Adiabatic cooling, an alternative to direct expansion air conditioning?

Many buildings are subject to occasional overheating problems.

An air conditioning system with refrigerant can prove to be heavy in terms of investment, installation and maintenance costs and is sometimes ill-suited to large-volume industrial or tertiary premises; this is why adiabatic cooling can be a real alternative depending on the case.

The principle

Adiabatic cooling makes it possible to cool the outside air before introducing it into a given volume without using refrigerant gases for this purpose.

It implements the principle of water evaporation when a flow of hot air passes through a moistened filter medium. The water thus evaporated will cool the incoming air flow because it is necessary to bring heat to the water so that it evaporates. This system requires a water point near the device and must be connected to a network for blowing the air introduced.

This adiabatic cooling can be:
– Direct: when the humidified air is blown directly into the area;
– Indirect: when the humidified air serves as an intermediary to cool another blown air.

On the Mollier diagram above, it should be remembered that air at 20% relative humidity and 30°C will be transformed into humid air at 79% relative humidity and cooled to a temperature of 18° vs. The air thus humidified and cooled will be introduced into the volume to be cooled.

Advantages and disadvantages

Adiabatic cooling has the following advantages:

  • No refrigerant used therefore a very low environmental impact;
  • Reduced operating and maintenance costs compared to traditional direct expansion air conditioning;
  • Reduced power consumption, no compressor, only fan consumption;
  • Particularly suitable for large volume tertiary and industrial premises requiring a substantial supply of fresh air.

However, the following drawbacks should be noted:

  • The system is ineffective in tropical climates (hot outdoor air is already very humid);
  • Its cooling power is limited depending on the humidity and temperature conditions outside;
  • Requires control against the development of microorganisms
  • Requires a water point near the device.

To find out more, do not hesitate to contact us!