Mobile QR Code QR CODE : Korean Journal of Air-Conditioning and Refrigeration Engineering
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
  • ISSN : 1229-6422 (Print)
  • ISSN : 2465-7611 (Online)

열회수형 환기장치의 타입별 By-pass 제어에 따른에너지 최적 운영 방안에 관한 연구 Energy Saving Optimal Operation Strategy for By-pass Control by Various Types of Energy Recovery Ventilator

https://doi.org/10.6110/KJACR.2020.32.7.309

Chul Ho Kim ; Won Hee Kang ; Min Kyeong Park ; Kwang Ho Lee ; Kang Soo Kim

Energy use by buildings accounts for about 36% of the overall energy consumptions. Energy recovery ventilator (ERV) system help to offer optimal solutions.: fresh air, better climate control, and energy efficiency. However, when outdoor air conditions are favorable to the control of the indoor environment, such as in spring and autumn in Korea, heat exchange in ERV increases energy consumption instead of decreasing it. When the heat exchange is unnecessary, there is a need for using by-pass control, which directly induces outdoor air without passing through a heat exchanging device. Therefore, this study was carried out with simulations using EnergyPlus v.9.3.0 for the various types of ERV with by-pass controls. From the result of simulations for the proper operating control method of ERV, it was found that using heat-exchange mode in the heating season and using bypass mode in both the intermediate season and a part of cooling season provided the largest energy savings. The results also showed that adopting this method in weather conditions in Incheon saved 15.3~20.4% energy as compared to using a VAV system. Also, the results show by-pass time ratio in the intermediate season is higher than those of partial cooling season and heating season.

주거용 건축물의 열교환환기장치 TAB 전후 에너지 성능 비교 분석 및 실태조사 Building Energy Performances of Pre/Post TAB Practices for Heat Recovery Ventilation Systems in Residential Buildings and its On-site Surveys

https://doi.org/10.6110/KJACR.2020.32.7.323

Dong Jun Kim ; Taeryong Kim ; Jongil Park ; Jeong-Hun Lee

This study confirmed the necessity of a TAB (testing, adjusting, and balancing) practice for a ventilation system in residential buildings. Sixty small-scale buildings installed with heat recovery ventilation systems were selected to investigate the building energy performances of pre/post TAB practices for the heat recovery ventilation systems. The results of the pre and post TAB practices are as follow. Before the TAB practices, buildings under the positive air pressure showed 23.3% difference of the amount of air supply on average; those under the negative air pressure at 26.8%. TAB practices can reduce the cooling energy demand by up to 15%, on average 1%, and heating energy demand by up to 34%, on average 5%.

CFD 시뮬레이션을 이용한 모듈형 지중열교환기의 성능 인자 검토 Study on the Performance Factor of the Modular Ground Heat Exchanger Using CFD Simulation

https://doi.org/10.6110/KJACR.2020.32.7.334

Kwon Ye Kim ; Jae Min Kim ; Yujin Nam

Recently, as a measure for global warming, zero energy building has become a major issue as a means of conserving energy and reducing carbon emission in the building. In this situation, the focus on renewable energy systems has intensified as well as ongoing technology development. Especially, the ground source heat pump system (GSHP) attains high efficiency by using the annual stable ground temperature. However, it is difficult to introduce it in small-scale buildings because of initial investment costs, such as excavation costs and the installation of the GSHP. In this study, the performance factors of the low-depth modular heat exchanger were reviewed for the development of the ground heat exchanger that is relatively inexpensive and can respond to small-scale buildings compared to the vertical type ground heat exchanger. Assuming an underground heat exchanger is installed in the ground, an analytical model was built and the circulating water temperature was calculated by using the CFD program. Additionally, to find out the factors affecting the performance of the low-depth ground heat exchanger, the prediction of heat exchange rate was performed.

지하주차장의 배연설비 방법 비교 연구 A Comparison Study on Methods of Smoke Exhaust System of Underground Parking Lots

https://doi.org/10.6110/KJACR.2020.32.7.340

Byung Hyun Lee ; Dong Wan Kim ; Kyung Hee Lee

In this study, three methods of the smoke exhaust system were set and analyzed to analyze the smoke exhaust performance. Case 1 : Method of the natural supply/natural exhaust, Case 2 : Method of using the supply fan/ventilation fan/exhaust fan, Case 3 : Method of using the supply fan/roof fan/supply fan. The analytical element was measured by measuring the visibility and the smoke concentration. The analysis results of the smoke exhaust performance were analyzed under the best conditions in Case 3 of the visibility and the smoke concentration. It is posited that it can be presented as an alternative when applying the smoke exhaust system.

후면 환기형 BIPV 시스템의 레이놀즈수에 따른 전력 및 열성능 특성에 관한 해석적 연구 Analytical Study on Electrical and Thermal Performance Characteristic of Back Side Ventilating Type BIPV Systems with Reynolds Number

https://doi.org/10.6110/KJACR.2020.32.7.348

Jun Un Park ; Hang Suk Suh ; Sung Joo Lee ; Yun Shic Choi

The purpose of this study was to analyze the electrical and thermal characteristics of the various types of ventilating BIPV systems. Compared with the conventional top and down block off type, the top and down open BIPV system using natural stack effect and mechanical ventilating type has potential to improve the conventional block off type BIPV systems’ in-site various problems like PV cell high temperature. These kinds of conventional block off BIPV have low efficiency power production and shut-off at the junction box for high humidity ratio environment condition. Hence, it is critical to compare the PV cell temperature, efficiency, and power production between the mechanical ventilating type BIPV and the conventional block off and natural ventilating type BIPV system. For this purpose, the IPMVP OPTION D analytical program TRNSYS and the type 567 model based on the Sandia model were used and the PV cell temperature, PV electricity efficiency, and BIPV system useful energy rate were estimated with different Reynolds number cases, such as the natural ventilation and the forced mechanical ventilation flow. As for results, first at the BIPV electrical point of view, the Reynolds number increasing led to lower PV cell temperature, higher PV efficiency, and higher PV power production. Especially, the maximum BIPV cell temperature occurred at 12 am on October 3. At that time, at each case-1 (Reynolds number 0) and case-9 (Reynolds number 30,304), the respective PV cell temperature value showed 67.6℃ and 36.3℃, respectively, and the corresponding PV efficiency indicated 8.0% and 12.3%, respectively. The individual PV production power value marks were 59.5 kW and 91.9 kW. Second, at the PV thermal view point, increasing Reynolds number induces more annually BIPV building heating useful energy. Particularly at each case-1 (Reynolds number 0) and case-9 (Reynolds number 30,304), the respective BIPV building heating useful energy showed 0 kWh/yr and 7,514 kWh/yr.