• Journal of the Korean Society of Clothing and Textiles
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• v.28 no.2
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• pp.292-302
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• 2004

The purpose of this study was to evaluate thermal properties of lab gowns developed from the point of safety and work efficiency. We evaluated thermal and subjective responses of subjects wearing functional new lab gowns (Type B, C, D) and a popular lab gown on the market (Type A). Type B was a new lab gown made of woven fabric with functional cuffs. Type C was a new apron made of woven fabric with arm protectors. Type D was a new lab gown made of non-woven material with functional cuffs and openings around the armpits. Temperature in the climatic chamber was set at 19$^{\circ}$C as an indoor temperature in winter and at 24$^{\circ}$C in summer. There were no significant differences in rectal temperature and heart rate among four types of gowns and between two air temperatures for 120 min. Mean skin temperature was much higher in the type A and B than in He type C and D (p .05). In the 19$^{\circ}$C air, clothing microclimate temperature on the back was the highest in the type B and was the lowest in the type C (p .05). Clothing microclimate humidity was not significant differences among gowns. In subjective .esponses, subjects perceived that Type B was the warmest gown in the 19$^{\circ}$C and the hottest and more humid in the 24$^{\circ}$C than other gowns. Inversely, type C was the coolest gown among four gowns. Both in the 19$^{\circ}$C and in the 24$^{\circ}$C, the Type D had gained most responses of being comfortable. In conclusion, the temperature difference of 5$^{\circ}$C was more of an influencing factor than the difference from four types of lab gowns. Secondly, we recommend the manufacturers to make lab gowns with functional cuffs for safety purposes. Thirdly, the spread of the type of apron with arm protector will contribute to increase of the frequency of wearing in summer. Fourthly, it is necessary to study continuously about lab gowns with non-woven materials for researchers exposed to toxic chemical and biological materials.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.6
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• pp.653-662
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• 2014

In this study, Mokpo national maritime university Training ship Centralizes Air Conditioning System was upgraded by installing onboard an Air-cooled Air conditioner. This resulted in the improvement of the performance and operation. This study compared refrigeration performance to former equipment and improving one. And through the actual measurement study about the cabin thermal environment, it will be used as basic data for marine air conditioning design and plan in the future. At same climate condition, when the Centralized Air Conditioning System and an improved air conditioning system operated, cabin temperature was at $24{\sim}28^{\circ}C$, humidity was 55~75 % as comfortable condition, Generator load measurement showed a saving of 48KW in the average load and 8 % in the full load factor. This also resulted in a saving of daily fuel oil consumption(FOC) at around 222 [${\ell}/day$] average. On the other hand, one cadet cabin(Cadet No.21) indicated a higher temperature due to heat transmission of engine room. It found us not to consider installing additional diffuser to reduce the heat transmission.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.11
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• pp.1079-1087
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• 2005

In this paper, thermal comfort and ventilation performance characteristics in the lecture room with the ventilation system and two different air-conditioning systems, system air-conditioner or fan coil unit, were evaluated by experimental and numerical methods. We compared the measured data with the computational results of the predicted mean vote and carbon dioxide concentration. Additionally the ventilation effectiveness was calculated numerically. From a viewpoint of the uniformity of PMVs in the lecture room, the thermal distribution performance of the system air-conditioner was more effective than the fan coil unit. Carbon dioxide concentration and ventilation effectiveness were barely affected by the type of the air-conditioning system.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.8
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• pp.1042-1050
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• 2003

A heating flow discharged from a 4-way ceiling type indoor unit has been investigated to determine the design parameters for the optimal flow control. The flow was measured by a PIV(particle image velocimetry) system and an experimental model of 1/10 scale with a transparent room was devised by satisfying the Archimedes number. This similarity is generally used in cases where the forced convection has similar magnitude of the natural convection. To optimize the heating flow, several vane angles and vane control algorithms of cross and right angle controls were considered. Regarding the vane angle, experimental results show that 30$^{\circ}$is an optimal angle to avoid re-suction flows without significant increase in flow noise. Temperature distribution measured in the environmental chamber ensures the increased thermal comfort when compared to the case, 60$^{\circ}$angle. At the optimal angle, applying open/close control gives rise to more uniform distribution of the heating flow than without control. Especially, the cross-control seems to be satisfactory for thermal comfort.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.1
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• pp.1-6
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• 2006

This study was performed to evaluate sleep efficiencies and conditions for comfortable sleep based on the analysis of EEGs and MST under four thermals conditions. Five female subjects who have similar life cycle and sleep patterns were participated for the sleep experiment. Their age was from 20 to 22 years old. They were healthy, and had regular sleep with consistent bed and wakeup time. It was checked whether they had a good sleep before the night of experiment. Experiments were performed in an environmental chamber of $4.1\times4.9\times2.7m$ size. EEGs were obtained from C3-A2 and C4-Al electrode sites. Sleep stages were classified, then TST, SWS latency and SWS/TST were calculated for the evaluation for sleep efficiencies on thermal conditions. As results, it was concluded that indoor thermal environments of $24\~26^{\circ}C$ was the best for comfortable and deep sleep.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.9
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• pp.810-816
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• 2000

Thermal comfort plays an important role in modern office buildings. Four major factors affecting thermal comfort are air temperature, velocity, humidity and radiation temperature. Distribution of these thermal factors in indoor space depends largely on the air flow which is related to the method of supplying and extracting air. In this study, an experimental analysis on indoor thermal comfort is conducted to study the difference between a ceiling supply cooling system and a floor supply one. The two cooling systems are applied to an office space during summer season and the distributions of temperature, velocity, radiation temperature and PMV are measured. Results show that the floor supply cooling system is superior in terms of thermal comfort and energy saving. Studies need to be done, however, to reduce the vertical temperature difference of a floor supply air conditioning system.

