https://doi.org/10.6110/KJACR.2023.35.5.215

Yeonju Kang ; Sangmu Bae ; Hobyung Chae ; Yujin Nam

To achieve the national carbon-neutral target, carbon reduction in the building sector is essential, and environmental impact assessments of hybrid systems such as photovoltaic and geothermal systems are required. Therefore, in this study, carbon emissions were calculated based on the life cycle evaluation method to understand the environmental load during the entire life cycle of the photovoltaic-geothermal hybrid system. The carbon emissions of the major equipment used in the target system were evaluated by dividing them into four stages: production, construction, operation, and disposal. In the single system (geothermal) and the hybrid system (photovoltaic-geothermal), carbon dioxide emissions increased during the production and construction stages, but due to the power generated from the PVT, an energy-saving effect of about 10% was observed in the operation stage.

https://doi.org/10.6110/KJACR.2023.35.5.224

Sang Moo Woo ; Hae Eun Song ; Yul Ho Kang ; Young Chull Ahn

This study investigated the influence of the operating conditions on an air purifier and extra FAN efficiency in reducing particulate matter in a classrooms. Computational fluid dynamics (CFD) simulation considering three locations of Air purifiers and operating conditions of four FANs was conducted to evaluate the optimal operating condition. In this study, the Clean Air Delivery Rate (CADR) of Air purifier was 2.4 m3/min (161.4 CMH) and 4.8 m3/min(322.8 CMH). Assuming the indoor particulate concentration is 150 μg/m3, the performance of reducing particle concentration varies by a maximum of 31.2% depending on the position of the air purifier and the operating condition of the FAN. When the CADR of the air purifier is low, particulate matter reduction performance can be improved by a FAN. When using the FAN, make sure that it does not interfere with the airflow of the air purifier.

https://doi.org/10.6110/KJACR.2023.35.5.235

Sungwoong Yang ; Young Uk Kim ; Sumin Kim

The goal of this study was to develop and evaluate building finishing materials with excellent thermal and flame retardant performances using eco-friendly materials such as hwangtoh and biochar. The hwangtoh binder without biochar was found to have better thermal insulation performance than gypsum and higher heat storage than concrete. . The use of rice hull biochar was the most effective approach for weight reduction, and when 10% of the maximum weight was mixed, the density decreased by 60%. The results showed that the insulation performance could be improved by lowering the biochar mixture. Heat capacity analysis results showed a small decrease after mixing bamboo biochar; however, in most cases, it showed a higher heat storage capacity compared to concrete. Flame retardant analysis results showed that when 5% of each biochar was mixed, the total heat emission was higher than that of the hwangtoh binder, and there was a possibility of more than semi-incombustible performance; however, there was no ignition. The weight loss was up to 10.5%, and no significant change was found in the structureforming strength.

https://doi.org/10.6110/KJACR.2023.35.5.244

Suyeon Bang ; Nari Yoon ; Yeonsook Heo

Double-skin facade (DSF) consists of two or more layers between which air flows. DSF can be used as a passive system by harnessing natural ventilation and preheating effect for heating, cooling, and ventilation. It can also be used with an active system either by simply alternating the passive mode with the existing active systems. Based on the capability of a DSF in providing preheated air by solar heat gains, this paper proposes a DSF-inspired solar heating system (hereinafter, the double-skin solar heating system) for integration into a building’s active system. This system warms up the air inside the DSF cavity and delivers the preheated air into an air-handling unit (AHU). We examined the architectural and material parameters of the system and analyzed the energy performance to quantify the benefit of such a system. For parametric analysis, a case study of a medium-sized office building was set up where the double-skin solar heating system was installed, and the geometry and thermal properties of the system were investigated. The parametric analysis demonstrated that the width of the double-skin solar heating system is the most influencing factor.

https://doi.org/10.6110/KJACR.2023.35.5.253

Jinkyun Cho ; Jinho Kim

n this paper, we propose a mobile negative pressure isolation room to ensure the safety of healthcare workers (HCWs) and provide rapid medical service, and analyze the performance of a ventilation system that can minimize virus cross-contamination through numerical analysis. The negative pressure isolation room uses a ventilation system with air flowing from the HCWs to the patient, a clean-contaminated zone separation, and pressure differential control applied to the anteroom/isolation room. CFD) simulation results showed that the negative pressure isolation room, which needs to maintain negative pressure, can prevent cross-infection by using a ventilation system with a rate of 6 ACH and maintaining a pressure differential of -2.5 Pa or higher with the anteroom/corridor, regardless of toilet exhaust operation. It is recommended to operate the toilet exhaust at all times to maintain the pressure differential in the existing hospital rooms. However, the independently configured mobile negative pressure isolation room operates efficiently even if the toilet exhaust fan is not in operation, making it a more energy and noise-efficient option.