• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.12
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• pp.830-836
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• 2012

In this study, the effects of heating control methods on heating control performance and energy consumption in the floor radiant heating control system of residential apartments were research by computer simulation. A general regression neural network(GRNN) control method for reducing indoor temperature overshoot and saving energy in floor radiant heating system is suggested. The GRNN control method shows good responses in comparison with the conventional and outdoor reset control methods for improving indoor thermal environment and reducing energy consumption.

• Fire Science and Engineering
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• v.27 no.2
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• pp.62-69
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• 2013

In this study, a full scale experiment was carried out to analyze the heat and smoke movement. The experiment was conducted a kindergarten that is scheduled to reconstruction. The kindergarten is a two-story building and the area of each floor is 252 $m^2$. 36 l heptane was used as a fuel and heptane was burned in a 0.8 m square steel pool. Maximum heat release rate was 1.7 MW at natural condition. Smoke movement and temperature variation were measured during the experiment. In the first floor corridor, smoke was moved downward about 1.4 m at 1 minute after a fire. Corridor was filled with smoke at 4 minutes after a fire. In the second floor, temperature was maintained at $70^{\circ}C$ or less. But, second floor rooms were filled with smoke.

• The Journal of the Acoustical Society of Korea
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• v.37 no.5
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• pp.338-342
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• 2018

In order to solve the floor impact sound problem in the upper and lower floors, the Ministry of Land, Transport and Maritime Affairs also notifies the physical properties of the resilient material affecting the floor impact sound level. The dynamic modulus of elasticity and the loss factor before and after heating are most related to the floor impact noise, especially for the cushioning material. Therefore, in this study, the rate of change with respect to the dynamic modulus and loss factor with temperature change was examined by increasing $10^{\circ}C$ by $10^{\circ}C$ from the temperature condition of $70^{\circ}C$ specified in the standard. The dynamic modulus of elasticity and the loss modulus were measured by using the pulse excitation method for eight kinds of samples. The calculation method was calculated by the time series analysis method using the damped vibration waveform.

• Transactions of Materials Processing
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• v.10 no.2
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• pp.123-129
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• 2001

This study is to investigate the effects of cold forming method with steel sheet of SCP3C to improve continuous productivity. Experiments were carried out in various working conditions, such as the number of stamping and the punch temperature. The effects of the punch temperature and the number of stamping on drawability of steel sheet of SCP3C as well as clearance and draw-in in the number of stamping were examined and discussed. More improvement of continuous productivity in case of cold stamping rather than by conventional stamping at room temperature is obtained. The optimum forming condition for drawing trunk floor panel of SCP3C is shown as the punch is cooled by coolant of $-5^{\circ}C$ and at the same time both the die and the blankholder are heated by stamping and frictional heat.

• Journal of the Korean housing association
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• v.14 no.5
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• pp.75-82
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• 2003

In this study, the thermal performance of the room control system is analyzed in terms of control performance, potential for coil expansion and energy consumption through experiments comparing the individual room control system and an existing system. The results of this study show that the existing system is not able to supply design water flow rate and does not accurately maintain the set point temperature in each room. However, the individual room control system can set a room air temperature for each room, for it is able to supply design water flow and accurately control the set point temperature in each room and can reduce the energy consumption compared to the existing system. Moreover, the individual room control system can reduce the number of coil division zone and facilitates the construction process, because it can extend the length of the coil division.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.8
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• pp.682-691
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• 2001

Most of radiant floor heating systems are operated in the intermittent heating mode in Korea. The application possibility of predictive suboptimal control for Koran residential house was investigated by computer simulation and experiment. For this study, TRNSYS program was used and an experimental facility consisting of tow rooms ($3\times4.4\times2.8 m$) identical in construction was built. The facility enabled simultaneous comparison of two different control method. And real multi residential hose was investigated. Results showed that outdoor air temperature prediction control was superior to the conventional control for radiant floor heating system operated in the intermittent heating mode. New control system resulted in good thermal environment and les energy consumption.

