Sweat and Wedge

Very often I am thinking about a wedge inside an air duct with air flowing over it. The wedge is able to seperate the air flowing over into two air flows, one air flow is high energy molecules, the other is low energy(Warm, colder). 

My thought experiment is inspired by sweat, when we sweat the fluid evaporates on our skin and the molecules that have high energy evaporate first and leave behind lower energy molecules, your sweat is separating high and low energy molecules and that is why it cools you down. Our bodies cool us down because molecules that have more heat evaporate more quickly so there is an imbalance. 

If you could seperate high and low energy molecules in the air then the air flows will change the air pressure around them, the warmer air molecules will cause normal air to expand and the low energy molecules would cause the surrounding air to shrink. In an enclosed space the shrinking and expanding air would cause wind, that would turn a turbine and generate electricity. 

The question is how could you cause the high energy molecules to go on one side of the wedge and low energy molecules on the other without using more energy than the turbine generates? The goal of the system would be to reduce net heat in the air to generate electricity. It is a puzzle I created in my head that I can't solve. I would love to have a small workshop and build test rigs to try different things.