Laboratory for the Quality Control in Buildings

Gasteiz / Vitoria, Spain

Laboratory for the Quality Control in Buildings

Gasteiz / Vitoria, Spain
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Escudero C.,Laboratory for the Quality Control in Buildings | Martin K.,University of the Basque Country | Erkoreka A.,University of the Basque Country | Flores I.,University of the Basque Country | Sala J.M.,University of the Basque Country
Energy and Buildings | Year: 2013

To obtain traceable thermal resistance of radiant barriers for building insulation laboratory tests have been carried out. Heat flow meter apparatus and guarded hot box methods have been used. The heat flow meter method has been evaluated as a method to characterize the insulating layer itself, while the guarded hot box method has been used as a tool to determine the total thermal resistance of a building component including a radiant barrier. A material with both surfaces of reflective material has been used in the study. The measurements have been carried out using two configurations in the heat flow meter apparatus: simple air chamber and double air chamber. The results have been compared with a simple analytical model of heat transfer according to ISO 6946 standard and with a Computational Fluid Dynamic (CFD) model. The CFD model enables to assess the relationship between experimental and analytically estimated results. The main conclusion is that the laboratory tests are valid for the thermal characterization of radiant barriers. It also follows that thermal resistance of radiant barriers can be estimated with precision using the simplified ISO 6946 methodology, as long as values of the thermal properties of the reflective material such as emissivity and conductivity are reliable. © 2013 Elsevier B.V.


Martin K.,Laboratory for the Quality Control in Buildings | Campos-Celador A.,University of the Basque Country | Escudero C.,Laboratory for the Quality Control in Buildings | Gomez I.,University of the Basque Country | Sala J.M.,University of the Basque Country
Energy and Buildings | Year: 2012

Nowadays, several regulations exist covering different general guidelines that must be considered in order to decrease the energy demand in residential buildings. One of the main ones consists in increasing the insulation of the building envelope with the aim of minimizing heat losses or gains. As a result, a proper treatment of thermal bridges and their in situ construction becomes more relevant because their relative effect on the overall thermal demand of the building increases. Nevertheless, there is still a great uncertainty about the dynamic behavior of thermal bridges and few energy simulation programs allow implementing them considering their thermal inertia. To obtain more information about the thermal response of thermal bridges, a series of tests have been carried out in a guarded hot box testing facility. The characteristics of a pillar thermal bridge have been studied in both steady and dynamic regime, being one of the main objectives of this study the determination of the area of influence of a thermal bridge. For this purpose, test results are compared with simulation ones. © 2012 Elsevier B.V. All rights reserved.


Martin K.,University of the Basque Country | Escudero C.,Laboratory for the Quality Control in Buildings | Erkoreka A.,University of the Basque Country | Flores I.,Laboratory for the Quality Control in Buildings | Sala J.M.,University of the Basque Country
Energy and Buildings | Year: 2012

Although there are specific rules in the standard ISO 10211 for the characterization of thermal bridges, they are mainly focused on steady state calculations to obtain the linear thermal transmittance (Ψ) or the temperature factor at the internal surface (fRsi). These parameters are respectively indicators of the additional heat flow and the risk of internal surface condensation of thermal bridges. However, in the calculations of building energy demand the dynamic thermal aspects of the envelope take a very important role. Moreover, a high percentage of the envelope is influenced by thermal bridges. Therefore it is necessary to take into account the implicit inertia of thermal bridges for accurate calculations. This paper presents a methodology based on thermoelectric analogy to calculate an equivalent wall of three homogeneous layers, which have the same dynamic thermal behaviour as the thermal bridge. Furthermore, each thermal bridge is associated with an influence area within the envelope, so that they can be easily implemented in building energy simulation programs where the heat flow is usually considered one-dimensional. © 2012 Elsevier B.V. All rights reserved.

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