solar thermal

Question 2

solar thermal history

Answer 2

first for burning ants; 17-1800s solar cookers; 1900s solar buildings/furnaces

Question 3

solar resource size

Answer 3

> 1600EJ/year

Question 4

where are best US resources

Answer 4

southwest

Question 5

passive solar building design

Answer 5

daylighting(illumination from sun not lighting), control(window shade), aperture(window), absorber(tile floor), distribution, thermal mass

Question 6

direct solar gain

Answer 6

most common passive solar design–sunlight penetrates directly into building

Question 7

indirect solar gain

Answer 7

insulating space collects/distributes the heat, but no light gets in; called a trombe wall (that sounds like “trombone” chad do you play the trombone?)

Question 8

daylighting

Answer 8

not really solar thermal; maximizing use of natural light in building design

Question 9

china & solar thermal

Answer 9

china is leader in installed capacity and expansion

Question 10

two types of solar hot water heating

Answer 10

passive and active!

Question 11

active solar water heaters

Answer 11

use pumps to circulate water through heat-absorbing solar thermal collectors

Question 12

passive solar water heaters

Answer 12

simpler than active. thermosiphon principle–when collector heats the water, it rises to be stored; then when needed, sinks and is reheated

Question 13

two types of thermosiphons

Answer 13

open loop, closed loop

Question 14

open loop thermosiphon

Answer 14

water circulates through solar collector–good for hot climates

Question 15

closed loop thermosiphon

Answer 15

working fluid circulates and warms a storage tank of water–good for climates where it freezes

Question 16

evacuated tube collectors

Answer 16

more insulated than flat collectors–vacuum between inner and outer tubes; can achieve much higher temperatures; good for cold climates or hot temp applications–57% of capacity, 78% new installs

Question 17

solar air heating collectors

Answer 17

absorbing medium captures energy from sun and heats air, which is circulated through building; <1% of solar thermal; glazed and unglazed

Question 18

solar salt ponds

Answer 18

if hot water is needed on a super large scale, use salt gradient pond–heat collects in dense, salty bottom

Question 19

US solar heating trends

Answer 19

more people are using solar to heat their swimming pools..

Question 20

solar cooking

Answer 20

trapping heat of sun to cook food–don_t need wood! No smoke! Portable! But weird culturally, and can only use when the sun is out.

Question 21

solar thermal electric gen types (four)?

Answer 21

point focus, line focus, continuous, segmented; examples: dish, trough, tower, linear fresnel

Question 22

solar thermal electric is also known as..

Answer 22

concentrated solar power

Question 23

parabolic trough/linear fresnel

Answer 23

concentrates solar energy onto a long receiver tube positioned along line focus of reflector

Question 24

central receiver (tower)

Answer 24

uses heliostats (sun tracking mirrors) that reflect solar energy to receiver atop a tower; this energy heats molten salt, which powers generator–salt can store heat for a while before generating

Question 25

parabolic dish

Answer 25

parabolic two-axis tracking concentrator to focus rays into a receiver at dish’s focal point

Question 26

how does a parabolish dish generate electricity

Answer 26

receiver shape focuses sun 30-60 times normal intensity; oil captures heat and circulates to heat exchanger, boils water, which powers turbine

Question 27

SEGS design

Answer 27

Solar electric generating system; natural gas system hybridizes plants in CA–operating for 27 years!

Question 28

linear fresnel

Answer 28

uses long flat mirrors that are really easy to manufacture; boils water directly–>turbine

Question 29

solar One and Solar Two

Answer 29

Solar One (10MW) in 1982 used oil/rocks for thermal storage–didn’t work that well; Solar Two (10MW) redesign used high temp molten salt storage

Question 30

thermal storage

Answer 30

enhances value to grid–can then generate during peak periods–lower cost than electrical storage

Question 31

dish/engine systems

Answer 31

use array of parabolic dish mirrors to focus solar energy onto receiver at focal point; fluid through stirling engine for electricity. Most efficient of solar thermal

Question 32

solar chimney

Answer 32

giant structure that captures hot air; air rises, turns turbines; nothing commercial yet and might be expensive

Question 33

solar thermal drivers

Answer 33

abundant supply, centralized utility scale, peak or baseload, clean energy, RPS compliance

Question 34

solar thermal barriers

Answer 34

site-specific, not yet competitively priced, competing with PV, habitat/land use, water

Question 35

environmental impacts of solar thermal

Answer 35

water, wastewater, land use, wildlife, salt spills, heat transfer fluid spills, zero air emissions