Just like the name suggests, a heat exchanger is a device that allows heat from a fluid to pass to another fluid without the two fluids necessarily coming into contact. A typical example is a hot shower system. The cold water in a pipe passes through a heated chamber and comes out the other side, having gained that heat.
Where Are Heat Exchangers Used
We use heat exchangers all the time and in some cases without knowing. It is used in the heating of buildings and even helping machines and engines work more efficiently. Refrigerators and air conditioners use heat exchangers in the opposite way from central heating systems. They take away heat from a compartment where it isn’t needed and pump it away in fluid form to a place where it can be dumped out of the way. The fluid that is used in cooling is completely closed off inside a network of pipes, so there is no contact whatsoever.
Heat exchangers also enable the recycling of heat in power plants and engines. This is made possible because exhaust gases often contain heat that would be wasted in the open air. With a heat exchanger, as the hot gases come out of the plant, the brush past copper fins with water flowing through them in the opposite direction. This water carries the heat away, back to the plant where it is recycled.
Types of Heat Exchangers
There are several different types of heat exchangers in the market, and they are generally classified into a few main types.
- Plate & Frame Exchangers: This type of exchangers are compact. Efficiency is achieved with a number of stacked heat transfer plates. The plates are then clamped together within a frame, hence the name.
- Gasketed Plate Exchangers: The distinguishing feature of this type of exchanger is titanium or other nickel alloys. The reason why the alloys are used is to achieve accurate fluid temperature control for heat recovery. They are mostly used in food applications.
- Shell & Tube: Just like the name suggests, these exchangers have a number of tubes enclosed in a shell. This design helps to withstand a wide range of pressures and temperatures.
- Brazed Plate: They are constructed without a gasket and can therefore be used for a greater range of pressures and temperatures. They are available in corrosion-resistant materials like copper and or nickel and are therefore suited for multiple applications.
Choosing the Right Heat Exchanger
When looking for a young heat exchanger for sale, there are a few factors you have to put into consideration to ensure you find the one that suits you the most. As mentioned earlier, heat exchangers come in different types and models, each one designed for a particular function and use. So, what criteria do you use when selecting a heat exchanger? Below are some of the factors to consider.
- Operating pressures & temperatures
- Temperature driving force
- Accessibility for cleaning and maintenance
- Application
- Fouling characteristics of the fluids
- Mechanical considerations, for example, material construction and thermal stresses.
If you aren’t too sure of what heat exchanger to purchase, you can always consult a professional.