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Engineering
Q:
Which describes a strength and a weakness of an evacuated tube solar collector compared with a flat-plate solar collector? a.
The evacuated tube collector sheds snow better, but requires more mounting space. b.
The evacuated tube collector requires long lasting seals, but is poor at shedding wet snow. c.
The evacuated tube collector is resistant to hailstones, but requires more mounting space. d.
The evacuated tube collector retains heat better at high temperatures, but requires more mounting space.
Q:
Which of these is an advantage of a thermostatically controlled tankless electric water heater? a.
It enables easy removal of the internal coil heat exchanger for cleaning. b.
It has a large reserve of domestic water in the assembly that inhibits biological growth. c.
It takes advantage of low initial temperatures when domestic water heating begins. d.
It uses fewer valves than traditional pressurized tank thermal storage.
Q:
Solar collectors mounted on a roof parallel to the roof surface use what type of mounting? a.
flush mounting b.
standoff mounting c.
awning mounting d.
ground mounting
Q:
What optical property represents the percent of solar radiation striking a material that passes through the material? a.
transparency b.
transmissivity c.
conductivity d.
absorptivity
Q:
Repurposed propane tanks can be used in both open and closed hydronic systems. a.
True b.
False
Q:
Thermal expansion is not a design concern with unpressurized thermal storage tanks. a.
True b.
False
Q:
Stratification in a thermal storage tank provides more useful energy than an evenly-mixed tank at the same average temperature. a.
True b.
False
Q:
Tankless water heaters have lower amperage requirements than tank-type electric water heaters. a.
True b.
False
Q:
Thermal storage prevents short cycling of the heat source. a.
True b.
False Indicate the answer choice that best completes the statement or answers the question.
Q:
What type of piping is commonly used with multiple pressurized tank arrays to achieve equal flow through each tank? a.
direct return b.
asymmetrical return c.
serial reverse return d.
parallel reverse return
Q:
What optical property represents the percent of thermal radiation released by a surface compared to that released by a black body at the same temperature? a.
transmissivity b.
absorptivity c.
emissivity d.
reflectivity
Q:
Which of these is an effect of flow through an internal heat exchanger coil? a.
decrease in fluid density b.
decrease in flow rate c.
pressure increase d.
head loss
Q:
What condition is present during stagnation? a.
reduced flow rate through the absorber plate b.
reduced fluid temperature through the absorber plate c.
increased flow rate through the absorber plate d.
no fluid flow through the absorber plate
Q:
Which factors affect the amount of heat held by a thermal storage tank? a.
tank pressure rating and water exit temperature b.
tank surface area and water inlet temperature c.
tank volume and pressure rating d.
tank volume and water temperature change
Q:
What material is typically used for the tubes in an evacuated tube solar collector? a.
copper b.
aluminum c.
glass d.
PVC
Q:
What is the recommended water flow direction when adding heat to an unpressurized thermal storage tank? a.
Hot water enters at the bottom of the tank and flows upward. b.
Hot water enters at the top of the tank and flows downward. c.
Hot water enters at the center of the tank and flows upward. d.
Hot water enters at the center of the tank and flows downward.
Q:
When mounting a collector on a roof, what should mounting hardware be fastened to? a.
roof decking b.
oriented strand board c.
rafters or top cord of wooden trusses d.
plywood
Q:
What is used to simultaneously supply heat from storage and supplemental heat from an auxiliary heat source? a.
outdoor reset controller and diverter valve b.
outdoor reset controller and differential temperature controller c.
temperature sensing controller and diverter valve d.
temperature sensing controller and differential temperature controller
Q:
When mounting a collector on a roof, how should structural rails be placed to avoid trapping water? a.
inch above the roof b.
1 inch above the roof c.
4 inches above the roof d.
flush with the roof
Q:
Unpressurized thermal storage tanks have several advantages. What is NOT one of these? a.
They eliminate the potential for biological growth in the tank. b.
They do not need a separate expansion tank. c.
They are less expensive than pressurized tanks. d.
They are protected from overpressure conditions.
Q:
Solar collectors cannot use infrared and ultraviolet wavelengths because they are diffuse. a.
True b.
False
Q:
Which is NOT a type of solar radiation? a.
infrared b.
direct c.
diffuse d.
inclined
Q:
The intensity of solar radiation remains constant outside Earths atmosphere. a.
True b.
False
Q:
Most solar collectors use glass with low iron oxide content for their glazing. a.
True b.
False
Q:
Diffuse solar radiation is the reason we see the sky. a.
True b.
False
Q:
For solar collectors, the absorptivity of the upper surface of the absorber plate should be as low as possible. a.
True b.
False
Q:
The National Renewable Energy Laboratory provides easily accessible data on solar radiation for south-facing vertical surfaces. a.
