What does HVAC engineering involve?

What does HVAC engineering involve?

Classification of HVAC systems by their purpose

🏠 Residential (Apartment / House)

➡️ Used for:

Split System (On/Off & Inverter)

The most common type of air conditioning, consisting of one indoor and one outdoor unit.
Operating principle: Air is cooled or heated by the circulation of refrigerant.

Components:

  • Indoor Unit
  • Outdoor Unit
  • Connecting Cable + Power Supply
  • Copper Pipes

Multi Split System

An air conditioning system where one outdoor unit serves multiple indoor units.

Components:

  • 2-5 Indoor Units
  • 1 Outdoor Unit
  • Connecting Cable + Power Supply, Control System
  • Branched copper pipes (Individual pairs of pipes run from the outdoor unit to each indoor unit)

Mini VRF System

This is a downsized version of a VRF / VRV system.

Components:

  • 4-8 Indoor Units
  • 1 Smart Outdoor Unit
  • Smart Control System
  • Central main line and branches (Refnet / Y-Joint) - this saves pipe quantity over long distances

🏢 Commercial (Office / Shop / Hotel / Mall)

➡️ Used for:

VRF / VRV - Variable Refrigerant Flow System

  • VRF (Variable Refrigerant Flow) - General technology name
  • VRV (Variable Refrigerant Volume) - The same technology, a patented trade term by Daikin

The system allows one outdoor unit to serve multiple indoor units. Ideal for commercial buildings for individual control and energy efficiency.
"Heat Recovery" feature - 3-pipe systems that can cool one room while heating another simultaneously.

Components:

  • Outdoor Unit (Inverter)
  • Indoor Units (Wall-mounted, Cassette, Ducted)
  • Copper Pipes + Refnet Joints / Y-Joint
  • Communication Cable
  • Central Controller

Rooftop Units - RTU

A packaged unit mounted on the roof. It processes air and supplies it to large spaces through ducts.

Components:

  • Monoblock Casing
  • Compressor & Coils (Combined)
  • Supply & Return Fans
  • Economizer (Outside air damper)

Packaged Units

A system similar to an RTU, where all components are in one "box". It can also be installed on the ground. Used in small commercial spaces.

Components:

  • Self-contained Unit (All-in-one block)
  • Thermostat (In-room control)
  • Ductwork

Chiller + FCU (Fan Coil Unit)

Hydronic System. The Chiller cools/heats water, which is supplied through pipes to the Fan Coil Units (FCU) in the rooms. Most modern chillers are Heat Pump (reversible) type (4-pipe system).

Components:

  • Chiller (Water cooling unit)
  • Hydronic Module (Pumps, tanks)
  • Fan Coil Units - FCU (Indoor blocks)
  • Piping System (Water pipes and insulation)

AHU + FCU (Air Handling Unit and Fan Coil)

A combined system. The AHU supplies fresh air centrally, while the FCU regulates the temperature in the room. VAV systems are also used for zonal regulation.

Components:

  • Air Handling Unit - AHU
  • Ducts & Diffusers
  • Fan Coils
  • VAV Boxes (Variable Air Volume)
  • Chiller / Boiler (Energy source)

DOAS (Dedicated Outdoor Air System)

A system that takes in 100% outside air, dehumidifies, cools, and supplies it to the building.

Components:

  • DOAS Unit (Special unit with moisture removal)
  • Energy Recovery Wheel
  • Ventilation Ducts

🏭 Industrial (Factory / Warehouse / Data Center)

➡️ Used for:

Chillers - Air / Water Cooled

Used for process cooling of equipment.

  • Air Cooled Chiller - Condensation occurs via ambient air.
  • Water Cooled Chiller - Condensation occurs via water (Cooling Tower).
  • Free Cooling - Reduces compressor operation at low temperatures.

Components:

  • Industrial Chiller
  • Cooling Tower (For Water Cooled only)
  • Process Pumps (High pressure pumps)
  • Buffer Tank

AHU - High Air Flow / Hygienic

Particularly powerful units. They often require special filtration (HEPA Filters) for a sterile environment.

Components:

  • Stainless Steel Casing
  • High Pressure Fans
  • HEPA / ULPA Filters
  • EC Fans (Energy-efficient fans)
  • Heat Recovery Section
  • Humidification System (Moisture control)

Industrial Ventilation Systems

Aspiration and exhaust systems. Extraction of harmful substances, dust, or smoke.

Components:

  • Centrifugal Fans ("Snail" fans)
  • Cyclones / Scrubbers (Air filtration from impurities)
  • MAU - Make-up Air Unit
  • Industrial Ducts

Precision Cooling - CRAC / CRAH

Used in Data Centers for precise control of temperature and humidity.

  • CRAC: Refrigerant-based.
  • CRAH: Chilled water-based.
  • Hot Aisle / Cold Aisle Containment.
  • Redundancy (N+1 / 2N configurations).

Components:

  • Precision Unit (Precision cooling cabinet)
  • Raised Floor
  • Humidifier / Reheater

Refrigeration Systems

Cold Storage. For storing products (-18°C, -25°C). NH3 or CO2 systems are used.

Components:

  • Refrigeration Rack (Compressor station)
  • Evaporators / Unit Coolers (Indoor evaporators)
  • Insulated Panels (Sandwich panels)

🎛️ BMS - Building Management System

➡️ Used for:

  • Commercial: In offices and hotels for comfort and energy management.
  • Industrial: For production processes (pharmaceutical, data centers).

BMS is the "brain of the building". It centrally manages and controls HVAC, lighting, and other systems.

Components:

  • Management Server & Software
  • DDC Controllers (Digital controllers - "little brains")
  • Sensors (Temperature, humidity, CO2, pressure)
  • Actuators & Valves (Dampers, valves)
  • User Interface / HMI (Graphic operator interface)
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