, more and more of it is wasted.

What is an example of the second law of thermodynamics?

There are two statements of second law of thermodynamics. Kelvin Plank statement: The best example of this statement is Human Body. We eat food (High temperature reservoir). When we do some work our body warms up and rejects heat into the environment (Low temperature reservoir).

What is concept of entropy?


Entropy, the measure of a system's thermal energy per unit temperature that is unavailable for doing useful work. Because work is obtained from ordered molecular motion, the amount of entropy is also a measure of the molecular disorder, or randomness, of a system.

What does the First Law of Thermodynamics mean?

The First Law of Thermodynamics states that heat is a form of energy, and thermodynamic processes are therefore subject to the principle of conservation of energy. This means that heat energy cannot be created or destroyed.

What is efficiency in thermodynamics?

Definition of thermodynamic efficiency. : the ratio of work output to heat-energy input in a heat-engine cycle or of heat energy removal to work input in a refrigeration cycle.

What is Thermodynamics The study of?

Thermodynamics is a branch of physics that deals with heat and temperature, and their relation to energy, work, radiation, and properties of matter. The initial application of thermodynamics to mechanical heat engines was quickly extended to the study of chemical compounds and chemical reactions.

What is the difference between light and heat?

Heat and light are different but they are both forms of energy. Heat is a form of kinetic energy contained in the random motion of the particles of a material. Light is a form of electromagnetic energy. The higher the temperature of the object, the shorter the wavelength of the EM radiation.

What is the difference between Exergy and energy?


Exergy is consumed due to irreversibilities. Exergy consumption is proportional to entropy creation. The main important difference between energy and exergy: energy is conserved, while exergy, a measure of energy quality or work potential, can be consumed.

Is Carnot engine 100 efficient?

No,, never . It can be 100℅ 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.

What is thermal efficiency of an engine?

The thermal efficiency of a heat engine is the percentage of heat energy that is transformed into work. Thermal efficiency is defined as. The efficiency of even the best heat engines is low; usually below 50% and often far below.