• Proceedings of the ESK Conference
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• 1998.04a
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• pp.124-130
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• 1998

본 연구의 목적은 트레드밀 운동시 신체에 가해지는 중량별 부하가 심박수, 환기량, 호흡수, 이산화탄 소배출량, 산소섭취량, 체중당산소섭취량, 호흡교환률 등에 어떠한 영향을 미치는 지를 측정하여 훈련이 나 운동처방에 도움이 될 수 있는 자료를 얻고자 하였다. 피검자들은 성인 남녀 각 5명씩을 대상으로 하였으며, 신체 중량별 부하는 남자에게 안정시, 무부하, 5kg부하, 10kg부하, 15kg무하로 하였으며, 여자 에게는 안정시, 무부하, 5kg부하, 10kg부하로 구분하여 측정하였다. 운동부하는 트레드밀(TC-1200, Technogym, Italy)을 이용하여 중량별로 4km/hr로 3분간 실시하였다. 단계별 운동부하에 의한 인체에 미치는 호흡순환계의 변화를 조사하기 위해 호흡순환계의 변인을 측정 분석한 결과, 다음과 같은 결론 을 얻었다. 남자그룹의 경우는 심박수, 환기량, 이산화탄소배출량, 산소섭취량, 체중당산소섭취량, 호흡 교환률에 대한 중량별 평균차의 검증에서 안정시와 무부하, 5kg부하와 10kg부하, 10kg부하와 15kg부하 사이 에는 유의한 차이가 나타났고, 무부하와 5kg부하 사이에서는 유의한 차이가 없었다. 호흡수에있어서는 10kg 부하와 15kg부하 사이에서만 유의한 변화가 나타났다. 여자그룹의 경우는 심박수, 환기량, 이산화탄소배출 량에 대한 중량별 평균차의 검증에서는 안정시와 무부하, 무부하와 5kg부하, 5kg부하와 10kg부하 사이에서 유의한 변화가 나타났으며, 산소섭취량과 제중당산소섭취량에 있어서는 안정시와 무부하, 무부하와 5kg부하 사이네서만 유의한 변화가 나타났다. 또한 호흡교환률과 호흡수에 있어서는 안정시와 무부하 사이에서만 유의한 변화가 나타났으며, 무부하와 5kg부하, 5kg부하와 10kg부하 사이에는 유의한 차이가 없었다. 이와 같은 결과를 종합해 보면 남자에게는 걷기시에 단계별 무게부하가 호흡순환계에 영향을 미친다고 볼 수 있 으나, 5kg까지의 부하는 호흡순환계에 영향을 미치지 않고 일을 수행할 수 있음을 알 수 있다. 그리고 여자에게는 걷기시에 단계별 무게부하가 운동시 심박수와 환기량, 이산화탄소 배출량에는 영향을 미치고 호흡 교환률과 호흡수에는 영향을 미치지 않음으로보아, 여자에게는 걷기시에 단계별 무게 부하가 호흡순환계에 영향을 받고있음을 알 수 있다.

• Horticultural Science & Technology
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• v.33 no.5
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• pp.647-657
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• 2015

To investigate a method for calculation of the heating load for environmental designs of horticultural facilities, measurements of total heating load, infiltration rate, and floor heat flux in a large-scale plastic greenhouse were analyzed comparatively with the calculation results. Effects of ground heat exchange and infiltration loss on the greenhouse heating load were examined. The ranges of the indoor and outdoor temperatures were $13.3{\pm}1.2^{\circ}C$ and $-9.4{\sim}+7.2^{\circ}C$ respectively during the experimental period. It was confirmed that the outdoor temperatures were valid in the range of the design temperatures for the greenhouse heating design in Korea. Average infiltration rate of the experimental greenhouse measured by a gas tracer method was $0.245h^{-1}$. Applying a constant ventilation heat transfer coefficient to the covering area of the greenhouse was found to have a methodological problem in the case of various sizes of greenhouses. Thus, it was considered that the method of using the volume and the infiltration rate of greenhouses was reasonable for the infiltration loss. Floor heat flux measured in the center of the greenhouse tended to increase toward negative slightly according to the differences between indoor and outdoor temperature. By contrast, floor heat flux measured at the side of the greenhouse tended to increase greatly into plus according to the temperature differences. Based on the measured results, a new calculation method for ground heat exchange was developed by adopting the concept of heat loss through the perimeter of greenhouses. The developed method coincided closely with the experimental result. Average transmission heat loss was shown to be directly proportional to the differences between indoor and outdoor temperature, but the average overall heat transfer coefficient tended to decrease. Thus, in calculating the transmission heat loss, the overall heat transfer coefficient must be selected based on design conditions. The overall heat transfer coefficient of the experimental greenhouse averaged $2.73W{\cdot}m^{-2}{\cdot}C^{-1}$, which represents a 60% heat savings rate compared with plastic greenhouses with a single covering. The total heating load included, transmission heat loss of 84.7~95.4%, infiltration loss of 4.4~9.5%, and ground heat exchange of -0.2~+6.3%. The transmission heat loss accounted for larger proportions in groups with low differences between indoor and outdoor temperature, whereas infiltration heat loss played the larger role in groups with high temperature differences. Ground heat exchange could either heighten or lessen the heating load, depending on the difference between indoor and outdoor temperature. Therefore, the selection of a reference temperature difference is important. Since infiltration loss takes on greater importance than ground heat exchange, measures for lessening the infiltration loss are required to conserve energy.

