Comment on Makarieva et al . ‘A critique of some modern applications of the Carnot heat engine concept: the dissipative heat engine cannot exist’

2010 ◽  
Vol 467 (2125) ◽  
pp. 1-6 ◽  
Author(s):  
Marja Bister ◽  
Nilton Renno ◽  
Olivier Pauluis ◽  
Kerry Emanuel
Keyword(s):  
Wind Speed ◽  
Heat Engine ◽  
Dissipative Heating ◽  
Dissipative Heat ◽  
External Objects ◽  
Laws Of Thermodynamics ◽  
Physical Laws ◽  
Work Done ◽  
Fundamental Physical ◽  
Engine Concept

Makarieva et al . (2010) assert that a dissipative heat engine is impossible and criticize earlier published work that they claim violates the laws of thermodynamics. Here we show that the earlier work does not violate fundamental physical laws and suggest that Makarieva et al . (2010) were misinterpreting expressions for wind speed as ones for work done on external objects. Moreover, we dispute their assertion that dissipative heating is necessarily compensated by a reduction of external heating.

scholarly journals A critique of some modern applications of the Carnot heat engine concept: the dissipative heat engine cannot exist

2010 ◽  
Vol 466 (2119) ◽  
pp. 1893-1902 ◽  
Author(s):  
Anastassia M. Makarieva ◽  
Victor G. Gorshkov ◽  
Bai-Lian Li ◽  
Antonio Donato Nobre
Keyword(s):  
Heat Input ◽  
Heat Engine ◽  
External Heat ◽  
Mechanical Work ◽  
Physical Models ◽  
Carnot Cycle ◽  
Engine Model ◽  
Dissipative Heat ◽  
Internal Dissipation ◽  
Engine Concept

In several recent studies, a heat engine operating on the basis of the Carnot cycle is considered, where the mechanical work performed by the engine is dissipated within the engine at the temperature of the warmer isotherm and the resulting heat is added to the engine together with an external heat input. This internal dissipation is supposed to increase the total heat input to the engine and elevate the amount of mechanical work produced by the engine per cycle. Here it is argued that such a dissipative heat engine violates the laws of thermodynamics. The existing physical models employing the dissipative heat engine concept, in particular the heat engine model of hurricane development, need to be revised.

Processes and Responses

2017 ◽  
Author(s):  
Jochen Rau
Keyword(s):  
Heat Engine ◽  
Cyclic Process ◽  
Free Enthalpy ◽  
Initial State ◽  
Thermodynamic Potentials ◽  
Grand Potential ◽  
Laws Of Thermodynamics ◽  
Cyclic Processes ◽  
Energy Exchanges ◽  
Thermodynamic Processes

Thermodynamic processes involve energy exchanges in the forms of work, heat, or particles. Such exchanges might be reversible or irreversible, and they might be controlled by barriers or reservoirs. A cyclic process takes a system through several states and eventually back to its initial state; it may convert heat into work (engine) or vice versa (heat pump). This chapter defines work and heat mathematically and investigates their respective properties, in particular their impact on entropy. It discusses the roles of barriers and reservoirs and introduces cyclic processes. Basic constraints imposed by the laws of thermodynamics are considered, in particular on the efficiency of a heat engine. The chapter also introduces the thermodynamic potentials: free energy, enthalpy, free enthalpy, and grand potential. These are used to describe energy exchanges and equilibrium in the presence of reservoirs. Finally, this chapter considers thermodynamic coefficients which characterize the response of a system to heating, compression, and other external actions.

