Energy Conservation Techniques Flashcards

A motor operating at 40% of its rated load is likely to have:

Answer: Reduced efficiency and lower power factor

Lightly loaded motors run below peak efficiency and have a poor power factor, which makes them candidates for right-sizing.

Which method best reduces simultaneous heating and cooling in a building?

Answer: Widen the deadband between heating and cooling setpoints

A wider deadband keeps heating and cooling from fighting each other in the same space.

Static pressure reset on a VAV supply fan typically uses which input to lower the duct pressure setpoint?

Answer: Terminal unit damper positions

Trim-and-respond logic lowers static pressure until the most-open VAV damper is nearly fully open, which saves fan energy.

Insulating bare hot water and steam piping in a mechanical room primarily saves energy by:

Answer: Reducing radiant and convective heat loss to the surroundings

Insulation cuts heat loss from hot surfaces, which reduces the fuel needed to keep fluid temperatures up.

Which retrofit typically gives the greatest lighting energy reduction in a warehouse with high-intensity discharge fixtures?

Answer: LED high-bay fixtures with occupancy controls

LED high-bays use far fewer watts than HID and can instantly dim or switch off with occupancy sensors.

Utility power factor penalties can be reduced by installing:

Answer: Capacitor banks for power factor correction

Capacitors offset inductive reactive power, which raises the power factor and avoids utility penalties.

Retro-commissioning (RCx) of an existing building primarily focuses on:

Answer: Optimizing existing systems and controls to operate as intended

Retro-commissioning finds and fixes operational problems in existing equipment and controls, often with low-cost changes.