1. Heating and cooling of rooms:
- The mechanism of heating a room by a heater is entirely based on convection.
- The air molecules in immediate contact with the heater are heated up.
- These air molecules acquire sufficient energy and rise upward.
- The cool air at the top being denser moves down to take their place. This cool air in turn gets heated and moves upward.
- In this way, convection currents are set up in the room which transfer heat to different parts of the room.
- The same principle but in opposite direction is used to cool a room by an air-conditioner.
2. Cooling of transformers:
- Due to current flowing in the windings of the transformer, enormous heat is produced.
- Therefore, transformer is always kept in a tank containing oil.
- The oil in contact with transformer body heats up, creating convection currents.
- The warm oil comes in contact with the cooler tank, gives heat to it and descends to the bottom. It again warms up to rise upward.
- This process is repeated again and again. The heat of the transformer is thus carried away by convection to the cooler tank.
- The cooler tank, in turn loses its heat by convection to the surrounding air.
