Open Courtyards Creating Cool Spaces in Buildings

Solution

Under some circumstances, architectural designs can be used to take advantage of the sun as a driving force for maintaining air movement.
Warm air is less dense than cool air and therefore will rise in an environment of cool air. This movement is called convection.
The relatively static cooling system used in a courtyard house can provide the basis for understanding modifications that can generate air movement by convection. In hot dry zones, air temperature drops considerably after sunset from re-radiation to the night sky. The air is relatively free of water vapor that would reflect the heat or infrared radiation back toward the ground, as happens in warm humid regions.
To enhance thermal comfort, the principle of convection has been effectively used in the architectural design of houses by employing the courtyard concept.
Accordingly, people learned to close their houses to the outside and open them inwardly onto internal courtyards, which are open to the sky. This arrangement promotes drops in air temperature.
As evening advances, the warm air of the courtyard – that was heated directly by the sun and indirectly by radiation from the warm buildings – rises and is gradually replaced by the already cooled night air from above. This cool air accumulates in the courtyard in laminar layers and seeps into the surrounding rooms, cooling them. In the morning, the air of the courtyard – that is shaded by its four walls – and the surrounding rooms heat slowly and remain cool until late in the day when the sun shines directly into the courtyard.
In this way, the courtyard serves as a reservoir of coolness. The courtyard concept is universally applied in the traditional architecture of countries in hot arid regions.