Preface

Heat exchangers are devices that exchange thermal energy between two or more fluids. They are used in both cooling and heating applications to increase or decrease the temperature of a fluid or develop a phase change. Therefore, thermal energy storage, properties of the fluids involved, and construction materials are relevant parameters for the design of heat exchangers (see **Figure 1**).

Several studies on heat exchangers are focused on heat recovery, energy exchange with novel fluids, and redesign and optimization of geometry.

This book begins by discussing energy-saving and heat recovery as essential factors in heat transfer processes. It presents thermoeconomic analyses that include thermodynamic and economic parameters. It also examines novel fluids and applications in heat transfer. The selection of working fluids is relevant to determine the operating conditions in heat exchangers. Electrically conductive fluids in the presence of magnetic and electric fields are studied by magnetohydrodynamics. A chapter on the numerical analysis of heat transfer by natural convection in a concentric annulus is presented, considering ramping temperature and ramped motion of the boundaries. The book also reviews the state-of-the-art cooling systems in electronic equipment. In addition, it presents some suggested techniques for the design and analysis of heat exchangers for use in heating, cooling, humidification, and dehumidification. The book ends with a discussion of the design and optimization of heat exchangers, including exchangers with phase change that have application in refrigeration systems. Topics of optimization of heat exchangers include operating cost, pressure drops, heat transfer area, and maximum effectiveness.

**Figure 1.** *Heat exchanger air-water.*

The editor would like to sincerely thank her co-editors, Miriam Navarrete and Víctor Velázquez, for their valuable support. Without them, this book would not have been possible.

> **Laura Castro Gómez** Centro de Investigación en Ingeniería y Ciencias Aplicadas, Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos, México
