10.5 Part 2 Applications of Thermal Energy Transfer (Convection)

A radiator heats up the room by convection.

As the air above the radiator heats up, hot air rises up due to it's expansion and decrease in density. Cool air in the surrounding will then sink due to it's greater density. Hence, a cycle will go on and a convection current is produced.






In a refrigerator, the freezer at the top of the unit contains the evaporator, which cools the air.

As cold air is denser than warmer air, it sinks to the bottom of the freezer. There, the cold air flows through the vents into the refrigerator cabinet where it sinks to the bottom of the fridge.

Air which is warmed by the contents of the fridge rises as the cold air displaces it, and the 'warm' air enters into the freezer compartment where the cycle begins again.






Convection current occuring when air-con is turned on.

The air-conditioner is located up high so that only warm air enters the unit. As the warm air enters, the cold air expelled from the outlet vent sinks to the floor, displacing the warmer air and pushing it towards the air intake os the air conditioner.