• Journal of the Korean housing association
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• v.21 no.3
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• pp.1-9
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• 2010

The purposes of this study were to determine the actual state of indoor environments of solitary elderly houses in the rural district during winter and to analyze the relationship between the influencing factors and indoor physical elements. Field surveys consisted of measurements of physical elements, observations of living factors, and resident's responses in interviews. Field surveys were carried out in 4 houses from $28^{th}$ of February to $2^{nd}$ of March 2008. The elements measured were air temperature, relative humidity, floor temperature, seating-place temperature, CO2 concentration, CO concentration, and illumination. The results showed that the average indoor temperature for houses was $13.5{\sim}22.5^{\circ}C$, relative humidity was 30.6~55.4%, floor temperature was $13.9{\sim}24.0^{\circ}C$, temperature when seated was $27.6{\sim}51.1^{\circ}C$, $CO_2$ concentration was 1434.6~3305.5 ppm, CO concentration was 2.8~8.4 ppm, and illumination was 31.0~96.7 lux. The residents' clothing values were 1.10~1.78 clo. The environment was evaluated as being in an unsuitable state, and it was revealed that the main reason was the lack of heating and ventilation.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2008.11a
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• pp.452-457
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• 2008

The purposes of this study were to determine the actual state of indoor environment and to analyze the relationship between the living factors and indoor physical elements in solitary elderly houses at rural district during winter. The field surveys were consisted of measurements of physical elements, observations of living factors, and interviews of resident's responses. The field surveys were fulfilled in 4 houses from February to March 2008. Measuring elements were air temperature, relative humidity, floor temperature, seated place temperature, $CO_2$, CO, and illumination. The results showed that the average of indoor temperature for houses was $13.5{\sim}22.5^{\circ}C$, relative humidity was $30.6{\sim}55.4%$, floor temperature was $13.9{\sim}24.0^{\circ}C$, seated place temperature was $27.6{\sim}51.1^{\circ}C$, $CO_2$ was $1434.6{\sim}3305.5ppm$, CO was $2.8{\sim}8.4ppm$, illumination was $31.0{\sim}96.7lux$. The residents' clothing values were $1.10{\sim}1.78clo$. Most of the residents' subjective responses were in discord with the physical elements. It was evaluated to be uncomfortable state, and the main reason was revealed lack of heating and ventilation.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.2
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• pp.190-195
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• 2012

In this study, as a complementary study of the former study on indoor thermal environment in a tower type apartment house at tropical nights, a field measurement was conducted in winter season. Mainly, characteristics of heat storage and heat emission in apartment structures, in this study, were investigated. As results, indoor air temperature was changed in the range of $22.5^{\circ}C{\pm}1.0^{\circ}C$, and followed not the change of outdoor air temperature but the changed pattern of floor surface temperature. Wall surface temperature was unresponsive to the change of floor surface temperature compared with the change of indoor air temperature because wall structure was composed of concrete which has large heat capacity, and was changed in the range of $22.3^{\circ}C{\pm}0.6^{\circ}C$. Heat was stored continuously into the structures of wall and ceiling through the measurement term. and this means that a large heat capacity of the apartment structure acts as a disadvantage in winter season, too. As a total review of the study with the former study, a large heat capacity of the apartment structure acts against indoor thermal comfort in winter season as well as in summer season.

• Journal of Power System Engineering
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• v.18 no.4
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• pp.23-28
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• 2014

In order to increase the performance of conventional hot water floor heating system, the bubble jet loop heat pipe for the system was developed. This experiment was conducted under next conditions : Working fluid was R-134a, charging ratio was 50%. A temperature of hot water, room temperature and flow rate were $60^{\circ}C$, $15^{\circ}C$ and 0.5~1.5 kg/min, respectively. The experimental results, show that bubble jet loop heat pipe had a high effective thermal conductivity of $4714kW/m^{\circ}C$ and a sufficient heat flux of $73W/m^2$ to heat the floor to $35^{\circ}C$ in case of the 1.5 kg/min of flow rate. So the bubble jet loop heat pipe has a possibility for appling of the floor heating system. Additionally, the visualization of bubble jet loop heat pipe was performed to understand the operating principle. Bubbles made by the narrow gap between inner tube and outer tube of evaporating part generate pulsation at liquid surface of working fluid. The pulsation had slug flow and wavy flow. So working fluid circulates in the bubble jet loop heat pipe as two phase flow pattern. And large amount of heat is transferred by the latent heat from evaporating part to condensing part.