Notes for Installing Concealed Ceiling Air Conditioning Duct Systems

Notes for Installing Concealed Ceiling Air Conditioning Duct Systems

Ceiling-concealed ducted air conditioning systems are increasingly being used, not only in shopping centers but also in residential apartments. Ducted systems provide even cooling and offer great aesthetics. However, in order for the system to achieve maximum efficiency, it must be installed accurately and properly. So, what are the important considerations when installing concealed ceiling air conditioning duct systems?

Functions of Concealed Ceiling Air Conditioning Ducts

Air ducts play a crucial role in HVAC systems by delivering and distributing cooled air to the required spaces and supplying fresh air. Their main functions include:

1. Even air distribution: Ducts distribute cool air from the AC unit to different areas of the room, maintaining stable and comfortable temperatures.

2. Supplying clean air: Air ducts are typically designed to pass through filters, which remove dust, bacteria, and unpleasant odors before the air is supplied to living or working spaces.

3. Space-saving: Since ducts are concealed within the ceiling, they do not take up floor space, optimizing layout and creating a spacious environment.

4. Aesthetic appeal: Concealed ducts are hidden above ceilings, allowing interior design to remain unobstructed and visually pleasing.

5. Efficiency and energy savings: Properly designed ducts minimize air loss, helping the system operate efficiently and saving energy.

Thus, ducts play a major role in the superior performance of ducted air conditioning systems. Therefore, installation and construction of duct systems are critical steps that require special attention.

Why Pay Attention When Installing Concealed Ducted Air Conditioning Systems?

Proper installation requires attention to duct size, thickness, and ceiling height, in order to ensure stable system performance and reduce construction errors.

Issue 1: Duct Size and Thickness

Why must duct size and thickness comply with manufacturer standards?
Compliance ensures stable and efficient operation of the HVAC system in residential, public, and industrial buildings. Galvanized sheet metal ducts, for instance, must follow thickness standards to meet technical requirements. Minimum thickness is specified depending on materials such as black steel, galvanized sheet, stainless steel, aluminum, rigid plastics, fiberglass-reinforced plastics, brick, concrete, or gypsum board. Steel ducts also follow thickness classifications such as Sch5, Sch10, Sch30, Sch40, Sch80, and Sch120.

Consequences of non-compliance:

• Reduced system performance and ineffective ventilation/air conditioning.

• Increased system pressure leading to leakage or equipment damage.

• Negative impacts on air quality, safety, and energy efficiency.

What to do if ducts do not meet standards?

• Redesign the ductwork to comply with TCVN 5687:2010 or international standards.

• Ensure sufficient air exchange rates (minimum 2 ACH).

• Select proper sound attenuator sizes.

• When using flexible ducts for FCU (Fan Coil Units), avoid unnecessary flexible joints, ensure independent supports, and install isolation valves on water inlets/outlets.

Issue 2: Ceiling Height

Common problems if ceiling height is not considered:

• Unstable duct system operation.

• Reduced cooling efficiency.

• Difficult maintenance and reduced equipment lifespan.

• Complications in repair and higher costs.

How to ensure suitable ceiling height?

• Insulate refrigerant and drain pipes adequately (10&ndash30 mm insulation thickness).

• Design a complete HVAC layout before installation.

• Ensure ceiling space matches duct size and airflow velocity requirements.

How to determine proper ceiling height?
According to ASHRAE recommendations:

• Outdoor air intake openings must be at least 2 m above ground level (3 m in high-wind areas).

• Ceiling space must allow for duct sizing, insulation, and accessibility.

Issue 3: Other Potential Errors

How to minimize installation errors?

• Strictly follow manufacturer standards for duct size and thickness.

• Ensure ceiling clearance.

• Perform installation correctly: indoor unit placement, outdoor unit placement, refrigerant piping, electrical wiring, vacuuming, refrigerant charging, and test running.

How to verify system quality after installation?

• Inspect duct cleanliness, dimensions, and sealing.

• Check system operating principles.

• Perform test runs and commissioning.

• Ensure professional contractors provide warranty and after-sales service.