Haihdutusjäähdytys

Haihdutusjäähdytys, also known as evaporative cooling, is a process that cools air through the evaporation of water. This method relies on the principle that when water evaporates, it absorbs heat from its surroundings, thus lowering the temperature of the air.

The most basic form of evaporative cooling is natural. For example, when we sweat, the evaporation of perspiration from our skin cools our bodies. In HVAC systems, direct evaporative coolers, often called swamp coolers, use a fan to draw warm, dry air through a wet pad. As the water in the pad evaporates, it cools the air, which is then circulated into a space. This process increases the humidity of the air.

Indirect evaporative cooling systems are more complex. They use a heat exchanger to cool the air without adding moisture to it. In these systems, one stream of air is cooled by evaporation, and this cool air then passes through a heat exchanger, transferring its coolness to a separate stream of air that is supplied to the conditioned space. This method offers the benefit of cooling without increasing indoor humidity.

Evaporative cooling is most effective in dry climates where the relative humidity is low. In humid environments, the rate of evaporation is significantly reduced, making the cooling effect much less pronounced. The energy consumption of evaporative coolers is generally lower than that of traditional air conditioning systems that use refrigerants. This makes them a more environmentally friendly option in suitable climates.