Design Considerations for Air Cooled Heat Exchanger

by Engineering Geek Expert in industrial engineering including piping,

Air-cooled heat exchangers (ACHEs), also known as air coolers, are used extensively in the oil & gas industry, petrochemical plants, refineries, power plants, and other processing operations. These ACHIEs units are used for process cooling and condensing streams with ambient air through direct heat transfer from the fluid. Air cooling is often economically advantageous compared to water cooling because it reduces maintenance costs, consumes lesser electricity, easy to install, and involves fewer types of equipment.

Types of Air Cooled Heat Exchanger

Forced Draft: The tube section is placed on the discharge side of the fan, and the air is forced through tubes.
Induced Draft: The tube section is located on the suction side of the fan, and the air is induced or pulled through the tubes.

A typical ACHE comprises of following components:

One or more finned or bare tube bundles
One or more fans to provide cooling Air
An air moving device such as an axial flow fan, stack or blower
Plenum to enclose space between the fan(s) and the tube bundle
A driver and power transmission device to rotate the air moving device.

Primary Considerations for Equipment layout

The equipment of ACHE needs a proper flow of air for cooling. So, choose a location of air fin fan cooler that is not directly crowded or bounded by other constructions or tools to avoid blocking the path of plenty of airflows.
It is recommended to fix the static equipment on the top of the pipe rack or other structure to avoid any obstruction in proper airflow. Also, installing air-cooled heat exchangers on top of the pipe rack saves ample space of the infrastructure and results in building a compact plant.
The tube bundle length is defined and fixed based on the width of the pipe rack.
The ACHE on the pipe structure should be located in such a way that the bundles are easily accessible with a crane, at least from one side.
Provide a regular staircase to access the air fin coolers platform.
If air-cooled heat exchangers are grade mounted, then the area beneath the air cooler shall be surfaced to safeguard the tubes from the flow of sand/ dust.

Key factors to be considered during the piping layout

The air coolers are generally used when a massive quantity of vapor is required for condensation, or a vast amount of gas or liquid needs to be cooled.

The primary considerations that need to be taken care while pipe structuring are as follows:

The piping distribution to the air cooler should be symmetrical.
It is essential to keep the number of bends or elbow minimum when the supply line has low pressure. Moreover, consider the functionality and stress requirements of the ACHE.
Keep the length of all branch pipes of tube bundles similar to ensure equal distribution of fluids in all packages.
The loads from thermal expansion, pipe, insulation, fluid weight, and pressure of piping generated on the bundle nozzle should be less than the limits defined by EN-ISO 13706.

With this, we hope that we were able to provide you useful considerations for the air-cooled heat exchanger. If you’re looking for equipment engineering services, consider hiring a proficient team of skilled engineers having experience in managing projects across industrial equipment and engineering companies.