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Indicate whether the statement is true or false.
1. Most solar collectors use glass with low iron oxide content for their glazing.
a.
True
b.
False
2. For solar collectors, the absorptivity of the upper surface of the absorber plate should be as low as possible.
a.
True
b.
False
3. A Sydney tube is often paired with a parabolic reflector fixed behind each tube.
a.
True
b.
False
4. Flat-plate collectors without glazing or insulation are commonly used for domestic water heating.
a.
True
b.
False
5. 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.
6. 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
7. 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
8. 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
9. What material is commonly used to form absorber strips in flat-plate solar collectors?
a.
copper
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b.
aluminum
c.
glass
d.
PVC
10. Which instrument measures instantaneous solar radiation intensity?
a.
thermometer
b.
radiameter
c.
pyranometer
d.
dynamometer
11. 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
12. 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
13. What material is typically used for the tubes in an evacuated tube solar collector?
a.
copper
b.
aluminum
c.
glass
d.
PVC
14. 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
15. When mounting a collector on a roof, how should structural rails be placed to avoid trapping water?
a.
½ inch above the roof
b.
1 inch above the roof
c.
4 inches above the roof
d.
flush with the roof
16. What is used to calculate net collector area for an evacuated tube solar collector?
a.
outer dimensions of the collector housing
b.
dimensions of exposed glazing
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c.
dimensions of the absorber plate and headers
d.
dimensions of the mounting surface minus the dimensions of the absorber plate
17. What is a realistic limit for the number of collectors that can be mounted side by side?
a.
three
b.
five
c.
eight
d.
ten
18. 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.
19. 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
20. 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
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1. True
2. False
3. True
4. False
5. False
6. d
7. a
8. b
9. a
10. c
11. c
12. d
13. c
14. c
15. a
16. b
17. c
18. d
19. a
20. b