Editing Heat exchanger (section)

===Plate===
{{Main|Plate heat exchanger}}
[[Image:Plate frame 1.svg|thumb|right|Conceptual diagram of a plate and frame heat exchanger]]
[[Image:Plate frame 2.png|thumb|right|A single plate heat exchanger]]
[[Image:PHE Trieste 013.jpg|thumb|right|An interchangeable plate heat exchanger directly applied to the system of a swimming pool]]
Another type of heat exchanger is the [[plate heat exchanger]]. These exchangers are composed of many thin, slightly separated plates that have very large surface areas and small fluid flow passages for heat transfer.  Advances in [[gasket]] and [[brazing]] technology have made the plate-type heat exchanger increasingly practical. In [[HVAC]] applications, large heat exchangers of this type are called ''plate-and-frame''; when used in open loops, these heat exchangers are normally of the gasket type to allow periodic disassembly, cleaning, and inspection. There are many types of permanently bonded plate heat exchangers, such as dip-brazed, vacuum-brazed, and welded plate varieties, and they are often specified for closed-loop applications such as [[refrigeration]]. Plate heat exchangers also differ in the types of plates that are used, and in the configurations of those plates. Some plates may be stamped with "chevron", dimpled, or other patterns, where others may have machined fins and/or grooves.

When compared to shell and tube exchangers, the stacked-plate arrangement typically has lower volume and cost. Another difference between the two is that plate exchangers typically serve low to medium pressure fluids, compared to medium and high pressures of shell and tube.  A third and important difference is that plate exchangers employ more countercurrent flow rather than cross current flow, which allows lower approach temperature differences, high temperature changes, and increased efficiencies.