plate heat exchanger
One is composed of multiple, thin, slightly separated plates that have very large surface areas and fluid flow passages for heat transfer.
This stacked plate arrangement can be more efficient, in a given space, than the tank and tube heat exchanger. Advances in gasket and welding technology have made the plate type heat exchanger increasingly practical.
In HVAC applications, large heat exchangers of this type are called plate and frame heat exchangers; when used in open circuits, these heat exchangers are normally of the gasket type to allow for periodic disassembly, cleaning and inspection.
There are many types of permanently bonded plate heat exchangers, such as brazed and vacuum brazed immersion plate varieties, and they are often specified in closed loop for applications such as refrigeration. Plate heat exchangers also differ in the types of plates used, and in the configurations of those plates. Some plates may be marked with “chevron” or other patterns, where others may have machined fins and/or slots.
Tube and Shell Heat exchangers
These exchangers have a group of tubes that contains liquid that must be heated or cooled. The second fluid runs over the tubes that are been heated or cooled so it can give heat or receive it, as needed.
A tube bundle can be composed of various types of tubes: plain, longitudinally finned, etc. Shell and tube heat exchangers are typically used for high pressure applications (with pressures above 30 bar and temperatures above 260°C). This is because shell and tube heat exchangers are robust due to their shape.