Variable-frequency drives are widely used in centrifugal applications (such as pumps and fan systems), but the approaches used to calculate their energy savings are often flawed, resulting in estimates that are less accurate than they easily could be.

A new technology that reduces ventilation rates during slow periods makes it possible for restaurants and institutions to significantly reduce the amount of wasted energy. Lower fan speeds also means less noise. The concept calls for control of kitchen ventilation-fan speed based on the amount of ...