SOFTWARE FOR CALCULATING CONDUCTANCE AND TRANSMITTANCE
In building technology, the testing of the insulation capacity of building materials is an important topic of study. In addition to laboratory measurements of the thermal properties of materials, their behaviours is also studied through tests on field, in order to obtain information on the behaviours in different climates. The total heat flow through a material consists of a conductive, convective and radioactive part. In order to measure the heat transmission, a heat flow meter and some thermometers are used, assembled on both sides (interior and exterior) of a wall. After recording the flow and temperatures for a few hours, measured with high precision, the data is elaborated to obtain the average heat transmission of the wall.
Description
The GTLAB program enables conductance and transmittance calculations by importing data measured with an heat flux meter.
CONDUCTANCE
The conductance calculation is carried out with the progressive averages method. By this method, the conductance is obtained not by using instantaneous values for temperature and heat flux, but by taking account of the values calculated on averages obtained from the total of the readings performed.
TRANSMITTANCE
The transmittance calculation is carried out by selecting the surface coefficients of heat exchange, which combine the effects of the above phenomena and are tabulated in UNI 7357/76 Regulations and subsequent
adaptations according to the geometrical situation (e.g. vertical, horizontal structure, etc.), and in the UNI regulations accompanying Law 10/91 (e.g. in the UNI 10345 regulations for window elements).