• Journal of Yeungnam Medical Science
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• v.15 no.2
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• pp.325-340
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• 1998

A cross-sectional study was conducted to evaluate the relationship between sick building syndrome(SBS) and the environmental factors affecting SBS on 130 underground workers and 60 controls. The study consisted of 1) a review of environmental condition 2) measurement of temperature, $O_2$, $CO_2$, CO, and formaldehyde and 3) a questionnaire survey of symptom prevalence and perception of environmental conditions using indoor Air Quality questionnaire recommended by National Institute for Occupational Safety and Health. Bronchitis and dust allergy were more prevalent in underground workers significantly(p < 0.05). Among the 18 symptoms related to the indoor air pollution, the experience rate of dry, itching or irritated eyes, sore or dry throat, chest tightness, tired or strained eyes and dry or itchy skin symptom was significantly different between the underground workers and controls. The diagnostic criteria of SBS was defined as at least 1 symptom is experienced 1-3 times a week during the last 1 month among 18 indoor air pollution related symptoms which can be relieved by moving out of the underground. Applying the criteria, the mean symptom score was significant higher in underground workers than controls significantly (p < 0.05). These resalts indicated that underground workers are under inappropriate ergonomic and physical condition and inadequate ventilation. Their experience rate of symptoms related to indoor air pollution and prevalence of SBS was significantly higher than controls. To reduce the prevalence of SBS of underground workers, the surveillance system of indoor air quality, restriction of using fuel in underground and legislative regulations for the environment are needed to establish a better indoor air quality. Early detection, treatment and prevention of SBS through medical attention is also needed.

• Proceedings of the KIEE Conference
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• 2005.11b
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• pp.145-147
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• 2005

This paper presents a methodology for satisfying the thermal comfort of Indoor environment and reducing the summer peak demand power by minimizing the power consumption for an Air-conditioner within a space. KEPCO(Korea Electric Power Corporation) use the fixed duty cycle control method regardless of the indoor thermal environment. This method has disadvantages that energy saying depends on the set-point value of the Air-Conditioner and DLC has no net effects on Air-conditioners if the appliance has a lower operating cycle than the fixed duty cycle. A variable duty cycle estimates the PMV(Predict Mean Vote) at the next step with a predicted temperature and humidity coming from the back propagation neural network model. It is possible to reduce the energy consumption by maintaining the Air-conditioner's OFF state when the PMV lies in the thermal comfort range. The proposed methodology uses the historical real data of Sep. 7th, 2001 from a classroom in seoul to verify the effectiveness of the variable duty cycle method comparing with fixed duty cycle. The result shows that the variable duty cycle reduces the peak demand to 2.6times more than fixed duty cycle and increases the load control ratio by 8% more. Based on the variable duty cycle control algorithm, the effectiveness of DLC is much more improved as compared with the fixed duty cycle.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.7 no.2
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• pp.310-318
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• 1995

In this study, indoor thermal parameters were measured to investigate the characteristics of thermal environments and 138 occupants were questioned to evaluate Korean thermal comfort in office building in winter. Thermal sensation was estimated by using PMV(Predicted Mean Vote) and ET*(New Effective Temperature) indices. Comparing present experimental result with international standards and that of other research, Korean thermal responses were discussed. Seasonal difference between summer and winter was also discussed. It was found that TSV(Thermal Sensation Vote) is more sensitive than PMV to the variation of temperature and that the measured percentage of dissatisfied is higher than PPD(Predicted Percentage of Dissatisfied) in real office building environments. By regression analysis, the following regression equation has been obtained; TSV=0.432ET*-8.814 and neutral temperature is $20.4^{\circ}C$ in this case. Thermal comfort range based on 80% satisfaction is also $19.4{\sim}22.4^{\circ}C$.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.1
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• pp.39-46
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• 2005

The present study concerns an experimental study of a R-22 heat pump system consisted of liquid and liquid heat exchangers. The test was performed for various systems of a single-, tandem-, and two stage-cycle at the same environmental conditions of temperature. Various experiments of the heat pump system were peformed to compare the heating capacity and COP, when the outdoor temperature is near $-15^{\circ}C$ and the indoor temperature is $20^{\circ}C.$ As the results of the present study, the system of Tandem(parallel) cycle showed the best heating performance, while the discharge temperature of refrigerant was too high. In case of the system of two stage cycle, the performance characteristics were significantly improved by employing the inter cooler.

