ABSTRACT
This chapter discusses the basic design methods, both rating and sizing, for two-fluid direct-transfer heat exchangers. The most common tasks in heat exchanger design are rating and sizing. A recuperator-type heat exchanger is classified according to the flow direction of the hot- and cold-fluid streams and the number of passes made by each fluid as it travels through the heat exchanger. Performance calculations of a heat exchanger are carried out when the heat exchanger is available, but it is necessary to determine the amount of heat transferred, pressure losses, and outlet temperatures of both fluids. Heat exchanger walls are usually made of a single material, although a wall may sometimes be bimetallic or coated with a plastic as a protection against corrosion. In the rating problem, the heat exchanger already exists or the heat exchanger configuration is selected by approximate sizing.
