Convection: the transfer of heat through the movement of either a gas (air) or a liquid.
The body loses heat this way when the surrounding air temperature is less than the body’s skin temperature. For example, the body loses heat during windy winter months because of the air movement surrounding the body; the higher the wind chill, the more heat the body loses. Or, if the body is in cold water with constant movement, like a current the body will lose heat, which can cause hypothermia.
In a warm or humid environment, a designer can use air movement and ventilation to increase evaporation and keep occupants cooler through convection.
Heat is transferred in 3 ways:
- Conduction: The transfer of heat between substances which are in direct contact with each other. Conduction occurs when heat flows through a solid.
- Convection: The movement of gases and liquids caused by heat transfer. As a gas or liquid is heated, it warms, expands and rises because it is less dense resulting in natural convection.
- Radiation: When electromagnetic waves travel through space, it is called radiation. When these waves (from the sun, for example) hit an object, they transfer their heat to that object.
Similarly, by minimizing drafts, you can keep people comfortable in a cool environment.