Engineer's Notebook: Backward-Curved Fans PDF

Electrical engineers can design and manufacture fractional horsepower (200 W to 600 W) fan motors with efficiencies near 90 percent while we seem to be content to couple them to fan wheels with efficiencies of around 30 percent. The author says mechanical engineers can do better, and the benefits are enormous since almost all unitary air conditioners and heat pumps are shipped with the same type of forward-curved blade, sheet-metal blower wheels.