Underfloor Air Distribution (UFAD) Air Conditioning System: An Energy-Efficient Ventilation Solution for Future Buildings

 

I. System Overview

The Underfloor Air Distribution (UFAD) system is an innovative HVAC design. It utilizes the space beneath the raised floor in a building's structure to convey conditioned air, effectively regulating indoor temperature, humidity, and air quality. Different from traditional ceiling air supply systems, UFAD places air supply outlets on the floor or close to the ground, and achieves stratified ventilation through the natural buoyancy of air - fresh cold air spreads from the bottom, while hot air and pollutants rise to the top and are discharged. This design not only optimizes the air flow organization but also significantly enhances energy utilization efficiency.

 

II. Working Principle and Technical Features

The core of the UFAD system lies in its unique air supply path and air stratification mechanism:

1.Air Supply Path: The air conditioned by the air - conditioning system is transported through the plenum beneath the floor to the air supply diffusers in each area, directly acting on the areas where people are active and reducing the air flow circulation in ineffective spaces.

2.Air Stratification: Cold air, with a greater density, naturally sinks and covers the lower part of the room; hot air and pollutants, with a smaller density, rise to the vicinity of the ceiling and are finally discharged through the exhaust outlets at the top. This stratification phenomenon reduces the mixing of cold and hot air and lowers the strict requirements for the air supply temperature.

3.Flexible Control: The system supports zonal adjustment. Users can independently control the air supply volume and temperature according to the needs of different areas, further improving energy efficiency and comfort.

 

III. Core Advantages

1.Energy Saving and Consumption Reduction:

   - The air supply temperature can be increased by 2 - 4℃, reducing the load on the refrigeration unit and improving the coefficient of performance (COP) of the refrigeration cycle.

   - Stratified ventilation reduces the total air treatment volume, and the energy consumption of the fan is reduced by about 30%.

2.Health and Comfort:

   - Fresh air is directly delivered to the areas where people are active, reducing the accumulation of pollutants in the breathing zone.

   - Low - temperature and low - speed air supply avoids the draft feeling of traditional mixed ventilation and improves thermal comfort.

3.Optimization of Building Costs:

   - It reduces the need for ceiling space, lowering the building's floor height and construction costs.

   - The raised floor facilitates the layout of pipelines and later maintenance, shortening the construction period.

4.Environmental Adaptability:

   - It is suitable for various building types such as office buildings, schools, and museums, and performs particularly well in high - heat - load scenarios (such as data centers).

 

IV. Application Scenarios and Development Trends

Since the UFAD system was first applied in high - heat - load scenarios such as computer rooms in the 1950s, it has gradually expanded to the civilian sector. Currently, in regions such as Europe and Japan, it has become the mainstream choice for commercial buildings, educational facilities, transportation hubs, and other places. For example, libraries and airport lounges achieve local and precise temperature control through the UFAD system, while open - plan offices benefit from its flexible workstation adjustment function. In the future, with the promotion of green building standards, UFAD will be combined with intelligent control systems to further achieve on - demand cooling and the goal of carbon neutrality.

 

V. Comparison with Other Systems

Compared with traditional mixed ventilation and displacement ventilation systems, UFAD has more advantages in terms of energy efficiency and comfort:

-Mixed Ventilation: It relies on high - speed air to mix cold and hot air, resulting in high energy consumption and easy generation of noise.

-Displacement Ventilation: Although it also utilizes the principle of buoyancy, it has a lower air supply speed and a higher temperature, and is suitable for scenarios with lower constant - temperature requirements.

-UFAD: It combines the advantages of both, supporting high - temperature air supply for energy saving and meeting the dynamic load requirements through zonal control.

 

VI. Conclusion

The underfloor air distribution air conditioning system provides an efficient, healthy, and sustainable ventilation solution for modern buildings through scientific air flow organization design. Its stratified air supply mode not only reduces energy consumption but also significantly improves the indoor environmental quality, becoming an important direction for the development of future green building technologies. With technological innovation and cost optimization, the UFAD system is expected to accelerate its popularity globally, promoting the building industry to move towards low - carbon and intelligent development.