REVIEW

1
REVIEW
Electrical Systems
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

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What is peak demand and under what circumstances i
s 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 2030. 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 Councils 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 Page 33
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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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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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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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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? 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 Page 50
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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 Page 50
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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.
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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

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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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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
buildings 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 buildings thermal base load, but a
larger cogen unit can be installed if storage
tanks for hot water are added.
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What does a fuel cell produce?
A fuel cell produces electricity, heat, and water
by an electrochemical reaction.
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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.
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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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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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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.
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Name 2 steps that should be taken prior to the
start of field testing.

1. Providing and maintaining necessary documentation
   required for testing
2. Meeting with the CxA prior to testing to go over
   forms and what will happen on test day

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Why would a CxA plan for deferred testing?
Deferred testing is used when a building system ca
nnot be tested until the building is actually occu
pied  and the system is being utilized under desig
n conditions.
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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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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

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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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