A Brief Overview of Heat Transfer and the Different Types of Heat Exchangers

A Brief Overview of Heat Transfer and the Different Types of Heat Exchangers


In addition to waste heat boilers and thermal energy storage, there are other types of equipment with various purposes that require heat exchangers to function. As their name implies, heat exchangers are an important device that enables heat to be transferred from one source to another. It’s important to note that these devices are necessary in a variety of industries.

How Heat Is Transferred

In order to transfer heat, there are a variety of specific conditions that need to be in place. These include between two or more fluids, between solid surfaces and a fluid, or between solid particles and a fluid. When considering the type of heat exchange that needs to occur, it’s important to determine the different temperatures that will be in thermal contact.

In order for a heat transfer to occur, the fluids must be at different temperatures. Furthermore, these fluids must come into thermal contact. This is because convection needs to be involved with each fluid and conduction must pass through the separating wall. Furthermore, as the Second Law of Thermodynamics has demonstrated, heat is only able to flow, or be transferred from, hotter to cooler fluids.

Types of Heat Exchangers

There are three basic types of heat exchangers. In addition to parallel-flow or counter-flow configuration heat exchangers, cross-flow and shell-and-tube configuration heat exchangers are also utilized. If you’re familiar with screw plug heaters, these are basically U-tube heat exchangers. Screw plug heaters may also be referred to as breech lock exchangers. While screw plug heaters may have a variety of applications and/or purposes, they are primarily used to seal the tube side of shell-and-tube heat exchangers so that leakage does not occur.

How Fluid Exchange Occurs

In addition to there being three types of heat exchangers, there are also two different categories of fluid exchange. The first is a single-pass heat exchanger, and the second is a multi-pass heat exchanger. As their names imply, when fluids pass through a heat exchanger just once, this is referred to as a single-pass heat exchanger. When the fluids pass through a heat exchanger more than once, then this is referred to as a multi-pass heat exchanger. The type of fluid that needs to pass through these devices will will determine which type of heat exchanger is used.

How Parallel Flow Heat Exchangers Work

In parallel flow heat exchangers, for instance, the tube-side fluid and the shell-side fluid will both flow in the same direction. When this type of heat exchanger is used, both fluids enter the heat exchanger simultaneously from the same end. These fluids also possess a significant difference in temperature.

How Cross Flow Heat Exchangers Work

When using a cross flow heat exchanger, there is just one fluid flowing through the tubes. The second fluid, however, will pass around the tubes in a perpendicular fashion.

The Lifespan of Heat Exchangers

It’s important to note that the shell portion of these heat exchangers may have a lifespan of 40 or more years. This takes into consideration that they are well-maintained, are free from corrosion, and/or something else doesn’t occur that damages the shell. This underlines the importance of heat exchangers and all other equipment receiving routine inspection, maintenance, repairs, and replacement.

Learn More About Heat Exchangers

In order to determine the type of heat exchanger needed by your operation, it’s important to contact an expert for more detailed information. Given that operating and monitoring these and other relevant types of equipment entails following stringent safety regulations.

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