Certified Energy Auditor Certification Energy Audit Process 4 — Questions and Answers
Question 1: What is the purpose of weather-normalizing energy consumption data during an audit?
- To adjust billing data to account for weather variability so years can be fairly compared (Correct answer)
- To calculate peak solar irradiance on the roof
- To size a new HVAC system replacement
- To determine occupant thermal comfort levels
Correct answer: To adjust billing data to account for weather variability so years can be fairly compared
Weather normalization uses heating and cooling degree-days to adjust historical energy data, removing the effect of year-to-year weather differences for valid comparisons.
Question 2: Which energy conservation measure (ECM) typically offers the shortest simple payback period in commercial buildings?
- Window replacement with triple-pane glazing
- Occupancy sensor lighting controls (Correct answer)
- Ground-source heat pump installation
- Building envelope re-insulation
Correct answer: Occupancy sensor lighting controls
Occupancy sensors are low-cost controls that eliminate lighting energy waste in unoccupied spaces, delivering rapid payback typically within one to two years.
Question 3: During combustion testing of a natural gas boiler, an auditor measures flue gas O2 at 10%. What does this indicate?
- Fuel-rich combustion causing incomplete burn
- Excessive excess air reducing thermal efficiency (Correct answer)
- Optimal stoichiometric combustion
- CO2 scrubber malfunction
Correct answer: Excessive excess air reducing thermal efficiency
High flue gas O2 (optimal is ~3–4%) indicates excessive excess air, which carries away heat in the flue gases and reduces boiler combustion efficiency.
Question 4: An auditor recommends adding VFDs to chilled water pumps that currently run at constant speed. What operational scenario maximizes the energy savings from this measure?
- When the system operates at full design load year-round
- When the system frequently operates at partial load (Correct answer)
- When the pump head exceeds 200 feet
- When condenser water temperature is above 85°F
Correct answer: When the system frequently operates at partial load
VFD savings follow the affinity laws: power varies with the cube of speed, so partial-load operation (reduced flow) yields dramatic energy reductions.
Question 5: What is the key difference between a Measurement and Verification (M&V) plan and an energy audit report?
- An M&V plan outlines how savings will be confirmed after implementation, while the audit report identifies and estimates potential savings (Correct answer)
- An M&V plan replaces the need for utility bill analysis
- The audit report is required by ASHRAE; M&V is optional
- M&V plans only apply to renewable energy systems
Correct answer: An M&V plan outlines how savings will be confirmed after implementation, while the audit report identifies and estimates potential savings
The audit report identifies ECMs and projects savings; the M&V plan specifies the post-installation methodology for measuring and verifying that projected savings are actually achieved.
Question 6: A commercial kitchen exhaust hood runs at full speed 24/7 regardless of cooking activity. Which upgrade would an auditor most likely recommend?
- Replace the exhaust hood with a higher-capacity model
- Install demand-controlled kitchen ventilation (DCKV) with heat/opacity sensors (Correct answer)
- Add a heat recovery unit to the dishwasher
- Upgrade to a condensing water heater
Correct answer: Install demand-controlled kitchen ventilation (DCKV) with heat/opacity sensors
DCKV systems modulate exhaust fan speed based on real-time cooking load detected by temperature or opacity sensors, reducing fan energy and makeup air conditioning costs.
Question 7: When preparing an energy audit report, which financial metric accounts for the time value of money, unlike simple payback?
- Cost per kWh saved
- Net Present Value (NPV) (Correct answer)
- Energy Use Intensity (EUI)
- Demand charge reduction ($/kW)
Correct answer: Net Present Value (NPV)
NPV discounts future cash flows to present value, accounting for the time value of money and providing a more rigorous investment analysis than simple payback.
Certified Energy Auditor Certification Energy Audit Process 4
What is the purpose of weather-normalizing energy consumption data during an audit?