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NEW QUESTION # 16
Which type of single-phase alternating-current motor has the highest efficiency?
- A. Electronic-commutated motor
- B. Shaded-pole motor
- C. Permanent split-capacitor motor
Answer: A
NEW QUESTION # 17
An outdoor parking area has 25 light poles. Each pole has a 420 Watt (ballast included) high-pressure sodium (HPS) luminaire. The parking area lights are illuminated 4,500 hours per year and the electricity cost is $0.08
/kWh. What is the annual energy cost reduction if each luminaire is replaced with a 220-Watt (driver included) LED luminaire?
- A. $2,200/yr
- B. $2,600/yr
- C. $1,800/yr
- D. $1,500/yr
- E. $1,200/yr
Answer: C
Explanation:
To determine the annual energy cost savings from switching to LED luminaires:
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NEW QUESTION # 18
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 < 0%
- C. IRR > 15%
- D. IRR = 15%
Answer: C
NEW QUESTION # 19
In an ammonia-water absorption chiller, what material is the refrigerant?
- A. Water
- B. Ammonia
- C. Some form of fluorocarbon
- D. Lithium bromide
Answer: B
NEW QUESTION # 20
A facility has a monthly peak power demand of 1,000 kW and an average power factor of 80%. The facility pays a demand charge of $7.50/kVA-month. What is the additional cost per month because the power factor is less than 100%?
- A. $2,244/month
- B. $1,875/month
- C. $187/month
- D. $0/month
- E. $3,370/month
Answer: B
Explanation:
To calculate the additional cost due to a power factor of less than 100%, follow these steps:
Step 1: Convert Real Power (kW) to Apparent Power (kVA)
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Step 2: Compute Additional kVA Due to Power Factor
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NEW QUESTION # 21
Which type of lighting control technique operates in "manual on" and "auto-off mode, and can be used in situations where there is brief occupancy that do not need lights on?
- A. Microphonics technology
- B. PIR/Microphonics dual technology
- C. Vacancy sensor
- D. Occupancy sensor
- E. Photocell control
Answer: C
NEW QUESTION # 22
The temperature in an unconditioned mechanical room is found to typically be around 23°C warmer than ambient air. If the air intake of an air compressor located in the mechanical room is routed through a nearby wall so that ambient air is fed directly to the air compressor's intake, what impact can be expected on the air compressor's energy requirement?
- A. Decrease energy use by 7.6%
- B. No measureable change in energy use
- C. Decrease energy use by 3.8%
- D. Increase energy use by 3.8%
- E. Increase energy use by 7.6%
Answer: A
NEW QUESTION # 23
An office building is illuminated with T8 fluorescent lamps. Which of the following is the best schedule for group relamping (total replacement of all the T8 fluorescent lamps in the building)?
- A. Every 4 years
- B. When you reach 70% of the rated lamp life
- C. When 20% of the ballasts have failed
- D. When 25% of the lamps have failed
- E. When the building owner changes
Answer: B
NEW QUESTION # 24
According to the institute of Electrical and Electronic Engineers (IEEE) standard 519. "Recommended Practices and Requirements for Harmonic Control in Electrical Power Systems." the maximum total harmonic distortion (THD) for general low voltage systems less than 600 votts) should be:
SELECT THE CORRECT ANSWER
- A. Less than 10%
- B. Less than 5%
- C. Greater than 1%
- D. Less than 20%
- E. Less than 1%
Answer: B
Explanation:
The Institute of Electrical and Electronics Engineers (IEEE) Standard 519, titled "Recommended Practices and Requirements for Harmonic Control in Electrical Power Systems," sets forth guidelines to maintain the quality of electrical power by limiting harmonic distortions. According to IEEE 519, for general low-voltage systems (defined as systems with a voltage less than 600 volts), the Total Harmonic Distortion (THD) of the voltage waveform should not exceed 5%. This threshold ensures the reliable operation of electrical equipment and minimizes potential issues such as overheating or malfunctioning caused by excessive harmonics.
Therefore, the correct answer is C. Less than 5%.
NEW QUESTION # 25
Exhaust gases from an industrial furnace flow through a heat-recovery steam generator, which generates medium-pressure steam. This steam is used in a steam turbine to generate shaft power driving a fan. Which type of combined heat and power (CHP) cycle does this process describe?
- A. This cycle is not a combined heat and power system
- B. Combined cycle
- C. Topping cycle
- D. Bottoming cycle
Answer: D
NEW QUESTION # 26
What is the uniform series present worth factor (P/A, i%, n) for an annual interest rate of 15% and a lifetime of 20 years?
- A. 4.676
- B. 0.160
- C. 6.259
- D. 0.214
Answer: C
NEW QUESTION # 27
A 1OO-kW packaged engine-generate combined heat and power (CHP) system has the specifications listed below. The CHP equipment operates fully loaded for 8.000 h/yr. What isthe annual fuel cost for the ChP equipment?