• Journal of Environmental Science International
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• v.14 no.2
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• pp.215-220
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• 2005

Thermal neutrality is not enough to achieve thermal comfort. The temperature level can be the optimal, and still people may complain. This situation is often explained by the problem of local discomfort. Local discomfort can be caused by radiant asymmetry, local air velocities, too warm and too cold floor temperature and vertical temperature difference. This temperature difference may generate thermal discomfort due to different thermal sensation in different body parts. Therefore, thermal comfort can not be correctly evaluated without considering these differences. This study investigates thermal discomfort sensations of different body parts and its effect on overall thermal sensation and comfort in air-heating room. Experimental results of evaluating thermal discomfort at different body parts in an air-heating room showed that thermal sensation on the shoulder was significantly related to the overall thermal sensation and discomfort. Although it is known that cool-head, warm-foot condition is good for comfort living, cool temperature around the head generated discomfort.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.533-536
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• 2002

A heating flow discharged from a 4-way ceiling type indoor unit has been investigated using a PIV(particle image velocimetry) system For the PIV measurements, an experimental model of 1/10 scale with a transparent room was devised by satisfying the Archimedes number, which is generally used in case that the forced convection has the similar magnitude as the natural convection. To optimize the heating flow, several vane angles and vane control algorithms of cross and right angle controls were considered. Regarding the vane angle, the experimental results show that it should be less than $30^{\circ}$ to avoid re-suction flows which decrease the performance of the air-conditioner. At the vane angle of $30^{\circ}$, applying open/close control gives nae to more uniform distribution of the heating flow than without control. Especially, the cross-control seems to be satisfactory for the thermal comfort.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.31 no.8
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• pp.15-18
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• 2002

축열 공조방식 중 현재 가장 많이 보급되고 있는 방식은 빙축열 방식과 수축열 방식이다. 본래 축열식 공조는 열원 용량을 감소하고, 값싼 심야전력을 통해서 운전비용(running cost)의 절감을 목적으로 하지만, 열을 저장하기 위한 "축열조"가 필요하므로, 필연적으로 초기투자비(intial cost)의 증가를 동반하며, 기존의 건물에는 쉽게 적용할 수 없는 등의 문제점이 있다. 따라서 축열을 위한 초기비용을 증가시키지 않는 축열식 공조방식으로서 건축물 자체가 가지는 높은 열용량에 착안하여 구조체 축열에 관한 연구가 최근 활성화되고 있다. 구조체 축열은 건축물 그 자체를 축열 매체로 이용하기 때문에 별도의 축열조가 필요 없고, 구조체 로부터의 "복사"형태로 거주영역에 직접적으로 작용하여 실내의 온열환경을 향상시킬 수 있다. 이 때문에 2차측 공조기의 용량을 절감시킬 수 있고, 축열 부위에서의 열반송이 필요없는 등, 구조체 축열 시스템은 기존의 빙축열과 수축열 방식에서는 없는 여러가지 장점을 가지고 있다. 구조체 축열 공조시스템은 기존의 공조시스템 중에서 급기구 부위만을 변경하여 주간에서 종래의 공조시스템과 같이 실내로 공조 공기를 급기하고, 야간에는 급기구에 설치된 댐퍼를 조절하여 천정면으로 공조 공기를 급기함으로써 구조체에 열을 축열시키는 방안이다. 본 시스템은 기존의 설비시스템을 이용하여 건축물의 구조체를 축열, 공조개시전 및 주간의 부하를 대폭 줄임으로써 에너지를 절감시킬 수 있다는 장점을 갖는다. 따라서 구조체 축열 공조시스템은 "지구환경 유지.전력부하 평준화.안전성.에너지 절약.비용절감.쾌적성"의 모든 조건을 만족시키는 유력한 차세대 공조 방식이 될 것으로 판단되며, 본 보에서는 공기순환형 구조체 축열시스템을 소개하고자 한다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.4
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• pp.318-328
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• 2003

Numerical simulation using computational fluid dynamics (CFD) is performed to calculate the velocities and temperature profiles of air in adjacent to a worker within the individual local air conditioning system. The calculation domain is the space of ㄴ between walls and a worker in the climate room. The fresh air is supplied from the three different inlets located on the right, left and center wall in the climate room. In this study, the calculated data of velocities and temperature profiles of air in the nearest the skin of a worker are used to calculate the PMV (Predicted Mean Vote) for evaluation of thermal comfort of a worker in the local air conditioning system. Because the data of veto-cities temperature profiles of air in adjacent to a worker and the PMV of a worker are the design parameters of the local air conditioning system. The results of calculation show that the fresh air velocity and injection position are closely related to the PMV value. In individual air condition system of ㄴ, the appropriate PMV are obtained when the fresh air velocity and position are 1.0 m/s, throat of a worker and are 1.5 m/s, head of a worker, respectively. The method of numerical calculation is effective to obtain the optimum velocity and position of the fresh air for optimum the PMV and energy saving in individual local air conditioning system.