Indirect active solar heating systems usually circulate _____. ...

[mp14]

Indirect active solar heating systems usually circulate _____.
 
  a. an antifreeze solution in the closed loop
  b. a synthetic oil blend in the closed loop
  c. deionized water in the open loop
  d. an antifreeze solution in the open loop

Question 2

A thermosiphon system is a type of _____.
 
  a. evaporative heating system
  b. valance cooling system
  c. passive solar heating system
  d. air turnover heating system

[tdewitt]

Answer to Question 1

a

Answer to Question 2

c

[mp14]

Excellent

[Joy Chen]

Thanks for the timely response, appreciate it