Thermodynamics and Energy Conversion

Abstract

This chapter discusses thermodynamics and energy relations of seawater. Much of the physics of the liquid state can be elucidated through a better understanding of the molecular character of the main constituents of seawater—namely, H2O, Na+, Cl–, and Mg++. Other than these major constituents, seawater contains nearly all known natural elements, some of which are present in exceedingly minute amounts. However, it is the properties of pure water and the dissolved salts that account for the dominant characteristics of the medium. Water enters into important oceanic processes in all three of its phases—gaseous, liquid, and solid. The latent heat of vaporization and condensation are the major means by which the sea communicates with the atmosphere. The addition of salt to water alters its thermodynamic properties in various ways, some of which have important qualitative and quantitative effects. The addition of salt also increases the density and depresses both the temperature of maximum density and the freezing point temperature. The physical laws that underlie the coupled hydrodynamic and thermodynamic equations are Newton's equations, conservation laws for mass, salinity, and heat flow, the first and second laws of thermodynamics, an equation of state, and an equation for internal energy or enthalpy. © 1988, Academic Press