Convection - Application of Convection

The mechanism of heating a room by a heat convector or heater is entirely based on convection.​

How a Room Heater Works

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 again. In this way, convection currents are set up in the room, which transfer heat to different parts of the room.

Step-by-step mechanism:

1. Air near the heater absorbs heat and expands – becoming less dense.
2. This warm, lighter air rises upward toward the ceiling.
3. Cool, denser air from the top sinks downward to replace it.
4. The sinking cool air reaches the heater, gets heated again, and rises.
5. This cycle repeats continuously, setting up convection currents throughout the room.​

Due to the current flowing in the windings of the transformer, enormous heat is produced. Therefore, a transformer is always kept in a tank containing oil.​

How Transformer Oil Cooling Works

The oil in contact with the 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 warms up again to rise upward. This process is repeated again and again.

Step-by-step mechanism:

1. Current flowing through the transformer windings generates large amounts of heat.
2. The oil directly touching the transformer body heats up and rises (becomes less dense).
3. The warm oil reaches the cooler tank walls, releases its heat to them, and descends to the bottom.
4. The cooled, denser oil sinks back to the transformer body and heats up again.
5. This cycle continues repeatedly — carrying heat away from the transformer by convection.​
6. The cooler tank, in turn, loses its heat by convection to the surrounding air.​