Free Certified Energy Auditor Certification Trivia Questions and Answers — Questions and Answers
Question 1: The phrase "lumens per watt" refers to lighting efficiency.
- False
- True (Correct answer)
Correct answer: True
'Lumens per watt' (lm/W) is indeed the standard metric for measuring lighting efficiency, also known as luminous efficacy. It quantifies how much visible light (lumens) a light source produces for each unit of electrical power (watt) it consumes. A higher lumens per watt value indicates a more energy-efficient light source.
Question 2: The full load rating of a chiller is 0.7 kW/ton. Given that this unit has a 200 ton rating, what is the full load kW?
- 75
- 286
- 140 (Correct answer)
- 500
Correct answer: 140
The full load kW of a chiller is calculated by multiplying its cooling capacity in tons by its full load rating in kW per ton. In this scenario, a 200-ton chiller with a rating of 0.7 kW/ton requires 0.7 kW/ton * 200 tons = 140 kW. This calculation directly yields the total electrical power consumed when the chiller operates at its maximum capacity.
Question 3: Ground source heat pumps may not achieve predicted levels of efficiency because of
- Soil contamination
- Improperly installed ground loop (Correct answer)
- Oversizing
- Poor water treatment
Correct answer: Improperly installed ground loop
Ground source heat pumps rely on the efficient transfer of heat with the earth through a buried ground loop. If this ground loop is improperly installed—for example, if it's too short, incorrectly spaced, or poorly backfilled—it can significantly impede heat exchange. This reduced thermal conductivity directly compromises the system's ability to operate at its predicted efficiency levels, leading to underperformance.
Question 4: The minimal requirements are specified in ASHRAE standard 62-2010 for:
- Acceptable indoor air quality levels (Correct answer)
- Motor efficiencies
- HVAC equipment sizing
- Chiller efficiencies
Correct answer: Acceptable indoor air quality levels
ASHRAE Standard 62.1, titled "Ventilation for Acceptable Indoor Air Quality," specifically outlines the minimum ventilation rates and other provisions for commercial and institutional buildings. Its primary purpose is to ensure indoor air quality that is acceptable to human occupants and minimizes adverse health effects. The standard does not primarily address motor efficiencies, HVAC equipment sizing, or chiller efficiencies, which are covered by other ASHRAE standards.
Question 5: There are 50 employees working in an office building, which is occupied 250 days a year. Each employee is thought to use an average of 1 gallon of hot water per day for hand washing. City water is 60°F while the required hot water temperature is 120°F. Determine the annual energy consumption for heating this water:
- 25 Mbtus
- 15.4 MMBtus
- 12.50 MMBTUs
- 6.25 MMBtus (Correct answer)
Correct answer: 6.25 MMBtus
To calculate the annual energy consumption, first determine the total annual hot water usage: 50 employees * 1 gallon/day/employee * 250 days/year = 12,500 gallons/year. Using the specific heat of water (8.34 lbs/gallon * 1 Btu/lb°F) and the temperature difference (120°F - 60°F = 60°F), the energy required is 12,500 gallons * 8.34 lbs/gallon * 1 Btu/lb°F * 60°F = 6,255,000 Btu. Converting this to MMBtus (million BTUs) gives approximately 6.25 MMBtus.
Question 6: 13 amps at 240 volts are required to run a three-phase induction motor. There is a 0.9 power factor. Identify the kW.
- 5.16
- 6.32
- 5.54
- 4.86 (Correct answer)
Correct answer: 4.86
For a three-phase induction motor, the real power (kW) is calculated using the formula P = (√3 * V * I * PF) / 1000. Plugging in the given values: P = (1.732 * 240 V * 13 A * 0.9) / 1000. This calculation results in approximately 4.86 kW. The √3 factor is essential for three-phase power calculations, and the power factor (PF) accounts for the efficiency of power utilization.
Question 7: Every year, a hospital uses 400,000 gallons of water for showers alone. The showers have 4.5 gpm, older-style showerheads. What is the annual water savings if they switch to new showerheads that adhere to the maximum flow rates permitted by the Energy Policy Act of 1992?
- 222,222 gallons per year
- 200,000 gallons per year
- 177,778 gallons per year (Correct answer)
- 285,765 gallons per year
Correct answer: 177,778 gallons per year
The Energy Policy Act of 1992 (EPAct 1992) set a maximum flow rate of 2.5 gallons per minute (gpm) for new showerheads. The old showerheads use 4.5 gpm, so switching to compliant ones reduces the flow rate by a factor of 2.5/4.5. Therefore, the new annual water usage would be 400,000 gallons * (2.5/4.5) = 222,222 gallons. The annual water savings is then 400,000 gallons - 222,222 gallons = 177,778 gallons.
