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Energy Efficiency and Conservation Technologies
Published in Swapan Kumar Dutta, Jitendra Saxena, Binoy Krishna Choudhury, Energy Efficiency and Conservation in Metal Industries, 2023
Jitendra Saxena, Binoy Krishna Choudhury
Carnot cycle: A theoretical cycle of a heat engine, with working fluid being always in a state of ideal gas, operating at maximum thermodynamic efficiency between a source temperature and sink temperature comprising four thermodynamic processes, viz. isothermal heat addition (expansion), reversible adiabatic expansion, isothermal heat rejection (compression) and reversible adiabatic compression.
Power Generation and Refrigeration
Published in Marc J. Assael, Geoffrey C. Maitland, Thomas Maskow, Urs von Stockar, William A. Wakeham, Stefan Will, Commonly Asked Questions in Thermodynamics, 2022
Marc J. Assael, Geoffrey C. Maitland, Thomas Maskow, Urs von Stockar, William A. Wakeham, Stefan Will
Refrigeration is the process of removing heat from one zone and rejecting it to another zone of higher temperature. The primary purpose of refrigeration is to lower the temperature of one zone and then to maintain it at that temperature. In this case, heat is transferred from a low to a higher temperature, requiring a machine and a thermodynamic cycle, which are called refrigerators and refrigeration cycles, respectively.
Chemical Thermodynamics and Thermochemistry
Published in Armen S. Casparian, Gergely Sirokman, Ann O. Omollo, Rapid Review of Chemistry for the Life Sciences and Engineering, 2021
Armen S. Casparian, Gergely Sirokman, Ann O. Omollo
As a second component of thermodynamics, entropy is a measure of the statistical disorder or randomness of a system. The universe tends to move toward greater total disorder, and this is expressed in terms of entropy or S. Entropy, unlike enthalpy, can be found explicitly. Entropy specifically is a measure of the number of microstates available to a chemical system. Microstates are individual possible states of the system, where a state is a particular arrangement of positions for particles and a particular distribution of kinetic energy among those particles. This can be calculated as shown in Equation 5.6, where S is the entropy, k is Boltzmann’s constant, and W is the number of available microstates. S=klnW
Research on the usability of various oxygenated fuel additives in a spark-ignition engine considering thermodynamic and economic analyses
Published in Biofuels, 2023
Murat Kadir Yesilyurt, Battal Dogan, Abdülvahap Cakmak
Exergy specifies the quantity of the work potential of energy existing in any thermodynamic condition. According to the first law of thermodynamics, energy is conserved; to put it more clearly, the law of conservation of energy states that energy cannot be created or destroyed, but can only be transformed from one form to another. However, in contrast to energy conversion, exergy is not conserved and it is destroyed as a result of irreversibilities existing in the system. The study and use of clean alternative fuels for SI engines are of great importance in relieving the shortage of petroleum resources and environmental issues caused by fossil fuel burning. Therefore, alternative fuels for SI engines continue to be the subject of research efforts. Exergy analysis gives more valuable and detailed information than energy analysis about thermal systems, determining the exergy destruction and identifying its location, thus offering overall improvement in efficiency and playing a significant role in reducing the environmental impact caused by the investigated systems [31].
Entropy generation and mixed convection of CuO–water near an oblique stagnation point: modified Chebyshev wavelets approach
Published in Waves in Random and Complex Media, 2022
Tabinda Sajjad, Rizwan Ul Haq, Muhammad Usman
The second law of thermodynamics asserts that the state of entropy of the entire universe, as an isolated system, will always increase over time. ‘The process of heat transfer occurs in a specific direction from hotter region to colder region.’ Bejan and Kestin [36] were the first who discuss about entropy generation in fluids. Entropy is responsible for the loss of useful energy during the heat transfer process. It is important in application of any engineering model. Minimization of entropy can produce more economic models [37]. The production of system may increase by diminishing factors responsible for entropy generation [38]. Approximate entropy (ApEn) of blood pressure gives more clear results about higher and low risks of hypertensive crises [39]. Entropy analysis is used in facial electromyogram. It uses entropy change to discuss the tension and stress in human facial nerves. Entropy change could be considered as the composite measure in change in physiological behavior toward a stimulus or stressor [40]. Entropy of system increases when heat supply increases, e.g. entropy increases when solid is converted to liquid.
Intelligent computing through neural networks for entropy generation in MHD third-grade nanofluid under chemical reaction and viscous dissipation
Published in Waves in Random and Complex Media, 2022
Muhammad Asif Zahoor Raja, Rafia Tabassum, Essam Roshdy El-Zahar, Muhammad Shoaib, M. Ijaz Khan, M. Y. Malik, Sami Ullah Khan, Sumaira Qayyum
Entropy is a measurable physical attribute mostly linked with a condition or disorder, unpredictability, or uncertainty. It has many applications in biological systems, economics, sociology, meteorology, climate change, cosmology, and information systems, including telecommunications data transmission. Entropy has the effect of making specific processes irreversible. The second law of thermodynamics holds that the entropy of an isolated system left to spontaneous development cannot decrease with time because it always reaches a state of thermodynamic equilibrium, where the entropy is greatest. Using entropy optimisation, Alsaedi et al. [21] investigated the MHD TGNF flow by considering binary chemical reaction and activation energy past a stretching sheet. Hayat et al. [22] exemplified heat transmission in a mixed convective stream of carbon nanotubes with entropy generation subjected to a curved stretching surface. Under the influence of magnetic and electric fields, Khan et al. [23] explored EG in electro-magneto dynamical mixed convection flow. Nayak et al. [24] used EG to explore an MHD Hamilton’s Crosser flow by considering the Darcy-Forchheimer. The Jeffrey nanofluid stream under the effects of entropy generation was studied by Le et al. [25]. Using the Buongiorno model, Adnan et al. [26] evaluated the EG in a convective stream of hybrid nanofluid fluid using magnetic force impact. The EG was presented by Adnan et al. [27] in a nanofluid flow passing through convergent and divergent channels.