• 한국지열·수열에너지학회논문집
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• 제17권3호
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• pp.1-12
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• 2021

In this study, the effects of various operational conditions for floor radiant heating system were researched by experiments. Hot water supply set temperature, indoor air set temperature and supply water flowrate were considered as operational conditions. The control method for this system is On-Off control of automatic thermostatic valve. The purpose of this study is to evaluate indoor thermal control characteristics and energy performance, respectively. As a result, if lower supply water temperature is applied, the supply and return temperature difference is reduced and energy consumption of heat supply is also reduced.

• KIEAE Journal
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• 제13권3호
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• pp.111-120
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• 2013

The purposes of this study were to investigate the actual state of the indoor thermal and air environment in general apartment houses during winter in Cheongju City, to analyze the related factors with the indoor thermal and air environment, and to make suggestions for the improvement. A series of visiting field investigation was conducted in twenty units between 28th December, 2010, and 11th March, 2011. The field investigations included the measurement of physical indoor environmental conditions, the observation of architectural characteristics and resident's behavior, and the on-site questionnaire survey of residents. The measured values of each units were compared to evaluation standard and were categorized to group by the difference between units. Factors related to the difference of the measured values between the groups were analyzed. The findings are summarized as followed. The indoor temperature of apartment houses during winter in Cheongju City was generally suitable. The relative humidity was slightly dry, while the $CO_2$ concentration was found to be excessively high. The factors related indoor environment were analysed as heating operation, ventilation, gas range use, and hanging out the wash to dry in indoors.

• 한국주거학회논문집
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• 제20권4호
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• pp.19-29
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• 2009

The purpose of this study is to evaluate the air diffusion performance of a range of indoor units for room airconditioners; the wall-mounted type, floor-standing type, and ceiling-mounted type. These types of units, which have been widely used in housing spaces, will be studied with respect to thermal comfort and the energy performance using CFD analysis. In this study, current air conditioning status and related problems in housing spaces are examined, and a CFD analysis is performed in order to compare and analyze the thermal comfort and energy efficiency across each type of indoor-unit using the PMV, ADPI, EUC and FCEI indexes. The analysis results collectively considering thermal comfort and energy performance indicated that the ceiling-mounted type 4-way indoor unit showed the best diffusion performance in terms of thermal comfort, and had the second best diffusion performance in terms of energy performance after the wall-mounted type under certain conditions.

• 설비공학논문집
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• 제20권4호
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• pp.221-229
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• 2008

This study analyze indoor thermal comfort properties such as PMV, PPD and fluid variables when the cooling loads are light, occupant and ventilation. There are 6 cases to study for the indoor unit installation conditions and ventilation rates. Numerical method is used to study the indoor environmental properties and experimental study is adapted to analyze reaching time by variable cooling load conditions.

• 한국의류학회지
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• 제17권4호
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• pp.518-528
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• 1993

The purposes of this study are to know the environmental conditions of rural houses, thermal sensation and clothing weight of rural residents and to estimate the standard clothing weight according to their indoor living temperature. In this study, the 631 rural residents of both sexes and all generations were selected from 5 rural districts of Kyunggi, Kangwon, Chungnam, Chonnam and Kyungbuk province and the surveys which include clothes, environmental conditions and thermal sensation carried out 4 times-once in each season-from July 1989 to April 1990. The results of this study are· as follows. 1. The ranges of outdoor temperature are $21{\sim}31^{\circ}C$ in summer, $7{\sim}20^{\circ}C$ in spring/autumn, $-15{\sim}5^{\circ}C$ in winter and those of indoor temperature are $24{\sim}31^{\circ}C$ in summer, $15{\sim}23^{\circ}C$ in spring/autumn, $11{\sim}17^{\circ}C$ in winter. The ranges of indoor temperature is within comfortable range in spring, summer and autumn but in winter it is below the range. 2. There is a negative relationship between indoor temperature and clothing weight(r = -0.927) and the simple regression equation is as follows. Y = -61.97X + 2048.44(Y : total clothing weight $g/m^2$, X : indoor temperature $^{\circ}C$). 3. There is no significant difference of clothing weight among the thermal sensation, so clothing insulation can not affect the thermal sensation. 4. Clothing weight of light-clothing-weight group is 70~75% of middle-clothing-weight group and clothing weight of heavy-clothing-weight group is 130% of middle-clothing-weight group. So the standard clothing weight for rural residents in their indoor living is estimated as Fig. 6.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.1180-1185
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• 2006

Modern people spend most of time at indoor space, such as office or classroom. Especially, occupants are exposed to the airtight indoor air quality (IAQ) for a long time, At present, many studies on the air-conditioning systems are more focused on the individual thermal comfort than the thermal efficiency due to increase of the concern of health. There are several factors which are influenced thermal comfort, such as temperature, humidity, convection and air movement, etc. Also, the individual factor, such as age, gender, Physical constitution and habit, should be considered. The 4-way cassette type air conditioner is known to bring out better performance about thermal comfort than the traditional one. This study is performed on the higher ceiling environment than the common buildings or classrooms. Also, this study analyzed on the Indoor thermal comfort by diffusing direction of 4-way cassette air conditioner with various discharge angles, $45^{\circ},\;50^{\circ},\;55^{\circ}$ and $60^{\circ}$. Using a commercial code, FLUENT, three-dimensional transient air thermal flow fields are calculated with appropriate wall boundary conditions and standard $k-{\epsilon}$ turbulence model. Results of velocity and temperature distributions are graphically depicted with various discharge angles.

