Heat

Heat is a form of energy.

Usually, if you Add Heat Energy to a substance its Temperature Rises.

If you Remove Heat Energy its Temperature Falls.

However, if a substance is Changing State as you add (or remove) heat, there may not be any change in temperature.

The Heat Capacity (C) of an object is the amount of heat energy needed to change its temperature by 1 K (1 oC).

The Latent Heat (L) of an object is the heat energy needed to change its state without a change in temperature.

The Specific Latent Heat ( l ) of a substance is the amount of heat energy needed to change the state of 1 kg of that substance without a change in temperature.

Convection is the movement of heat through a liquid or gas by means of circulating currents caused by the heat.

Conduction is the transfer of heat through a substance by the passing on of vibration from molecule to molecule. There is no overall motion of the substance.

Radiation is the transfer of heat energy from one place to another in the form of Electromagnetic Waves.

The average amount of the Sun’s energy falling per second perpendicularly on 1 metre squared of the Earth’s atmosphere is the Solar Constant or Solar Irradiance.

Its value is about 1.35 kW ​m​-2​.

The U-value of a structure is the amount of heat energy conducted per second through 1 m2 of that structure when a temperature difference of 1 oC (i.e.1 K) is maintained between its ends.

A structure that is a Bad Insulator has a High U-Value. A structure that is a Good Insulator has a Low U-Value.