Jin-Hee Song

Empirical Validation of Heat Transfer Performance Simulation of Graphite/PCM Concrete Materials for Thermally Activated 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.

Study on the Characteristics of Thermal Output and Thermal Storage in a Thermally Activated Building System with Phase Change Material

Abstract TABS (Thermally Activated Building System) has recently applied by huge commercial buildings, airports, and convention centers in Europe. TABS provides night-time thermal storage by heating or cooling. The embedded water-basedheating and cooling system uses the high thermal inertia of concrete in the building construction, in which a heating orcooling pipe is embedded. The aim of this study is to analyze the thermal storage and thermal output of TABS applied with PCM (Phase Change Material). To achieve this, prototypes of TABS and the thermal properties of various PCMs wereinvestigated. By using the simulation program Physibel Voltra 6.0 W, the thermal storage and thermal output were evaluatedaccording to a heating and cooling operation schedule. Key words Thermally activated building system(TABS, 구체축열시스템), PCM, Phase change material(상변화물질), Thermal output(방열량), Thermal storage(축열)†Corresponding author, E-mail: limit0@ewha.ac.kr 1. 서 론 콘크리트 구조체를 이용하는 구체축열 공조시스템은 배관을 콘크리트 내에 매설하여 건물 구조체를 축열

Influence of Thermal Bridges on the Insulation Performance of Curtain Wall Panel Systems

Abstrct Thermal insulation plays a key role in saving energy consumed by buildings. To obtain a high level of insulation performance, repeated thermal bridges should be minimized. These bridges may cause a substantial heat loss through the building envelope. Recently, the application of curtain walls has been rapidly increasing. However, thermal bridges frequently occur in the non-vision panel system in which the insulation materials are installed because of the numerous metal members passing through the insulation layer. The aim of this study was to analyze the influence of thermal bridges on the insulation performance of curtain wall panels in terms of the energy performance and internal surface condensation risk. A three-dimensional steady state heat transfer simulation was performed for four types of panel systems: insulation-joined metal sheet, insulation-separated metal sheet, bracket-fixed metal panel and screw-fixed metal panel. The heat loss, effective U-value, lowest internal surface temperature and lowest temperature factor of each panel system with and without thermal bridges were calculated and compared.

Characteristic of Thermal Output of Thermally Activated Building System During the Heating Operation According to FDM Analysis

T his study is focused on the evaluation of thermal output of TABS (Thermally Activated Building System). The aim of this study is to evaluate TABS in terms of the temperature difference between heating medium supply temperature () and return temperature (), thermal output and the surface temperature distribution according to the design flow rate and the design flow temperature. Through the transient heat transfer simulation using temperature calculation using Crank-Nicolson FDM using Physibel Voltra 6.0 W, the temperature difference between  and , thermal output and the surface temperature distribution of specific TABS was calculated and evaluated. The results show that specific thermal output and temperature difference at 60°C of supply water temperature were about 162 W/m 2 , 13.6°C respectively