Säteilylämpötila

Säteilylämpötila is a Finnish term that translates to radiant temperature or radiative temperature. It refers to the temperature that a perfectly black object would need to have to absorb the same amount of thermal radiation as the object in question. This concept is distinct from the actual air temperature or the object's internal temperature, as it specifically accounts for the energy exchanged through electromagnetic radiation.

The radiant temperature is influenced by the temperature of surrounding surfaces and objects, as well as their emissivity and absorptivity. For example, a person in a cold room might feel colder than the actual air temperature suggests if the walls are significantly cooler, radiating less heat towards the person. Conversely, standing near a warm object, even in a cool environment, can lead to a higher perceived radiant temperature.

In practical applications, radiant temperature is important in fields like building physics and thermal comfort studies. It helps engineers and designers understand how heat is transferred through radiation and how it affects the perceived temperature and energy efficiency of a space. Measuring radiant temperature often involves instruments like radiometers that can quantify the thermal radiation incident on a surface. It is a crucial factor in assessing thermal discomfort, especially in environments with significant temperature differences between surfaces.