Convection can be found in many of the household appliances such as:
-electric kettle and radiator
The heating element of the electric kettle is found at the bottom. This is so that convection can be set up in the water to boil the water. The same reason goes for radiator.
The freezer(freezing compartment) containing the evaporator, which cools the air is located at the top of the refrigerator.
This is so because cold air is more dense than warmer air, so it will sinks and the warm air will rise up.
Soon, the entire space in the refrigerator will be cooled.
-Convection in with an air conditioner is similar to that of the refrigerator.
The air intake is located up high so that only warm air enters the unit.
After cooling, the cold air expelled from the outlet vent sinks to the floor while the warmer air rise towards the air intake.
And with these, convection is set up. The cycle will keep continuing to keep the surrounding air cold as long as the air-con is on.
-Household hot water system
The operation of a hot water system for a house is based on the principle of convection.
The system consists of a boiler, a water storage tank and a cold tank inter-connected by pipes arranged as shown in the figure.
Convection currents rise the hot water up from the boiler to the storage tank while cold water flows down to the boiler, where it in turn becomes heated.
Car engines are cooled by convection currents in the water pipes.
Water is a very good substance to carry the unwanted heat away from the engine to the radiator and the radiator is a heat exchanger where the hot water gives up its energy to the air.
When a car engine has been running for a long time, a lot of thermal energy/heat is produced.
It is necessary to cool the engine so that it does not over-heat.
The engine is surrounded by a water jacket.
When the water in the water jacket gets heated, it flows into copper tubes which include many cooling fins.
A fan causes air to flow past these tubes and cool the water in them.
The cooled water flows down, back into the engine through a hose at the bottom.
A water pump is normally employed to facilitate the flow of convection currents back into the jacket.