All of the following are types of mechanical ventilation except:

Perflation and aspiration is a type of Natural Ventilation. Types of ventilation: Natural ventilation: Wind: it blows through a room (perflation) and may exe a suction at its tail end (aspiration). Diffusion: when passes through smallest openings. Inequality of temperature. Mechanical (aificial) ventilation: Exhaust ventilation: air is extracted to outside by exhaust fans driven by electricity. Balanced ventilation: combination of exhaust and plenum ventilation. Air conditioning: simultaneously control of all factors especially temperature, humidity and air movement. Plenum ventilation: fresh air is blown into rooms by centrifugal fans.