1. Green Professional Building Skills Training
Electrical
Systems
REVIEW
Green Professional Building Skills Training

2. What are the benefits of sustainability in green building design?
Promotes new and better jobs
Helps fight climate change
Better Indoor Environmental Quality
Lowers operating costs
1 SUSTAINABILITY IN ELECTRICAL SYSTEMS
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3. What is peak demand and under what circumstances is it most likely to occur?
Peak demand (or peak load) is the maximum power drawn at any given time. Peak load is most likely to occur on the hottest days of the summer when the most air conditioners are in use.
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4. What is the difference between site energy and source energy and how are they related to electricity usage?
Site energy is the amount of energy delivered to a building and source energy is the amount of energy in the fuel used to generate the electricity. The amount of useful electrical energy delivered to a building is typically about one-third of the amount of energy used to generate it. The other two-thirds are lost in thermodynamic inefficiencies at the generating plant and in transmission.
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5. What are the codes and standards related to green building and what are their functions?
There are two standards or codes that are widely adopted and aimed at lowering energy consumption. The first is ANSI/ASHRAE/IES Standard 90.1, which has been made significantly more stringent with each revision, aiming for extremely efficient buildings as standard construction by A parallel effort is the International Energy Conservation Code (IECC), which is often adopted as the state or local energy code in conjunction with ASHRAE 90.1.
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6. What is ENERGY STAR and how does it relate to the LEED rating system?
The U.S. Green Building Council’s LEED rating system is a design standard, establishing criteria for the energy and water efficiency and broader sustainability of the design of buildings. ENERGY STAR is similar to LEED but aimed almost exclusively at energy-related items. A project pursuing an ENERGY STAR rating will install the high-efficiency systems used in LEED projects.
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7. What is a lumen, what is a foot-candle, and how are they related?
A lumen is the basic unit of visible light emitted from a source, analogous to the power in watts produced by a generator. A foot-candle is a measure of the illuminance, which is the amount of light falling on a surface. A foot-candle is the illuminance on a one square foot surface on which 1 lumen is uniformly distributed.
2 LIGHTING
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8. What is Lighting Power Density (LPD)?
The lighting power density (LPD) is the maximum electrical power allowed per square foot for lighting, and is specified by energy codes for different types of spaces.
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9. Lamps with a lower color temperature produce light of what color?
Lamps with lower color temperatures, 2700K – 3500K, produce yellower or visually "warmer" light and are typically used in residential spaces.
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10. How are magnetic ballasts different from electronic ballasts?
Magnetic ballasts may contain dangerous PCB's, are less efficient, and their lower frequency causes them to flicker and hum. Electronic ballasts use transistorized circuitry, create very high frequency AC which eliminates flicker, are smaller and lighter, and allow a more precise control of operation cycle.
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11. What type of lamps are discharge lamps and how do they work?
Metal halide lamps and sodium vapor lamps are discharge lamps. High-intensity discharge is an electric charge in gas vapor that produces light.
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12. What are some installation tips for occupancy sensors?
Some installation tips for occupancy sensors are:
Location is very important.
Proper sensor placement will diminish chances of nuisance action.
Locate PIR sensors at least 4 – 6 feet from HVAC diffusers and other heat sources.
Do not mount sensors in locations blocked by door swings.
Do not use with metal halide lamps.
Range of ceiling mounted sensors can be diminished by partitions.
Sensor placement should be included in all drawings.
Beware of in-rush with fluorescent lighting.
Be aware of minimum load requirements.
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13. What are vacancy sensors and how do they compare to occupancy sensors?
Vacancy sensors operate very much like occupancy sensors with the distinction that a person must manually turn the lights on, but sensors will turn them off after a set period of no detected motion.
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14. How is using a VFD on a motor efficient
How is using a VFD on a motor efficient? What is an important issue to keep in mind when wiring a VFD?
With a variable frequency drive (VFD) installed on a motor, the speed of the motor can be adjusted to match the load. This is much better than throttling the output, which wastes a significant amount of power. There should be no on/off switch external to a VFD combination because the controller may lose its program if switched off.
3 HEATING AND COOLING
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15. What are the effects of using oversized pumps, motors, or control valves?
Using oversized pumps, motors, or control valves leads to excessive energy consumption.
3 HEATING AND COOLING
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16. How do heat pumps work?
