https://doi.org/10.6110/KJACR.2024.36.7.325

Joo Yeon Roh ; Won Seok Lee ; Se Jin Lee ; Myoung Souk Yeo

This study investigates the connection between airtightness performance and differential pressure when converting general hospital wards into temporary negative pressure isolation rooms using portable HEPA filter units. The CONTAM simulation model was used to analyze a specific medical facility, conducting sensitivity and uncertainty analyses to identify key factors in the building's envelope components and estimate pressure differentials after improvements. The findings show that exterior walls, plenum inner walls, room ceilings, and ward doors are crucial in establishing the initial differential pressure. By reducing leakage areas in these components, the required volume flow rate of the portable HEPA filter units can be decreased by approximately 30% to maintain the necessary pressure standards of -2.5 ㎩. This study offers vital data for the design and operation of temporary negative pressure isolation facilities, emphasizing the need for further comprehensive evaluations.

https://doi.org/10.6110/KJACR.2024.36.7.332

Huijing Yan ; So Min Park ; Doo Sam Song

This study examined the errors in energy performance analysis results when using a similar building's usage profile for buildings without usage profiles in the domestic building energy analysis program, ECO2. Specifically, the analysis applies the existing ECO2 profiles for elementary school classrooms when targeting facilities like daycare center classrooms, where usage profiles are missing due to recent government-led green remodeling. However, in this study, the analysis of two daycare centers (A, B) revealed significant errors of 18% and 24% respectively when compared to actual energy consumption. To address this issue, specialized usage profiles for daycare center classrooms were developed based on long-term measurements from 20 daycare centers in Gyeonggi Province. When these newly developed profiles were applied, the errors between actual energy consumption and predictions for daycare centers A and B were reduced to 13% and 6% respectively.

https://doi.org/10.6110/KJACR.2024.36.7.342

Seung Hwan Park ; Hyery Shin ; Gyoung Seok Choi ; Yu Min Kim

This study analyzed national R&D projects to gain insights into the present state of core technologies and practical implementation strategies. In the field of passive technology, the development of windows and exterior insulation materials plays a significant role. The average level of insulation technology stands at 0.179 W/m2K, while the average window technology level is 0.967 W/m2K. Building Energy Management Systems (BEMS) make up 32% of the active technology sector. Although there has been insufficient progress in the development of high-efficiency heat pumps, their efficiency has steadily increased from 3.1 COP in 2010 to 4.42 COP in 2023, indicating promising advancements in the future. Clean energy technologies, especially solar power, hold the largest market share, while hydrogen energy requires further technological development. Green remodeling technologies account for approximately 52% of the non-residential sector and only 3.7% of the mid-rise residential buildings sector due to various procedural and permitting issues. With recent expansion of government support from public to private buildings, green remodeling of low-rise residential buildings is rapidly on the rise. As a decarbonization strategy, there is a high demand for new renewable energy sources and the development of high-efficiency heat pump technology. Given the widespread aging of buildings in the domestic environment, green remodeling emerges as the most urgent need for enhancing building energy efficiency.

https://doi.org/10.6110/KJACR.2024.36.7.357

Chi Kwang Kim ; Jeong Soo Park ; Min Chan Park ; Jae Keun Lee ; Young Chull Ahn

The underground subway stations are open spaces that are not separated from the outside. As a result, the energy consumption for cooling is high. Therefore, it is necessary to reduce the latent heat load of the supplied air and decrease energy consumption by utilizing discarded unused energy. In this study, a heat-pump based liquid desiccant system was developed. This system can be implemented in conjunction with a turbo chiller that is already installed in an existing subway station. A demonstration system was installed at the Minam station in Busan to investigate the removal of latent heat load and the recovery rate of unused energy. The results of the demonstration facility installed at Busan Minam subway station, with the existing chiller, show a COP of 6.83, a dehumidification rate of 18.60kg/h, and a heat recovery rate of 88.9%.

https://doi.org/10.6110/KJACR.2024.36.7.366

Neul Ha ; Yoong Chung ; Jinwoo Yoo ; Sangho Sohn ; Chan Ho Song ; Jungchul Kim

Recently, the industry has witnessed a widespread development of environmentally friendly heat pump systems. These systems primarily utilize new refrigerants with a low Global Warming Potential (GWP), which tend to be more expensive. Particularly in large-scale systems, falling film evaporators have garnered increasing attention due to their ability to reduce the required amount of refrigerant compared to flooded evaporators. In this study, we investigated the performance of a falling film evaporator using one of these low GWP refrigerants, R-1234ze(E), under various operating conditions. We installed an experimental set-up for an 8 kW nominal capacity falling film evaporator. We considered three parameters as variables: inlet water temperature, inlet mass flow rate, and refrigerant saturation temperature. To determine the convective heat transfer coefficient on the refrigerant side, we employed the Wilson plot method.