Related Experiment Video
Updated: Apr 10, 2026
09:18
Laser-heating and Radiance Spectrometry for the Study of Nuclear Materials in Conditions Simulating a Nuclear Power Plant Accident
Published on: December 14, 2017
11.2K
Heat devices in nonlinear irreversible thermodynamics
Y Izumida1, K Okuda2, J M M Roco3
1Department of Information Sciences, Ochanomizu University 2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8620, Japan.
Summary
This study uses nonlinear irreversible models to analyze heat devices, revealing how heat leaks and internal dissipations impact engine efficiency and refrigerator performance. Understanding these factors optimizes thermodynamic system design.
Area of Science:
- Thermodynamics
- Nonlinear system analysis
- Heat transfer
Background:
- Traditional thermodynamic models often simplify irreversibilities.
- Understanding nonlinear effects is crucial for real-world heat device performance.
- Heat leaks and internal dissipations significantly affect device efficiency.
Purpose of the Study:
- To investigate the global performance characteristics of heat devices using nonlinear irreversible models.
- To analyze efficiency at maximum power for heat engines and COP at maximum cooling power for refrigerators.
- To elucidate the interplay between heat leaks and internal dissipations in determining device performance.
Main Methods:
- Application of nonlinear irreversible thermodynamic models.
- Analysis of global performance metrics including maximum efficiency and efficiency at maximum power.
- Evaluation of maximum coefficient of performance (COP) and COP at maximum cooling power.
Main Results:
- The interplay between heat leaks and internal dissipations critically influences device performance.
- Nonlinear models provide a more accurate prediction of efficiency and COP under realistic operating conditions.
- Deviations from ideal performance are quantified based on the degree of irreversibility.
Conclusions:
- Nonlinear irreversible models are essential for accurate heat device performance prediction.
- Optimizing heat devices requires careful consideration of both heat leaks and internal dissipations.
- The findings offer insights for designing more efficient heat engines and refrigerators.
Related Concept Videos
01:14Reversible and Irreversible Processes
6.3K
The thermodynamic processes can be classified into reversible and irreversible processes. The processes that can be restored to their initial state are called reversible processes. It is only possible if the process is in quasi-static equilibrium, i.e., it takes place in infinitesimally small steps, and the system remains at equilibrium However, these are ideal processes and do not occur naturally. An ideal system undergoing a reversible process is always in thermodynamic equilibrium within...
6.3K
01:18Entropy
3.9K
The first law of thermodynamics is quantitatively formulated via an equation relating the internal energy of a system, the heat exchanged by it, and the work done on it. A quantitative formulation of the second law of thermodynamics leads to defining a state function, the entropy.
When an ideal gas expands isothermally, the disorder in the gas increases. From the molecular perspective, the gas molecules have more volume to move around in.
Consider an infinitesimal step in the expansion, which...
When an ideal gas expands isothermally, the disorder in the gas increases. From the molecular perspective, the gas molecules have more volume to move around in.
Consider an infinitesimal step in the expansion, which...
3.9K
02:39Entropy
38.1K
Salt particles that have dissolved in water never spontaneously come back together in solution to reform solid particles. Moreover, a gas that has expanded in a vacuum remains dispersed and never spontaneously reassembles. The unidirectional nature of these phenomena is the result of a thermodynamic state function called entropy (S). Entropy is the measure of the extent to which the energy is dispersed throughout a system, or in other words, it is proportional to the degree of disorder of a...
38.1K
01:30The Carnot Cycle
4.5K
Converting work to heat is an irreversible process, and the purpose of a heat engine is to reverse the effect partially. Heat engines aim to increase the efficiency of the reversal, that is, maximize the work retrieved from heat. If the efficiency of a heat engine were 100%, it would imply reversing the process completely without introducing any other effect. Thus, it would violate the second law of thermodynamics.
What could be the theoretical limit to the efficiency of a heat engine? The...
What could be the theoretical limit to the efficiency of a heat engine? The...
4.5K
01:15Statements of the Second Law of Thermodynamics
5.3K
The second law of thermodynamics can be stated in several different ways, and all of them can be shown to imply the others. The Clausius’ statement of the second law of thermodynamics is based on the irreversibility of spontaneous heat flow. It states that heat will not flow from the colder body to the hotter body unless some other process is involved. Additionally, as per the Kelvin’s statement, it is impossible to convert the heat from a single source into work without any other...
5.3K
01:20The Carnot Cycle and the Second Law of Thermodynamics
4.2K
The Carnot engine works between two heat reservoirs of fixed temperatures. The Carnot cycle begs the following question: Is it possible to devise a heat engine that is more efficient than a Carnot engine between two fixed temperatures? The answer lies in designing a Carnot refrigerator.
Since the individual steps in a Carnot cycle can be reversed, the entire cycle is, thus, reversible. If a Carnot cycle is reversed, it becomes a Carnot refrigerator. It extracts heat Qc from a cold reservoir at...
Since the individual steps in a Carnot cycle can be reversed, the entire cycle is, thus, reversible. If a Carnot cycle is reversed, it becomes a Carnot refrigerator. It extracts heat Qc from a cold reservoir at...
4.2K