Certified Energy Auditor Certification Certified Energy Auditor Steam Systems and Process Energy Questions and Answers 1 — Questions and Answers
Question 1: What is the approximate latent heat of vaporization of steam at 212°F (100°C) at atmospheric pressure?
- 970 BTU/lb (Correct answer)
- 1,150 BTU/lb
- 540 BTU/lb
- 800 BTU/lb
Correct answer: 970 BTU/lb
The latent heat of vaporization of steam at 212°F and atmospheric pressure is approximately 970 BTU/lb.
Question 2: Which type of steam trap is best suited for high-pressure applications and provides continuous condensate drainage?
- Thermodynamic (disc) trap (Correct answer)
- Float and thermostatic trap
- Inverted bucket trap
- Bimetallic trap
Correct answer: Thermodynamic (disc) trap
Thermodynamic (disc) traps are compact, durable, and well-suited for high-pressure steam applications with continuous condensate removal.
Question 3: In a steam distribution system, what percentage of energy input is typically lost through failed-open steam traps?
- 15–25% (Correct answer)
- 1–3%
- 50–60%
- 5–8%
Correct answer: 15–25%
A failed-open steam trap can waste 15–25% of a facility's total steam output, making trap surveys a high-priority audit task.
Question 4: What does a steam flash tank recover in a condensate return system?
- Low-pressure flash steam from high-pressure condensate (Correct answer)
- Superheat from steam headers
- Blowdown heat from boilers
- Latent heat from exhaust gases
Correct answer: Low-pressure flash steam from high-pressure condensate
A flash tank captures low-pressure steam produced when high-pressure condensate drops in pressure, which can then be reused for low-pressure processes.
Question 5: Which metric is commonly used to express boiler efficiency as measured by the flue gas method?
- Combustion efficiency (stack loss method) (Correct answer)
- Thermal efficiency
- Fuel utilization efficiency
- Carnot efficiency
Correct answer: Combustion efficiency (stack loss method)
Combustion efficiency using the stack loss method measures boiler efficiency by analyzing flue gas temperature and oxygen/CO2 content.
Question 6: What is the primary energy-saving opportunity identified when boiler blowdown heat recovery is implemented?
- Recovering heat from blowdown water to preheat makeup water (Correct answer)
- Reducing feedwater chemical usage
- Lowering stack gas temperature
- Improving combustion air mixing
Correct answer: Recovering heat from blowdown water to preheat makeup water
Blowdown heat recovery uses a heat exchanger to transfer thermal energy from hot blowdown water to incoming cold makeup water, reducing fuel consumption.
Certified Energy Auditor Certification Certified Energy Auditor Steam Systems and Process Energy Questions and Answers 1
What is the approximate latent heat of vaporization of steam at 212°F (100°C) at atmospheric pressure?