True b.
False Indicate the answer choice that best completes the statement or answers the question.
Q:
A Sydney tube is often paired with a parabolic reflector fixed behind each tube. a.
True b.
False
Q:
What angle describes the tilt of Earth relative to its orbital plane? a.
declination angle b.
inclination angle c.
deviation angle d.
solar azimuth angle
Q:
Flat-plate collectors without glazing or insulation are commonly used for domestic water heating. a.
True b.
False
Q:
Why is solar time different from clock time? a.
Clock time was developed prior to solar time and the two do not agree. b.
The suns declination angle varies within a time zone. c.
Latitude varies within a time zone. d.
Longitude varies within a time zone.
Q:
In the Northern Hemisphere, the ideal collector azimuth angle is 90. a.
True b.
False Indicate the answer choice that best completes the statement or answers the question.
Q:
Why can compass needles be misaligned with reference to the true north/south line? a.
Some error is introduced by the time of year. b.
Earths declination angle varies by location on the surface. c.
Earths magnetic field is not always aligned parallel with its polar axis. d.
Earths magnetic field varies with declination angle.
Q:
What is the roof slope angle below which flat-plate collectors are preferred in climates subject to persistent high-moisture snowfall? a.
30 degrees b.
45 degrees c.
50 degrees d.
60 degrees
Q:
Which diagram aids in determining the suns position in the sky? a.
sun path diagram b.
declination angle diagram c.
solar chart d.
position angle chart
Q:
What are two factors that influence instantaneous collector thermal efficiency? a.
intensity of solar radiation and ambient air temperature b.
outlet fluid temperature and ambient air temperature c.
intensity of solar radiation and outlet fluid temperature d.
average yearly amount of solar radiation incident on the collector and average air temperature
Q:
Which classic instrument for determining shading potential was developed in 1978? a.
SolarSpy b.
Shadefinder c.
Solar Pathfinder d.
Sun Eye 210
Q:
With which type of solar collector does the instantaneous thermal efficiency vary the most as the inlet parameter changes? a.
glazed flat-plate collector b.
unglazed pool collector c.
evacuated tube collector d.
glazed and insulated pool collector
Q:
What type of chart is used to obtain the deviation of a magnetic compass needle from true north? a.
isogonic b.
isometric c.
sun path d.
azimuth angle
Q:
What material is commonly used to form absorber strips in flat-plate solar collectors? a.
copper b.
aluminum c.
glass d.
PVC
Q:
Which tool, developed by the University of Nebraska-Lincoln, helps visualize the motion of the sun across the sky dome? a.
Sky Pathfinder b.
Motions of the Sun Simulator c.
Azimuth Change Simulator d.
Earths Angle Simulator
Q:
Which instrument measures instantaneous solar radiation intensity? a.
thermometer b.
radiameter c.
pyranometer d.
dynamometer
Q:
What drove the ancient Greeks and Romans to pursue passive solar architecture? a.
need for cooking heat b.
depletion of firewood c.
frequent cloud cover d.
interest in the stars and sun gods
Q:
Approximately when is the vernal equinox? a.
January 20 b.
March 20 c.
June 21 d.
September 21
Q:
Which is NOT a unit of surface total radiation? a.
kWh/m2/day b.
Btu/ft2/day c.
kWh/m/day d.
Btu/ft2/month
Q:
The first use of solar energy for domestic water heating took place in the ____. a.
1750 b.
early 1800s c.
late 1800s d.
mid-1900s
Q:
At what time of day is the sun highest in the sky and directly above a true north/south line? a.
noon b.
solar noon c.
summer solstice d.
summer equinox
Q:
Oversizing a modulating heat source relative to the design heating load will minimize short cycling. a.
True b.
False
Q:
The reset ratio for a given system depends on the temperature units chosen. a.
True b.
False Indicate the answer choice that best completes the statement or answers the question.
Q:
What are the two major subassemblies within a relay? a.
spring and contacts b.
coil and contacts c.
coil and spring d.
pendulum and terminals
Q:
Which of these is a common type of solid-state sensing element? a.
positive temperature coefficient thermistor b.
negative temperature coefficient thermistor c.
k-type thermocouple d.
j-type thermocouple
Q:
Which type of control is typically used with a room thermostat? a.
on/off control b.
floating control c.
modulating DC output control d.
differential control
Q:
Which type of relay contact will allow the signal to pass when the coil is off? a.
normally closed b.
normally open c.
center-off d.
center-on
Q:
Which heat emitter typically has the highest thermal mass? a.
cast-iron radiator b.
four-inch concrete slab c.
radiant ceiling panel d.
tube and plate floor
Q:
What is an example of a modulating DC output signal? a.
an on/off signal b.
a digital signal c.
