EMP Energy Efficiency & Conservation Techniques 2 — Questions and Answers
Question 1: A facility manager installs occupancy sensors in conference rooms that were previously lit 24/7. The rooms are occupied only 30% of the time. What is the approximate energy savings percentage for lighting in those rooms?
- 10%
- 30%
- 70% (Correct answer)
- 90%
Correct answer: 70%
Sensors eliminate lighting during the 70% of time rooms are unoccupied, saving approximately 70% of lighting energy.
Question 2: Which metric is used to measure the energy efficiency of a chiller system?
- Power Factor (PF)
- Coefficient of Performance (COP) (Correct answer)
- Energy Use Intensity (EUI)
- Demand Response Factor (DRF)
Correct answer: Coefficient of Performance (COP)
COP measures the ratio of cooling output to electrical energy input for chiller systems.
Question 3: An energy manager wants to reduce peak demand charges. Which strategy is MOST effective for demand-side management?
- Installing LED lighting
- Load shifting using thermal energy storage (Correct answer)
- Adding insulation to roof
- Upgrading to high-efficiency motors
Correct answer: Load shifting using thermal energy storage
Thermal energy storage shifts cooling loads to off-peak hours, directly reducing peak demand charges.
Question 4: What is the purpose of a Variable Frequency Drive (VFD) installed on a pump motor?
- To increase motor insulation resistance
- To convert AC power to DC power permanently
- To match motor speed to actual load requirements, reducing energy waste (Correct answer)
- To protect against voltage surges
Correct answer: To match motor speed to actual load requirements, reducing energy waste
VFDs adjust motor speed to match actual demand, reducing energy consumption significantly at partial loads.
Question 5: A building's air handling unit operates at constant volume. Converting it to variable air volume (VAV) typically reduces fan energy by what percentage range?
- 5–10%
- 15–20%
- 30–60% (Correct answer)
- 70–90%
Correct answer: 30–60%
VAV systems reduce fan energy by 30–60% because fan power varies with the cube of airflow volume.
Question 6: Which type of lighting control strategy is BEST suited for perimeter office spaces with significant daylight availability?
- Time scheduling only
- Occupancy sensors only
- Daylight harvesting with dimming controls (Correct answer)
- Manual switching only
Correct answer: Daylight harvesting with dimming controls
Daylight harvesting dims electric lights in proportion to available natural light, maximizing savings in daylit zones.
Question 7: An energy manager reviews a compressed air system audit and finds the system leaks at a rate equivalent to 25% of total compressed air production. What is the recommended first action?
- Replace all compressors immediately
- Implement a leak detection and repair (LDAR) program (Correct answer)
- Increase system pressure to compensate
- Add a larger air receiver tank
Correct answer: Implement a leak detection and repair (LDAR) program
A leak detection and repair program targets the source of waste, which is the most cost-effective compressed air conservation measure.
EMP Energy Efficiency & Conservation Techniques 2
A facility manager installs occupancy sensors in conference rooms that were previously lit 24/7.
The rooms are occupied only 30% of the time.
What is the approximate energy savings percentage for lighting in those rooms?