Generating Electricity from Cooling Towers

Cooling Tower

Here is an idea depicts the ability of exploiting the inflow air from the bottom of a cooling tower to its top in turning a blades of a wind turbine connected to an electrical generator to produce electricity.

the ambient temperature: Ta = 303 K,
the temperature inside the cooling tower at its bottom: Ti = 333 K,
hence, the difference in temprature is dT = 30 K.

this dT causes pressure difference causing the air molecules to fllow from the bottom to the outside ambient uprising towards the top of the cooling tower.

The speed of input airflow is calculated according to the free convection velocity equation:

   

                                                                                                             

This is the speed of input air without any resistance. This air passes through the cooling sinks (radiators) which present an air-resistance; also it reduces the total area that the air passes through A1.                                                                                                

Where:

As the flow rate is constant,

The air density inside the tower is calculated from the following expressions:
  -The Pressure difference between inside and outside:                                 
                   
    

               

-The pressure difference according the relationship of stack-effect:

According to these two equations: 

Hence the air density inside the tower:

After estimating both the air density and its speed, output power equals to:

This electrical output power can be increased by making constructional modifications on the cooling tower. The aim of these modifications is to increase A2, as well as reducing air flow resistance.