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Korean Journal of Air-Conditioning and Refrigeration Engineering

Korean Journal of Air-Conditioning and Refrigeration Engineering

ISO Journal TitleKorean J. Air-Cond. Refrig. Eng.
  • Open Access, Monthly
Open Access Monthly
  • ISSN : 1229-6422 (Print)
  • ISSN : 2465-7611 (Online)

Korean Journal of Air-Conditioning
and Refrigeration Engineering

A journal devoted to investigations of HVAC and building technologies in various climatic conditions

• Editors-in-Chief: Yun, Rin

ECO2에서 자연채광에 따른 Dimming-control의 에너지 절감 효과 표현 방법 Calculation Method of Energy Saving effect for Dimming-control according to Day-lighting in ECO2

https://doi.org/10.6110/KJACR.2024.36.6.271

Jae Woo Yoon ; So Min Park ; Ji Soo Shim ; Doo Sam Song

The objective of this research was to devise a methodology for quantifying the lighting energy conservation benefits afforded by dimming controls in daylight-responsive buildings, utilizing the ECO2 program. Initially, the influx of natural light into the designated area was quantified via RELUX simulation, allowing for the tailoring of artificial lighting levels at each location to correspond with the fluctuating density of daylight across different seasons and times of day. Through employing varying proportions of natural illumination during both clear and overcast conditions throughout the year, the artificial lighting intensity was accordingly modulated. Upon implemention of this approach, the maximum achievable lighting energy efficiency through dimming control was identified to be 58.6%. Furthermore, correction coefficients for the established ECO2 lighting intensity were determined by comparing the lighting intensities with and without the implementation of dimming control. Hence, by integrating these calibrated lighting intensities that account for dimming controls into daylighting environments, the energy-saving potential can be effectively depicted in ECO2.

CFD에 기반한 벽체형 공기식 BIPVT의 열 및 전기 효율 분석 Numerical Study of Wall-Type Air-Based Building Integrated Photovoltaic-Thermal System on Thermal and Electrical Efficiency

https://doi.org/10.6110/KJACR.2024.36.6.281

Hobyung Chae ; Sangmu Bae ; Jinhwan Oh ; Yujin Nam

This paper provides foundational research into enhancing a building-integrated photovoltaic/thermal (BIPVT) system, focusing on predicting performance by examining the configuration of heat exchangers and flow rates in an air-based BIPVT system. Numerical analysis software (Ansys Fluent) was employed to calculate heat gain and PV efficiency under defined conditions: insulated sides of the BIPVT, a steady back panel temperature aligned with the building wall temperature (25℃), and maximal solar irradiance (1,000 W/m2) in steady-state scenarios. The findings indicate that PV cell temperature increases with greater internal fin spacing of heat exchangers and decreased flow rate. Conversely, the outlet temperature decreases with an increased flow rate. The efficiency of the PV system varied between 10.5% and 12.2%, with heat gain values ranging from 54.4 to 254.4 W/m². The pressure loss within the system ranged from approximately 3.9 to 27.8 Pa across a flow rate spectrum of 0.2 to 0.9 kg/s, demonstrating a linear increase with the flow rate. Additionally, variations in pressure loss based on fin spacing resulted in a reduction of approximately 67.3% in Case 2 and 48.0% in Case 3 compared to Case 1.

양방향 열거래를 위한 허브축열시스템의 냉/난방기간 실증운영결과 분석 Analysis of Empirical Operation Results of Cooling/Heating season of Hub Thermal Energy Storage for Bidirectional Heat trading

https://doi.org/10.6110/KJACR.2024.36.6.289

Deukwon Kim ; Dongwon Lee ; Minhwi Kim ; Jaehyeok Heo ; Joon Heo ; Kyoungchon Min

