• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.970-975
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• 2008

This study considers indoor thermal comfort in an ondol space by supply vent configurations to prevent cold draft in winter. A specially-designed vent cap has been investigated in comparison with a round pan-type vent and a simple opening without a cap. Numerical simulations have been conducted using CFD to analyze thermal comfort indices such as Predicted Mean Vote (PMV) and Effective Draft Temperature (EDT) as well as air distribution index i.e. Air Diffusion Performance Index (ADPI). Results show the new vent cap provides improved thermal comfort conditions especially near ondol heated floor, as the cold outdoor air spreads upwards along the vertical wall before reaching occupant region near floor. This paper includes discussions on the flow and comfort distributions created by the thermal jets from the vents.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.2
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• pp.143-152
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• 2002

It is critical for radiant floor cooling system using Ondol to cause condensation on a floor surface. To solve this problem, a radiant floor cooling system integrated with dehumidification was proposed and evaluated in terms of its applicability and prevention of condensation. Therresults show that the proposed system of radiant floor cooling integrated with dehumidification properly maintained the indoor setpoint temperatures and prevented the condensation on a floor surface. To achieve more stable indoor temperatures and humidity control, a further study for the operation of dehumidification panel will be needed.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.17 no.5
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• pp.598-606
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• 1988

The radiation heat-transfer coefficient is generally used to calculate radiant heat exchange of heating space. The coefficient is evenly adopted in most cases, but it is not correct in actual cases. The purpose of this paper is to grasp the changing aspect of radiation heat-transfer coefficient needed for heating load calculation of radiant heating space. Surface temperatures are measured in an Ondol space, and the coefficients are derived and examined. Gebhart's Absorption Factor Method is used for the calculations of the rates of instantaneous radiant exchange in the room. As the result, it is confirmed that the coefficients are variant according to surface temperatures, and proper coefficients are needed for each of conditions.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.7
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• pp.607-616
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• 2002

This study has been conducted to evaluate the applicability of the control method in the dehumidification-integrated radiant floor cooling system in terms of stability of the room air temperature and the control variables through experiments. To do this, the relationship between the control variables in preventing floor surface condensation is first analyzed and the control method is predetermined through simulations. The results are as follows. First, it is necessary to determine the operation status of the dehumidification system according to the relationship between floor surface temperature and dew point temperature in the conditioned space. Second, outdoor reset with indoor temperature feedback control is better than on/off bang-bang control with respect to temperature stability in controlling the room air temperature and the possibility of energy savings. Finally, the humidity sensor can be located with the current thermostat in that there are small differences in absolute humidity in vertical distribution.

• Transactions of the Korean Society of Mechanical Engineers
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• v.11 no.3
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• pp.409-424
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• 1987

Simulation on the hot water ONDOL heating system was made in order to investigate the variation of room temperature and specific fuel consumption of boiler. Heat balance equation was derived by response factors and solved implicitly. Variation of room temperature and specific fuel consumption of boiler were calculated with respect to the thickness of room floor, the absorptivity of wall for solar radiation, on-off temperature range of boiler and air exchange. The results show that specific fuel consumption of boiler is independent of the thickness of room floor and decreases with increasing the absorptivity of wall and on-off temperature range of boiler. However, it increases with increasing the air exchange. They also show that, when the absorptivity and on-off temperature range of boiler are increased, the amplitudes of room temperature variation increase.

• Journal of the Korean housing association
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• v.15 no.3
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• pp.73-82
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• 2004

The objective of this study is to demonstrate the potential of radiant cooling systems using Ondol as an alternative cooling system in residential buildings. For this purpose, computer simulation and model experiments have been performed for the system performance analysis regarding comfort, floor surface condensation, and supply water temperature. The results of this study is the following: In radiant floor cooling system, room air temperatures were maintained within the set temperature range of $\pm$1$^{\circ}C$ without any discomfort condition. And taking into account only the condensation occurrence, it was possible to achieve radiant floor cooling for a period of about 77% of the total cooling period in weather condition of Seoul. The minimum supply water temperature is about 15$^{\circ}C$, so renewable energy system such as ground heat exchange system can be used as an alternative in cooling source. Also, floor surface condensation can be prevented by integrating with the dehumidification system.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.7 no.3
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• pp.160-166
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• 1978

Heat loss to the ground in ondol heating system is analyzed mathematically using conformal mapping and variable transformations, Both two-and three-dimensional systems are analyzed. Heated house is assumed to be rectangular shape. Mean value of heat loss to the ground can be obtained using Figure 2. Effects of thermal parameters to heat loss are discussed. Numerical examples are also given.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.4 no.2
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• pp.119-128
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• 1975

Natural draft and flow which low temperature moist gas produces in the chimney of an Ondol heating system were numerically analysed. Among several factors involved inlet gas temperature has the strongest influence on the chimney performance and then next specific humidity of the gas. Thermal conductivity of the chimney wall, however, has little influence on the performance of such a low temperature chimney. Under given flow conditions there exists an optimum chimney height which gives a maximum flow rate for a given chimney diameter. This optimum value of chimney height inereases with increase in chimney diameter, inlet gas temperature and specific humidity.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.333-334
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• 2023

Interest in the commercialization of research results is increasing according to the recent social atmosphere. In the field of construction, new technologies are also being actively commercialized. Pre-analysis of products is an important procedure for future market entry. This study aims to conduct a product-based importance-performance analysis as one of the preliminary analysis methods for the commercialization of technologies developed in the field of construction and to explore their applicability. This study conducts a survey on those involved by setting the categories of product quality, convenience, and usability for the commercialization of previously developed pipeline inspection product. Based on this, we would like to present an analysis that calculates importance and performance of the product and helps to set the development direction through interrelationship analysis.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• v.11 no.2
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• pp.213-216
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• 2006