Adiabatic coolers are an efficient and effective machine for cooling. As a direct placement for air conditioning in dry climates like Philippines, it is an example of how man can work with nature. Being so much less expensive than air conditioning, it almost seems that we are getting something for nothing.

          Re-circulated spray of water is used to provide cool air. In order to perpetuate the process it is necessary to use a water pump to continuously re-circulate spray of water. 

After the adiabatic saturator has achieved a steady state condition, the temperature indicated by an accurate thermocouple immersed in the collecting basin is the thermodynamic wet-bulb temperature. Certain combinations of air will result in a given wet-bulb temperature and can be defined by writing an energy balance about the saturation. This energy balance, written on the basis of unit mass flow of air (Stoecker & Jones, 1958)

          h₁          =        h₂   -  (W₂  -   W₁)  h_f

          Where:

                   W₂     =        the humidity ratio of saturated moist air at t*,

                   W₁     =        the humidity ratio of unsaturated moist air

entering the spray,

                   h₂          =      specific info being of saturated moist air entering

the spray, kJ/kg

                   h₁      =        specific enthalpy of saturated moist air at

temperature t*, kJ/kg

                   h_f       =        specific enthalpy of water of t*, kJ/kg

                   t*       =        temperature of the adiabatic saturation, °C.

If the heat exchange contact between the air and water spray is 100%, the dry bulb temperature of the entering air should drop down to its wet bulb temperature, the air should become fully saturated. This is however never achieved because of the bypass factor, a small portion of the air will not come in contact with the spray and so it comes out of the saturator at the same condition as it entered. Hence the total air quantity at the outlet of the saturator is a mixture of the by-passed and the saturated air. Thus the efficiency (or saturation efficiency) of the saturation is expressed as %. (ANANTHANARAYAN, 1982)

h_sat  =

Where:       

          t₁       =        dry bulb temperature of entering air, °C

          t₂           =        dry bulb temperature of leaving air, °C

          t_W      =        wet bulb of air, °C

(t₁  -   t₂)      =        is the wet bulb depression of the entering air, °C

The fans are extensively used for air-conditioning applications requiring about 51,000 cmh (3000 cfm) and maximum static of 75 to 100 mm (3 to 4) WG. Forward curved blade blowers are employed to deliver large volumes of air against relatively low static pressure, usually encountered in air conditioning.

          The power required to move a volume rate of air through a head (total pressure) is expressed as Air horsepower (Ahp). (ANANTHANARAYAN, 1982)

                Where:

                   Q       =        air flow

                                      Rate in                m³/min         cfm

                   P_t       =        Total

                                      Pressure in           mm WG         inches WG

                   K       =        Static pressure      0.000218      0.000157

Mechanical efficiency of the fan    =