Quite simply, a heat exchanger is a piece of equipment that transfers heat between two fluids. The fluids can either be in the form of a liquid or a gas and must be at different temperatures.
Where can we find heat exchangers?
One of the most common heat exchangers is found in most homes across the country, can you guess what it is? That’s right it’s a radiator.
Radiators work when hot water heats cold air which then provides enough heat to make the room in your house warm.
There are over 35 million of the second most common heat exchanger in the UK alone and you can find this heat exchanger in your car. The way that this heat exchanger works is the radiator cools the water coming from the engine with air from the atmosphere.
But heat exchanges can be found in a variety of different products and industries including factories, planes and ships.
But how do heat exchangers work exactly?
Generally all heat exchangers will work by passing fluid through tubing or piping, all whilst another fluid or gas flows around the tubes or pipes. The fluids will never come into direct contact with each other but will allow heat to be transferred. This process is what is known as a heat exchanger.
Like anything else, there are several ways to make heat exchangers work far more efficiently. For example, you can add an appliance that will increase the surface area, but by adding extras to the product you will be adding weight. Another option is to decrease the size of the tubing or piping. If you can then make thin walls you will not be adding a weight penalty.This also means you have a much lighter and more compact heat exchanger.
By having smaller piping or tubing means that you can have many more tubes or pipes. This means that you have more surface area which you can use to transfer the heat in a given volume.
There are two common types of heat exchanger which are called the shell and tube and plate and fin. In the shell and tube version, fluid will pass through a set of tubes, all while the other fluid flows through a sealed shell that surrounds the tubes. The second version, the plate and fin, contains lots of thin metal plates or fins that make up a large surface area.
The fluids can also flow in many different directions. There is parallel flow which is where the fluids flow in the same direction, there is counterflow which is where the fluids flow in opposite directions, or finally there is cross flow, this is where the fluid flows at right angles.
Even though you will find heat exchangers in so many different products and they all work in many different ways, there is one thing you should take away from this article and that is the realisation that all heat exchangers do the same thing, essentially they all pass heat from one fluid to another.