The imperative of climate change calls for carbon reduction throughout diverse sectors, and within the HVAC industry, leveraging renewable energy emerges as a pivotal strategy for carbon mitigation. The heat pump(HP) system stands out as an advanced technology for the efficient exploitation of renewable energy, having attained significant technological sophistication and being adopted for a wide range of applications. This investigation embarked on empirical research aimed at augmenting the effective deployment of HP systems, with a special emphasis on the heat pump integrated with thermal energy storage (HP-TES). A novel hub thermal energy storage(hub TES) framework, facilitating bidirectional heat exchange and optimizing the use of the HP system, was developed and empirically assessed. Employing a hub TES system of 400-ton capacity situated in Busan Myeongji International City resulted in operational cost savings of approximately 18.5% when juxtaposed with conventional central heating supply systems. The introduction of the hub TES system, underpinning bidirectional heat trading, effectively mitigated the fluctuating nature of renewable energy sources by catering to diverse thermal demands. Furthermore, the study verified the dual benefits of enhanced heat supply stability and reduced operational costs through the communal utilization of thermal infrastructure.

다중열원 축열조 연계 히트펌프 시스템의 성능예측을 위한 축열조 모델 개발 Development of a Thermal Energy Storage Model for Performance Prediction of Heat Pump Systems Linked with Multiple Heat Sources

https://doi.org/10.6110/KJACR.2024.36.6.300

Soowon Chae ; Yujin Nam

This investigation delves into the formulation of a Thermal Energy Storage (TES) system, which is intricately integrated with a multi-source heat pump, aiming at the optimization of renewable energy utilization within building infrastructures. By juxtaposing one-dimensional (1D) and two-dimensional (2D) TES models, this study endeavors to mitigate the inefficiencies engendered by the intermittency inherent in renewable energy sources. The analysis elucidates that the 2D TES model markedly surpasses the 1D variant in faithfully rendering the storage and transference of thermal energy, resulting in pronounced enhancements in both heating and cooling efficiencies across diverse operating conditions. Noteworthy outcomes underscore that the 2D model facilitates up to approximately 4.5% more heating efficiency and 7.6% improved cooling efficiency compared to the 1D model, underlining its prowess in optimizing energy consumption and curtailing operational cycles. This superiority is ascribed to the 2D model’s comprehensive examination of heat transfer phenomena, encompassing a refined depiction of transverse temperature gradients, crucial for bolstering TES system efficacy. Moreover, the exposition emphasizes the role of the 2D TES model in advancing sustainable development objectives through its enabling of more effective integration of renewable energy into edifice energy schematics. This scrutiny not only propels the domain of energy efficiency forward but also proffers pragmatic methodologies for the design and management of energy-conserving buildings, directing us towards a more sustainable horizon.

설비공학 분야별 최근 연구 동향:2023년 설비공학논문집 발표논문에 대한 종합적 고찰 A Review of the Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2023

https://doi.org/10.6110/KJACR.2024.36.6.310

Joon Ahn ; Dong-Seon Kim ; Sumin Kim ; Hyun Jung Kim ; Yujin Nam ; Youn Cheol Park ; Young-Jin Baik ; Kwang Ho Lee ; Jae-Weon Jeong ; Jinkyun Cho ; Honghyun Cho

This article offers a comprehensive overview of the latest research findings in the realms of heating, cooling, ventilation, sanitation, and building and plant indoor environments. It does so through a thorough examination of articles published in the Korean Journal of Air-Conditioning and Refrigeration Engineering over the course of 2023. Below is a summarised outline of the papers that were reviewed. (1) The range of topics scrutinised in the domain of building mechanical systems extends to general building energy facilities, the energy efficiency within HVAC systems, and pertinent health and safety considerations. (2) The sphere of indoor environment research encompasses a wide array of subjects, including IAQ (Indoor Air Quality), ventilation strategies, air purification techniques, calculations of cooling and heating loads, adoption of renewable energy sources, considerations for medical facilities, and fire safety measures. (3) In the realm of refrigeration, studies have delved into evaluative analyses of thermal comfort inside vehicles via numerical methods as well as the design of absorber heat exchangers for absorption refrigeration systems. (4) The research interests within heat transfer and thermo-fluid engineering spanned methodologies for bolstering heat transfer through boiling and condensation, examination of fouling characteristics in HVAC heat exchangers, optimisation of geothermal heat pump controls, analysis of flow distribution within printed circuit heat exchangers, and the consequences of fouling on the performance of fin-tube heat exchangers.