Heat exchanger
A heat exchanger, which passes heat from one fluid to another without mixing them. It is drawn as a circle crossed by a zigzag line.
Easily confused with
How to read it
A heat exchanger moves heat from a hotter fluid to a cooler one through a metal wall, with no direct contact between the two fluids. The DOE’s Mechanical Science handbook calls tube and shell the most basic and most common construction: a set of tubes inside a container called the shell, with one fluid in the tubes and the other around them. Kuphaldt’s Lessons In Industrial Instrumentation describes the same shell-and-tube design.
Both the DOE’s chart and Kuphaldt’s draw the heat exchanger as a circle with a zigzag line running through it and connections for the two streams. The DOE’s chart gives alternatives, among them a rectangle with a zigzag inside.
Also searched as: heat exchanger p&id symbol, heat exchanger symbol, shell and tube heat exchanger symbol.
This explains what a symbol represents on a diagram. Companies vary the symbols, and a diagram's own legend sheet takes precedence.
Look-alikes
A plain circle with a line leaving at a tangent is a centrifugal pump. A plain circle with letters inside is an instrument bubble, not equipment.
Read next
- Next in P&ID symbolsVessel or tankA vessel, tank or drum: process equipment that holds liquid or gas. It is drawn as a tall rectangle with rounded ends.
- The same shape in African flagsFlag of EthiopiaEthiopia’s flag is green, yellow and red in equal horizontal stripes with a blue disc in the centre holding a yellow star of equal lines with yellow rays. Ethiopia’s Flag Proclamation makes the green labour, fertility and development, the yellow hope, justice and equality, and the red sacrifice and heroism for freedom and equality; the blue disc is peace and the star the unity of Ethiopia’s nations, nationalities and peoples.
More P&ID symbols
The same shape elsewhere
Browse symbols drawn with circles or lines.
Sources
- DOE Fundamentals Handbook: Mechanical Science, Volume 1 of 2, DOE-HDBK-1018/1-93, January 1993, U.S. Department of Energy (University of Cambridge Engineering Department mirror), Module 2, Heat Exchangers
- Lessons In Industrial Instrumentation, Tony R. Kuphaldt, version 2.33, 2024 (CC BY 4.0), Tony R. Kuphaldt (ibiblio.org), 2.10 Elementary thermodynamics; 7.5.9 Process equipment
Researched, edited and approved by Rory Hansen before publishing. Last reviewed October 9, 2026. How we research
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