types of hvac system

Types and Working Principles of HVAC Systems

You may be planning to install an HVAC system at your home or commercial space, but maybe you’re a first-time buyer or someone who has little to no knowledge of the HVAC systems. What is the HVAC system and totally aware of the HVAC working principle, don’t worry this article will guide you through all the questions rising in your mind about the HVAC system?  

What does HVAC System mean?

The full form of HVAC is heating, ventilation, and air conditioning these describe the three basic functions HVAC performs. HVAC system controls the indoor temperature through heating and cooling, it also controls humidity level in the indoor environment by controlling the airflow in and out of the room. It filters the air to ensure a clean and fresh airy environment inside the room.

The types of HVAC systems that we have within the industry HVAC is broad in general for every single area of the application you have specialized equipment to be used based on preferences such as economic aspects, client preferences, space requirements, capacity and, an extensive list of other considerations to be taken into account before actually choosing the HVAC system that you want to install. 

So, in this article, we’ll be going through the different types of HVAC systems and with the generic perspective without diving into extensive details just in order for you to have a complete idea about the different HVAC systems that we have.

Types of HVAC Systems

Now HVAC systems can be classified under two categories the first one is the decentralized HVAC system and the second one is the centralized HVAC system. In this article, we’re going to be highlighting the main differences between centralized and decentralized HVAC systems.

1. Decentralized HVAC System

Now the first system we’re going to be talking about is the decentralized HVAC system. A decentralized HVAC system is the HVAC system in which every single zone or space has a designated unit.

All those designated units provide the cooling requirements, where you have the basic components of the refrigeration cycle the compressor, evaporator, condenser, and expansion valve. It’s the system where you have designated units with all the major components of the refrigeration cycle present in an interlinked manner.

Refrigerants are responsible for acquiring the heat from your space so for seed for a decentralized HVAC system. 

Decentralized HVAC Working Principle

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Now the example we’ll be using for a decentralized HVAC system is the split unit system. The unit most probably you’ve seen this within your house or within buildings. The split unit system is called split because of the fact that you have the indoor unit and the outdoor unit. Both the unit is quite separated from each other.

On one side, we have the evaporator which is present inside the zone or the space, on the other side, you have the condenser which is placed outdoors or on the rooftop.

In the indoor unit, the evaporator is connected to the outdoor unit which is the condenser through copper piping. These units perform the refrigerant in a closed cycle between the indoors and the outdoors.

The heat load is picked up from the indoors by the refrigerant it evaporates then it goes all the way out to the condenser, present outdoors and it releases the heat into the environment. Cycle repeats itself

VRF is also an example of an HVAC system where a single outdoor unit is connected to multiple indoor units. That’s the major difference between the fact that every single indoor unit receives a different amount of refrigerant.

2. Centralized HVAC System

Now the second type that we have for the HVAC system is the centralized HVAC system. The centralized HAVC system is present in one geographic location where the plant is responsible for generating the whole cooling requirements which are then transmitted towards your space or zones.

Now for the centralized on the other hand, the cooling to all of the spaces that you’re dealing with is being provided by a central plant present in a single location. So, let’s say you have one location which is responsible to generate the whole cooling requirements which are then transferred to provide the cooling requirements to the entire space.

Let’s go through the elaborate definition of a centralized HVAC system. It is a centralized cooling plant which is generating chilled water to be supplied to units. However, for a centralized HVAC system, we’re having chilled water passing through a piping network responsible for taking the heat from your space. Coldwater is passing through a piping network which is called FCU. FCU stands for fan coil unit and AHU stands for air handling unit which in turn they blow the cold air into the space as the heat is being absorbed by the circulating cold water. 

The main difference between a centralized and a decentralized HVAC system is in the equipment allocation. As per the cooling requirement in addition to the type of refrigerant, the type of fluid also plays an important role in the cooling efficiency.

For a decentralized HVAC system, the main fluid is responsible for absorbing the heat but for a centralized HVAC system, it’s the chilled water, passing through a piping network that is responsible for absorbing the heat. 

Centralized HVAC Working Principle

Now talking about the working principle of the centralized HVAC system, a headshield is equipment that helps to generate cold water. The hot water goes in the chiller and its heat is absorbed using the same concept of the refrigeration cycle, then the cold water comes out and it goes towards the building or the space that you want to cool. A blower which is a fan installed inside helps in circulating air from the coil to your space.

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