2 to 10 volts DC d.
2 to 10 volts AC
Q:
In which situation would radiant wall panels be preferable to radiant floor panels? a.
finish flooring with high thermal resistance b.
finish flooring with low thermal resistance c.
if the floor and wall surfaces are not compatible with contact adhesive d.
if the flooring is painted
Q:
Which term describes the number of independent, simultaneous electrical paths through a switch? a.
throws b.
lines c.
rungs d.
poles
Q:
In which system is air pulled through a heat exchanger by a blower? a.
conduction fan coil b.
forced fan coil c.
blow-through fan coil d.
draw-through fan coil
Q:
Which time delay relay operating mode prevents contacts from moving until the specified delay period has elapsed from when the input signal is turned on? a.
delay-on-break b.
delay-on-make c.
interval timing d.
repeat cycle
Q:
What type of tubing is typically used in heated thin slabs? a.
steel b.
copper c.
PEX or PEX-AL-PEX d.
PVC
Q:
In which type of control is the rate of heat delivery modified with changes in outdoor temperature? a.
variable control b.
on/off control c.
outdoor floating control d.
outdoor reset control
Q:
What is the maximum recommended resistance of finish flooring when a renewable energy source is used in a heated slab-on-grade floor system? a.
R-value 0.2 b.
R-value 0.5 c.
R-value 1.0 d.
R-value 1.5
Q:
Which term best describes the actual variation in the controlled variable as the system operates? a.
control differential b.
operating differential c.
exact differential d.
overshoot
Q:
Which statement best describes the water temperature as it passes through fin-tube baseboard? a.
The water temperature continually drops. b.
The water temperature continually increases. c.
It depends on the mounting orientation of the unit. d.
It depends on the temperature of the incoming water.
Q:
Which is the most accurate approach to heat metering? a.
determining the heat load and periodically adjusting the reset ratio b.
setting the on/off differential to a relatively large value c.
measuring instantaneous values of flow rate, temperature, and fluid properties and integrating them d.
estimating flow rate while measuring temperature to allow a quick response to temperature changes
Q:
What is NOT a typical application of hydronic radiant panel heating? a.
floor heating b.
wall heating c.
ceiling heating d.
water heating
Q:
Which type of control is most typically used with 3-way mixing valves that have an electronically controlled mixing assembly? a.
on/off control b.
floating control c.
mixing proportional control d.
no control is necessary with this type of valve
Q:
A nonlinear relationship between heat output and flow rate represents a more challenging design condition than a linear relationship. a.
True b.
False
Q:
Strong inductive loads can produce what undesirable condition in a sensor circuit? a.
electrical noise b.
cavitation c.
short cycling d.
overshoot
Q:
Varying either water temperature or flow rate are two primary methods of controlling the heat output of hydronic heat emitters. a.
True b.
False
Q:
Where is the line voltage section represented on a ladder diagram? a.
at the top b.
at the bottom c.
on the left side d.
on the right side
Q:
Temperature sensors mounted to the external surface of a pipe should not be insulated so as to provide accurate temperature measurements. a.
True b.
False
Q:
Building orientation could not be determined before the advent of detailed satellite imaging. a.
True b.
False
Q:
In a condensing boiler, where does the condensation occur? a.
in the combustion chamber b.
in the primary heat exchanger c.
in the secondary heat exchanger d.
at the water inlet
Q:
The thermal mass of a heated slab-on-grade floor is best described as ____. a.
high relative to other hydronic heating emitters b.
low relative to other hydronic heating emitters c.
about the same as most other hydronic heating emitters d.
dependent on the type of soil beneath the floor
Q:
What is the best description of the operation of a microbubble air separator? a.
It creates areas of reduced pressure using a coalescing media. b.
It creates areas of increased pressure using a coalescing media. c.
It uses a float-type air vent to allow air to escape naturally. d.
It consolidates small bubbles into large ones by narrowing the length of the pipe.
Q:
For standard fin-tube baseboard, what is the preferred energy source? a.
a solar collector b.
a high-temperature boiler c.
a low-temperature boiler d.
any renewable energy source
Q:
Which type of valve routs flow through different parts of a system depending on its current operating mode? a.
3-way mixing valve b.
3-way diverting valve c.
port valve d.
backflow preventer
Q:
Above-floor tube and plate panels typically operate at what water temperature? a.
higher compared to slab systems b.
lower compared to slab systems c.
about the same as slab systems d.
a wider range of water temperatures than slab systems
Q:
What is the primary function of a hydronic mixing valve? a.
to raise water temperature coming from the heat source b.
to lower water temperature coming from the heat source c.
to mix two system fluids d.
to regulate flow rates between different zones of a system