Journal of Thermal Envelope and Building Science, 2004
The Boltzmann transformation method is used to determine the liquid water diffusivity from moistu... more The Boltzmann transformation method is used to determine the liquid water diffusivity from moisture content profiles as measured in a capillary water absorption experiment. An inter-laboratory comparison for analyzing the reliability of the determination method showed that the inaccuracy in the liquid water diffusivity is caused by scatter in the transformed data and by uncertainty in the boundary conditions at the intake surface and ahead of the steep moisture front. A methodology is proposed based on (1) the evaluation of the validity of the diffusion approach, (2) a simplified handling of the boundary conditions, (3) smoothing of the scattered data and (4) the evaluation of the quality of the determined liquid water diffusivity. For HAM (Heat-Air-Moisture transport) calculations values of the liquid water diffusivity for moisture contents higher than the capillary moisture content are disregarded. The liquid water diffusivity can be described by an exponential function limited at...
Journal of Thermal Envelope and Building Science, 2004
Several advanced non-destructive techniques are available to measure the evolution of content pro... more Several advanced non-destructive techniques are available to measure the evolution of content profiles with time, allowing the analysis of unsaturated flow and the determination of the moisture diffusivity of porous building materials. The reliability of six different techniques is investigated: the NMR-technique, the MRItechnique, the γ-ray attenuation technique, the capacitance method, the X-ray projection method and the TDR-technique. All of them were applied to measure the moisture content evolution during free uptake experiments on two building materials. Considering the limitations of some of the techniques, a good overall agreement is obtained. The work presented is an outcome of the EU-initiated HAMSTAD-project.
ABSTRACT Implications of moisture in building and construction are of interest to the internation... more ABSTRACT Implications of moisture in building and construction are of interest to the international community because of their huge economical consequences, including effects on health, maintenance and repair, retrofitting and conservation, as well as on common welfare. The present day knowledge offers a potential to tackle such problems, both in the design process and during the service life of building. In 2001, the European Commission initiated the project ‘‘HAMSTAD’’ (Heat Air and Moisture Standards Development) to propose a better modelling methodology than the traditional Glaser method. HAMSTAD focused on the development of draft standardisation procedures on determination methods of moisture transfer properties and a draft methodology for certification of advanced moisture modelling codes. To stimulate competitiveness and progress, the project was carried out following an ‘open methodology’ instead of a system of deterministic and prescriptive (pre-) standards. This paper outlines the project and highlights the main outputs, serving as an introduction to the following more detailed research papers resulting from that work.
This case study concerns a very extensive study of the thermal comfort in 6 Belgian establishment... more This case study concerns a very extensive study of the thermal comfort in 6 Belgian establishments of an international store chain. Since years the employees complained about bad thermal comfort: globally too hot during summer and locally
During the past two decades, pressure on the building industry increased gradually. Energy effi-c... more During the past two decades, pressure on the building industry increased gradually. Energy effi-ciency, indoor air quality, comfort, durability, sustainability all became key issues within a framework of growing cost awareness. Hence, this multiplication of issues emphasized the need for a new methodology to assess building quality, called the performance concept. This paper uses performances to evaluate an advanced building envelope system: transparent insulation (TIM). But first, the performance concept itself is clarified and a performance array for hygro-thermal evaluation proposed, from the building down to the envelope. This array is then used to analyze the TIM-choice. The study shows that performances not only are a tool when evaluating an envelope solution but also help in improving it.
Theme I Building materials That theme mainly deals with heat and mass flow properties, their meas... more Theme I Building materials That theme mainly deals with heat and mass flow properties, their measurement and their interaction with flow governing potentials.
... construction. Some even advance 100% as an objective and propose the zero house as the final ... more ... construction. Some even advance 100% as an objective and propose the zero house as the final goal. Zero indicates that only renewable energy is consumed for heating (and cooling), hot water production and household. This ...
Journal of Thermal Envelope and Building Science, 2004
The Boltzmann transformation method is used to determine the liquid water diffusivity from moistu... more The Boltzmann transformation method is used to determine the liquid water diffusivity from moisture content profiles as measured in a capillary water absorption experiment. An inter-laboratory comparison for analyzing the reliability of the determination method showed that the inaccuracy in the liquid water diffusivity is caused by scatter in the transformed data and by uncertainty in the boundary conditions at the intake surface and ahead of the steep moisture front. A methodology is proposed based on (1) the evaluation of the validity of the diffusion approach, (2) a simplified handling of the boundary conditions, (3) smoothing of the scattered data and (4) the evaluation of the quality of the determined liquid water diffusivity. For HAM (Heat-Air-Moisture transport) calculations values of the liquid water diffusivity for moisture contents higher than the capillary moisture content are disregarded. The liquid water diffusivity can be described by an exponential function limited at...
Journal of Thermal Envelope and Building Science, 2004
Several advanced non-destructive techniques are available to measure the evolution of content pro... more Several advanced non-destructive techniques are available to measure the evolution of content profiles with time, allowing the analysis of unsaturated flow and the determination of the moisture diffusivity of porous building materials. The reliability of six different techniques is investigated: the NMR-technique, the MRItechnique, the γ-ray attenuation technique, the capacitance method, the X-ray projection method and the TDR-technique. All of them were applied to measure the moisture content evolution during free uptake experiments on two building materials. Considering the limitations of some of the techniques, a good overall agreement is obtained. The work presented is an outcome of the EU-initiated HAMSTAD-project.
ABSTRACT Implications of moisture in building and construction are of interest to the internation... more ABSTRACT Implications of moisture in building and construction are of interest to the international community because of their huge economical consequences, including effects on health, maintenance and repair, retrofitting and conservation, as well as on common welfare. The present day knowledge offers a potential to tackle such problems, both in the design process and during the service life of building. In 2001, the European Commission initiated the project ‘‘HAMSTAD’’ (Heat Air and Moisture Standards Development) to propose a better modelling methodology than the traditional Glaser method. HAMSTAD focused on the development of draft standardisation procedures on determination methods of moisture transfer properties and a draft methodology for certification of advanced moisture modelling codes. To stimulate competitiveness and progress, the project was carried out following an ‘open methodology’ instead of a system of deterministic and prescriptive (pre-) standards. This paper outlines the project and highlights the main outputs, serving as an introduction to the following more detailed research papers resulting from that work.
This case study concerns a very extensive study of the thermal comfort in 6 Belgian establishment... more This case study concerns a very extensive study of the thermal comfort in 6 Belgian establishments of an international store chain. Since years the employees complained about bad thermal comfort: globally too hot during summer and locally
During the past two decades, pressure on the building industry increased gradually. Energy effi-c... more During the past two decades, pressure on the building industry increased gradually. Energy effi-ciency, indoor air quality, comfort, durability, sustainability all became key issues within a framework of growing cost awareness. Hence, this multiplication of issues emphasized the need for a new methodology to assess building quality, called the performance concept. This paper uses performances to evaluate an advanced building envelope system: transparent insulation (TIM). But first, the performance concept itself is clarified and a performance array for hygro-thermal evaluation proposed, from the building down to the envelope. This array is then used to analyze the TIM-choice. The study shows that performances not only are a tool when evaluating an envelope solution but also help in improving it.
Theme I Building materials That theme mainly deals with heat and mass flow properties, their meas... more Theme I Building materials That theme mainly deals with heat and mass flow properties, their measurement and their interaction with flow governing potentials.
... construction. Some even advance 100% as an objective and propose the zero house as the final ... more ... construction. Some even advance 100% as an objective and propose the zero house as the final goal. Zero indicates that only renewable energy is consumed for heating (and cooling), hot water production and household. This ...
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