Heat Exchanger Functions

February 19, 2015

There are countless terms used in mechanical engineering. They describe functions and features of complex processes, breaking down stages of that process into theoretical practices and practical concepts that are governed by physical laws. Thankfully, some examples of this verbal sparring are easy to translate. The phrase heat exchanger is one of these instances, an exception to the complex terminology rule. The wording means exactly what it appears to state, that a heat exchanger is a device designed to transfer energy from one source to another, with that power taking the form of heat, the galvanic energy that all life requires to function.

In proving that engineering can never stay simple, the science that underlies the principles of heat exchange quickly devolve into the murky realm of thermal dynamics, but we can anchor ourselves on certain incontrovertible truths. Heat exchangers used in factories, in oil refineries, and in building environmental systems, all share the same operational parameters, that of efficiently moving energy from one fluid to another, or from one fluid to a solid surface. The key in efficiently accomplishing this function lays in creating the largest possible surface area between the two mediums. In an ideal world we'd simply create enormous assemblies of flat metal, copper or some other medium with excellent thermal conductivity, and sit back to watch one-hundred percent of the energy being transferred. Unfortunately, we live in a less than ideal world, an existence where engineers have created innovative means of achieving this large surface area.

The flash point of steam driven through a gas boiler works in concert with a building heat exchanger to generate a heated airflow. Meanwhile, in the oil refinery industry, heat exchangers adopt a more dramatic operational mode. They adopt high-pressure structural components, pressurized vessels, to contain two or more fluids in a network of pipes, the methodology adopted by those clever engineers we were just talking about. Crude oil is fed through the labyrinthine tubing. Entering a furnace, the liquid is rapidly heated to activate the core fractionation process we all depend on for our refined fuels. The role of the heat exchanger at this point is to aid in the distillation process by cooling the fractions, injecting a cooler secondary liquid to exchange energy with the oil. Vaporized crude oil then liquefies and moves on to the next stage of the refinement process.

The questionable viability of the antiquated shell and tube heat exchanger in a modern oil refinery has given rise to more efficient variants with greater energy transferal coefficients. The result is the introduction of units with smaller footprints, a major requirement in an offshore oil drilling setting. Check out plate-type exchangers and the option to replace traditional tube networks with high-flux networks for more information on the future of the heat exchanger.

Contact Details

Fusion - Weld Engineering Pty Ltd
ABN 98 068 987619

1865 Frankston Flinders Road,
Hastings, VIC 3915

Ph: (03) 5909 8218

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