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Öğe Basics of heat transfer: Conduction(Elsevier, 2023) Varuvel, E.G.; Sonthalia, A.; Aloui, F.; Saravanan, C.G.In this chapter the fundamental concepts of thermodynamics are presented. The relation of heat to other forms of energy and the energy balance is also discussed. As a system moves from one equilibrium state to another, thermodynamics can provide the information about the amount of heat transfer. It cannot, however, provide any information on how long the process will take. The design engineers, however, are more interested in the rate of heat transfer. Heat transfer can take place through conduction, convection, and radiation. This chapter further discusses the heat transfer through conduction in detail. It is well known that heat transfer through a medium has magnitude as well as direction. The heat conduction rate in a given direction is proportional to the temperature gradient, that is, the temperature varies with distance in the given direction. In general, heat transfer is three-dimensional and time dependent. The temperature in a medium varies with position as well as with time. If the temperature is independent of time, then conduction is in a steady state otherwise it is in a transient state. This chapter also discusses conduction through plane/composite wall, composite cylinder, and fins. For simplicity the analysis is carried out in one dimension under steady-state conditions. Heat conduction under transient conditions for a lumped system is also discussed. © 2023 Elsevier Inc. All rights reserved.Öğe Basics of heat transfer: Convection(Elsevier, 2023) Varuvel, E.G.; Sonthalia, A.; Aloui, F.; Saravanan, C.G.This chapter discusses the mechanism of heat transfer through the motion of the bulk fluid also known as convection. This heat transfer can be either forced or free depending on how the initiation of the fluid motion takes place. In forced convection, a pump or a fan is used to force the fluid to flow through a pipe or over a surface. While fluid motion by natural means such as buoyancy (warmer fluid rises) takes place in natural convection. Another way of classifying convection is it can be either external or internal. When a fluid flows over a surface it is known as external flow and when it flows through a duct it can be classified as internal flow. © 2023 Elsevier Inc. All rights reserved.Öğe Basics of heat transfer: Heat exchanger(Elsevier, 2023) Varuvel, E.G.; Sonthalia, A.; Aloui, F.; Saravanan, C.G.Heat exchangers facilitate the exchange of heat between two fluids having different temperatures. The heat exchange involves conduction between the walls separating the fluids and convection in each fluid. The chapter starts with the discussion on classification of heat exchangers. Then the overall heat transfer coefficient and log mean temperature difference (LMTD) for different configurations of heat exchanger is discussed. As the heat exchanger gets fouled over a period of time a fouling factor is introduced that considers the variation in LMTD. Similarly, a correction factor is introduced for multi-pass arrangements. The effectiveness—number of transfer units (NTU) method is also discussed for analyzing the heat exchanger when the outlet temperature of the fluids is unknown. Lastly, selecting the heat exchanger for a particular application is also briefly discussed. © 2023 Elsevier Inc. All rights reserved.Öğe Handbook of Thermal Management Systems: E-Mobility and Other Energy Applications(Elsevier, 2023) Aloui, F.; Varuvel, E.G.; Sonthalia, A.Handbook of Thermal Management Systems: e-Mobility and Other Energy Applications is a comprehensive reference on the thermal management of key renewable energy sources and other electronic components. With an emphasis on practical applications, the book addresses thermal management systems of batteries, fuel cells, solar panels, electric motors, as well as a range of other electronic devices that are crucial for the development of sustainable transport systems. Chapters provide a basic understanding of the thermodynamics behind the development of a thermal management system, update on Batteries, Fuel Cells, Solar Panels, and Other Electronics, provide a detailed description of components, and discuss fundamentals. Dedicated chapters then systematically examine the heating, cooling, and phase changes of each system, supported by numerical analyses, simulations and experimental data. These chapters include discussion of the latest technologies and methods and practical guidance on their application in real-world system-level projects, as well as case studies from engineering systems that are currently in operation. Finally, next-generation technologies and methods are discussed and considered. © 2023 Elsevier Inc. All rights reserved.Öğe Need of battery thermal management systems(Elsevier, 2023) Sonthalia, A.; Varuvel, E.G.; Aloui, F.; Saravanan, C.G.Due to thermal runaway issues, the thermal safety of lithium ion battery has always been a concern all over the world. The cell is highly sensitive to temperature and has a narrow operating temperature range. At different temperatures, complex electrochemical reactions take place. The effect of ambient temperature in different seasons and internal heating can cause side reactions leading to thermal runaway which should be considered while designing the battery thermal management system. This chapter focuses on the cause of thermal runaway at all temperature ranges. Such as at low-temperature capacity fade and lithium dendrite and plating can occur causing internal short circuits. At normal temperature range, side reactions can speed up, reducing the battery life while thermal runaway can occur at high temperatures. © 2023 Elsevier Inc. All rights reserved.Öğe Some studies on reducing carbon dioxide emission from a CRDI engine with hydrogen and a carbon capture system(Elsevier, 2022) Varuvel, Edwin Geo; Thiyagarajan, S.; Sonthalia, A.; Prakash, T.; Awad, S.; Aloui, F.The increased use of fossil fuels in the transportation sector has led to an exponential rise of carbon dioxide in the atmosphere. The carbon dioxide (CO2) is the major cause of global warming resulting in climate change and extreme weather conditions. This study explores the ways of reducing the CO2 emission from the exhaust of a common rail engine. The reduction in CO2 emissions were achieved by a combination of methods. It includes the use of low carbon biofuels (cedarwood oil (CWO), and wintergreen oil (WGO)), induction of zero-carbon, hydrogen in the intake manifold and a zeolite-based after-treatment system. In diesel, CWO and WGO were blended 20% by volume and experiments were conducted at different load conditions. The results shows that 20% blending of winter green oil resulted in maximum CO2 reduction of 20% as compared to diesel. The emission was further reduced with the induction of hydrogen along with the after-treatment system. It is seen that a maximum of 54% reduction in CO2 emission could be achieved with the combination for WGO in comparison to diesel without much affecting the other emissions and performance parameters. © 2021 Hydrogen Energy Publications LLC
