Selection of HVAC System and Basic HVAC Fundamental Components

HVAC systems are key components of building mechanical systems that provide occupants with thermal comfort and good indoor air quality. According to multiple zones, locations, and distribution, HVAC systems can be divided into central and local systems.

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Heating, ventilation, and cooling or air-conditioning equipment are the three main types of HVAC equipment. Central HVAC systems are housed in a central equipment room away from buildings and deliver conditioned air via a delivery ductwork system. All-air, air-water, and all-water systems are included in central HVAC systems. Heating and cooling panels, as well as water-source heat pumps, should be considered central systems.

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There is no requirement for ductwork and local HVAC systems can be located inside or adjacent to a conditioned zone. Local heating, air conditioning, ventilation, and split systems are examples of local systems.

Choosing an HVAC system

The building configuration, the climate conditions, and the owner's desire all play a role in system selection. The design engineer is in charge of evaluating various systems and recommending multiple options to meet the goal and satisfy the building owner. 

Climate change (e.g., temperature, humidity, and space pressure), building capacity, spatial requirements, cost (capital, operating, and maintenance costs), life cycle analysis, and reliability and flexibility are some of the criteria that can be considered.

However, there are some constraints to consider when choosing a system. The available capacity according to standards, building configuration, available space, construction budget, available utility source, and heating and cooling building loads are all examples of these constraints.

An HVAC system's fundamental components

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The following are the basic components or equipment of an HVAC system that delivers conditioned air to satisfy space and occupant thermal comfort and achieve indoor air quality:

1. Mixed-air plenum and outdoor air control
2. Air filter
3.  Supply fan
4. Exhaust or relief fans and an air outlet
5. Outdoor air intake
6. Ducts
7. Terminal devices
8.  Return air system
9. Heating and cooling coils
10.  Self-contained heating or cooling unit
11. k. Cooling tower
12.  Boiler
13. Control
14. Water chiller
15. Humidification and dehumidification equipment

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HVAC system classification

HVAC systems are divided into two categories: 

• central and 
• decentralized or local. 

The primary equipment location determines whether the system is centralized, such as conditioning the entire building as a whole unit or decentralized, such as conditioning a specific zone as part of a building separately. As a result, the air and water distribution system should be designed around the system classification and primary equipment location. When deciding between two systems, the criteria mentioned above should be used.