• Land and Housing Review
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• v.10 no.1
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• pp.25-32
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• 2019

In this study, the case analysis data on underground temperature are presented. In addition, numerical analysis of the ventilation load reduction plan was derived according to the residence schedule change for the building with cool tube. The research scope and method are as follows. The overall system principle was examined through reviewing the theory of the Cool tube system. Case study and analysis were conducted. Numerical simulation was used to examine the change in energy usage. Also, the change of load energy in case of varying amount of ventilation was derived based on actual building room schedule. When the Cool tube system was applied to the residential buildings, the cooling load was reduced from 3,331 kW to 193 kW, which showed a reduction effect of about 90%.The heating load was reduced from 42,276kW to 32,575kW by 23%.Also, result shows that the cooling load decreased by 24% and the heating load decreased by 66% when the number of ventilation according to the occupancy schedule was applied.

• Journal of Bio-Environment Control
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• v.24 no.3
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• pp.147-152
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• 2015

In order to develop the cooling load estimation method in the greenhouse, the cooling load calculation formula based on the heat balance method was constructed and verified by the actual cooling load measured in the fog cooling greenhouse. To examine the ventilation heat transfer in the cooling load calculation formula, we measured ventilation rates in the experimental greenhouse which a cooling system was not operated. The ventilation heat transfer by a heat balance method showed a relatively good agreement. Evaporation efficiencies of the two-fluid fogging system were a range of 0.3 to 0.94, average 0.67, and it showed that they increased as the ventilation rate increased. We measured thermal environments in a fog cooling greenhouse, and calculated cooling load by heat balance equation. Also we calculated evaporative cooling energy by measuring the sprayed amount in the fogging system. And by comparing those two results, we could verify that the calculated and the measured cooling load showed a relatively similar trend. When the cooling load was low, the measured value was slightly larger than calculated, when the cooling load was high, it has been found to be smaller than calculated. In designing the greenhouse cooling system, the capacity of cooling equipment is determined by the maximum cooling load. We have to consider the safety factor when installed capacity is estimated, so a cooling load calculation method presented in this study could be applied to the greenhouse environmental design.

• Journal of Bio-Environment Control
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• v.24 no.2
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• pp.100-105
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• 2015

The calculation method of infiltration loss in greenhouse has different ideas in each design standard, so there is a big difference in each method according to the size of greenhouses, it is necessary to establish a more accurate method that can be applied to the domestic. In order to provide basic data for the formulation of the calculation method of greenhouse heating load, we measured the infiltration rates using the tracer gas method in plastic greenhouses equipped with various thermal curtains. And then the calculation methods of infiltration loss in greenhouses were reviewed. Infiltration rates of the multi-span and single-span greenhouses were measured in the range of $0.042{\sim}0.245h^{-1}$ and $0.056{\sim}0.336h^{-1}$ respectively, single-span greenhouses appeared to be slightly larger. Infiltration rate of the greenhouse has been shown to significantly decrease depending on the number of thermal curtain layers without separation of single-span and multi-span. As the temperature differences between indoor and outdoor increase, the infiltration rates tended to increase. In the range of low wind speed during the experiments, changes of infiltration rate according to the outdoor wind speed could not find a consistent trend. Infiltration rates for the greenhouse heating design need to present the values at the appropriate temperature difference between indoor and outdoor. The change in the infiltration rate according to the wind speed does not need to be considered because the maximum heating load is calculated at a low wind speed range. However the correction factors to increase slightly the maximum heating load including the overall heat transfer coefficient should be applied at the strong wind regions. After reviewing the calculation method of infiltration loss, a method of using the infiltration heat transfer coefficient and the greenhouse covering area was found to have a problem, a method of using the infiltration rate and the greenhouse volume was determined to be reasonable.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.32 no.7
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• pp.41-44
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• 2003

