Certified Energy Auditor Certification Certified Energy Auditor Steam Systems and Process Energy Questions and Answers 2

Question 1

In process energy auditing, what does the term 'specific energy consumption' (SEC) measure?

Accepted Answer

Energy used per unit of production output

Answer

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 (O₂) level in flue gas that indicates optimal combustion efficiency for a natural gas boiler?

Accepted Answer

2–4%

Answer

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?

Accepted Answer

Wet or missing insulation causing hot spots

Answer

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?

Accepted Answer

~1% improvement in efficiency

Answer

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?

Accepted Answer

To visualize where energy is consumed and lost throughout the process

Answer

A Sankey diagram visually represents the magnitude of energy flows and losses in a process, helping prioritizers identify the largest inefficiencies.

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