When considering the temperature test chamber as a
constant temperature chamber that has achieved an arbitrary uniform temperature, the uncertainty at that achieved
temperature can be separated into the two factors of
chronological temperature fluctuation in time, and spatial
temperature fluctuation, refer to as temperature uniformity.
Temperature uniformity reflects the quality of chamber design
regarding isolation, location of heaters and air circulation
patterns. Temperature uniformity is represented through two
methods: temperature variation in space base on the center of
the working space, and temperature gradient considering the
entire working space. We can evaluate the temperature
uniformity is defined as follows: