Simultaneous Heat and Mass Transfer

Abstract

In process operations where material is transferred between phases, usually between liquid and vapor phases, the transport process may be described in terms of heat transfer and mass transfer. When both expressions are developed and handled simultaneously, the resulting equations show that heat and mass transfer affect each other. Equations applied to humidification and dehumidification processes are presented. These expressions could equally well be applied to drying, evaporation, or crystallization processes. The conceptual design of counterflow cooling towers or dehumidification towers is discussed, as are the mechanical and operating features of these columns, costs, and environmental impacts. In all of these processes the air–water system is usually of concern. Thus the properties of moist air are developed and displayed on psychrometric charts.