EMP Assessment & Monitoring Methods 2 — Questions and Answers
Question 1: Which metering configuration allows a facility to separately track energy consumption for individual production lines or departments?
- Whole-building metering
- Sub-metering (Correct answer)
- Net metering
- Interval metering
Correct answer: Sub-metering
Sub-metering installs meters downstream of the main utility meter to isolate and track energy use by specific end-uses, departments, or equipment.
Question 2: In an energy audit, what does the term 'baseline normalization' primarily address?
- Calibrating measurement instruments
- Adjusting energy data to account for variable conditions like weather or production (Correct answer)
- Standardizing utility billing cycles
- Converting energy units across different fuel types
Correct answer: Adjusting energy data to account for variable conditions like weather or production
Baseline normalization adjusts historical energy data for independent variables (weather, occupancy, production volume) so that true energy performance changes can be isolated.
Question 3: A power quality analyzer detects a power factor of 0.72 at a manufacturing plant. What is the most likely corrective measure an energy manager would recommend?
- Install variable frequency drives on motors
- Add power factor correction capacitors (Correct answer)
- Replace incandescent lighting with LEDs
- Upgrade the transformer capacity
Correct answer: Add power factor correction capacitors
Power factor correction capacitors supply reactive power locally, reducing the reactive component of current and improving power factor toward unity.
Question 4: What is the primary purpose of a continuous commissioning (CC) program in a building?
- To replace outdated HVAC equipment on a scheduled basis
- To optimize and maintain building system performance through ongoing monitoring and adjustments (Correct answer)
- To certify that new construction meets energy codes
- To audit utility bills for billing errors
Correct answer: To optimize and maintain building system performance through ongoing monitoring and adjustments
Continuous commissioning uses ongoing data collection and analysis to identify and correct building system inefficiencies, maintaining peak performance over time.
Question 5: Which statistical method is most appropriate for developing an energy prediction model when multiple independent variables (production, weather, shifts) affect consumption?
- Simple linear regression
- Multiple linear regression (Correct answer)
- Moving average
- Pareto analysis
Correct answer: Multiple linear regression
Multiple linear regression models the relationship between energy consumption and several independent variables simultaneously, providing a more accurate predictive baseline.
Question 6: During a walk-through energy audit, an auditor notices motors running at full speed despite variable load requirements. Which monitoring approach would best quantify the energy savings potential?
- Spot measurement of motor nameplate data
- Short-term logging of motor current and speed across operational cycles (Correct answer)
- Annual utility bill comparison
- Infrared thermography of the motor housing
Correct answer: Short-term logging of motor current and speed across operational cycles
Short-term data logging of motor current and speed captures actual load profiles across varying operating conditions, enabling accurate energy savings calculations for VFD installation.
Question 7: What does a 'degree-day' measurement capture for use in energy monitoring?
- The number of hours a building operates above peak load
- The difference between the mean daily outdoor temperature and a reference base temperature (Correct answer)
- Total solar radiation received per day
- The average daily electricity demand in kWh
Correct answer: The difference between the mean daily outdoor temperature and a reference base temperature
A degree-day quantifies the deviation of the mean outdoor temperature from a base temperature (typically 65°F), used to normalize heating and cooling energy consumption for weather differences.
EMP Assessment & Monitoring Methods 2
Which metering configuration allows a facility to separately track energy consumption for individual production lines or departments?