Heat Exchanger Design

Heat exchangers are any devices designed to perform heat transfers, and include refrigerators, swamp coolers, or radiators. Heat exchangers work by transferring thermal energy from one liquid to another through a separator or by direct contact. These devices can either be used to direct heat transfers towards an object, as in refrigeration, or away, as in radiators. Because of the various applications of heat exchangers, various designs exist.

Basic Heat Exchanger Principles

The basics of heat transfer involve the second law of thermodynamics, which basically states that two thermodynamic systems, when allowed to interact, will move towards a thermodynamic equilibrium. In other words, when hot and cold substances are brought into contact with one another, the hot substance will cool and the cool substance will heat up, resulting in a median temperature.

TRADITIONAL PLATE EXCHANGER CALCULATION

Number of plates 100 (101) [-] Plate Length 8.000 [m] Plate Width 0.500 [m] Plate Thickness 0.002 [m] Hot and Cold gap 0.008 [m] Hot water temperature 353.15 [K] Cold water temperature 293.15 [K] Hot and Cold fluid mass flow 400.0 [kg/s] Hot and Cold fouling resistance 0.00005 [m2W/K] Plate metal conductivity 50 [W/m/K] Water properties are taken at average temperatures. As the hot and cold inlet temperatures are 80 and 20 degrees Centigrade, respectively, the average temperature is 50 degree C. The film correction for the heat transfer coefficient is neglected for the hand calculation. It is small and of opposite influence at each process side.

Heat Exchange Concepts & Heat Exchangers

Heat Exchange Concepts & Heat Exchangers

Heat Exchanger Fundamentals

Heat exchange is a natural phenomenon occurring throughout our environment. It drives the weather cycles and energy exchange between ecosystems. Harnessing its utility through accurate control of heat exchange has been a focus of our industry for over a century.

Heat exchangers allow control over the dynamics of heat transfer between fluids. They are used in widespread applications, such as solar heating, pool heating, domestic water heating, radiant floor heating, food processing, marine applications, general industrial process control, and more.

Below are parametric thermodynamic equations that define the nature of heat exchange and performance of a heat exchanger for any given application. Once these thermal parameters are determined they can be used to calculate heat exchanger performance in order to select the most suitable product based on the specific application.