About evaporative air cooler (1)

1.Introduction of evaporative air cooler
   Evaporative air cooler has not compressor and freon gas. Energy efficient evaporative air cooler help meet the needs of today. Evaporative air cooler are designed to provide the most natural method of creating cool air with important saving-energy cost compared to using trad air conditioners.
   The Evaporative air cooler is designed to provide comfort and relief from the heat in those situations and pleaces where other types of cooling are more costly or where it is simply not possible to implement them.
   Evaporative air coolers provide an energy efficient option for cooling your home or workplace in the most natural way.They cool the air by means of the evaporation of water, which works best in hot,dry climates.They do not require power hungry components like compressors and not release freon gas.The low power consumption translates into significant saving-energy bills compared to using trad air conditioners.These are ideal for cooling garden patios, outdoor restaurants,large open area like warehouses and so on.
2.The principles of evaporative air cooler  
   As water is evaporated, energy is lost from the air, reducing the temperature. Two temperatures are important when dealing with evaporative cooling system.

                                                           evaporative cooling system
                        
2.1 Dry Bulb Temperature  
     This is the temperature that we usually think of as air temperature, measured by a regular thermometer exposed to the air stream.
2.2 Wet Bulb Temperature    This is the lowest temperature that can be reached by the evaporation of water only.
When considering water evaporating into air, the wet-bulb temperature, as compared to the air's dry-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 humidity is below 100% and the air begins to absorb water. Any given volume of air can hold a certain amount of water vapour and the degree of absorption will depend on the amount it is already holding.
   The term humidity describes how much water is already in the air; relative to the amount it is capable of holding. Air is saturated when it cannot hold any more water. Imagine it as a sponge, if 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 vapour. This energy is obtained in an adiabatic process from the air itself. Air entering an evaporative air cooler gives up heat energy to evaporate water. During this process, the dry bulb temperature of the air passing through the cooler is lowered.
3. How does an evaporative air cooler Work

        Evaporative air cooler uses evaporation to cool the air. In an evaporative cooler, such as Aolan, a pump circulates water from the reservoir on to a cooling pad, which in turn becomes very wet. A fan draws air from outside the unit through the moistened pad. As it passes through the pad the air is cooled by evaporation. The key to effective evaporative cooling is ensuring that each of the cooling pads are completely saturated at all times during operation and that the systems fan & motor are sized and designed to deliver the appropriate airflow for the home.