https://doi.org/10.6110/KJACR.2025.37.10.461

Won-Jong Lee ; Kyung Jin Bae ; Oh Kyung Kwon

In industrial processes that recover waste heat for energy reuse, the heat source is often polluted air. When the surface temperature drops below the dew point, condensate can form during the heat recovery process. Pillow-plate heat exchangers are advantageous due to their high resistance to fouling, easy maintenance, and excellent heat transfer performance, as they facilitate heat exchange between two fluids through a single plate rather than an extended surface. Their straightforward design also promotes efficient condensate drainage. Despite numerous experimental studies on pillow-plate heat exchangers, research evaluating their performance in hot and humid conditions is still scarce. This study presents an experimental setup designed to assess the performance of a pillow-plate heat exchanger under such conditions, analyzing heat transfer performance across various operating scenarios. When varying the parameters on the water side, the heat transfer rate changed by approximately 10?20%. In contrast, altering the parameters on the air side resulted in changes of about 25?60%. Overall, it was found that the influence of air-side parameters was approximately 28.2% greater within the tested range. Notably, the heat transfer rate showed significant sensitivity to changes in parameters that affect the absolute humidity of the air.

https://doi.org/10.6110/KJACR.2025.37.10.469

Haneul Choi ; Seolyee Han ; Gwangwoo Han ; Dongeun Jung ; San Jin ; Jonghun Kim

This study investigates the potential implementation of Grid-Interactive Efficient Buildings (GEBs) in South Korea by analyzing four key regulatory frameworks: the Standard for Building Energy Saving, the Standard for Building Energy Saving Green Homes, the Zero Energy Building Certification, and the Green Building Certification. These frameworks were assessed based on their support for four core GEB strategies: data collection and monitoring, integration of distributed energy resources (DER), demand flexibility control, and grid interactivity. The findings indicate that while data monitoring and DER installation are adequately addressed, provisions for demand flexibility and grid connectivity are limited. Notably, the standards for building energy management systems offer a foundational mechanism for enabling GEB functionality and future institutional development. The study concludes that GEB capabilities can be gradually integrated into the existing prescriptive framework and highlights the importance of developing performance-based metrics and simulation tools for quantitative evaluation and long-term implementation of GEB strategies.

https://doi.org/10.6110/KJACR.2025.37.10.480

Jin Man Kim

This study proposes a heat pump-based Pre-Conditioned Air (PCA) system as an alternative to the Auxiliary Power Unit (APU), which emits a significant amount of CO₂ during aircraft ground operations. We designed a series of four single-stage compression heat pump modules and evaluated various HydroFluoroOlefin (HFO) refrigerants. R1234ze(E) was selected as the most suitable refrigerant based on both the Coefficient of Performance (COP) and the maximum pressure ratio of the system. Additionally, we analyzed the performance of the designed heat pump cycle using 10 years of weather data from Incheon International Airport. As a result, we confirmed that the designed heat pump system could reduce CO₂ emissions by up to 62% compared to the conventional APU system, demonstrating the technical and environmental feasibility of the PCA heat pump system.

https://doi.org/10.6110/KJACR.2025.37.10.488

Sang-Jin Park ; Hyojik Lee ; Seungnam Yu ; Eui Kwang Jeong

Heating, Ventilation, and Air Conditioning (HVAC) systems are typically viewed as secondary maintenance targets because their failures usually result in only temporary discomfort and inconvenience for indoor workers, rather than causing facility damage or safety hazards. However, in nuclear fuel cycle facilities, HVAC systems function as containment systems to isolate radioactive materials, making them essential for facility safety. Among these systems, the air-supply and exhaust fans are the most critical components for maintaining negative pressure conditions, as their reliability directly affects overall facility safety. Therefore, implementing Fault Detection and Diagnosis (FDD) and Condition-Based Maintenance (CBM) for these fans is crucial to enhancing the safety and reliability of the facility. This study conducted a vibration-based diagnosis of the air-supply and exhaust fans in a domestic nuclear fuel cycle facility to assess the overall integrity of the fan system, which includes an impeller, bearings, pulleys, belts, and a motor. The results showed that the vibration-based FDD method effectively detects high vibrations, identifies failure types, and pinpoints faulty components. Considering the increasing demand for safety enhancements in nuclear fuel cycle facilities and the growing importance of CBM for their HVAC systems, adopting vibration-based CBM technology for air-supply and exhaust fans is expected to further improve facility safety. Additionally, transitioning from a breakdown maintenance approach to a CBM-based proactive strategy is anticipated to enhance the efficiency of nuclear fuel cycle facility management.

https://doi.org/10.6110/KJACR.2025.37.10.497

Minjong Kim ; Jumi Baek ; Dong Hee Yoon ; Doosam Song

This study introduces an optimized mobile-based Scan-to-BIM workflow designed to address the increasing demand for energy-efficient retrofitting of aging buildings. Traditional Scan-to-BIM methods often face challenges related to high costs and lengthy processing times, which restrict their practical application. In contrast, mobile LiDAR technology presents a more accessible and time-efficient solution. Field experiments were conducted at two renovation sites?a public health center and a community welfare facility?utilizing three iOS-based 3D scanning applications: 3D Scanner App™, RTAB-Map, and Polycam. These applications were evaluated based on point cloud quality, noise levels, registration performance, and 2D drawing accuracy. Among the applications, RTAB-Map yielded the most stable and geometrically accurate point clouds with minimal noise artifacts. In terms of processing speed, uBuilder excelled due to its simplified alignment algorithm. Drawing accuracy was measured using Mean Bias Error (MBE) and the Coefficient of Variation of the Root Mean Square Error (CVRMSE), both of which satisfied the monthly performance criteria outlined in ASHRAE Guideline 14. After a comprehensive assessment of accuracy and efficiency, the combination of RTAB-Map and uBuilder emerged as the optimal configuration. These findings offer valuable insights into the implementation of mobile Scan-to-BIM for digital documentation, thereby promoting sustainable renovation practices within the building sector.