Design of air conditioning system for large meeting rooms

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Design of air conditioning systems for large conference rooms (Large Conference Room / Auditorium)

It is necessary to consider both thermal comfort, air quality (IAQ) and low noise.

This includes managing the large heat loads generated by people. Electrical appliances and lighting, with design guidelines that should be followed as follows:

✅ Air conditioning system design guidelines: large conference room

1. Calculation of heat load (Cooling Load)
 • Use Manual N or Software calculations such as
 • Consider:
 • Number of people (approximately 1 people/1.2–1.5 sq m.)
 • Heat from equipment: projectors, lights, AV systems.
 • Heat from sunlight (Solar gain) if there is a glass wall.
 • Ventilation air (Fresh Air) as standard.

2. Selecting the type of air conditioning system.

System suitable for advantages and cautions
Chilled Water AHU + Duct, large room > 200 sq m., consistently cool, precise control. Must have a cold water pipe system.
VRF / VRV System, room 100–300 sq m, energy saving Takes up little installation space. Must have separate Fresh Air.
Package Unit + Duct for temporary use or open areas, easy to install, zones cannot be controlled independently.

3. Air Distribution Design
 • Cold air supply (Supply Air)
 • Use a Slot Ceiling Diffuser or Circular Jet Nozzle for high ceilings.
 • Air Speed at Diffuser: 400–600 FPM
 • Distribute air throughout the area without “Cold Draft”.
 • Return Air
 • Install the Grille on the back wall of the room or under the cushion / alcove.
 • There must be adequate Return Air channels to avoid noise or excessive pressure.

4. Ventilation (Ventilation Air)
 • Must have Fresh Air that meets standards:
 • At least 10–15 CFM/person or approximately 7.5 liter/second/person.
 • Through the Pre-filter and Medium Filter system (MERV 8–13)
 • If the room is used for a long time, you must consider a CO₂ Sensor to control the amount of Fresh Air using Demand Control Ventilation (DCV).

5. Noise control
 • The noise level in the conference room should be within NC 25–35 (Noise Criteria).
 • Select equipment with low noise levels.
 • Use a Flexible Duct or Sound Attenuator to reduce noise from the AHU.

6. Automation control
 • Use a BMS / Thermostat system to separate zones (in the case of having separate rooms).
 • Set the time to turn on/off the system according to the usage period.
 • Control relative humidity: 50–60%

📌 Brief summary of guidelines

Topic Recommendations
Recommended system: AHU + Chiller or VRF
Diffuser air supply at multiple points distributes air evenly.
Return Air, wall mounted / under floor with air filter
Fresh Air ≥ 10 CFM/person with Pre/Medium Filter
Cooling 23–25°C RH: 50–60%
Sound ≤ NC 30
Thermostat + BMS control