The key difference between counterflow and parallel flow heat exchanger is that counterflow heat exchanger is highly efficient because it can exchange a maximum amount of heat, whereas parallel flow heat exchanger is less efficient because it cannot exchange a high amount of temperature.
A heat exchanger is an apparatus that is helpful in removing heat from a liquid having a high temperature. According to their mechanism, there are typically two primary classifications for heat exchangers named: parallel flow and counterflow heat exchangers. These are also known as inline and crossflow heat exchangers, respectively. The counterflow process is the opposite of the parallel flow process.
CONTENTS
1. Overview and Key Difference
2. What is Counterflow Heat Exchanger
3. What is Parallel Flow Heat Exchanger
4. Counterflow vs Parallel Flow Heat Exchanger in Tabular Form
5. Summary – Counterflow vs Parallel Flow Heat Exchanger
What is Counterflow Heat Exchanger (or Crossflow Heat Exchanger)?
Counterflow heat exchangers are exchangers in which the two fluids flow in parallel but opposite directions. We can categorize these heat exchangers depending on the flow arrangement. The most common types include plate, shell and tube, double-pipe, one phase, and multi-phase counterflow heat exchangers.
Figure 01: A Heat Exchanger
In counterflow heat exchangers, the hot and cold sections tend to move perpendicular to each other. In other words, these exchangers use flows that move in the opposite direction to each other. It is a more efficient heat exchanger compared to other forms. In these apparatuses, the heat flow is maximum. Therefore, the efficiency is also higher than that of the parallel heat exchanger mechanism. Moreover, the temperature in the cooling fluid can sometimes exceed the warmer fluid temperature coming from the inlet.
What is Parallel Flow Heat Exchanger (or Inline Heat Exchanger)?
A parallel flow heat exchanger is a type of exchanger having a parallel fluid direction. In other words, the fluids having a high temperature and a cold temperature both move towards the same direction through separate tubes, which allows the heat to be transferred from a high-temperature liquid to a low-temperature liquid.
This process is less efficient compared to the counterflow method because this process cannot absorb a maximum amount of temperature from the warm liquid. This is because when the two liquids move in the same direction, the temperature difference between the two liquids becomes gradually low. However, this method is important when the flows at the outlet have a similar temperature together, and we also need these flows to have a closely similar temperature.
What is the Difference Between Counterflow and Parallel Flow Heat Exchanger?
A heat exchanger is an apparatus that is helpful in removing heat from a liquid having a high temperature. The key difference between counterflow and parallel flow heat exchanger is that counterflow heat exchanger is highly efficient because it can exchange a maximum amount of heat, whereas parallel flow heat exchanger is less efficient because it cannot exchange a high amount of temperature. In brief, the counterflow process is the opposite of the parallel flow process.
The below infographic presents the differences between counterflow and parallel flow heat exchangers in tabular form for side by side comparison.
Summary – Counterflow vs Parallel Flow Heat Exchanger
Counterflow heat exchangers are exchangers in which the two fluids flow in parallel but opposite directions, while a parallel flow heat exchanger is a type of exchanger in which the two fluids flow parallelly in the same direction. The key difference between counterflow and parallel flow heat exchanger is that counterflow heat exchanger is highly efficient because it can exchange a maximum amount of heat, whereas parallel flow heat exchanger is less efficient because it cannot exchange a high amount of temperature.
Reference:
1. Linquip, et al. “Counter Flow Heat Exchangers and Its Working Principles.” Linquip.
Image Courtesy:
1. “Tubular heat exchanger” By KoenB – own work, using Blender and YafRay (Public Domain) via Commons Wikimedia