As the name implies, heat exchangers are industrial equipment designed to transfer heat for industrial processes. Although there are many different types of heat exchangers within each industry, their functions are largely the same. These products not only heat elements up, but they may also cool them down as needed. Both heating and cooling may be extremely important to the efficiency of the plant, but cooling is often the more important task since many pieces of equipment will not function properly and safely if overheated.
In industrial applications, heat exchangers serve a number of important applications. In some units, the exchangers will capture the heat which is being released and redirect it into the process so that it can be put to use to increase efficiency and save the plant money. Other heat exchangers keep machinery or chemicals within a safe operating temperature.
How Do Heat Exchangers Work?
Heat exchangers are designed with many different features, depending on the industry and the equipment. The most basic function of the exchanger is that it exposes a warmer medium to a cooler medium. Most often, this is accomplished through a set of tubing, along with other components such as fans, condensers, belts, coolants, and lines, and specialized equipment to improve the airflow or increase heating and cooling efficiency.
Heat exchangers can take a hot or cold substance and change its physical state as needed. For instance, a liquid might be transformed into a gas or a solid, or a gas might be changed into a sold. This is done through either direct contact or indirect contact.
In a direct contact system, the hot and cold fluids will directly interact with each other. This is typically done with both the hot and cold materials are the same substance or when it is okay for them to mix.
The indirect contact system keeps the two fluids separate. This system is often used when one of the substances might contaminate the other or create a new substance if the chemicals interact.
Heat exchangers are typically classified using the following criteria:
- The physical state of the fluids (i.e. liquid, solid, or gas)
- How the heat exchange process is happening
- The flow arrangement of the heat exchanger
- The design or construction of the exchanger
Flow Arrangement Types
The heat exchanger might be classified based on the arrangement of the two fluids within the system. In a parallel-flow system, each liquid enters the exchanger from the same end, and they both travel parallel to each other. In the countercurrent flow system, the fluids enter from opposite ends of the exchanger and travel towards each other. Within the cross-flow system, the hot and cold fluids enter the exchanger at different points and typically cross paths with each other at right angles.
Whichever type of heat exchanger is implemented, it only works at peak performance when it is well taken care of and serviced on a regular basis to prevent downtime.
