Energy Audits Flashcards
7 cards from real EMP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Energy Audits flashcards as text
An energy auditor observes that a facility's boiler is operating with an excess air level of 80%. This condition primarily results in:
Answer: Increased stack losses and reduced boiler efficiency
Excessive excess air carries unnecessary heat out the stack, significantly reducing boiler combustion efficiency; the optimal range is typically 10–20% excess air.
What is the primary purpose of a 'measurement and verification' (M&V) plan developed as part of an energy audit?
Answer: To establish a methodology for quantifying actual energy savings after ECMs are implemented
An M&V plan defines how savings from implemented ECMs will be measured or calculated post-installation, ensuring accountability for projected energy reductions.
When auditing a facility's power distribution system, a poor power factor (e.g., 0.70) is most efficiently corrected by installing:
Answer: Power factor correction capacitors at the load or distribution panel
Capacitors supply reactive power locally, reducing reactive current drawn from the utility, improving power factor, lowering demand charges, and reducing distribution losses.
During an energy audit of a data center, which metric is used as the primary indicator of energy efficiency for the entire facility infrastructure?
Answer: Power Usage Effectiveness (PUE)
PUE is the ratio of total facility power to IT equipment power; a PUE of 1.0 is perfect, while the industry average is around 1.5–1.6, making it the standard data center efficiency metric.
A commercial building audit reveals significant solar heat gain through south-facing windows in summer. Which passive measure would most cost-effectively reduce this cooling load?
Answer: Installing exterior horizontal overhangs sized to block summer sun
Properly sized exterior overhangs block high summer sun angles while admitting low winter sun, providing seasonal shading without reducing winter solar heat gain.
In an industrial energy audit, which motor characteristic contributes most to energy waste when a motor is consistently loaded below 40% of its rated capacity?
Answer: Significantly reduced motor efficiency and power factor at low loads
Motors operating well below rated load have reduced efficiency and particularly poor power factor, meaning both real and reactive power are wasted; right-sizing the motor is the recommended solution.
Which of the following best describes the concept of 'normalization' in energy audit baselines?
Answer: Adjusting historical energy data to account for weather, occupancy, or production variables
Normalization adjusts baseline energy data for variables like heating/cooling degree days or production output so that true savings from ECMs can be isolated from changes in operating conditions.