A parallel "Air Purifier Fan": dual fan pressure parallel unchanged, but the wind will rise. Increase the amount of air so that the cooling effect of the increase in power dissipation if the design may be considered too small to resolve the fan increases.
2, the series "Air Purifier Fan": the results of a series fan is pressure to increase, but the wind changed. This approach can not solve the heat problem, "Air Purifier Fan" is generally used when wind resistance is too close to use, to ensure air flow.