The Radiant Temperature Asymmetry Transducer MM0036 consists of two identical surfaces (A and B), that independently measure net incident radiation on each plane surface. Measurement results from the transducer are used to evaluate radiant asymmetry discomfort from hot and cold surfaces (according to ISO 7730). By measuring plane radiant temperature (tpr) in several directions the mean radiant temperature can also be calculated.

Radiant temperature asymmetry is defined as the difference between the plane radiant temperatures (tpr) on two opposite sides of a small black element. The parameter tpr describes the heat radiation in one direction. It is defined as the uniform surface temperature of a half-room that produces the same incident radiation on a black surface as the actual environment. In addition to measuring tpr and radiant temperature asymmetry, the transducer also measures Net Incident Power.

Net Incident Power is the net amount of radiation that a black surface receives from the environment. Incident power is greater than Net Incident Power, because the surface of the transducer itself radiates energy. Incident Power is easily calculated using the net incident power when the temperature of the transducer is known.
Each face of the transducer consists of a reflective gold-plated element and a black-painted element of the same size. Both elements are connected to a centre block via thermopiles. When either heated or cooled by the environment, the gold-plated element gains or loses heat entirely by convection whereas the black element loses or gains heat both by convection and radiation. Thus, as both elements have essentially the same temperature, the resultant difference voltage produced across the thermopiles is a function of the net heat transfer by radiation between the black element and the environment. The tpr is calculated from this measurement and from the temperature inside the centre block, which is measured using a Pt100 temperature-sensitive resistor . Both sets of elements are covered with polyethylene shields. These prevent air velocity from influencing the results.