27/07/2025
Did you know a dome building can cool a building instead of electricity powered air conditioning?
The use of domes in architecture can be seen all over the world, but its not just for their aesthetic beauty, they actually have a very practical use. Domes use several very clever ways of regulating temperatures and can keep the interior of buildings very cool compared to the temperatures outside.
The roots of dome-building trace back to ancient Mesopotamia, where mudbrick domes were documented in Central Asia as far back as the late third millennium BC. They have been found in Persian, Hellenistic, Roman, and Chinese architecture in the ancient world, as well as among a number of indigenous building traditions throughout the world.
The curved shape of a dome creates air circulation. Hot air naturally rises towards the top of a dome, it creates a convection current of warm air rising up that pulls in cool air underneath it. This is enhanced by ventilation openings (such as oculi or small windows) at the top. These allow hot air to escape while drawing in cooler air from below which facilitates air movement.
The multiple layers of a dome, such as bricks, concrete and plaster, act as natural insulation. The thick layers slow down heat transfer, preventing rapid temperature fluctuations. So during the day, the dome absorbs heat from sunlight and at night, it gradually releases this stored heat, maintaining a more stable indoor temperature.
Domes reflect a significant portion of incoming solar radiation due to their curved surfaces which reduces direct heat gain compared to flat surfaces. And inside, the rounded shape means they distribute heat more evenly throughout the space as there are no sharp corners or edges where hot air can accumulate.
The oculus is a circular opening at the apex of the dome that allows sunlight to flood the interior, creating dramatic lighting effects and illuminating the space. It also allows for natural air circulation and ventilation, preventing the buildup of stale air.
Despite its seemingly precarious opening, the oculus is crucial to the dome's stability. Domes experience compressive hoop stress, especially at their apex. The oculus, by reducing the weight at the top, helps to distribute these stresses more effectively. It can be seen as a three-dimensional keystone for the dome, ensuring its overall stability by allowing for the equal distribution of forces.