002 S5

123456789
Across
  1. 2. collectors used on ground source heat pumps when area is limited
  2. 4. considered to be a carbon neutral energy source
  3. 5. used to capture solar energy
  4. 6. a solar thermal system with a pump
  5. 8. converts a low temperature heat from a source to a higher temperature heat
Down
  1. 1. has a cycle of changing from liquid to gas in heat pumps
  2. 3. part of a wood burner
  3. 7. solar thermal systems ? carbon dioxide emissions
  4. 9. used to extract ground source heat