Key Design Guidelines of Capillary Radiant Air Conditioning System

The capillary radiant air conditioning system is a new type of energy-saving and comfortable air conditioning system that can replace traditional central air conditioning. It uses water as the heat transfer medium and provides heating and cooling through evenly arranged capillary tube mats.

This system requires only 17–19°C supply/return water in summer and 30–32°C in winter, much higher than the 7–12°C in summer and 40–45°C in winter for conventional water systems. Therefore, it saves a significant amount of energy. Since heat is transferred by gentle radiation, there is no uneven air distribution, fan noise, or large temperature difference as in traditional air conditioning. With a dedicated fresh air system, it provides much better comfort. To reduce initial cost and avoid negative effects on interior decoration, higher design requirements are needed for capillary radiant systems.

Below are key design points for reference:

1. Understand Building Envelope Load

The capillary radiant system only handles sensible heat at 17–19°C. If the surface temperature drops below the dew point (about 16.8°C), condensation will occur, causing water damage and mold on the ceiling.
Latent heat is removed by the fresh air system. Better insulation and fewer cold bridges improve energy efficiency and reduce initial investment.

2. Determine Fresh Air and Supply Air Volume

Fresh air volume follows standard ventilation rates or per capita requirements.Supply air volume must cover the remaining cooling load not handled by capillaries. Higher building load requires larger air volume and more air outlets to reduce noise.

3. Choose Capillary Installation Method

Capillaries tube mats can be installed on the ceiling, walls, or floor. Ceiling installation is most common. For better cooling performance, wall and floor installation is recommended. Floor heating provides better comfort in winter. Installation can be adjusted based on budget and comfort requirements.

4. Select Fresh Air Treatment Method

For high-energy buildings, simple fresh air + full heat exchanger may not be enough. A rotary dehumidifier can be used but increases cost. A mixed system of fresh air + return air with a dehumidifier and heat exchanger is usually more practical.

5. Select Outdoor Chiller

Capillaries and fresh air units require different water temperatures. If capillary tube mats use an independent chilled water source, a smaller chiller can be used. If they share the same chiller, total cooling capacity must include both capillary and air system loads.

6. Automatic Control System

Capillary systems are more complex than traditional systems. Improper operation may cause problems.
A reliable automatic control system is strongly recommended.