it is called a blower because of what it does. it blows air, any roots supercharger does it, it forces air out of itself faster than the engine can take it creating pressure within the intake manifold. a twin screw is not a blower, it compresses air within the housing via male and female rotors
pressure = heat. to prove how inefficient blowers are think about this. the crank transfers energy to the supercharger via mechanical force. mechanical force then pushes air but it gives off heat in the process. where is the added heat coming from? energy cannot be created. heat = wasted energy in this situation
