With the winter season in full swing right now, there’s no doubt that your heating system is one of your most-prized home appliances. Your heating system is made up of various components that work together for seamless temperature control in your home. One of the most underappreciated and lesser-known components is the heat exchanger.
Regular use of your heat exchanger wears it out, causing malfunctions that make operating your heating system unsafe and ineffective. It is best if all homeowners gain more information and knowledge about their heat exchangers. Here’s a guide to get you accustomed to this important part of your HVAC system.
What Is a Heat Exchanger?
The heat exchanger is a piece of equipment used in various occupations/appliances including heating, refrigerators, and even power plants. A heat exchanger uses fluids to transfer energy. A medium is used to absorb heat from one fluid usually a fuel to another that is used to increase or to reduce temperatures in your home.
The heat exchange takes place by incorporating the subject of heat flow from high temperatures to lower temperatures. Unlike other heat exchange mediums, a heat exchanger involves the transfer of heat between mediums with zero contact.
The fluid mediums are kept from contact with materials of high thermal conductivity. The materials create a space for heat exchange with no need for fluid contact in the transfer of heat.
How Does a Heat Exchanger Work?
The components apply the laws to thermodynamics to form a foundation for the creation of heat exchanges. The heat can only be transferred when there exists a temperature difference from a higher temperature to a lower one using conduction and convection.
When the heat is shifted from the fuel fluid to the surface wall, convection takes place. As the high-temperature fluid moves along the heat exchanger, it losses its heat to its surroundings, which is also known as the high thermal conductivity wall. Once the material gains heat, it transfers the heat to the other low-temperature fluid through conduction then convection once again.
Heat transfer between the fluids and system walls is dependent on the flow of the liquid which can be in three types of flows:
- The countercurrent flow is the fastest and most effective way of heat transfer in heat exchangers. Here, the two fluids move in different opposing directions. In this flow, the temperature difference must be huge for an even transfer heat rate.
- Parallel flow as the name suggests features the two system fluids moving parallel to each other. The parallel or current rent flow can cause the heat loss and is not the best for heat transfer.
- Another working flow of heat exchange is the crossflow. Crossflow is commonly used with gas-liquid fluids that are 90 degrees to the cross-flow process. The heat exchange process takes place accurately but is slightly less effective than the countercurrent flow.
Types of Heat Exchangers
There are various types of heat exchangers in the current market, and settling for one can be tricky. Here are some of the main heat exchanger types.
1. Double Tube Heat Exchangers
The system features a tube inside another tube design. The design has two small tubes fitted inside a large diameter tube to prevent the two heat exchange fluids from mixing.
This design is easy to maintain with leaks easily detectable. In addition, their compact nature makes them great for indoor heating units and is effective in heat transfer.
2. Shell and Tube Heat Exchangers
These systems are the most flexible option among heat exchangers and feature several tubes inside a large cylinder-like shell. They are used when heating involves loads of fluids or fuel because they can sustain the heat pressure and higher than usual temperatures. The heat exchanger can be pulled apart to make its maintenance easy and complete.
3. Plate Heat Exchanger
The heat exchanger uses similar titanium or steel plates, glued together with rubber fiber to transfer heat. The plate heat design is one of the most basic among heat exchangers but provides higher effectiveness due to the plate’s surface area.
The plates can be several in one heat exchanger with their number determined by factors such as:
- Rate of flow
- Difference in pressure
- The current temperature
- Fluid content
One of the important aspects to consider about your heat exchangers is how to maintain them. Dirty heat exchangers reduce their ability to transfer heat which can cause various problems for instance uneven heating and cooling of your home. Furthermore, leaks due to cracks or openings can cause exposure to carbon monoxide which can cause breathing difficulties and fatal poisoning when inhaled over long periods.