• Journal of Energy Engineering
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• v.25 no.3
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• pp.130-135
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• 2016

The thermal performance of amorphous steel fibers mixed floor heating system was evaluated. Analysis of results, depending on the hot water supply temperature changes, the average temperature of the bottom of the hot water supply temperature is an amorphous steel fiber floor heating system is about 2~4% higher. The average temperature of the floor surface to 1.5m air amorphous steel fiber system is 1~2% higher. The amount of heat supplied to indoor air (1.5m) from the bottom surface of amorphous steel fiber floor heating system is about 7~8% higher

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.2
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• pp.86-96
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• 2010

The paper describes development and evaluation of a simple method for determining gradient of modified linear setpoint variation to reduce peak electrical cooling demand in buildings using building precooling and setpoint adjustment. The method is an approximated approach for minimizing electrical cooling demand during occupied period in buildings and involves modified linear adjustment of cooling setpoint temperature between $26^{\circ}C$ and $28^{\circ}C$. The gradient of linear variation or final time of linear increase is determined based on the cooling load shape in conventional cooling control having a constant setpoint temperature. The potential to reduce peak cooling demand using the simple method was evaluated through building simulation for a calibrated office building model considering four different weather conditions. The simple method showed about 30% and 20% in terms of reducing peak cooling demand and chiller power consumption, respectively, compared to the conventional control.

• Journal of Navigation and Port Research
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• v.33 no.4
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• pp.289-294
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• 2009

The living performances of crews and passengers in cabins have been less received attention, while Korea is a top leading country in ship building industry. To develop a high value added ships like 5-star cruisers, researches on the comfort and productivity in cabins should be carried out with urgent. The purpose of this study is to measure and analyze of the ship's indoor thermal conditions in spring, summer and winter, and also to compare the seasonal differences, of which conditions are supplied from and controlled by marine HVAC The temperature, humidity and air supply volume of 5 different needs of cabins on a training ship were measured through a year, which was launched at Dec. 2005 and totally 246 crews can go on board for education. The following results were obtained: (1)In the spring, the temperature in cabins was measured as $20{\sim}25^{\circ}C$ and humidity was below 30%. (2)In the summer, the temperatures was controlled at $21{\sim}27^{\circ}C$ in almost cabins and humidity was between $40{\sim}60%$ which is known as comfort conditions. (3)In the winter, temperature and humidity was maintained between $19{\sim}26^{\circ}C$, and humidity was between $10{\sim}50%$. (4)It is clear that the humidity conditions in cabins are not properly controlled at all through a year to satisfy the Comfort Standards provided by ASHRAE and/or ISO, In conclusion, humidification and dehumidification of cabins must be treated with importance for more comfort living and working environments for crews and passengers.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2008.11a
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• pp.255-260
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• 2008

The purposes of this study were to determine the actual state of the indoor air quality by TVOC concentration and residents' responses and to analyze the influencing factors of IAQ in newly built university dormitory. The field measurements on the levels of TVOC and HCHO were carried out three times at an interval of 4 weeks in 3 rooms of a dormitory. The questionnaire survey on the residents that inquired into the lifestyle, the consciousness related to IAQ, and the responses of SHS was fulfilled. According to the results, the level of TVOC was approximately $0.14{\sim}18.5ppm$ and HCHO was $0.23{\sim}6.89ppm$ during 3 month since construction completion, which are seriously in excess of standard level, and seemed to be on the decrease as time goes by. The factors influencing the differences of the levels of TVOC or HCHO were the amount of ventilation including infiltration, heating temperature, relative humidity, or the use of living things including chemical. However, the residents rarely felt the responses of SHS and did not be conscious of the importance of ventilation.

• Proceedings of the IEEK Conference
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• 2009.05a
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• pp.48-50
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• 2009

This paper presents an IAQ(Indoor Air Quality) Monitoring System using equipments for measurement of fine Particle($PM1{\sim}PM10$), $CO_2$, VOCs(Volatile Organic Compounds), temperature and humidity for IAQ monitoring of subway station which millions of people use a day. The necessity of IAQ monitoring system is getting increased for more effective subway station monitoring in line with the recent government's regulation for IAQ is reinforcing. Subway Station is an unusual case. The structure of subway station is closed and complicated. Therefore when data of equipments are transferred, transmission error can happen occasionally. To prevent transmission error, an IAQ Monitoring System is needed the appropriate position and selection of equipments or sensor module. In addition IT(Information Technology) can be utilized like "WiBro(Wireless Broadband)" and "GateWay" for facilitate movement of data and construction of IAQ monitoring system of subway station.

• International Journal of High-Rise Buildings
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• v.2 no.4
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• pp.293-314
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• 2013

Double-Skin Façade (DSF), which is a kind of passive indoor environmental control technique, is effective way to control environmental loads while maintaining the transparency especially in perimeter zone and hence the adoption example of DSF keep increasing recently. The objective of this study was to perform a field survey of air quality environment with natural ventilation through DSF and thermal environment within office building with six stories during a mild climate period in Japan. Moreover, to understand the comprehensive environmental performance of the target building, questionnaire survey was conducted to subjectively evaluate the productivity and satisfaction with the environmental factors in office space. In this field measurement, there was a positive correlation between the DSF internal ventilation flow and the amount of solar radiation on the DSF normal surface; the primary driving force for ventilation in the DSF was considered to be the buoyancy force caused by solar radiation. The results of questionnaire survey with regard to productivity level indicated the need for improvement in the thermal (temperature) and spatial environment (room size and furniture placement).