Numerical analysis reliability control for a double‐pipe heat exchanger with virtual entropy generation method

In this work, we have considered a non-canonical scalar field dark energy model in the framework of flat FRW background. It has also been assumed that the dark matter sector interacts with the non-canonical dark energy sector through some interaction term. Using the solutions for this interacting non-canonical scalar field dark energy model, we have investigated the validity of generalized second law (GSL) of thermodynamics in various scenarios using first law and area law of thermodynamics. For this purpose, we have assumed two types of horizons viz apparent horizon and event horizon for the universe and using first law of thermodynamics, we have examined the validity of GSL on both apparent and event horizons. Next, we have considered two types of entropy-corrections on apparent and event horizons. Using the modified area law, we have examined the validity of GSL of thermodynamics on apparent and event horizons under some restrictions of model parameters.

The science of thermodynamics is built primarily on two fundamentally natural laws, known as the first and second laws. The first law of thermodynamics is simply an expression of the conservation of energy principle. It asserts that energy is a thermodynamic property, and that during an interaction, energy can change from one form to another but the total amount of energy remains constant. The second law of thermodynamics asserts that energy has quality as well as quantity, and actual processes occur in the direction of decreasing quality of energy. The attempts to quantify the quality or “work potential” of energy in light of the second law of thermodynamics has resulted in the definition of the property named exergy. In this chapter, basic relations for the first and second laws of thermodynamics are provided for closed systems and control volumes. The concepts of entropy and exergy derived from the second law are thoroughly discussed.KeywordsEntropy ChangeEntropy GenerationHeat EngineExergy AnalysisExergy EfficiencyThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Bioenergy, sustainability, and the second law

A scale-invariant model of statistical mechanics and modified forms of the first and the second laws of thermodynamics

Thermodynamic analysis of sugar production systems was carried out based on the application of the First Law of Thermodynamics (energy characteristics) as well as on the joint application of the First and Second Law of Thermodynamics (exergy characteristics). Based on this analysis, three groups of energy-saving options were formed: using waste energy resources; changing energy parameters; based on structural changes in the system. It is shown that the identified energy-saving potentials can serve as a basis for the subsequent optimization of sugar production systems. However, the final decision on the application of these energy-saving options requires a thermo-economic approach, since the implementation of most of them requires significant capital investment. The main exergetic characteristics of a typical sugar production scheme with a capacity of 3000 tons of sugar per day have been calculated, analysis of which showed that the main source of exergy losses (more than 70 %) in sugar production systems are the boiling processes, which also have a low degree of thermodynamic perfection (0.54). Losses of exergy in these processes as well as in others are caused by big heat fluxes and irreversibility of heat exchange processes at significant temperature drops, and as dissipative losses of centrifugation processes, mechanical separation, diffusion and transport of streams. The presented thermodynamic analysis is the basis for the subsequent thermo-economic optimization of sugar production systems.

The result of this study shows the performance of Ihovbor Gas Power Plant in Benin, Edo State Nigeria using first and second law of thermodynamics. Analysing the efficiency of the plant using first law of thermodynamics showed that with increase in inlet air temperature, the energy conversion efficiency of the plant reduces. The exergy efficiency of the plant also confirmed that increase in inlet air temperature results in decrease of the exergetic efficiency of the plant. Analysis of each of the components showed the greatest destruction of exergy was in the combustion chamber while the least is the Gas turbine section. Using numerical method in analyzing the gas turbine plant when retrofitting with an evaporative inlet air cooler showed better performance in energy conversion as power generation increased with an average of 1% per 1oC degree fall in temperature, the work ratio and thermal efficiency of the plant also increased. The analysis of the modified plant using second law of thermodynamics showed an increase in magnitude of both the exergy destroyed and the efficiency of the plant. Analysis showed that integrating evaporative cooler as component of the inlet air cooler increases the efficiency of the Air compressor by over 0.8% thus increasing the plant’s exergetic efficiency.

The performance of turbochargers is heavily influenced by heat transfer. Conventional investigations are commonly performed under adiabatic assumptions and are based on the first law of thermodynamics, which is insufficient for perceiving the aerothermodynamic performance of turbochargers. This study aims to experimentally investigate the non-adiabatic performance of an automotive turbocharger turbine through energy and exergy analysis, considering heat transfer impacts. It is achieved based on experimental measurements and by implementing a novel innovative power-based approach to extract the amount of heat transfer. The turbocharger is measured on a hot gas test bench in both diabatic and adiabatic conditions. Consequently, by carrying out energy and exergy balances, the amount of lost available work due to heat transfer and internal irreversibilities within the turbine is quantified. The study allows researchers to achieve a deep understanding of the impacts of heat transfer on the aerothermodynamic performance of turbochargers, considering both the first and second laws of thermodynamics.