Comparison of fundamental physical properties of the model cells (protocells) and the living cells reveals the need in protophysiology

2016 ◽  
Vol 16 (1) ◽  
pp. 97-104 ◽  
Author(s):  
V.V. Matveev
Keyword(s):  
Physical Properties ◽  
Origin Of Life ◽  
Sodium Pump ◽  
Molecular Model ◽  
Biological Evolution ◽  
Living Cells ◽  
Real Problem ◽  
The Origin Of Life ◽  
Physical Laws ◽  
Fundamental Physical

AbstractA hypothesis is proposed about potassium ponds being the cradles of life enriches the gamut of ideas about the possible conditions of pre-biological evolution on the primeval Earth, but does not bring us closer to solving the real problem of the origin of life. The gist of the matter lies in the mechanism of making a delimitation between two environments – the intracellular environment and the habitat of protocells. Since the sodium–potassium pump (Na+/K+-ATPase) was discovered, no molecular model has been proposed for a predecessor of the modern sodium pump. This has brought into life the idea of the potassium pond, wherein protocells would not need a sodium pump. However, current notions of the operation of living cells come into conflict with even physical laws when trying to use them to explain the origin and functioning of protocells. Thus, habitual explanations of the physical properties of living cells have become inapplicable to explain the corresponding properties of Sidney Fox's microspheres. Likewise, existing approaches to solving the problem of the origin of life do not see the need for the comparative study of living cells and cell models, assemblies of biological and artificial small molecules and macromolecules under physical conditions conducive to the origin of life. The time has come to conduct comprehensive research into the fundamental physical properties of protocells and create a new discipline – protocell physiology or protophysiology – which should bring us much closer to solving the problem of the origin of life.

Closed-Cycle OTEC Systems

1994 ◽  
Author(s):  
William H. Avery ◽  
Chih Wu
Keyword(s):  
Thermal Equilibrium ◽  
Constant Pressure ◽  
Cold Water ◽  
Heat Engine ◽  
Heat Removal ◽  
Working Fluid ◽  
Closed Cycle ◽  
Work Done ◽  
Heat Engine Cycle ◽  
Design Pressure

The Rankine closed cycle is a process in which beat is used to evaporate a fluid at constant pressure in a “boiler” or evaporator, from which the vapor enters a piston engine or turbine and expands doing work. The vapor exhaust then enters a vessel where heat is transferred from the vapor to a cooling fluid, causing the vapor to condense to a liquid, which is pumped back to the evaporator to complete the cycle. A layout of the plantship shown in Fig. 1-2. The basic cycle comprises four steps, as shown in the pressure-volume (p—V) diagram of Fig. 4-1. 1. Starting at point a, heat is added to the working fluid in the boiler until the temperature reaches the boiling point at the design pressure, represented by point b. 2. With further heat addition, the liquid vaporizes at constant temperature and pressure, increasing in volume to point c. 3. The high-pressure vapor enters the piston or turbine and expands adiabatically to point d. 4. The low-pressure vapor enters the condenser and, with heat removal at constant pressure, is cooled and liquefied, returning to its original volume at point a. The work done by the cycle is the area enclosed by the points a,b,c,d,a. This is equal to Hc–Hd, where H is the enthalpy of the fluid at the indicated point. The heat transferred in the process is Hc–Ha Thus the efficiency, defined as the ratio of work to heat used, is: . . . efficiency(η)=Hc–Hd/Hc–Ha (4.1.1) . . . Carnot showed that if the heat-engine cycle was conducted so that equilibrium conditions were maintained in the process, that the efficiency was determined solely by the ratio of the temperatures of the working fluid in the evaporator and the condenser. . . . η=TE–Tc/TE (4.1.2) . . . The maximum Carnot efficiency can be attained only for a cycle in which thermal equilibrium exists in each phase of the process; however, for power to be generated a temperature difference must exist between the working fluid in the evaporator and the warm-water heat source, and between the working fluid in the condenser and the cold-water heat sink.

scholarly journals Relativistic quantum heat engine from uncertainty relation standpoint

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Pritam Chattopadhyay ◽  
Goutam Paul
Keyword(s):  
Uncertainty Relation ◽  
Relativistic Quantum ◽  
Heat Engine ◽  
Potential Well ◽  
Relativistic Case ◽  
Heat Engines ◽  
Quantum Heat Engine ◽  
Thermodynamic Variables ◽  
The One ◽  
Work Done