A heat pump movies heat from one location (the source) at a lower temperature to another location called the heat sink at a higher temperature using mechanical work, generally supplied by an electric motor. The device operates by passing refrigerant through a heat exchanger called the evaporator, where the heat required to boil it into a vapor is taken from the fluid in which the evaporator is immersed, either air or water. Cooled air or water is the result of this process.
3 HEATING AND COOLING
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17. What are some of the capabilities of building management and information systems?
Some capabilities of BMS systems are:
Scheduling timely operation of equipment
Controlling temperature, pressure, and humidity
Controlling fans and pumps to regulate the flow of air and water
Responding of equipment to fire alarm system operations
Alarming and providing building operators with notifications of predefined conditions
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18. Give examples of central, distributed, renewable energy and nonrenewable energy generation.
Central generation: Large generation stations powered by coal, natural gas, nuclear power, or hydropower
Distributed generation: Rooftop photovoltaics, gas-fired cogeneration, and small local wind turbines
Renewable energy generation: Solar energy, tidal power
Nonrenewable energy generation: Fossil fuels
4 RENEWABLE AND DISTRIBUTED ENERGY
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19. Why is a secure disconnect system needed for a distributed generator?
A secure disconnect system is needed for a distributed generator because it can be dangerous if the grid has gone down and the distributed source continues to generate electricity, as the power could electrocute workers. A secure disconnect ensures that even if the building continues to generate power, none of it should feed back to the affected grid.
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20. What should you consider when determining the most cost-effective size of a building's cogeneration system?
You should make sure the cogen system is always running at full capacity by measuring the minimum electric load of the building. Then determine the building’s thermal load and compare it to the thermal output of the cogenerator, to not waste thermal energy. The simplest approach is to specify a cogen unit with a thermal output about equal to the building’s thermal base load, but a larger cogen unit can be installed if storage tanks for hot water are added.
4 RENEWABLE AND DISTRIBUTED ENERGY
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21. What does a fuel cell produce?
A fuel cell produces electricity, heat, and water by an electrochemical reaction.
4 RENEWABLE AND DISTRIBUTED ENERGY
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22. What is the relationship between maximum voltage and maximum power in photovoltaic panels?
In photovoltaic panels, a connection in parallel means that the current will be high but the voltage will be low. Connection in series means that the current will be low but the voltage will be high. A typical PV panel will generate the highest voltage when no current is being drawn; this is the open circuit voltage. The short circuit current is the largest current, produced when the output terminals are connected to each other through a zero-resistance ammeter.
4 RENEWABLE AND DISTRIBUTED ENERGY
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23. What type of power is generated in a PV cell and how is it used in a building?
The power generated in a PV cell is DC, but the power used in most buildings is AC. This means that the panels have to be connected to an inverter to convert the DC power to AC power.
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24. What are some factors to consider when determining the most effective location of a wind turbine?
Some factors to consider when determining the most effective location of a wind turbine are wind speeds and stresses on buildings. Turbines are placed where wind velocities are highest in order to maximize generated energy.
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25. What are the responsibilities of the CxA?
The CxA is responsible for the entire commissioning process. The CxA prepares the Cx Plan, forms, tests, and reports, and is responsible for training and turnover.
5 ASSURING BUILDING PERFORMANCE
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26. Name 2 steps that should be taken prior to the start of field testing.
Providing and maintaining necessary documentation required for testing
Meeting with the CxA prior to testing to go over forms and what will happen on test day
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27. Why would a CxA plan for deferred testing?
Deferred testing is used when a building system cannot be tested until the building is actually occupied 
and the system is being utilized under design conditions.
5 ASSURING BUILDING PERFORMANCE
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28. What is a proper comparison to estimate the energy and water consumption savings in a new building?
Designers construct a computer model of the building to determine what the energy and water consumption would have been if the building had been constructed using standard techniques and compare that to the actual energy and water levels after construction.
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29. Underfloor distribution of HVAC and wiring Building management systems
Describe some scenarios where inter-trade coordination is critical for building performance.
Floor penetrations
Underfloor distribution of HVAC and wiring
Building management systems
Low VOC materials
6 JOB MANAGEMENT
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30. What should every worker on a green building job understand?
Safety should never be compromised
This is a green and sustainable building project
Rating systems, such as LEED and ENERGY STAR
Strategies for conserving resources such as water, energy, and materials
The importance of good indoor air quality
What makes this project green
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