UTA11 Solar Systems

Question 1

What is the energy that the earth receives from the sun? (Page 15- 1)

Answer 1

Electromagnetic radiation

Question 2

Energy from the sun travels approximately how many miles in just over 8 minutes to reach earth? (Page 15-1)

Answer 2

90 million

Question 3

What is the amount of solar energy per unit area per unit of time that strikes the surface of the earth? (Page 15-1)

Answer 3

Solar insolation

Question 4

What term refers to the ability of glass to transmit visible radiation and to prevent the loss of heat from the collector plate that radiates at longer wavelengths (infrared frequencies)? (Page 15-1)

Answer 4

Greenhouse effect

Question 5

What is the most important and most expensive part of a solar- heating system? (Page 15-3)

Answer 5

Collector

Question 6

The choice of collector fluid is important because this is the lifeblood of the system. The cheapest, most readily obtainable, and thermally efficient fluid to use is what? (Page 15-5)

Answer 6

Ordinary water

Question 7

Silicone heat transfer fluids have many favorable properties that make them prime candidates for collector fluids. They do not freeze, boil, degrade, or corrode common metals, including aluminum. They have excellent stability in solar systems stagnating under what temperature? (Page 15-7)

Answer 7

400°F

Question 8

Ethylene glycol and propylene glycol are the two most commonly used antifreezes. A 50-50 water/glycol solution provides freeze protection down to about -30°F and also raises the boiling point to about what temperature? (Page 15-7)

Answer 8

230°F

Question 9

The three most common types of solar collectors are flat-plate collectors, evacuated tube collectors, and what other type of collectors? (Page 15-7)

Answer 9

Concentrating

Question 10

There are many types of concentrating collectors. The most popular types are the parabolic trough, the linear-trough fresnel lens, and the what? (Page 15-9)

Answer 10

Compound parabolic mirror

Question 11

Since water has a specific heat of 1 Btu/1b-°F, then 15 pounds of water storage is needed per square foot of collector or how many gallons of storage is needed for each square foot of collector? (Page 15-11)

Answer 11

1.8

Question 12

During the winter, typical liquid types of solar systems are seldom operated at delivery temperatures above what temperature? (Page 15-14)

Answer 12

150°F