CMP equipment specifications: Electrical output 100kw Electrical efficiency: 25% Thermal recovery efficiency: 50*6 Total CMP efficiency: 75% Additional information: Fuel cost: S3.S0/GJ Electricity cost S0.06/kWh Previous water heating efficiency:
8046 Mot water usage: 75,700 liters/day (21 *C temperature rise)
[The question from the previous image, which was about calculating the annual cost of heat loss through a wall, but had a discrepancy between the calculated cost and the provided answer choices]
- A. $43,776/yr
- B. $28,900/yr
- C. $32,668/yr
- D. $58,300/yr
- E. $52,222/yr
Answer: A
NEW QUESTION # 28
Using the lumen method, calculate the number of luminaires (fixtures) required to light a room to 200 lux.
Each luminaire has 2 fluorescent lamps, 3,000 lumens per lamp. The room is 20 meters by 30 meters. The total light loss factor (LLF) is 0.70 and the luminaire coefficient of utilization (CU) is 0.80.
- A. 48 luminaires
- B. 12 luminaires
- C. 60 luminaires
- D. 24 luminaires
- E. 36 luminaires
Answer: D
NEW QUESTION # 29
What instrument determines flow rate by measuring pressure differential?
- A. Hot-wire anemometer
- B. Ultrasonic flow meter
- C. Psychrometer
- D. Infrared camera
- E. Pitot tube
Answer: E
Explanation:
APitot tubemeasuresflow rateby determining thepressure differentialin a fluid.
Why is a Pitot Tube the Correct Answer?
* It measuresdynamic pressureandstatic pressurein a moving fluid.
* Using Bernoulli's equation, it calculatesvelocityandflow rate.
Analysis of Other Options:
* Psychrometer (A):Measures humidity, not flow rate.
* Infrared camera (B):Detects temperature differences, not pressure.
* Hot-wire anemometer (C):Measures air velocity using heat dissipation, but not pressure differential.
* Ultrasonic flow meter (E):Measures flow using sound waves, not pressure.
Thus, the correct answer isD. Pitot tube.
NEW QUESTION # 30
Which of the following is a closed-loop controller?
- A. Time clock schedule controller
- B. Manual dimmer for a light switch
- C. Thermostat for an air conditioning unit
- D. Accelerator pedal in an automobile
Answer: C
NEW QUESTION # 31
How does an enthalpy-based economizer control operate?
- A. Measuring the outdoor air dry-bulb temperature and relative humidity
- B. Using the dry-bulb temperature and relative humidity of both the outdoor-air and return-air
- C. Comparing the difference in dry-bulb air temperature measurements of the return air and the outdoor air
- D. Using a constant mixed air proportion control sequence
Answer: B
NEW QUESTION # 32
Which of the following color temperatures looks more like daylight?
- A. 4,500 K
- B. 6,500 K
- C. 3,500 K
- D. 2,500 K
Answer: B
NEW QUESTION # 33
Thermal scans of electrical equipment are useful for:
- A. Locating a loose electrical connection
- B. Reading current carrying capacity of installed conductors
- C. Measuring the load on a refrigerant system
- D. Locating areas of high power factor
Answer: A
Explanation:
Step 1: Purpose of Thermal Scans
Thermal scans (infrared thermography) detecttemperature variationsin electrical components.
* Loose connectionsincrease resistance # causeoverheating, which isvisible in thermal scans.
Step 2: Analysis of Each Option
* A. Locating areas of high power factor#Incorrect#Power factor is measured with power meters.
* B. Reading current-carrying capacity of conductors#Incorrect#Measured using ammeters and engineering data.
* C. Locating a loose electrical connection#Correct#Loose connections causeheat buildup, easily detected with thermal scans.
* D. Measuring the load on a refrigerant system#Incorrect#Refrigerant loads are measured using pressure sensors and flow meters.
Thus, the correct answer isC. Locating a loose electrical connection.
NEW QUESTION # 34
When should commissioning be included in the design and construction of a facility?
- A. When the planning process begins
- B. When the design is finalized
- C. When construction is finalized
- D. When the occupancy permit is accepted
- E. When installation of the energy systems begins
Answer: A
NEW QUESTION # 35
Natural gas costs $4.80/GJ. How much does it cost to heat 500 liters of water from 18°C to 50°C using a natural gas water heater with an efficiency of 85%? [The efficiency and fuel price are both based on HHV.
The specific heat of water (C) is 4.2 kJ/kg-°C.]
- A. $1.25
- B. $0.76
- C. $0.25
- D. $0.38
- E. $1.44
Answer: B
Explanation:
To calculate the cost of heating water using natural gas:
Step 1: Compute Energy Required to Heat the Water
Given:
* Mass of water= 500 L = 500 kg
* Temperature rise (#T)= 50°C - 18°C = 32°C
* Specific heat of water (Cp)= 4.2 kJ/kg-°C
Energy Required (Q)=m×Cp×#T
=500×4.2×32
=67,200 kJ=67.2 MJ
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NEW QUESTION # 36
What does a manometer measure?
- A. Distance
- B. Pressure
- C. Voltage
- D. Volume
Answer: B
Explanation:
Amanometeris used to measurepressure, particularly in gases and liquids.
Step 1: Analysis of Each Option
* Pressure (A):#Correct. Manometers are commonly used in HVAC, industrial, and lab applications.
* Volume (B):#Incorrect. Volume is measured using flow meters or tanks.
* Distance (C):#Incorrect. Distance is measured using rulers or lasers.
* Voltage (D):#Incorrect. Voltage is measured using voltmeters.
Thus, the correct answer isA. Pressure.
NEW QUESTION # 37
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