Double pipe heat exchangers are the simplest exchangers used in
industries. On one hand, these heat exchangers are cheap for both
design and maintenance, making them a good choice for small
industries. But on the other hand, low efficiency of them beside
high space occupied for such exchangers in large scales, has led
modern industries to use more efficient heat exchanger like shell
and tube or other ones.
But yet, since double pipe heat exchangers are simple, they are
used to teach heat exchanger design basic to students and as the
basic rules for modern and normal heat exchangers are the same,
students can understand the design techniques much easier. To start
the design of a double pipe heat exchanger, the first step is to
calculate the heat duty of the heat exchanger.
It must be noted that for easier design, it’s better to ignore heat
loss in heat exchanger for primary design. The heat duty can be
defined as the heat gained by cold fluid which is equal to the heat
loss of the hot fluid.