CSLB C-46 Solar (Trade Exam) — All Questions
7 questions
Which passive solar water heating system stores the water inside the collector itself?
- a.Indirect active system
- b.Integral collector-storage (batch)✓
- c.Evacuated-tube active system
- d.Direct active system
DOE describes integral collector-storage systems as a storage tank covered with transparent material so the sun heats the water in it. Active systems use pumps; ICS systems suit mild-freeze climates.DOE Energy Saver, Solar Water Heaters
In a one-tank solar water heating system, where is the backup heater?
- a.On the roof beside the collector
- b.In a separate tank downstream
- c.There is no backup in one-tank systems
- d.In the same tank as solar storage✓
DOE explains that in one-tank systems the backup heater is combined with the solar storage in one tank; in two-tank systems the solar tank preheats water for a conventional heater.DOE Energy Saver, Solar Water Heaters
How many Btu does it take to heat 40 gallons of water from 60 °F to 120 °F, using DOE's 8.35 pounds per gallon?
- a.About 20,040 Btu✓
- b.About 334 Btu
- c.About 2,400 Btu
- d.About 40,080 Btu
DOE's formula is gallons × 8.35 × temperature rise: 40 × 8.35 × 60 = 20,040 Btu. Leaving out the 8.35 pounds per gallon gives 2,400, which treats water as weighing one pound per gallon.DOE Energy Saver, Estimating the Cost and Energy Efficiency of a Solar Water Heater
What range of collector area does DOE give for solar pool heating, relative to the pool's surface area?
- a.150 to 200 percent of the surface area
- b.Exactly equal to the pool's volume in gallons
- c.50 to 100 percent of the surface area✓
- d.10 to 25 percent of the surface area
DOE says the surface area of the solar collector should equal 50 to 100 percent of the pool's surface area, more in cooler and cloudier areas and less with a pool cover.DOE Energy Saver, Solar Swimming Pool Heaters
How can a solar pool heating system help cool a pool in a hot climate?
- a.By adding glycol to the pool loop
- b.By reversing the pump at noon
- c.By circulating water through them at night✓
- d.By draining the collectors during the day
DOE notes that in hot climates the collectors can cool the pool during peak summer months by circulating water through them at night.DOE Energy Saver, Solar Swimming Pool Heaters
A pool holds 1,500 cubic feet of water. About how many gallons is that?
- a.About 11,220 gallons✓
- b.About 55 gallons
- c.About 1,500 gallons
- d.About 200 gallons
NIST defines a gallon as 231 cubic inches and a cubic foot as 1,728 cubic inches, so one cubic foot is about 7.48 gallons: 1,500 × 7.48 ≈ 11,220 gallons. Fifty-five is the volume in cubic yards.NIST Handbook 44 Appendix C
Which collector has parallel rows of transparent glass tubes and is used more often in U.S. commercial applications?
- a.Thermosyphon batch tank
- b.Evacuated-tube collector✓
- c.Unglazed flat-plate collector
- d.Integral collector-storage unit
DOE describes evacuated-tube collectors as parallel rows of transparent glass tubes, each with an absorber tube and fin, and says they are used more frequently for U.S. commercial applications. Unglazed collectors are typical for pools.DOE Energy Saver, Solar Water Heaters