11.4 : 热传递机制

An environment is considered thermoneutral when the human body neither consumes nor releases energy to maintain core temperature.

The body uses four mechanisms: conduction, convection, evaporation, and radiation, to maintain temperature when the environment is not thermoneutral.

Conduction is the heat flow between two objects when in direct contact. It happens when the skin comes into contact with a cold or hot object.

For example, an ice pack helps reduce fever, facilitating conductive heat loss.

Convection is transferring heat away from the body via air movement or transmitting heat to the air surrounding the skin.

For instance, a fan uses air to transmit heat away from the body.

Evaporation is the transfer of heat energy that occurs when a liquid transforms into a gas.

Sweating causes heat loss through evaporation.

Radiation is the transmission of heat from the surface of one object to another without direct contact. The body transfers heat from the uncovered surface of the body.

For example, the sun increases the temperature of the skin through radiation.