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  • Writer's pictureAnne Lee

Heat Exchanger Heating System: How Do They Work?

Updated: Jul 6, 2023


heat exhanger

What is A Heat Exchanger?


An HVAC system's heat exchanger heating and cooling systems is a part that converts thermal energy from one medium to another. A heat exchanger is a device that moves heat among two or more liquids.


A wall separates each liquid to keep the two from combining. In an HVAC system, a gas and a liquid may occasionally exchange heat. They have cooling and heating applications.


Water, steam, or a water-glycol mixture are the most typical fluids for heating coils. It could be chilled water or a refrigerant in cooling coils.


Heat enhances the capacity of air to store moisture. Condensation from this moisture will be recovered on the cooling side of the system.


Evaporator and condenser are the two primary categories of heat exchangers, both of which help to heat and cool homes and other structures.



Type heat exchanger?


Using a shell and tube heat exchanger, heat from one fluid (a liquid or a gas) can be transferred to another fluid (another liquid or gas) without the two having to mix or come into contact.


The fundamental idea behind a heat exchanger is that it moves heat without moving the fluid that carries it.


The shell-and-tube, tube-in-tube, and plate/fin coil heat exchangers are the most popular types of heat exchangers.


One fluid circulates through a set of metal tubes in a shell and tube heat exchanger while a second fluid travels through a sealed shell around the first set of tubes.


The two fluids might flow in parallel (also known as counterflow or counter-current), in opposition (also known as counterflow), or at an angle (also known as cross flow).



How a basic heat exchanger functions

Photo: How a basic heat exchanger functions. A tube that is coiling inside a bigger shell through which a colder fluid (shown in blue) is flowing in the opposite direction is filled with a hot fluid (shown in red). Without actually coming into touch and mixing, the fluids exchange heat: the hot fluid cools and the cold fluid warms. This is a simplified illustration of a shell and tube heat exchanger; in reality, these heat exchangers often consist of a lot of thin tubes that are enclosed in a big shell.




Heat exchangers used in air conditioning work in a similar manner as fin coil heat exchangers, which have numerous thin metal plates or fins with a huge surface area.


Following are some images of actual heat exchangers:


heat exchanger
A shell and tube exchanger

Photo : A shell and tube exchanger



A tube-in-tube heat exchanger

Photo : A tube-in-tube heat exchanger



The fin coil heat exchanger

Photo : The fin coil heat exchanger




How an air conditioner uses a heat exchanger?


How an air conditioner works

Heat is transferred from indoor spaces to the outside by use of air conditioners.


A substance known as a refrigerant is utilized to accomplish this, carrying, absorbing, and releasing heat as it transforms from a gas to a liquid and vice versa.


How heat exchangers works?

Here's how heat exchangers works:

  1. As the refrigerant passes through the different parts of the air conditioner, it transports heat.

  2. In the evaporator coils, which are found in the indoor unit, the refrigerant initially exists as a low-pressure liquid.

  3. Warm indoor air is circulated across the coils by a fan, and as the refrigerant absorbs the heat from the air, it turns into a gas. The outcome is a cooling of the space.

  4. The refrigerant, which is currently a low-pressure warm gas, then moves into the compressor, which is often housed in the outside unit, where it is transformed into a high-pressure hot gas.

  5. In the outer unit's condenser, the refrigerant is transferred.

  6. The refrigerant changes into a high-pressure, cool liquid as air passes over the condenser coils and removes heat from it.

  7. After further cooling in the expansion valve, the refrigerant will return to the evaporator to take up additional heat to expel the building.

In A Nutshell

The condenser is the primary element responsible for heat transmission even if the complete air conditioner may theoretically be called the heat exchanger.


Heat exchangers hold significant significance in numerous industrial and commercial operations, as they actively contribute to the maintenance of optimal temperature and efficiency within these systems.


If you require further information, please don't hesitate to reach out to us.

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