Types and Principles of Heat Exchangers

Table of Contents Menu

What is a heat exchanger?
Main types
Selection factors
Industries
Tube end closing for heat exchanger tubes
Reference
- Related videos

What is a heat exchanger?

A heat exchanger transfers heat between two or more fluids. The fluids may be separated by a solid wall so they do not mix, or they may be in direct contact. Heat exchangers are used in air conditioning, power plants, chemical plants, refineries and wastewater treatment.

Heat exchanger coil

Spin-closed copper tube end

Copper tube closing samples

The everyday example is a car radiator: coolant flows through the radiator tubes while air flowing across them carries the heat away.

Main types

Shell-and-tube

A bundle of tubes inside a cylindrical shell. One fluid flows through the tubes and the other around them on the shell side. Simple, strong and able to take high pressure – the most common industrial type.

Plate

A stack of corrugated metal plates, with hot and cold fluids flowing in alternate channels. The corrugations create turbulence and high efficiency, in a much smaller volume than shell-and-tube.

Plate-and-shell

Combines the efficiency of plates with the pressure capability of a shell: welded plates inside a shell, suited to high temperature and pressure.

Selection factors

Fluid type, temperature and pressure
Required heat duty
Available installation space
Ease of cleaning and maintenance
Corrosion resistance of the material

Q: Plate or shell-and-tube?
Plate heat exchangers are efficient and compact, suited to low and medium pressure. Shell-and-tube units take high pressure and are robust, suited to heavy industry and high temperature and pressure.

Industries

Air conditioning: central chilled and hot water circuits
Automotive: radiators, heaters, turbo intercoolers
Food processing: milk pasteurization, drink cooling, brewing temperature control
Chemical processing: reactor temperature control, process cooling
Solar and geothermal: heat recovery, ground-source heat pumps

Tube processing – bending, expanding, reducing and closing copper and stainless tubes – is a key step in making heat exchangers.

Tube end closing for heat exchanger tubes

Stainless steel and copper tubes for shell-and-tube heat exchangers and heat pipes often need a closed end. The TD-31040 heat pipe and heat exchanger tube closing machine from TONG DA Precision (Taiwan) spin-forms a one-piece closed end at room temperature – no weld, no plug. For small copper tubes that need a flat end, there is the TD-21025 flat-type closing machine. Send your tube specification for sample closing; quotations via sales@tdco.com.tw.