Types of Heat Exchangers and their Pros and Cons

A heat exchanger can simply be called one of the most important components of any machine. It protects appliances and equipment from overheating and keeps it cool. Since heat exchangers are used in a number of different machines, there are a number of different types of heat exchangers available in the markets today. It is important to be able to know the benefits and drawbacks of all these types so when one has to select one for a certain kind of equipment, they will know which one will work best. The application of the exchanger, the power of operations, the pressure of the fluids, the temperature driving force and many such things should be considered.

First up, there is the shell and tube heat exchanger which is easily the most commonly used exchanger out there. Since it is quite common, it is also widely understood and people generally have an idea about how this works. It is also highly versatile and can be used in a number of different equipment because of its flexibility. Most of these are small equipment, however. Also, the design pressures it allows and the temperatures it can withstand are the more diverse than any other type of exchanger. Since it is made of rugged material, it can withstand aggressive wear and tear. On the downside, it is not as thermally effective as other exchangers and it can fall prey to flow induced vibration and fail to work. It is also not good for temperature cross conditions since a number of different units will have to be used in the heat exchanger. There are also a number of stagnant areas on the shell side that can cause corrosion and it can also fall prey to flow mal-distribution.

Moving on, another common type of exchanger is called the compact heat exchanger and as one can understand by its name, it is quite small and can be fitted in smaller equipment. First and foremost, it is very cheap to buy and the initial costs of plate type purchase are very low. It also allows for a number of different configurations like spiral, gasketed, semi-welded and fully welded. The heat transfer coefficients are very high since the wall sheer stress is very high and thus, it can withstand nearly three times the amount of temperature that shell and tube exchangers can withstand. Fouling characteristics are comparatively low since the turbulence within the exchanger is quite high. This exchanger also allows cross temperatures to be achieved and is also very easy to install, setup and start. On the downside, though, since it is so small it does not allow a high range of temperatures and pressures to work through it. Also, since the path of flow is very narrow, there is a lot of clogging and plugging. The gasket units in the heat exchanger require special opening and closing up measures.

Lastly, there are the air cooled heat exchangers. They are great for areas where cooling water is scarce and one has to spend a lot of money to treat water and let it cool down. It is very effective in cooling down fluids of very high temperatures and it can bring down water bodies of eighty degrees Celsius down to nothing. The maintenance costs and operating expenditures are very low. Typically, they amount to thirty or thirty-five percent of what it would ordinarily cost to cool water. On the downside, however, the heat exchanger is very expensive since it is considered to be an important car component. Also, it is a lot bigger than a compact exchanger and will need a larger footing on which it will be installed. Lastly, the process outlet temperature is also quite high.