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- 검색키워드
- 주제어 : Portable Cooling Equipment (검색결과 2 건)
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이용균,김태영 대한기계학회 2022 大韓機械學會論文集B Vol.46 No.7
In this study, a compact and portable cooling equipment applicable to protective clothing was developed using thermoelectric modules (TEMs) to ensure the thermal comfort of workers wearing protective clothing in harsh working conditions. The air circulation flow rate and thermal resistance of a plate-fin heat sink used to enhance the operating performance of TEMs were theoretically modeled to achieve a target cooling power estimated using the amount of heat released from the human body. The cooling power and COP of the fabricated cooling equipment were experimentally derived and analyzed according to the change in the number of TECs and applied voltage. When a voltage of 5 V was applied to the four TECs, a maximum cooling power of 33 W, a circulation air temperature reduction of 7.6°C, and a COP of 0.87 were obtained. When a voltage of 2 V was applied to the two TECs, the highest COP of 1.82 was obtained, achieving a cooling power of 9.93 W. Finally, when the developed cooling system was applied to a worker wearing a protective clothing, a cooling power of ~50 W and circulation air temperature reduction of ~13°C were obtained. 본 연구에서는 기존 열전 냉각시스템의 낮은 열량제거 및 냉각성능(COP: coefficient of performance) 특성을 개선하여 방호복을 착용하고 열악한 상황에서 근무하는 작업자의 열적 쾌적성을 확보할 수 있는 휴대용 방호복 냉각장치를 개발한다. 목표 제거 열량을 달성하기 위해 순환 공기 유량과 방열핀 열저항을 이론적으로 모델링 하고, 이를 통해 설계·제작된 냉각장치의 성능검증 및 최적화를 위해 열전소자 개수와 인가전압 변화에 따른 제거 열량 및 COP를 도출하여 분석하였다. 병렬 연결된 4개의 소자에 5 V의 전압 인가 시 최대 33 W의 열량제거 및 7.6°C의 순환공기 냉각을 확인하였으며 이때의 COP는 0.87로 나타났다. 병렬 연결된 2개의 소자에 2 V의 전압인가 시 가장 높은 1.82의 COP를 획득하였으며, 이때의 제거 열량은 9.93 W로 나타났다. 방호복을 착용한 작업자에게 적용 시 ~13°C의 순환공기 온도 저감 및 ~50 W의 제거 열량을 확인하였다.
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여름철 비닐 하우스 오이 수확 농민의 작업 부담 및 온열 환경 평가
최정화(Jeong-Wha Choi),김명주(Myung-Ju Kim),이주영(Joo-Young Lee) 한국생활환경학회 2002 한국생활환경학회지 Vol.9 No.3
Physiological and subjective responses and work postures of the farmers and thermal environment during cucumber harvest in the greenhouse were investigated to evaluate the thermal environments and farmers' workload. Five career farmers (1 female, 4 males) volunteered as subjects. Farmers' work was monitored continuously for two days without any disturbance. The results were as follows. 1) Air temperature (Ta), air humidity (Ha), globe temperature (Tg) and WBGT for two days were mean 29~32℃, 70~81%RH, 30.3~44.5℃ and 27.6~32.9℃, respectively. By the WBGT, we evaluated that the thermal environment in the greenhouse gave a thermal burden to farmers. 2) The range of total work time was 161~298 minutes. The percentage of the work postures during the cucumber harvest was larger in order of sitting, standing and walking. 3) Rectal temperature (Tre) and mean skin temperature (Tsk) were 37.2(± 0.3)℃ and 33.2(±0.9)℃. Clothing microclimate temperature (Tel) on the chest and the back were 32.0(±0.8)℃ and 34.3(± 1.5)℃ (p < 0.(01). Clothing microclimate humidity (Hcl) was over 75%RH. Heart rate (HR) was 92(± 13) bpm and energy expenditure was 210(±43) kcal/hr. We evaluated that the harvesting cucumbers in the greenhouse was 'moderate work' by the physiological responses. 4) Average subjective responses of the farmers were 'somewhat hard", 'hot', 'very humid' and 'a little uncomfortable'. It is suggested that administrators should be concerned about the development and supply of portable cooling equipment as well as the improvements of working environment to alleviate farmers' heat strain and work load in summer.
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