ABSTRACT
A pump converts the energy provided by a prime mover, such as an electric motor, steam turbine, or gas engine, to energy within the liquid being pumped. Typical heating, ventilating, and air-conditioning (HVAC) systems utilize pumps to circulate water through piping systems. With only minor exceptions, these pumps are centrifugal pumps of several available configurations. For any centrifugal pump impellor, curves can be developed to show the full range of various flow/pressure relationships. Fans are devices designed to impart energy to the air in HVAC systems in order to effect the distribution of the air through the duct system. Centrifugal fans are widely used because they are capable of moving air over a wide range of flow rates and pressures. Efficiencies for fans using inclined, airfoil-shaped blades are relatively high, and these fans are generally less noisy. The duct connections at the fan outlet have a considerable effect on the performance of a fan.
