Different Types of Heat Exchangers Used on Ships

Blog | June 11th, 2020

Do you ever wonder how temperature is regulated on ships where there is definite weather uncertainty? Most people do. Technological advancements and innovations gave birth to useful machines such as heat exchangers. These systems onboard allows different uses and applications. And other ship systems depend on the cooling and heating of fluid in order to function properly. Below are different types of heat exchanger used on ships.

Shell and Tube Type Heat Exchanger

One of the most common heat exchangers used on ships is the shell and tube type heat exchanger. It is designed in such a way wherein a shell with several tubes allows the fluid to be cooled through those tubes while a secondary liquid flows over the tube and into the inside of the shell. This heat exchanger have two end plates – sealed on both sides, with a space for expansion – while the entire shell is fitted in a tube stack. It is one of the most cost-effective and low maintenance heat exchangers used on ships.

Plate Type Heat Exchanger

A plate type exchanger is composed of thin corrugated plates that are connected in a parallel manner. This is intended to create a cavity so that the fluid can flow freely inside it. The sides of the plate contain two different fluids that enables the heat transfer. The first and last plates also called as innermost and the outermost plates are connected by the frames on either side and further set in place by the tie bolts.

Plate Fin Heat Exchanger

The plate fin heat exchanger have similar characteristics to the previously-mentioned plate type heat exchanger. The only difference is the plate fin have fins to further ensure its efficiency. The material used is aluminium alloy so that it can carry out a higher rate of heat transfer while ensuring that the unit is as lightweight as it can be.

Fins are categorised as offset, straight, and wavy. Offset fins are specialised and positioned in such a way that they are perpendicular to the direction of the flow. Straight fins are positioned parallel to the direction of the flow and lastly wavy fins are in curved form so that the heat exchanging effect is maximised.

Dynamic Scrapped Surface Heat Exchanger

Dynamic scrapped surface utilises the continuous scrapping of the surface for better heat transfer efficiency and less system downtime. It uses blade scrapping produced by a blade unit with a motor-driven shaft with a timer. It is more often applied for highly viscous fluid wherein the heat transfer is caused by the increased fluid turbulence.

Phase Change Heat Exchanger

This heat exchanger changes the phase – solid to liquid or liquid to gas – through heat transfer. In order for this to happen, it must be in either a freeze or melt cycle.

Spiral Heat Exchanger

Concentric shape flow passages facilitates the functioning of spiral heat exchangers. It creates a turbulence flow of a fluid which in turns increases the heat transfer efficiency. The flow of fluid in spiral type is rotary current flow which itself possesses the property of self-cleaning of fouling inside the spiral body.

Direct Contact Heat Exchanger

The very property that defines this heat exchanger is its lack of walls. Both the mediums are in direct contact for the heat transfer process. It can be classified as gas to liquid, immiscible liquid-liquid and solid-liquid or solid-gas.

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