Ermittlung des Aufbaus und der Stoffkennwerte von Außenbauteilen mit Hilfe von In‐situ‐Messungen und FEM‐Berechnungen

Determination of the construction and the material identity values of outside building components with the help of in‐situ measuring procedures and FEM‐simulation calculations. The aims formulated nationwide and internationally to the climate protection can be achieved by combining of the energy‐efficient construction and rehabilitation of the existing buildings. Knowledge about the construction and the material identity values of the warmth‐transferring outside components is a condition for the energetic balance of buildings. The essential information to this can frequently be no more taken from the construction documents particularly for older buildings since they are no longer traceable or incomplete. At the example by univalve and bivalve out‐wall construction it is shown that the thermophysical qualities can be determined with the help of in‐situ measuring procedures and FE‐simulation calculations without destruction.     

Hygrothermische Wirkungen von Raum‐ und Außenoberflächen

The hygrothermal effect of inside and outside building envelope surfaces. In the past the protection of building constructions under outdoor and indoor climate conditions was one of the most important subjects building physics. Nowadays the energy balance and the hygrothermal performance of building envelopes are current topics. This paper deals with the coupled heat and moisture transfer on the internal and external envelope surfaces. By means of numerical simulation and laboratory investigation the influence of the internal surface of exterior walls on the indoor air humidity is demonstrated. The influence of evaporation cooling on the energy transfer in winter time and during the warm season requires investigations on dewing and driving. It depends on the hygroscopic parameters of the outside wall coating. The effect of infrared reflecting coating is determined. It is shown in which way heat sources integrated in exterior walls could be a possibility to avoid microbiological growth on building envelopes.     

Experimentelle und numerische Untersuchungen von Brandszenarien vor Fassaden unter Berücksichtigung verschiedener Abstände

Experimental and numerical investigations of fire scenarios in front of façades considering various distances Constructional boundary conditions, e. g. walls or façades, close to ignition sources affect the fire formation and the plume. It is already known, that boundaries (e. g. walls) constrain the entrainment of air and oxygen into the plume and the combustion of gas or flammable products is completed at larger heights. How far the location of the fire sources, the building geometry and the heat release rate affect the characteristics of a flame is investigated at the Institut für Baustoffe, Massivbau und Brandschutz (iBMB) of TU Braunschweig in line with a series of experiments with a square gas burner. For the implementation of the fire tests the test rig in Braunschweig is provided with extensive measurement techniques to determine heat flux, wall‐bounded temperatures, temperatures for plume measurements and upward velocity. In this paper the data of the fire tests are discussed and compared with the results of a CFD‐Model and selected empirical calculation approaches.     

Lichttechnisches und energetisches Verhalten von Fassaden moderner Verwaltungsbauten – Teil 1: Lichttechnisches Verhalten

Daylight and thermal energy performance of facades in office buildings, Part 1: Daylight performance. Regarding the impact on indoor illumination facade systems have to provide an appropriate visual indoor environment. In addition daylight penetrating the room through the facades should favourably influence the overall building energy balance. Daylight utilization can directly reduce energy consumption for electric lighting and can indirectly – due to the higher luminous efficacy of daylight compared to commonly used artificial lighting systems – reduce the thermal loads within the conditioned building spaces. In part 1 of this contribution the influence of different facade solutions on room illumination is systematically investigated by means of a parametric study of significant room, outdoor, environmental and climatic parameters for ten facade systems. The facade systems considered are conventional, permanently shaded, and light redirecting systems. The analysis of system performance is based on newly developed characteristics which allow the analysis and optimization of different facade systems under working conditions. Part 2 of the contribution shows the energetic interaction of the facade dependent internal loads by artificial lighting system and solar heat gains.     

Lichttechnisches und energetisches Verhalten von Fassaden moderner Verwaltungsbauten – Teil 2: Energetisches Verhalten

Daylight and thermal energy performance of facades in office buildings, Part 2: Thermal energy performance. In part 1 of this contribution the influence of different facade solutions on room illumination was systematically investigated by means of a parametric study of significant room, outdoor environment and climatic parameters for ten facade systems. Part 2 of the contribution shows the energetic interaction of the facade dependent internal loads by the artificial lighting system and the solar heat gains through the considered facades. The interactions are discussed for four facade systems considered of being representative.     

Überlegungen zum hygrothermischen Verhalten von Außenwänden im Holztafel‐/Holzrahmenbau mit direkt beschichteten Beplankungen

Im vorliegenden Artikel wird gezeigt, dass es möglich ist, im Versuch erhaltene hygrothermische Messwerte aus Bewitterungsversuchen an Außenwänden im Holztafel‐/Holzrahmenbau mit direkt beschichteten Beplankungen mit dem Programm WUFI 4.0 nachzurechnen. Anschließend erfolgte die hygrothermische Berechnung der Wandkonstruktionen mit dem in WUFI 4.0 enthaltenen Klimadatensatz von Holzkirchen. Die erhaltenen Zeitkurven der relativen Luftfeuchte und Lufttemperatur dienten als Eingabewerte in WUFI‐BIO 2.0 zur Berechnung des Risikos eines Schimmelpilzwachstums in der Konstruktion. Das Risiko eines Schimmelpilzwachstums in der Konstruktion konnte mit den Berechnungen nicht generell ausgeschlossen werden. Es wird empfohlen, innere Dampfbremsfolien mit s_d ⩾ 25 m zu verwenden. Weiterführende Untersuchungen sollten an realen Bauobjekten erfolgen. To observe the hygrothermal behavior of exterior walls in timber frame construction with direct rendered sheathings. The presented paper shows that it is possible to calculate with the program WUFI 4.0 the hygrothermal measurement data of weathering tests in the climate chamber on exterior walls in timber frame construction with direct rendered sheathings. Afterwards, hygrothermal calculations of walls under the use of climate data from Holzkirchen/Germany were conducted. The obtained relative humidity time diagrams and temperature time diagrams were used as input values in WUFI‐BIO 2.0 to calculate the risk of mould growth in the construction. In general, the risk of mould growth in the construction could not be excluded with the calculations. Therefore, the use of interior vapor barrier sheets with s_d ⩾ 25 m is recommended. Further research should take place on real buildings.