Evaporative air conditioning uses evaporation to help cool the air. Based on the principles of evaporation, hot and dry outside air is drawn through water-soaked cooling pads. As the air is pushed through these pads, the water evaporates and the heat in the air is absorbed, which lowers the air temperature. A fan then pushes the cool air throughout the house via a network of ducts.
The key to effective evaporative air conditioning is ensuring that each of the cooling pads are completely saturated during operation and that the systems fan and motor are sized and designed to deliver the appropriate airflow for the space. The evaporative cooling air process works by evaporating liquid water into vapor using heat from the air while the total energy in the air is maintained.
The heat used to evaporate water into water vapor is called latent heat (hidden heat that cannot be detected with a thermometer) of evaporation. For example, it is the heat from the hot pavement that evaporates the water after a summer rainstorm. As the liquid water changes its state into vapor, it absorbs heat from its surroundings; the energy it absorbs is contained in the molecular structure of the vapors.
Evaporative cooling is only possible because of this natural phenomenon of latent heat. This results in the temperature and the sensible heat (that you can feel or sense) of the air dropping. The moisture vapor that is added to the air increases the humidity and the latent heat of the air. An evaporative air conditioner is a system that cools air through the evaporation of water. Evaporative cooling is different from traditional air conditioning systems, which use chemical vapor compression refrigeration cycles.
Evaporative cooling and evaporative coolers describe this natural phenomenon, however, there are many other terms that are commonly used with the same meaning including evaporative air conditioning, adiabatic cooling, ducted evaporative cooling, swamp coolers and desert coolers.Evaporative Air Conditioning Benefits Cooling in the South America Frequently Asked Questions
The benefits of evaporative air conditioning are plenty, there’s never been a better time to invest in an evaporative air conditioner which is simple to maintain and operate and offers superior product performance.
With energy prices escalating and summers typically involving heat waves, evaporative air conditioning offers a significant edge on refrigerated cooling, when it comes to energy efficiency, healthier air flow and performance.
To understand how evaporative cooling works in different climates zones in the South America, it’s good to revisit the principles of evaporative cooling. As water is evaporated, sensible heat from the air is converted to latent heat, reducing the temperature. Two temperatures are important when dealing with evaporative cooling.
This is the temperature that we usually think of as air temperature measured by a regular thermometer exposed to the air stream. Typically, the temperature in South America is measured in degrees Fahrenheit (oF).
Wet bulb temperature
This is the lowest temperature that can be reached by saturating air with water vapor. When considering water evaporating into air, the wet bulb temperature is a measure of the potential for evaporative cooling. The dry and wet bulb temperature can be used to calculate the relative humidity.
Evaporation will take place when the relative humidity is below 100% and the air begins to absorb water. Any given volume of air can hold a certain amount of water vapor and the degree of absorption will depend on its starting temperature and the amount of vapor it is already holding.
The term relative humidity describes how much water is already in the air, relative to the amount it can hold. Air is saturated when it cannot hold any more water.
If we imagine air as a sponge, and the sponge held half as much water as it was capable of holding, it would be 50% saturated. In the case of air, we would describe the relative humidity as being 50%.
Energy is required to change water from liquid to vapor. This energy is obtained in an adiabatic process from the air itself. Air entering an evaporative air cooler gives up sensible heat energy to evaporate water. Through this process, the dry bulb temperature of the air passing through the cooler is lowered.