Description: "Brushless Cooling Fan" curtain air systems Drag pulling (heat, smoke, odor, dust, exhaust workshops, factories), and the other end into the fresh air of principle. Many people ask, suction fan is how the outside air is sucked in or hot air, "Brushless Cooling Fan" how would cool? This is new to ask every language. Called air friction. Example: 38 degrees riding a motorcycle, and does not sweat, because of the wind. Something very hot wind blowing, but also because of the wind. Wind is divided into negative (forward): If a large exhaust fan. "Positive for the (turbulence): If a small fan blowing straight." So "Brushless Cooling Fan" 38 degrees in the outdoor air friction will drop 4-5 degrees when the wind pulling (in one minute ventilation), wind to human skin, the pores distribute heat blown away, but down about 3-4 degrees, which is the negative pressure ventilation and cooling systems heat.