• KIEAE Journal
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• 제15권5호
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• pp.107-112
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• 2015

Purpose: This study desires to investigate an effect of indoor temperature, humidity, and illuminance targeting a planting system of double-skin facade and cavity space adjacent to the outside within a certain period of winter. Through this, the study suggests a basic material about an energy conservation effect of double window system using planting to reduce heating load of a building in winter, so desires to contribute to indoor thermal comfort effect and illuminance correction study of double window and indoor plant. Method: Considering effects such as day and night climatic elements and air conditions in winter, illuminance measurement was conducted through a double-skin facade of space, a subject of the measurement, on the basis of practical residence time of a resident, and this study analyzed characteristics of indoor illuminance about this. The study measured and compared a change of insolation, dry-bulb temperature, and relative humidity at each indoor-outdoor measuring point, so measured and compared characteristics of an indoor temperature effect by elements of double-skin facade and indoor plant. Result: Through this study, the researcher could determine that indoor plant within double window in winter not only blocks solar radiation but also photosynthesizes, so is somewhat disadvantageous to winter thermal comfort reducing heating load. In addition, solar radiation going through interior plays a role to bring down somewhat high humidity to about 50% of reasonable humidity, so plays a direct role of maintenance of comfortable indoor space. Although there are effects such as blocking of solar radiation and temperature reduction, this has a positive influence on humidity control and proper illuminance distribution. The researcher could determine that illuminance, temperature, and humidity by solar radiation penetration for the whole measuring time play a role to supplement indoor environment mutually.

• 설비공학논문집
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• 제15권8호
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• pp.683-689
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• 2003

The thermal comfort of an indoor swimming pool is different from that of general indoor space because of the characteristics of large space and the wear conditions of swimmers. Dew condensation by humid air not only makes mold on the floor, wall and roof but also decreases the durability of buildings by penetrating into their structures. In this study, the characteristics of the flow field, the temperature field and the humidity distribution in an indoor swimming pool have been examined by the numerical method to estimate the level of thermal comfort and the generation rate of dew condensation. The results showed that the dew condensation regions were spread widely at the eastern parts of the swimming pool due to the insufficient air flow rate with low velocity and temperature. To prevent the generation of dew condensation in a region, a sufficient warm air flow rate should be supplied to make an air mixing. The values of PMV at horizontal plane of 1.5 m height have the range of -1.0∼1.2, which means the suitable level for swimmers.

• Journal of Advanced Marine Engineering and Technology
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• 제32권2호
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• pp.276-283
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• 2008

The purpose of this study is to measure and analyze the ship's indoor thermal conditions and also to integrate experimental database of those which are supplied and controlled by marine HVAC. On this study, temperature, humidity and air volume of 6 different needs' cabin are measured like previous report on a newly-launched training ship during 25th through 27th of July, 2007. Followings are the results of this study. (1)The air supply volumes to each cabins are measured 250CMH(Recreation room), 800CMH(Conference room), 1.000CMH(Bridge), 5,100CMH(Lecture room) respectively. (2)The temperatures are maintained at $21{\sim}27^{\circ}C$ in almost cabins through measuring period, but the temperatures are fluctuated over ${\pm}4^{\circ}C$ at the bridge and conference room. (3)The relative humidities are shown between $40{\sim}60%$ known as comfort conditions, but the conference room is needed to dehumidified because of over 70% humidity. (4)From the student cabins' measurements which have different supply diffuser(s), it is clear that the design is suitable for this case. (5)Because of temperature diversities, only 32% among the measured data are satisfied with the comfort standard range proposed by ASHREA.

• KIEAE Journal
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• 제4권3호
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• pp.179-186
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• 2004

The evaluation of the indoor environment of the Assembly Hall in the University, which is designed to be a large space, requires efficient design of its heating system that takes into consideration natural convection and the characteristics of the occupant's spaces. Indoor thermal environment was measured in the field and simulated with CFD code. The estimations of temperature distribution and indoor airflow distribution must be carried out simultaneously, as the thermal stratification is induced by natural convection flows. In order to simulate the even distribution of factors affecting the indoor environment, including temperature and airflow, Phoenics is used. The turbulent flow model adopted is the RNG k- model. The inlets and outlets of the air-conditioning systems, material and thermal properties, and the size of the test room ($35m{\times}18m{\times}10m$) are used for the simulation. Since the Assembly Hall is symmetric, half of the space is simulated. A Cartesian grid is used for calculation and the number of grids are respectively $60{\times}45{\times}35$. The results of the computer simulation during winter conditions are compared with the measurements at the typical points in the assembly hall with the heating system. After evaluating the results of the computer simulations, the methods of the heating system and layout are suggested.