How Does the Thermostat Work?

Thermostats – or temperature regulators – are an integral part of any home, business, static or mobile, simple conventional or complex intelligent (smart) heating and cooling system.

Thermostats are found from the radiators or electric heaters of our house to the spacecraft in the distant space. From the washing machine in our laundry room to the nuclear power plants.

Thermostat operation

The main task of thermostats and what makes them very important in our lives is the regulation of temperature:

1)of the surrounding area through a heating or cooling medium (eg air conditioner) so that we and those around us feel comfortable,

2)various useful objects, such as the car engine. Temperature regulation in objects such as car engines is necessary for their proper operation, since in case of overheating they will be damaged.

The operation of the mechanical thermostat is based on the physical properties of thermal expansion and contraction by means of which an electrical circuit closes and opens.

The mode of operation of the bimetallic strip is the most classic example:

In an electrical circuit a sensor (bimetallic strip) keeps the circuit closed and therefore electricity flows freely. If the strip bends then the circuit opens and therefore the electricity stops flowing.

Mechanic thermostat is made of two strips of different metals very well glued together: a strip of copper and a strip of iron. The degree of contraction and expansion of each metal against heat (thermal expansion) is different. The increase in temperature increases the movement of the metal atoms resulting in them taking up more space and thus expanding the metal.

Because when iron is heated it expands less than the copper, the result will be that the plate will bend towards the side of the iron and therefore the circuit will open, as a result of which the flow of electricity will stop.