Two stage evaporative cooler is the latest technology to use the process of cooling through evaporation. The best results so far in evaporative cooling have been achieved through this method. This method comprises two stages as you can guess from the name of the process. These two stages are:

  • Indirect Stage
  • Direct Stage

Two Stage evaporative Cooler Direct Method

This is the first stage in this process. At this stage, hot air from outside is cooled through indirect contact with water.

How it works

First of all, water is cooled down to prepare it for the first stage. First of all, a water chiller is used to cool down the water by passing air through a coil which is circulating water in it, the water is cooled down, a fan in the cooling compartment throws out the air which is used to cool water because it absorbs the heat and becomes hot. Then this water is circulated through a coil and air is passed through it, which makes the air temperature drop down several degrees. This stage intakes hot dry air and passes out cool dry air. Now, this cool dry air is ready for further process in the next stage.

Direct Stage

In “direct stage” cool dry air from the first stage is passed through the cooling pads. The chilled water from the first stage is being showered onto these cooling pads, which further reduces the air temperature down several degrees. This very cool air is then supplied to the building through the ducting.

Advantages Of Two Stage Evaporative Cooler
  1. The main advantage of these machines is that they are highly energy saving.
  2. They use up to 80% less energy than the traditional Air conditioners.
  3. They provide fresh air.
  4. They are cheap and easy to maintain.
  5. They are usually cheaper than the compressor using systems.
  6. They can work in environments where a heat source is inside the building.
Limitations Of Two Stage Evaporative Cooler

Everything in this world has its limitations so does this system, but the research work is on over these limitations, maybe after some time they become more capable than they are today. Some of its major limitations are discussed in the following:

  • They can’t work as effectively in the humid areas as semi-humid or dry areas.
  • They need water supply constantly.
  • Corrosion on the structure.
  • Minerals from water, scaling on the cooling pads.

Research and development are ongoing on these limitations and some companies have also developed some solutions such as magnetic ionization process to stop minerals from making layers on pads. Anti-corrosion systems etc. But this tech is new in the market and still under evolution process.