Which type of ventilation system uses natural air currents?

Natural ventilation systems are designed to utilize the natural movement of air caused by temperature differences, wind, and pressure variations within the environment. This type of system leverages the principles of buoyancy and airflow, allowing fresh air to enter and stale air to exit a space without the need for mechanical aids.

In mines, where air quality and circulation are critical for safety and health, natural ventilation can help maintain suitable conditions by allowing fresh air to flow through, especially in areas where mechanical ventilation may not be feasible or justified due to costs or the specific layout of the mine. Natural ventilation systems are particularly effective in surface mines or surface facilities where the environment allows for adequate air exchange through windows, openings, and ventilation shafts.

Mechanical ventilation systems rely on powered fans or blowers to circulate air, while forced air systems specifically implement fans to push air into a space. Controlled ventilation systems, on the other hand, involve the use of both mechanical and natural means but are designed to manage airflow more actively than natural systems alone. Thus, the defining characteristic of natural ventilation systems is their dependence on the environment rather than artificial means to facilitate air movement.