Certified Energy Manager (CEM) (CEM) Free Practice Test

Question 1

In a chilled water thermal energy storage system, chilled water is stored at 4°C and used for supply water.
Chilled water return is 14°C. Calculate the storage capacity required to hold 50 GJ of thermal cooling. (The specific heat of water (C) is 4.2 kJ/kg-°C. Assume no system losses.)

A. 766 m³

B. 2,618 m³

C. 1,356 m³

D. 1,191 m³

E. 4,180 m³

Correct Answer: D

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Question 2

According to ISO 50001. when performing internal audits on the energy management system in an organization the internal auditor should do which of the following?
SELECT THE CORRECT ANSWER

A. Review the written procedures related to the area under audit

B. Focus on the areas of significant energy use

C. All of the above

D. Look for opportunities for energy improvement and to minimize bureaucracy in the energy management system

E. Assess actual activities as practiced against what the written procedures state

Correct Answer: C

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Question 3

A 3 MW rated wind-powered turbine has a rotor diameter of 113 meters. What is the efficiency of the wind turbine at rated power if it is operating in wind power calculated at 8.6 MW? Assume an air density of 1.225 kg/m³.

A. 59.3%

B. 42.7%

C. 28.4%

D. 34.9%

Correct Answer: D

Question 4

What instrument determines flow rate by measuring pressure differential?

A. Psychrometer

B. Ultrasonic flow meter

C. Infrared camera

D. Pitot tube

E. Hot-wire anemometer

Correct Answer: D

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Question 5

Problems Caused by Harmonic Distortion
Which of the following problems is unlikely to be caused by harmonic distortion?
SELECT THE CORRECT ANSWER

A. Torque pulsation in motors

B. "Nuisance" tripping of circuit breakers

C. Circulating currents in motor shafts

D. Degraded power factor C. Lighting "flicker"

Correct Answer: C

Question 6

Which motor parameter is the most difficult to determine accurately?
SELECT THE CORRECT ANSWER

A. Output power capacity

B. Operating load factor using slip calculations

C. Operating (rotating) speed

D. Input power

Correct Answer: B

Question 7

Which of the following instruments is most useful for tracking long-term boiler performance?

A. The exhaust stack temperature sensor

B. The boiler room ambient temperature sensor

C. The pressure gauge

D. The drum water level gauge

E. The feedwater temperature sensor

Correct Answer: A

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Question 8

If installed without ancillary equipment, photovoltaic power cells generate what type of power?

A. Square-wave alternating current

B. Sinusoidal alternating current

C. Direct current

Correct Answer: C

Question 9

Using an interest rate of 15%, an energy project has a net-present value (NPV) of $3,500. Which statement is true about the project's internal rate of return (IRR)?

A. IRR > 15%

B. IRR = 15%

C. IRR < 0%

D. IRR < 15%

Correct Answer: A

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AEE Certified Energy Manager (CEM) (CEM) Free Practice Test