• International Journal of Aeronautical and Space Sciences
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• 제1권2호
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• pp.30-42
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• 2000

On-orbit thermal environment test of KOMPSAT was performed in early 1999. An analysis of the test data are addressed in this paper. For the thermal-environmental simulation of spacecraft bus, an artificial heating through the radiator zones and onto some critical heat-dissipating electronic boxes was made by Absorbed-heat Flux Method. Test data obtained in terms of temperature history were reduced into flight heater duty cycles and converted into the total electrical power required for spacecraft thermal control. Verification result of flight heaters dedicated to the bus thermal control is presented. Additionally, an exhaustive heating-control process for maintaining the spacecraft thermally safe and for realistic simulation of the orbital-thermal environment during the test are graphically shown. Qualitative suggestions to post-test model correlation are given in consequency of the analysis.

• Steel and Composite Structures
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• 제11권4호
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• pp.341-358
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• 2011

This paper presents the effects of thermal environment and temperature-dependence of the material properties on axisymmetric bending of functionally graded (FG) circular and annular plates. The material properties are assumed to be temperature-dependent and graded in the thickness direction. In order to accurately evaluate the effect of thermal environment, the initial thermal stresses are obtained by solving the thermoelastic equilibrium equations. Governing equations and the related boundary conditions, which include the effects of initial thermal stresses, are derived using the virtual work principle based on the elasticity theory. The differential quadrature method (DQM) as an efficient and robust numerical tool is used to obtain the initial thermal stresses and response of the plate. Comparison studies with some available results for FG plates are performed. The influences of temperature rise, temperature-dependence of material properties, material graded index and different geometrical parameters are carried out.

• 한국주거학회논문집
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• 제12권1호
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• pp.85-92
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• 2001

The purpose of this study is to investigate the characteristic of the thermal environment at a living room by the heating system(floor radiation heating, forced convection heating, combined heating, radiation convection heating), and to compares the change of the thermal environment after operating the heating with after the operation stopped based on the floor radiation heating. This study proposes the basic data for the design and the development of the thermal storage structure heating system which not only utilizes fully the characteristic of the comfortable thermal environment but also reduces the preheating period and be able to use the off-peak electricity.

• 한국태양에너지학회 논문집
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• 제25권2호
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• pp.45-51
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• 2005

The solar shading height for the cultivation of plants is a very important factor because it has an effect on the variations of the solar energy. In this study, the solar shadings were built in Daegu region to investigate the optimum thermal conditions for the cultivation of plants and to provide the basic data. The thermal environment factors (dry bulb temperature, relative humidity, air velocity) were then measured and analyzed. It is found that the heights of the solar shadings have an uniform effect on the thermal environment for the cultivation of plants: the higher the heights of the solar shadings the higher temperature was obtained. But surprisingly this trend was not found for the relative humidity and the air velocity.

• 한국주거학회논문집
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• 제13권2호
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• pp.23-29
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• 2002

The purpose of this study was to find out the present condition of indoor thermal environment and to investigate the environmental needs of the elderly through the measurement of outdoor and indoor physical thermal environment elements and the questionary survey of the response to thermal environment in two welfare facilities for the aged in Taegu during summer in 2001. The 38 residents among the total of 134 residents were asked to record their feelings. The result of this study was as follows. The indoor thermal environment in the facilities subjected leer this study was seemed to be comfortable comparatively. But the values of mean indoor temperature measured were about 1.6-1.8$^{\circ}C$ higher than that of a existing domestic research suggested as thermal comfort zones for the elderly during summer, and most residents fe1t somewhat hot in inner space. And the value of indoor relative humidity in one facility was out from the range of comfort humidity(40-70%). Also there were differences by the geographical location between the two.

• 환경영향평가
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• 제18권6호
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• pp.321-330
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• 2009

Spatiotemporal changes in the thermal environment in a large city, Seoul, Korea were analyzed using a thermal index, perceived temperature (PT), to standardize the weather conditions. PT is a standard index for the thermal balance of human beings in thermophysiological environment. For the analysis of PT, the data from long-term monitoring and intensive observations in and around the inner-city stream called 'Cheonggye' in Seoul, were compared with a reference data from the Seoul weather station. Long-term data were monitored by installing two automatic weather stations at 66m (S1) and 173m (S2) away from the center of the stream. Through the analysis of the data during the summer of 2006 and intensive observation periods, it was revealed that the stream's effects on the PT extended up to the distance of the S1 site. In winter, the increase of the PT between pre- and post-restoration was stronger at S1, which was nearer than S2 from the stream. These results suggest that PT can be used as an effective model in analyzing the changes of the thermal environment in relation with the changes of water surface areas.

