Conference Agenda

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Session Overview
Poster introductions 12: Heat and moisture transfer - experimental
Thursday, 26/Aug/2021:
11:15am - 11:35am

Session Chair: Prof. Hans Janssen, KU Leuven
Location: Room 1 - Room 082, Building: 116

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11:15am - 11:18am

Thermal insulation of autoclaved materials

Jerzy Zbigniew Piotrowski, Anna Stepien

Kielce University of Technology, Poland

The construction industry relies on the production of building materials, which are created as a result of particular actions of binding materials widely used in construction, and directly condition the quality of life of a society. Malolepszy wrote: “knowledge of building materials is our common good and should not confine to narrow circle of specialists”. Following these thesis, one should create possibilities of conscious choice and use of building materials not only among scientists and constructors, but among the whole society. Two types of additives are used in building materials: additives with a crystalline structure (SiO2) and additives with an amorphous structure (fly ash), which affects the properties and durability of materials.

In the last decade industry is also moved on the fight against global warming and overproduction of materials. In May 2019, the level of CO2 concentration in the atmosphere exceeded 415ppm, which was the highest result in the last 50 years. Overproduction is, in turn, associated with the excessive use of natural resources (SiO2) and since 2010 there has been talk of the “sand deficit”. One way to combat overproduction is to use and promote recycling to avoid excess waste. The article describes the method of managing recycled glass sand in autoclaved materials and checking their thermal properties. This study describes the relationship between the physical (thermal isolation), mechanical and microstructural properties of autoclaved materials which undergone hydrothermal treatment and consist of lime (7%) and were modified through the introduction of glass components (up to 90%). For this modification, a certain amount of crystalline SiO2 was replaced with amorphous glass sand. Hydrated calcium silicates are formed in building materials (CaO-SiO2-H2O). Process parameters (temperature, pressure) were found to have a significant impact on the series of chemical reactions as well as on the formation and transformation of solid hydrates.

11:18am - 11:21am

Experimental study of hygrothermal conditions in a wooden room for numerical comparisons

Clemence Legros1,2, Amandine Piot1, Monika Woloszyn2, Mickael Pailha2

1University of Grenoble Alps, CEA, LITEN, INES, Grenoble, France; 2University of Savoie Mont Blanc, CNRS, LOCIE, Chambéry, France

The use of hygroscopic materials indoors has a significant impact on the hygrothermal balance of a room air. It affects both the temperature and the relative humidity. Numerical tools still lack of accuracy in predicting these parameters and some discrepancies are observed between their predictions and experimental measurements. It may be caused by the model itself or by incorrect inputs data (materials properties, occupancy schedule, ventilation rate, etc…) Therefore, an experimental study has been carried out at the room scale under real climate to obtain an experimental dataset as a basis for numerical comparisons. The hygrothermal parameters of the room air have been measured for different loads while all the inputs (heat and moisture generation, air exchange and materials properties) have been properly quantified. This article presents the experimental setup and some of the experimental data obtained.

11:21am - 11:24am

Laboratory observation of interior surface heat transfer at balcony door

Jan Tywoniak, Kamil Staněk, Martin Kny, Daniel Adamovsky

Czech Technical University in Prague, Czech Republic

This paper is focused on heat transfer phenomena at window surfaces and at adjacent areas of the building envelopes with extra attention to energy optimized buildings. Low-energy and passive buildings are characterized by reduced heat losses and consequently modified energy distribution in rooms. Therefore, the principal research question is whether it is still correct to use the usual standard values of surface heat transfer on the interior side and how is the relation of convective and radiation part of it. After a field observations and a first experiments (already published) a set of other full-scale experiments was performed in laboratory, in the well-insulated testing space representing a typical room in a dwelling. It was equipped with one triple glazed balcony door. The air temperature outside the testing space corresponds to winter conditions. In the interior, the floor heating and warm air heating was alternatively applied. In the first step, in the opening in the envelope an opaque panel without extra frame (the simplest possible geometry) having similar thermal transmittance as the triple glazed balcony door was installed and studied for reference. A combination of infrared imaging (IR) and particle imaging velocimetry (PIV) was used here to study the situation near to surfaces in detail. A situation without any obstacles at interior side and with a curtain fully covering the area of balcony door was observed. From the measured data the surface heat transfer coefficient along the height of the room was evaluated. In the next step a real balcony door was installed and measurement repeated. Paper will summarize the results and bring some recommendation about use of this coefficient as well as an input for the discussion if the surface condensation is automatically eliminated due to installation of windows with passive house qualities.

11:24am - 11:27am

Optimal Density for Balancing the Thermal Conductivity and Compressive Strength of Foamed Ceramic

Yue Lei1, Xing Zheng1, Mei Dou2, Lihong Zheng2, Mingfang Tang1, Chi Feng1

1School of Architecture and Urban Planning, Chongqing University, Chongqing, PR China; 2China Southwest Architectural Design and Research Institute Corp. Ltd, Chengdu , Sichuan, PR China

Abstract. Foamed ceramic becomes increasingly popular in building engineering due to its thermal, acoustic and other advantages. However, conflicts often exist between its different properties. In this paper, we seek a balance between the thermal conductivity and the compressive strength of foamed ceramic. Experiments are performed on foamed ceramic with different densities. Nonlinear regression is then adopted to quantify the relationship between the thermal conductivity/compressive strength and the bulk density. The results indicate that both the thermal conductivity and the compressive strength increase with the rising density. Based on the requirements in the Chinese national standard, the optimum density range of foamed ceramic is proposed, satisfying a balance between the thermal and mechanical performance.

11:27am - 11:30am

The effect of rising damp on heat transfer performance and energy consumption of two kinds of Chinese blue-brick masonry walls

Zhen-yi Kong1, Hua-rong Xie1, Yi-ke Cai1, Xue Tan1, Shuichi Hokoi1, Yong-hui Li1,2

1School of Architecture, Southeast University; 2Key Laboratory of Urban and Architectural Heritage Conservation of Ministry of Education (Southeast University)

Rising damp is common in brick buildings due to groundwater and natural precipitation, which not only causes deterioration of the walls, but also significantly affects the heat transfer coefficient, thermal inertia, and building energy consumption. In order to clarify the effects of rising damp on the heat transfer through traditional Chinese brick solid wall and cavity walls, two types of wall of 1 m wide and 3 m high were built in the laboratory. The heat transfer performance under the influence of capillary rising was tested by heat flow meter method. Based on the data obtained from the experiment, the Energyplus was used to simulate the energy consumption of a Chinese typical residential building influenced by rising damp. The results proposed 3.67 W/m²·K and 3.61 W/m²·K as the recommended heat transfer coefficient for the moisture affected parts in the experimental solid and cavity wall, and the rising capillary water increased the heat transfer coefficients by 74% and 84% respectively. The heating and cooling load of the solid-wall building under the influence of capillary water increased by 18.5% and 29.6%, respectively, while of cavity-walls building increased by 6.5% and 11.8%.

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