scholarly journals Empirical Validation of Heat Transfer Performance Simulation of Graphite/PCM Concrete Materials for Thermally Activated Building System

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Jin-Hee Song ◽  
Hye-Sun Jin ◽  
Su-Gwang Jeong ◽  
Sumin Kim ◽  
Seung-Yeong Song ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Behavior ◽  
Three Dimensional ◽  
Construction Materials ◽  
Empirical Validation ◽  
Efficient Technology ◽  
Dynamic Simulations ◽  
Thermally Activated ◽  
Hollow Core Slab ◽  
Building System

To increase the heat capacity in lightweight construction materials, a phase change material (PCM) can be introduced to building elements. A thermally activated building system (TABS) with graphite/PCM concrete hollow core slab is suggested as an energy-efficient technology to shift and reduce the peak thermal load in buildings. An evaluation of heat storage and dissipation characteristics of TABS in graphite/PCM concrete has been conducted using dynamic simulations, but empirical validation is necessary to acceptably predict the thermal behavior of graphite/PCM concrete. This study aimed to validate the thermal behavior of graphite/PCM concrete through a three-dimensional transient heat transfer simulation. The simulation results were compared to experimental results from previous studies of concrete and graphite/PCM concrete. The overall thermal behavior for both materials was found to be similar to experiment results. Limitations in the simulation modeling, which included determination of the indoor heat transfer coefficient, assumption of constant thermal conductivity with temperature, and assumption of specimen homogeneity, led to slight differences between the measured and simulated results.

Investigation the influence of spacer yarns orientation angle on the thermal behavior of 3D textile reinforced concrete (TRC)

2021 ◽  
pp. 095440622110473
Author(s):  
Sayyed Behzad Abdellahi ◽  
Sayyed Mahdi Hejazi ◽  
Hossein Hasani
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Finite Element ◽  
Reinforced Concrete ◽  
Thermal Behavior ◽  
Three Dimensional ◽  
Orientation Angle ◽  
Element Model ◽  
Textile Reinforced Concrete ◽  
Cementitious Matrix

Thermal behavior such as heat transfer is an important parameter for construction composites. Three-dimensional textile reinforced concrete (TRC) is one of the construction composites which is recently being used in the building industry. Therefore, in this study, the thermal behavior of three different TRC samples was investigated by a heat transfer test using an infrared method. The cementitious matrix was reinforced by 3D fabric with three different spacer yarn orientation angles. The cementitious matrix was fabricated by cement and waste stone powder. The TRC sample was put on the hot plate of the heat transfer apparatus and the temperature variations of the top surface of the sample were obtained. According to the test results, increasing the orientation angle of spacer yarns leads to a decrease in the thermal conductivity of the TRC sample and reduces heat transfer. On the other hand, a theoretical model was used to calculate the thermal conductivity and resistance coefficients of sandwich samples. Furthermore, a 3D finite element model was used to predict the heat transfer of TRC specimens. A unit cell of the TRC model was created in Abaqus software and finite element (FE) analysis was carried on a created model. Thermal conductivity and thermal resistance of samples according to FE results were calculated and compared with experimental results. FE results showed good agreement with the experimental data.

3D Numerical Simulation of the Transient Thermal Behavior of a Simplified Building Envelope Under External Flow

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
F. Barmpas ◽  
D. Bouris ◽  
N. Moussiopoulos
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Thermal Behavior ◽  
Temperature Variation ◽  
Building Materials ◽  
Three Dimensional ◽  
External Flow ◽  
Building Envelope ◽  
Simulation Software ◽  
Parametric Studies

Understanding building envelope performance and thermal mass effects is becoming increasingly important under the scope of low energy building construction and energy conservation. In the present paper, a three-dimensional computational fluid dynamics methodology is presented for the numerical simulation of the flow and heat transfer that determine the thermal behavior of simplified building envelopes. This is dominated by a conjugate heat transfer approach, which involves conduction, convection, solar heat gains, ambient temperature variation, and the effects of thermal radiation losses to the sky. Validation results include comparison both with measurements from fundamental laboratory studies of heat transfer from surface mounted cubes and with numerical results from well established commercial building energy simulation software. Numerical issues, such as temporal and spatial discretization, are addressed, and parametric studies are performed with regard to the effect of external flow Reynolds number and temperature variation in the building envelope, depending on the individual orientation of the external walls with respect to the flow and on the thermal properties of the building materials. Results from the parametric studies performed indicate that the transient three-dimensional calculations provide important information regarding the effect of external flow properties, such as the approaching flow temperature, velocity, and direction on the thermal behavior of the building envelope. In addition, it has been clearly demonstrated that the methodology is also capable of taking into account the complex effects of parameters such as the building material properties.

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