Kuldekanal

A kuldekanal, or cold air duct, is a passive cooling system that utilizes naturally occurring temperature differences to ventilate and cool buildings. The concept relies on the principle that cold air is denser than warm air and therefore sinks. In a kuldekanal system, a shaft or channel is designed to collect cooler outside air, often from a shaded or elevated location, and direct it downwards into the building.

As the cooler air enters the lower levels of the building, it displaces warmer air, which rises. This warmer air can then be vented out through openings in the upper parts of the building, creating a continuous natural ventilation cycle. This process helps to reduce the indoor temperature without the need for mechanical cooling systems like air conditioners.

The design of a kuldekanal is crucial for its effectiveness. Factors such as the height and cross-sectional area of the duct, the location of air inlets and outlets, and the overall building layout play a significant role. Shading of the air inlet is also important to ensure that the air being drawn in is indeed cooler than the ambient air.

Kuldekanal systems are particularly effective in climates with significant diurnal temperature variations, where nights are cooler than days. They can also be integrated with other passive cooling strategies, such as thermal mass and natural ventilation techniques, to further enhance their performance. While they require no energy to operate, their effectiveness is dependent on ambient conditions and proper design.