• 한국의류학회지
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• 제22권7호
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• pp.826-832
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• 1998

In order to understand the influences of wearing clothings with different thermal insula-tions when men were exposed from $25^{\circ}C$ environment to 18$^{\circ}C$ environment, thermoregulatory responses were measured on 4 healthy female college students. Subjects rested wearing T-shirts, trousers, and socks called LC(total weight 541g) at 25$\pm$1$^{\circ}C$, 50$\pm$5% R.H. and then exposed to the room conditioned in 18$\pm$1$^{\circ}C$, 50$\pm$5$^{\circ}C$ R.H. with LC as it was(LC Type) or with T-shirts, trousers, socks, training wear upper garment, the training wear lower garment called HC (total weight 1368g)(HC Type) for 120 min. The results can be summarized as follows: 1) When subjects were exposed from $25^{\circ}C$ environment to 18$^{\circ}C$ environment, decrease of rectal temperature was significantly smaller in LC Type than in HC Type. 2)Increase of heat production and weight loss had no significant difference between two types of clothing. 3)Internal thermal conductance was higher in HC Type and external thermal conductance was higher in LC Type. Therefore total thermal conductance was higher in LC Type than in HC Type. 4)Decrease of skin temperature was greater in LC Type than in HC Type. 5)Subjects felt colder with LC Type than with HC Type, but did not feel differently in comfort sensation between two types of clothing. It was suggested that less decrease of rectal temperature in LC type inspite of more dry heat loss from body might be ascribed to a shift of blood from the shell area to the core area originating in the vasoconstriction and the lowered internal thermal conductance. In conclu-sion, the importance of the state of internal heat distribution in the homeostasis seemed to be reaffirmed.

• 설비공학논문집
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• 제17권11호
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• pp.1072-1078
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• 2005

The present study has been conducted to tune a PID controller for large thermal systems such as a thermal environment chamber. In spite of large thermal mass of the thermal chamber under test, its response delay time was found to be negligible mainly due to high air recirculation rate. In general, heating and cooling capacities tend to be small compared the size of a thermal environment chamber, which leads to long transient periods of one hour or so. In the study, a PI tuning method is suggested which makes system responses faster while reducing overshoots and hunting by utilizing efficiently proportional band of actuators.

• 한국환경과학회지
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• 제20권7호
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• pp.881-890
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• 2011

In this study, thermal environment changes for a marathon course of IAAF World Championship, Daegu 2011 were modeled to provide improvements of thermal environment, so that runners could have the maximum condition and citizens pleasant streets. The three biggest size of intersections were selected for the study. Envi-met, 3G microclimate model, were used for a thermal environment analysis and three different cases - present status, planting roadside tree scenario, and roof-garden scenario - were compared. The followings are the results of the study. 1. The highest thermal distribution were shown at 1 p.m., but there was no significant difference between a thermal distribution at 1 p.m. and that at 5 p.m. since a heat flux from buildings affects thermal distributions rather than insolation does. 2. Tree planting or adding environmental friendly factors might lead a temperature drop effect, but the effect was not significant for areas covered with impermeability packing materials such as concrete or asphalt (especally, for Site case 2) 3. The combination of tree planting and adding environmental friendly factors also brought a temperature drop effect (Site 1 and 2) and this case showed even better result if green spaces (especially, parks) were closed.

• 한국주거학회논문집
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• 제21권2호
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• pp.41-48
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• 2010

This study shows how the water space outside the housing impacts the indoor thermal environment. CFD simulation was used for this experiment to analyze the interior environment focusing on the effect of temperature control and the thermal comfort. A shape of perfect square, which creates the very basic space formation, was used and the simulation was processed looking at the size, distance, and the location of the water space. The results of the experiment are as follows. Firstly, introducing a water space with the same floor area size of the simulation model decreased the indoor temperature by 1 Celsius (3.72%). It was determined the interior environment was considered as a comfort zone when the water space was greater than 70% of the floor area. Secondly, there was not much influence to the level of thermal comfort of the interior environment when the distance to the water space from the housing was greater than 2 meters. Lastly, interpreting the location of water space, the effect of controlling the total areas' temperature was the greatest following with the surrounding of the formation. There barely was any change to the temperature considering the side and the rear of the area.