The below-ground courtyard :
A view of below ground courtyard and it's trees.
Using the earth's heat in winter, and its cool in summer, is very cheap and safe. In the internal court yard houses they use Godal Baghjeh or below ground court yard, that normally has trees and a pond to produce a fresh and cool place for inhabitants. Trees do not let the sun shine in this courtyard in summer, but in winter you can use the sun rays. In summer there is a considerable difference of temperature between this courtyard and a ground-level courtyard.
An internal view of the
below-ground courtyard