Keeping Cool

Air conditioning, power plants, petroleum refineries, combustion engines and more – all of these have a vitally important part in common.  Not sure what that is? That’s fine, what they have in common is a device called a heat exchanger.  Now believe it or not, you are probably quite familiar with one heat exchanger, but know it under a different name; it’s the radiator in your car.  Heat exchangers are critical for keeping various devices cool so that they don’t overheat and malfunction.  You have probably seen someone on the side of the road before with their hood open and smoke pouring out, this is a result of a radiator failing.

All Kinds of Heat Exchangers

There are various kinds of heat exchanges available on the market and these are used for different applications.  Here’s a quick list of the most common heat exchangers.

  • Microchannel heat exchangers
  • Phase-change heat exchangers
  • Direct contact heat exchangers
  • Dynamic scraped surface heat exchanger
  • Fluid heat exchangers
  • Waste heat recovery units
  • Pillow plate heat exchanger
  • Plate fin heat exchanger
  • Adiabatic wheel heat exchanger
  • Plate and shell heat exchanger
  • Shell and tube heat exchanger
  • Plate heat exchanger
  • Double pipe heat exchanger

As you can see there are a lot of heat exchangers, but today we will just discuss one briefly.

Shell and Tube Heat Exchanger

This exchanger can be found most commonly in power plants, hydraulics, oil refineries and other large chemical processing plants.  It is designed to work under high pressures.  The basic structure consists of a large pipe (the shell) that encases a number of smaller tubes within it.  In the shell is one liquid and in the tubes is another liquid.  These two liquids transfer heat between each other through the wall of the tubes.  Sometimes the tubes or the shell contain a gas instead of a liquid.  One example of this is in large power plants with steam-driven turbines – such as nuclear power plants.  Here they use a shell and tube heat exchanger to recycle steam by cooling it and turning it into condensate water.

One of the most important requirements for this style of heat exchanger is the right tube material.   The material needs to conduct heat well and also be compatible for long periods of time with both the fluids under high pressures and temperatures, otherwise they will fail.  There are a couple different styles of shell and tube exchangers, depending on where one is being installed will affect which design choice is made.  One of the benefits to this kind of exchanger is how easy it is to maintain.

 

 

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