The ps3 fan has 3 fan speeds (factory standards)
In summer its humid hot etc the air blowing out might not be HOT but the components inside are so this is what its cooling down!
You can notice the fan is louder when it goes at full speed but this is normal
3RD party fans DO NOTHING IN THE SLIGHTEST!
Get AIR CON
Or get a small fan blowing air onto the console. And make sure it isn't clogged up with dust.