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논문 : 정보처리 및 복합기술 ; 온실에서 방울토마토 수확작업시 작업자의 생리학적 및 생체역학적 반응 측정
선우훈 ( H. Seonwoo ),임기택 ( K. T. Lim ),김장호 ( J. H. Kim ),손현목 ( H. M. Son ),정종훈 ( J. H. Chung ) 한국농업기계학회 2011 바이오시스템공학 Vol.36 No.3
Physiological signals such as body temperature, heart rate, blood pressure and heart rate variability and biomechanical workload for stress analysis were investigated during the cherry tomato harvesting work in a greenhouse. The skin temperatures raised 0.05℃/min, 0.03℃/ min, and 0.08 ℃/min in standing, stooping and squatting postures, respectively. Breath rate significantly increased from 18 to 28 breaths/min during the cherry tomato harvesting work. As the heart rate during the work ranged from about 72 to 110 beats/min (bpm), the cherry tomato harvesting work appeared to be a light intensity task of less than 110 bpm. The worker`s average energy consumption rate in three positions during 43 min working time was 65.74 kcal (91 kcal/h in 70 kg). This was a light intensity of work, compared to 75 kcal/h in 70 kg of basic metabolic energy consumption rate of a worker with 70 kg weight; The maximum shear force on the disk (L5/ S1) due to static workload in the cherry tomato harvesting work was 446 N in the stooping posture, 321 N in the squatting posture and 287 N in the standing posture. Acute stress index expressed with the heart rate variability, increased parasympathetic activation up to about 70 while workers were doing most agricultural work in this study. This study provided a system to measure quantitatively workers` physiological change, kinematics and kinetic factors without any restrictions of space in the greenhouse works.
최경식 ( Kyeongsik Choi ),안태영 ( Taeyoung An ),선우훈 ( Hoon Seonwoo ) 한국농업기계학회 2021 한국농업기계학회 학술발표논문집 Vol.26 No.1
Most of the domestic farmers use fossil fuels as an energy source for greenhouse heating. However, fossil fuels are difficult to supply and demand reliably due to soaring international oil prices, and environmental problems such as air pollution continue to occur. Accordingly fossil fuel consumption can be reduced and there is no fear of depletion, and geothermal heat pump systems, new and renewable energy with low risk of environmental pollution, need to be applied. A lot of cost and time are required for empirical research in a greenhouse. On the other hand, simulation techniques that analyze fluid flow and heat transfer based on computers are mainly used to shorten time and cost and predict under various environmental conditions. In this study, a geothermal heat pipe for greenhouse heating installed in a glass greenhouse in Goheung was analyzed using ANSYS FLUENT, a commercial CFD (Computational Fluid Dynamics) program. By setting the flow rate and temperature value in the pipe, data such as the energy transfer process, average flow rate, and temperature change of the model to be analyzed could be checked. More efficient geothermal heat pump greenhouse heating can be expected through design change and application based on the flow analysis of this process.
온실 냉난방에 사용되는 지중열교환기의 유량조건에 따른 수치해석
최경식 ( Kyeongsik Choi ),박성완 ( Sungwan Park ),선우훈 ( Hoon Seonwoo ) 한국농업기계학회 2022 한국농업기계학회 학술발표논문집 Vol.27 No.2
New and renewable energy is being suggested as a key solution to fossil energy depletion and environmental problems, and the importance of new and renewable energy is recognized again due to instability in oil prices instability and response to climate change regulations. In this study, numerical analysis was conducted on a single U-tube of borehole heat exchanger (BHE) in a ground source heat pump (GSHP) system containing ground soil and grout to be applied to greenhouse cooling and heating. For numerical analysis, ANSYS Fluent software a commercial computational fluid dynamics (CFD) program, was adopted. Using this program, the heat transfer performance of the fluid in each flow pipe and the temperature distribution around the pipe were analyzed according to the cooling and heating conditions of the ground heat exchanger (GHE). The outlet temperature for each volume flow rate was higher in cooling and heating condition, and the lower the velocity, the higher the inlet and outlet temperature difference. This is because when the flow rate is low, the velocity decreases, and the temperature variation increases. In addition, when the flow rate is high, the velocity increases, and the temperature variation decreases. As the flow rate increases, the heat transfer increases and the pressure drop also increases.