Structure and Features of Plate Heat Exchangers

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Structure of a plate heat exchanger
How it works
Main advantages
Common applications
Further reading: closing tubes for shell-and-tube units and heat pipes
Reference
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Structure of a plate heat exchanger

A plate heat exchanger is built from a stack of pressed stainless steel plates with a corrugated pattern. Adjacent plates are turned 180° to each other, so the ridges cross and form many contact points; in brazed or vacuum-welded designs these contact points are joined into a pressure-resistant flow structure.

Heat exchanger coil

TD-31040 closing machine for heat exchanger tubes

Each plate has four corner ports for the hot and cold fluids. The crossing channels create strong turbulence, which greatly improves heat transfer.

How it works

Hot and cold fluids flow in alternate channels between the plates and exchange heat through the thin plate wall. The corrugations increase turbulence and effective surface area, giving high performance in a compact unit.

Main advantages

High efficiency: turbulent flow gives a much higher heat transfer coefficient than shell-and-tube
Compact: about a third of the volume of a shell-and-tube unit for the same duty
Easy to expand: add or remove plates to change capacity
Easy to clean: gasketed designs can be opened for maintenance
Less material: plates are typically only 0.5–1.0 mm thick

Common applications

Chilled and hot water exchange in central air conditioning
Heating, pasteurizing and cooling food and drinks
Temperature control in chemical processes
Swimming pool water heating
Heat recovery in solar and geothermal systems
Marine engine cooling and fresh water generation

Q: Which plate material?
304 stainless steel suits most clean water and general chemicals. For more corrosive fluids, use 316 stainless or titanium. Food applications need hygienic-grade materials.

Q: How often should it be cleaned?
It depends on how clean the fluids are; inspection every six to twelve months is a common guideline. If efficiency drops or pressure drop rises noticeably, open and clean it.