Certified Energy Auditor Certification Certified Energy Auditor Steam Systems and Process Energy Questions and Answers 2 — Questions and Answers
Question 1: In process energy auditing, what does the term 'specific energy consumption' (SEC) measure?
- Energy used per unit of production output (Correct answer)
- Total annual energy cost
- Peak demand per production shift
- Energy intensity per square foot of facility
Correct answer: Energy used per unit of production output
SEC measures how much energy is consumed per unit of product manufactured, serving as a key performance indicator for process efficiency.
Question 2: What is the typical oxygen (Oâ‚‚) level in flue gas that indicates optimal combustion efficiency for a natural gas boiler?
- 2–4% (Correct answer)
- 8–10%
- 0%
- 12–15%
Correct answer: 2–4%
A flue gas O₂ level of 2–4% indicates near-optimal air-to-fuel ratio for natural gas combustion, balancing efficiency and safety.
Question 3: Which type of insulation failure is most commonly identified during an infrared thermography survey of steam piping?
- Wet or missing insulation causing hot spots (Correct answer)
- Pipe wall corrosion
- Pressure relief valve leakage
- Condensate pump cavitation
Correct answer: Wet or missing insulation causing hot spots
Infrared thermography detects hot spots on steam piping that indicate wet or missing insulation, which increases surface heat losses significantly.
Question 4: What is the rule-of-thumb energy saving for every 40°F (22°C) reduction in boiler flue gas temperature for a natural gas boiler?
- ~1% improvement in efficiency (Correct answer)
- ~5% improvement in efficiency
- ~10% improvement in efficiency
- ~0.1% improvement in efficiency
Correct answer: ~1% improvement in efficiency
As a general rule, reducing flue gas exit temperature by 40°F improves boiler combustion efficiency by approximately 1%.
Question 5: In a process heating audit, what is the purpose of calculating a sankey (energy flow) diagram?
- To visualize where energy is consumed and lost throughout the process (Correct answer)
- To determine peak electrical demand
- To map compressed air flow rates
- To schedule preventive maintenance
Correct answer: To visualize where energy is consumed and lost throughout the process
A Sankey diagram visually represents the magnitude of energy flows and losses in a process, helping prioritizers identify the largest inefficiencies.
Question 6: Which standard published by ASHRAE provides guidance on the energy audit of industrial and commercial steam systems?
- ASHRAE Standard 211 (Correct answer)
- ASHRAE Standard 90.1
- ASHRAE Standard 55
- ASHRAE Guideline 14
Correct answer: ASHRAE Standard 211
ASHRAE Standard 211 establishes procedures and reporting requirements for commercial and industrial energy audits, including steam system evaluation.
Certified Energy Auditor Certification Certified Energy Auditor Steam Systems and Process Energy Questions and Answers 2
In process energy auditing, what does the term 'specific energy consumption' (SEC) measure?