AbstractEstablished heat engines in quantum regime can be modeled with various quantum systems as working substances. For example, in the non-relativistic case, we can model the heat engine using infinite potential well as a working substance to evaluate the efficiency and work done of the engine. Here, we propose quantum heat engine with a relativistic particle confined in the one-dimensional potential well as working substance. The cycle comprises of two isothermal processes and two potential well processes of equal width, which forms the quantum counterpart of the known isochoric process in classical nature. For a concrete interpretation about the relation between the quantum observables with the physically measurable parameters (like the efficiency and work done), we develop a link between the thermodynamic variables and the uncertainty relation. We have used this model to explore the work extraction and the efficiency of the heat engine for a relativistic case from the standpoint of uncertainty relation, where the incompatible observables are the position and the momentum operators. We are able to determine the bounds (the upper and the lower bounds) of the efficiency of the heat engine through the thermal uncertainty relation.

scholarly journals What limits limits?

2020 ◽  
Author(s):  
Yong-Chun Liu ◽  
Kun Huang ◽  
Yun-Feng Xiao ◽  
Lan Yang ◽  
Cheng-Wei Qiu
Keyword(s):  
Research Field ◽  
Related Research ◽  
Physical Systems ◽  
Physical Laws ◽  
Fundamental Physical

Abstract Physical systems are usually constrained by a variety of limits originating from fundamental physical laws. Breaking a limit typically represents a breakthrough in the related research field. We review different limits in physical systems and discuss the scenarios of “breaking the limit” in three categories, which clarify some mis-interpretations and ambiguities in the literatures.

Testing of a CR5 Solar Thermochemical Heat Engine Prototype

2010 ◽  
Author(s):  
Richard B. Diver ◽  
James E. Miller ◽  
Nathan P. Siegel ◽  
Timothy A. Moss
Keyword(s):  
Heat Engine ◽  
Chemical Conversion ◽  
Liquid Hydrocarbon ◽  
Lessons Learned ◽  
Solar Furnace ◽  
Liquid Fuels ◽  
Test Facility ◽  
Efficient Production ◽  
Solar Thermochemical ◽  
Engine Concept

Sandia National Laboratories (SNL) is investigating thermochemical approaches for reenergizing CO2 and H2O feed stocks for input to synthetic liquid hydrocarbon fuels production. Key to the approach is the Counter-Rotating-Ring Receiver/Reactor/Recuperator (CR5), a novel solar-driven thermochemical heat engine concept for high-temperature carbon dioxide and water splitting based on two-step, nonvolatile metal oxide thermochemical cycles. The CR5 integrates two reactors, recuperators, and solar receiver and intrinsically separates the product gases. The CR5 thermochemical heat engine concept and the underlying thermodynamics and kinetics have many uncertainties. While results from laboratory scale material tests are promising, they are different than what occurs in a CR5. To evaluate the potential of the CR5 we have designed and built a CR5 prototype. The overall objective of the SNL Sunshine to Petrol (S2P) project is to show a solar thermochemical pathway for the efficient production of liquid fuels from CO2 and H2O feed stocks. To achieve the overall long-term goal of 10% efficient conversion of sunlight to petroleum, the thermochemical solar conversion of sunlight to CO needs to be 20% efficient. The short-term goal for the CR5 prototype is to demonstrate a solar to chemical conversion efficiency of at least 2%. In this paper, we present initial test results for the CR5 prototype in the 16 kWt National Solar Thermal Test Facility (NSTTF) solar furnace in Albuquerque, NM. Lessons learned from the initial tests and approaches for improving performance to achieve our goals are also presented.

