Project Details
Projekt
Investigation of the room side heat transfer into building envelope components and development of a calculation method
Subject Area
Construction Material Sciences, Chemistry, Building Physics
Term
since 2020
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 438770440
A reliable determination of the thermal and hygric properties of building components is essential for any building technology strategy. This includes energy performance certificates as well as certificates for moisture protection or energetic and hygrothermal simulations. Basis for all thermal and hygric certificates and calculations are the climatic conditions and the geometrical and structural-physical parameters of the building components or constructions. These include in particular: (1) the assumable indoor climate,(2) the properties of the heat transport from the room interior into the external building component,(3) the structural-physical material properties of the external building component layers,(4) the properties of the heat transport from the external building component into the outdoor environment as well as (5) the outdoor climate.The outdoor climate referred to in (5) is very well known due to extensive data acquisition and the development of test reference years for different regions in Germany. The structural-physical parameters listed in (3) are also well known for the building materials to be used. The situation is similar for the indoor climate listed in (1). For this there already exist normative specifications and additionally detailed results from an extensive long-term survey.In comparison, the heat transmission resistance Rs listed in (2) and (4) represent “blank areas on the map”. There exist very different approaches for the heat transmission resistance on the external building component in the normative specifications. Furthermore, research results show that different conditions have a large influence on the value of the heat transmission resistance. Measured values can deviate from the normative specifications up to a factor of 10.This is where the research proposal at hand comes into play. A significant contribution to a better understanding of the room side heat transfer within buildings is planned, as the room side heat transfer (in comparison to the outside heat transfer) represents the decisive influence on structural physics calculation methods. For this purpose progressive simulation and measurement methods are applied.As in the previously described 5 aspects used for calculating thermal and hygric processes in buildings the heat transfer is the last not sufficiently known aspect, in this research project the basis for the considerable improvement of the calculation methods is to be developed. For the construction practice the research project will deliver insights into the reduction of energetic and hygric structural damages.
DFG Programme
Research Grants
