How does air cooled heat exchanger work?

An air-cooled heat exchanger (ACHE) works by using ambient air to remove heat from a process fluid, typically a liquid or gas. Here's a basic rundown:

1. **Heat Exchange Surface**: The ACHE consists of finned tubes through which the process fluid flows. These fins increase the surface area for better heat transfer.

2. **Process Fluid Flow**: The hot process fluid enters the tubes and flows through them. This fluid could be anything from steam in a power plant to a hydrocarbon in an oil refinery.

3. **Air Flow**: Ambient air is forced or naturally drawn over the external surface of the tubes. Fans are commonly used to ensure a steady flow of air.

4. **Heat Transfer**: As the air passes over the tubes, heat from the process fluid transfers to the air. This cools down the process fluid inside the tubes.

5. **Cooling**: The now heated air is expelled into the atmosphere, and the cooled process fluid continues its journey through the system.

6. **Efficiency**: The efficiency of an ACHE depends on factors like the air flow rate, the temperature difference between the process fluid and the ambient air, and the design of the heat exchanger itself.

These heat exchangers are commonly used in applications where water is scarce, expensive, or where water cooling isn't practical, such as in remote locations or in industries like oil and gas refining.