Emergent Causal Laws and Physical Laws

2020 ◽  
Vol 50 (5) ◽  
pp. 622-635
Author(s):  
Ranpal Dosanjh
Keyword(s):  
Emergent Properties ◽  
Causal Laws ◽  
Strong Emergentism ◽  
Physical Laws ◽  
Fundamental Physical

AbstractContrasting accounts of physicalism and strong emergentism face two problems. According to the neutrality problem, contrasting supervenience-based formulations of these positions cannot be neutral with respect to certain unrelated metaphysical commitments. According to the collapse problem, emergent properties can be accounted for using an appropriately expansive physical ontology, rendering strong emergentism metaphysically suspect. I argue that both these problems can be solved with a principled distinction between emergent causal laws and physical laws. I propose such a distinction based on a finite discontinuity in the behavior of fundamental physical constituents as a function of complexity.

Modeling of a New Crank-Less Rotary Heat Engine Concept for Solar Power Utilization

2018 ◽  
Author(s):  
Muhammad I. Rashad ◽  
Hend A. Faiad ◽  
Mahmoud Elzouka
Keyword(s):  
Degrees Of Freedom ◽  
Unit Cost ◽  
Heat Engine ◽  
Structure Design ◽  
Operating Conditions ◽  
Design Parameters ◽  
Working Fluid ◽  
Heat Engines ◽  
And Performance ◽  
Engine Concept

This paper presents the operating principle of a novel solar rotary crank-less heat engine. The proposed engine concept uses air as working fluid. The reciprocating motion is converted to a rotary motion by the mean of unbalanced mass and Coriolis effect, instead of a crank shaft. This facilitates the engine scaling and provides several degrees of freedom in terms of structure design and configuration. Unlike classical heat engines (i.e. Stirling), the proposed engine can be fixed to the ground which significantly reduce the generation unit cost. Firstly, the engine’s configuration is illustrated. Then, order analysis for the engine is carried out. The combined dynamics and thermal model is developed using ordinary differential equations which are then numerically solved by Simulink™. The resulting engine thermodynamics cycle is described. It incorporates the common thermodynamics processes (isobaric, isothermal, isochoric processes). Finally, the system behavior and performance are analyzed along with studying the effect of various design parameters on operating conditions such as engine speed, output power and efficiency.

scholarly journals A Simple Derivation of Tropical Cyclone Ventilation Theory and Its Application to Capped Surface Entropy Fluxes

2017 ◽  
Vol 74 (9) ◽  
pp. 2989-2996 ◽  
Author(s):  
Daniel R. Chavas
Keyword(s):  
Phase Space ◽  
Wind Speed ◽  
Tropical Cyclone ◽  
Analytical Solutions ◽  
Heat Engine ◽  
Vertical Wind Shear ◽  
Intensity Change ◽  
Necessary Condition ◽  
Surface Entropy ◽  
Entropy Flux

Abstract In a recent study, a theory was presented for the dependence of tropical cyclone intensity on the ventilation of dry air by environmental vertical wind shear. This theory was found to successfully capture the statistics of intensity dynamics in the historical record. This theory is rederived here from a simple three-term power budget and extended to analytical solutions for the complete phase space, including the change in storm intensity itself. The derivation is then generalized to the case of a capped surface entropy flux wind speed, including analytical solutions defined relative to both the traditional potential intensity and the capped-flux potential intensity. The results demonstrate that a cap on the surface entropy flux wind speed reduces the potential intensity of the system and effectively amplifies the detrimental effect of ventilation on the tropical cyclone heat engine. However, such a cap does not alter the qualitative structure of the phase-space solution for intensity change phrased relative to the capped-flux potential intensity. Thus, the wind speed dependence of surface entropy fluxes is important for intensity change in real-world storms, though it is not a necessary condition for intensification in general. Indeed, a residual power surplus may remain available to intensify a storm even in the presence of a cap, though intensification may be fully suppressed for sufficiently strong ventilation. This work complements a recent numerical simulation study and provides further evidence that there is no disconnect between extant tropical cyclone theory and the finding in numerical simulations that a storm may intensify in the presence of capped surface entropy fluxes.

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