Many industries that produce windows systems provide tools that allow users to determine the overall transmittance of the selected component. Our tool, in addition to the above, displays the heat flow and the isothermal diagram, providing a tool that measures the transmittance with a certain rigor to assess the quality of the different choices unresectable, by using the best way to mitigate the effects of the thermal bridges. The software, through a simple graphical interface, enables to select the climate data, the external frame typologies, the geometric features, the materials and the glass typologies. By starting the calculation, the instrument determines the thermal transmittance and checks the compatibility with the national regulations. The originality of this tool is that you can view the status of progress of the characteristics of the heat flow in a specific section, and immediately identify the possible points of heat loss( thermal bridges). In this way, the user can change the parameters to generate another solution that implements the overall performance of the exterior frame.
User interface
This tool is designed to be used by wide specialized users. After implementing the features of frame, the tool automatically generates the overall thermal transmittance and heat flow through THERM, a calculation software developed by the Lawrence Berkeley National Laboratory( LBNL), which analyzes the two-dimensional heat flows through different building components. A mesh automatic generator, processing the calculations according to the Finite Element Method, defines the section. The results obtained are consistent with the evaluation process developed by the NFRC( National Fenestration Rating Council), a non-profit organization that manages the consistency of assessment and labeling system for the energy performance of building components. The transmittance of the window is then calculated according to the following formula:
Uc, Ac: Thermal transmittance and projection of central glass area Ufr, Afr: Thermal transmittance and projection of frame area Ue, Ae: Thermal transmittance and projection of glass edge area Ud, Ad: Thermal transmittance and projection of divider area Ude, Ade: Thermal transmittance and projection of divider edge area
This method of calculation is considerably more detailed than the requirements of the UNI 10077- 2, because are considered the mode of transfer of edge effects from the glass to the frame without resorting to tabulated values, often overestimated( Fig. 2). As shown by the following formula( UNI 10077-2), in fact, the thermal transmittance of the glass edge is identified with the parameter ψ, the linear thermal transmittance, whose value, provided by the same law, is selected from a limited number of examples not always representing the real situation to be evaluated.
Climate data are set through a first drop-down menu that allows you to choose the region and a second one in which to select the city. The information is downloaded directly from the database file insqllite.
Software for the heat flow evaluation of the nearly-zero houses 271