“How can we transfer heat from one fluid to another without them being in contact?”
Fluids are often used as materials to heat other materials. However, sometimes fluids themselves need to be heated. So wouldn’t it be logical if we could use one fluid to heat another? However, there is one problem with this. If we have two fluids come into physical contact with one another, they will usually merge and mix with one another. So how could we prevent such a phenomena from happening? Well, let’s use our engineering mindset to figure this problem out. We know that pipes are a very efficient way to transport fluid phenomena. And we also know that heat can be transferred from inside the pipe to the outside. So what if we were to create a machine that would take on one fluid, extract the heat from it using piping and other mechanisms, and pass it onto a separate fluid? Well, this is the fundamental idea behind a device known as a heat exchanger, and it can be found in a vast multitude of devices, ranging from refrigerators to power plants to diesel engines.