Heat is able to move from one place to another. In some circumstances, for example in the home, it can be helpful to reduce the rate at which heat is lost. However, in order to understand how this can be achieved it’s important to first appreciate how heat is transferred.

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Infra red radiation

Thermal radiation, or infra red radiation, is emitted and absorbed by all objects. infra red radiation is a form of electromagnetic radiation. Cold objects only give out a little infra red radiation but the hotter an object becomes, the more it emits. For example, bodies emit and absorb thermal radiation and the hotter a body becomes the more it radiates out.

• – Dark, matt materials are both good absorbers and good emitters of radiation.
• – Light, shiny materials are both bad absorbers and bad emitters of radiation.

Infra red radiation has a number of uses:

• – infra red heaters
• – passive infra red devices (PIR) are used for home security alarm systems
• – thermal imaging cameras are used on police helicopters to find people in the dark
• – vacuum flasks to prevent heat loss

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Energy transfer by heating processes

Solar panels create energy not by producing electricity but by using the sun’s rays to heat up water. This is why they tend to be positioned on rooftops. The energy produced is known as solar energy.

Water is kept in a container underneath the solar panel. Cold water is pumped up to pipes in the panel. Here it’s heated up and then returned to the storage tank. Sometimes a boiler is also used to heat up the water in the tank further.

Solar panels have both advantages and disadvantages.