실내의 냉난방부하와 필요환기량을 동시에 처리하던 기존의 전공기 공조시스템과 달리 냉난방과 환기를 분리하여 개별적으로 담당하는 외기전담시스템에 관하여 소개한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.1
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• pp.52-57
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• 2009

In this study, a simulation program has been developed to predict the performance of energy recovery ventilators fur various indoor and outdoor conditions. In order to get a fundamental data about domestic air condition, the heat recovery ventilator is selected with the product of the wind quantity $250m^3/h$ Japanese M companies which are satisfied at High Efficiency Certification Standards. At the case on which the heat recovery ventilator is established, heating load decreases by 69.1% and cooling load decreases by 59.4% in Seoul, and heating load decreases by 66.4% and cooling load decreases by 59.6% in Pusan. The maximum humidification load of winter or summer time with $0.737{\ell}/h$ or $1.008{\ell}/h$ occurred in March from Kangnung or August from Mokpo respectively. In Southern part region and East Sea of winter time, the condensation or frost on exhaust side dose not occurred on exhaust side, but the area of that outside is occurred. Therefore, the preventive measure from the area except a southern part region and the east coast area must be considered, in order to condense or frost not to occur on exhaustion side in winter.

• Proceedings of the SAREK Conference
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• 2005.11a
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• pp.217-222
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• 2005

Building energy consumption according to the ventilation has been considered to be an important subject. The purpose of this study is to investigate the cooling loads in a test space with a forced ventilating system. In the test space, on/off controlled air-conditioning and forced ventilating facility were operated between 8:30 to 21:00 during 4 days and some important data like temperatures and energy consumption were measured to obtain actual cooling loads. The simulation was carried out in a mode of temperature level control using a TRNSYS 15.3 with a precisely measured air change amount and performance data of air-conditioner. Cooling loads including sensible and latent were compared between by experiment and by simulation. Both of cooling loads associated with ventilation show a close agreement within an engineering tolerance.

• Tuberculosis and Respiratory Diseases
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• v.44 no.2
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• pp.309-320
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• 1997

Background : There are many suggested methods for the indirect determination of anaerobic threshold(AT) using the changes of ventilatory parameters in response to ventilatory load accompanying the increase of blood lactic acid level during exercise and the threshold derived from them is called ventilatory threshold(VT). They include ventilatory equivalent method(VEM), End-tidal $PO_2$ method($PETO_2$). V-slope method(VSM), and respiratory quotient method(RQ). But in the patients with chronic airway obstruction(CAO), the AT determined by ventilatory methods may not reflect true AT because the patients with CAO show inadequate ventilatory response to the increase of blood lactic acid level during excercise. Methods : For the investigation of detection rate and reliability of above four VT determination methods in the patients with CAO, we performed the symptom-limited and maximal incremental exercise test in 17 patients with CAO and 12 normal controls. The incremental workload was 10 W /min in CAO group and 25 W/min in control group. The reliability of VT in each group was investigated by the calculation of Spearman correlation coefficient. Results : The detection rates of VT were 100% by RQ, 91.7% by both VEM and $POETO_2$, and 83.3% by VSM in normal control group, while 94.1% by RQ, 64.7% by VEM and $PETO_2$, and 83.3% by VSM in CAO group. Good correlations were noted among VEM, $POETO_2$, and VSM except RQ in normal control group. But there was no significant correlation except between VEM and $PETO_2$ in CAO group. Conclusions : RQ is very sensitive but crude and VEM is near similar to $PETO_2$. The clinical usefulness of VT determined by ventilatory method might be limited in patients with severe CAO.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.29 no.2
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• pp.39-45
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• 2000

1970년대부터 사용된 변풍량 공조 시스템 (Variable Air Volume System)은 실내 부하 변동에 따라 급기 온도를 일정하게 유지시키고 실별, 존별 송풍량을 변화시켜 실온을 제어하는 방식으로, 에너지 절약, 개별 제어 등의 장점 때문에 적용이 확대되었고 특히 단일덕트 변풍량 공조 시스템은 이러한 이유 때문에 많은 건물에 적용되고 있다. 그러나 현 제어시스댐의 풍량 측정의 문제점과 공조기내에서 풍량변화 및 급/배기 댐퍼의 개도 변경으로 인한 환기 댐퍼의 비선형 특성을 고려하지 않고 제어하기 때문에 외기량 확보를 정확히 유지 못하는 실정이다. 따라서 단일덕트 변풍량 시스템의 환기댐퍼 및 급기, 환기 팬의 제어 방식의 종류와 특성 및 문제점에 대하여 설명하고자 한다.