Based solely on the First Law of Thermodynamics, which addresses energy efficiency, heat pumps are considered to be a major asset for achieving the decarbonization goals of the Paris Agreement. Yet, this approach alone overestimates the potential for decarbonization and conceals certain root causes of carbon dioxide emissions arising from exergy destruction. This paper redefines the decarbonization potential of heat pumps holistically by applying the First and Second Laws of thermodynamics together. This research shows that power-to-heat energy conversion systems are responsible for exergy destruction, leading to additional carbon dioxide emissions, as the destroyed exergy must be offset by other means, possibly by burning fossil fuels. An exergy-based model was developed and used for different scenarios. Results were compared with boilers in heating mode fueled by fossil fuels or biogas, and with adsorption machines in cooling mode. Thermal energy storage systems and their optimal operational regimes for minimum environmental footprint have also been considered and modeled in accordance with the Second Law of Thermodynamics. A correction factor for the coefficient of performance of heat pumps has been developed to account for exergy destruction and emission avoidance associated with typical heat pump operation under electrical and ambient thermal inputs. Results show that today’s coefficient of performance must be higher to meet the emissions-mitigation and total electrification targets to mitigate global warming. The Second Law of thermodynamics shows that the case study about the comfort cooling system of a nature center building with ground source heat pumps and photovoltaic panels is responsible for emissions by 0.81 kg CO2 emissions/kWen-h, rather than saving 1.62 kg CO2/kWen-h by a no-heat pump case, comprising solar photovoltaic panels, adsorption cooling, and desiccant wheel. This case study also shows that the carbon dioxide emission responsibility resulting from exergy destruction during the power-to-heat process is as important as the direct emissions from electric power use. This paper concludes that the exergy destruction-related carbon footprint should not be neglected across all design and application phases to foster better awareness and establish exergy-rational strategy planning towards the Paris Agreement goals.

This chapter examines scientific ideas that led to the theory of deep time, with particular emphasis on the work of William Thomson, later Lord Kelvin. Kelvin used the laws of physics to reject Charles Lyell's theory of uniformitarianism to explain an eternal, unchanging Earth. The first law of thermodynamics holds that in any process, energy in the form of heat and work is conserved. The second law can be stated simply as: heat flows spontaneously from hotter to colder places, never the opposite. In describing geologic time as infinite and the Earth as unchanging, Lyell claimed that the Earth is a perpetual-motion machine, one that can not only win the energy battle but go on doing so forever. But the first and second laws of thermodynamics prove that such a machine is impossible. According to Kelvin, Lyell's theory “violates the principles of natural philosophy.” This chapter considers Kelvin's argument about the age of the Earth and how he pushed geology toward the twentieth century.

<div class="htmlview paragraph">The design of any complex system, especially eco-technical is very challenging due to the variety of processes, system composition, relation between different components and presence of the human. Process and technology selections affect the flow rate, composition, and phase of all resulting components. Therefore, evaluating alternative processes and/or technologies used often requires one to compare the relative environmental merits of distinctly different residual streams.</div> <div class="htmlview paragraph">Traditional thermodynamic analysis based on the first law of thermodynamics describes the conservation of energy. In this type of analysis all forms of energy are considered to be equivalent. The loss of quality of energy is not taken into account. It shows the energy flow to be continuous and energy balance is always closed. There can never be an energy loss, only energy transfer to the environment in which case it is useless.</div> <div class="htmlview paragraph">An exergy analysis, based on the first and second law of thermodynamics, shows the thermodynamic imperfection of a process and the system, including all quality losses of materials and energy. For quantifying the irreversibilities and determining system imperfections an exergy analysis has to be performed.</div> <div class="htmlview paragraph">The intent of this paper is to provide a better explanation of exergy method and show examples of it's application.</div>

Available energy analysis

Thermoelectric (TE) generation is becoming a valuable and promising research direction. Many researchers have carried out system analysis and performance optimization of thermoelectric technologies based on the generalized thermoelectric energy balance equations. However, it is assumed that TE legs have no heat exchange with the ambient except at the junctions of the hot and cold ends where heat flows in and out. Based on basic thermoelectric effects and fundamental theories of heat transfer, a detailed derivation of the revised generalized thermoelectric energy equations considering convective heat transfer between TE legs and the ambient has been carried out. Irreversible heat transfer processes have been analyzed by employing energy analysis based on the first law of thermodynamics and exergy analysis based on the second law of thermodynamics. The results show that convective heat transfer leads to a decrease in both energy and exergy efficiencies: the rate and magnitude of the decrease in exergy efficiency are greater than those of the decrease in energy efficiency. The exergy efficiency is relatively high despite the low energy efficiency in operation, revealing the features and advantages of thermoelectric generators (TEGs) in low‐grade energy utilization. For TEG efficient operation, the load resistance value should match the system's internal resistance, or at least be greater than that, to avoid a sharp drop in power output and efficiencies. In an attempt at theoretical analysis, the concept of entransy was first introduced into thermoelectric analysis, yielding two concise relational equations which reflect the intrinsic link between Carnot cycle efficiency, energy efficiency, exergy efficiency, and entransy flow transfer efficiency. The entransy analysis based on the index of entransy flow transfer efficiency, together with energy analysis and exergy analysis, may be a novel and valuable guideline for the operation and optimization of TEGs, which needs to be further investigated.

Experimental study on heat and exergy balance of a dual-fuel combined injection engine with hydrogen and gasoline

We consider the particle creation scenario in the dynamical Chern-Simons modified gravity in the presence of perfect fluid equation of state p=(γ-1)ρ. By assuming various modified entropies (Bekenstein entropy logarithmic entropy, power law correction, and Renyi entropy), we investigate the first law of thermodynamics and generalized second law of thermodynamics on the apparent horizon. In the presence of particle creation rate, we discuss the generalized second law of thermodynamics and thermal equilibrium condition. It is found that thermodynamics laws and equilibrium condition remain valid under certain conditions of parameters.

Coal to SNG: Technical progress, modeling and system optimization through exergy analysis