I have 2 same direct evaporative cooler with 2 different outlet air temperature. one of them is 21 degree Celsius and the other on is 22 degree Celsius. So it is clear that the first one cools faster than the second one. so we can say the first one spend less electrical energy for cooling a space.if electrical tools of coolers are the same.
How much saving the energy will be made?
Thank's.
Heat Energy1 Q1 =þ.v1 . cp .(T-T1)
Heat Energy 2 Q2 = þ.v2 .cp.(T-T2)
The heat energy to be dissipated is the same for both coolers, so with different Temperatures (T1 and T2 ) you can determine different volume flows needed. The different air volume flows will result in different Power requirements, as the pressure is the same (Power=air mass flow þ x volume) which will result in different power requirements, which is your resultant energy (power) saving.
QED
The previous answer was an approximation. The more accurate method would be to plot the different work points on a psychrometric chart for that area (height above sea level). The enthalpy (h≈cp .T) is more accurate, taking the differences in moisture content into consideration. Then the energy difference δ Q=þ.v. (h2 - h1 )
þ.v is the mass flow of air (density x volume flow per second)