What Is the Role of the Heat Exchanger?

Types

• The shell and tube heat exchanger is made of copper U-tubes in a carbon steel shell and is best used in a process system in which conditions are extremely abrasive and corrosive. The shell and coil heat exchanger is made of corrugated tubes inside a light compact shell; this heat exchanger works best where space is limited. The brazed heat exchanger is made up of a collection of plates brazed together without gaskets, which helps reduce leakage. Lightweight and compact, the brazed heat exchanger has a high turbulent flow and is best used with hydronic systems such as domestic hot-water heating, spas, ice and snow melting systems, and swimming pool systems.

Categories

• Flow arrangement determines the heat exchanger category. Parallel-flow heat exchangers allow two fluids to enter the exchanger at the same point and flow parallel to one another. Fluids in a cross-flow heat exchanger flow in a perpendicular fashion. A counterflow heat exchanger allows fluids to enter from opposite ends: Because this transfers the most heat, the counterflow exchanger is considered the most design-efficient.

Heat Transfer Operations

• The heat exchanger is able to condense a gaseous fluid by using a cooler fluid. Additionally, liquid can be boiled while condensing a hotter gaseous fluid. Other reasons for using a heat exchanger are to heat a cooler fluid by using a hotter fluid, or to lower the temperature of a hotter fluid by using a cooler fluid. Liquid may also be boiled by using a hotter fluid.

Residential Applications

• Heat exchangers are used in a variety of residential applications, including central, geothermal and solar heating; ice and snow melting; domestic hot-water heating; pool heaters and radiant floor heating.

Industrial Applications

• Heat exchangers are used in a number of industrial applications, including evaporators and condensers used in refrigeration systems; ground water systems; engine and transmission coolers; boiler coolers; wastewater recovery; and oil coolers. Heat exchangers are also used in chemical plants, power plants, petroleum refineries, power and refrigeration plants, as well as for the processing of natural gas.