• Journal of the Korean Solar Energy Society
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• v.27 no.3
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• pp.79-85
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• 2007

This paper addresses the indoor air quality when radiant floor heating is applied in large space. Radiant heat exchange between surfaces depends on the orientation and the temperature of the surfaces. Also, the temperature and the radiant characteristic of the wall and the roof that face the floor have great influence on the indoor air environment due to the largeness of the wall and the roof in large spaces. In this study, we simulate a test-cell(25X20X10) using a ies YE And using a CFD(microflo in VE), an indoor air environment was investigated to establish the optimum temperature of floor. At the first time of the heating, high floor temperature is demanded. At the middle of the heating, however, the temperature of the residential space was formed appropriately, although the temperature of the floor was set low.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.08a
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• pp.119-125
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• 2004

Radiant tube heaters are widely used for indirect heating in heat treatment processes such as continuous annealing line(CAL) or continuous galvanizing line(CGL). Main issues for radiant tube are temperature uniformity, lifetime, thermal efficiency. To achieve higher heat release, the radiant tubes are fired at a higher fuel rate and therefore local overheating occur. A numerical simulation based on a commercial code FLUENT has been performed to investigate local overheating of radiant tube heaters. To minimize local overheating, the effects of radiating fins, flue gas recirculation(FGR), two-stage combustion were investigated. More uniform temperature distribution was achieved in the longitudinal direction within the tube with radiating fins and this contributed to increase the life of radiant tubes. Furthermore, the radiant tube with radiating fins was proven to be more efficient than the one without fins. The effects of flue gas recirculation and two stage combustion on the efficiency of the radiant tube were also considered and the results were presented.

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1300-1305
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• 2004

The purpose of this experiment is to study the radiant cooling effects by a plate directly viewing the nighttime sky. The measurements are performed at a rooftop of the Engineering building at the Dongguk University in Seoul during the month of August in 2004. The radiant cooling effects are compared using three different types of plate surfaces such as galvanized Iron, black painted, and aluminum film coated galvanized iron plate. Among these plates, the black painted surface show the lowest temperature that is lower than its ambient temperature. The maximum radiant cooling temperature difference, that is ambient temperature minus plate temperature, observed is about 5K..

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.11
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• pp.1165-1173
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• 2001

The objectives of this study are to analyze the application of radiant floor cooling and to evaluate the control methods through experiments when the radiant heating system is used for cooling. Through the experiment analysis the control methods such as on/off control, variable flow control and outdoor reset with indoor temperature feedback control are evaluated and compared. The cooling curve (reset ratio) is found for radiant cooling, which shows tole relation between outside air temperature and supply water temperature. Comparison of cooling methods shows that outdoor reset with indoor temperature feedback control is more appropriate than on/off control and variable flow control with regard to prevention of the condensation and thermal comfort.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.6
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• pp.605-610
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• 2005

The purpose of this experiment is to study the radiant cooling effects by a plate directly viewing the nighttime sky. The measurements are performed on a rooftop of the Engineering building at the Dongguk University in Seoul during the month of August in 2004. The radiant cooling effects are compared using three different types of plate sufaces, namely, galvanized iron, black painted, and aluminum film coated galvanized iron plate. Among these plates, the black Painted surface showed the lowest temperature that is lower than the ambient temperature. The maximum radiant cooling temperature difference, which is ambient temperature minus plate temperature, observed is about 5 K.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.30 no.2
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• pp.68-82
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• 2018

Radiant floor heating systems with capillary tubes are energy saving systems in which hot water is circulated into capillary tube with a small diameter. In this study, the heating performance of capillary tube system is investigated in an experimental study and a simulation model. The results of the study showed that, the capillary tube radiant floor heating system maintains a more stable floor surface temperature in comparison a PB pipe system. In terms of energy consumption, the capillary tube radiant floor heating system proved to be more efficient than the PB pipe heating system at $40^{\circ}C$ of low temperature hot water supply. The difference between water temperature and room temperature can be held low for heating which saves energy. Low temperature radiant floor heating system with capillary tubes have significant advantages such as health improvement, low energy cost, optimum use of heat source(boiler) and higher operational efficiency.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.14 no.3
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• pp.187-199
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• 1985

The low-temperatured radiant heating System like a panel heating system is recognized as nice means to make comfortable indoor environment. Perhaps, 'Ondol' would be a typical example of the Panel heating system. Nevertheless. Occupants in a radiantly heated Space which has an asymmetric radiant field may feel thermally discomfort due to the asymmetric radiation. The aim of this Study is to suggest the fundamental technical data for establishing Standards of thermally comfortable environment when designing a radiant heating System. Thermal distribution of indoor environment and the skin temperature of the occupants were measured at experimental room in KIER (Korea Institute of Energy and Resources). Whole/Regional thermal and comfort Sensation votes of the occupants were taken simultaneously in order to investigate the relationships between thermal environmental factor and the occupants' responses. The effect of an asymmetric radiation on thermal environment and the occupants' responses was analyzed by using a v.r.t.(vector radiant temperature). By this means, the thermally neutral limits for the ambient air temperature and the floor surface temperature by the occupants' responses were Obtained. And the recommended temperature limits of the indoor surface were derived from the experimental work and the theory of radiant and will provide thermal neutrality for man without any discomfort on the part of the body.

• KIEAE Journal
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• v.12 no.4
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• pp.89-95
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• 2012

At present, many countries are trying to reduce green gas emissions to mitigate the effects of these gases on climate change. Year after year, there have been efforts to cut energy use for heating and cooling. Heating and cooling systems, common in all forms of housing, are increasing due to the constant supply of new housing resulting from improvements in economic growth and the quality of life. Thus, studies related to the design of cooling and heating systems to improve energy efficiency are expanding. Among the new designs, radiant floor cooling and heating systems which use capillary tubes are becoming viable means of reducing energy use. Radiant floor cooling and heating systems which use capillary tubes are creative and sustainable systems in which cool and hot water is circulated into capillary tube which has small diameter. In this study, the cooling and heating performance of this type of capillary tube system is investigated in an experimental study and a simulation using TRNSYS. The results of the experimental study show that under a peak load, a capillary tube radiant floor cooling system using geothermal energy can achieve desired indoor temperature without an additional heat source. The set room air temperature is maintained while the floor surface temperature, PMV and PPD remain within the comfort range. Also, this system is more economic than a packaged air conditioner system due to its higher COP. The results of the simulation show that the capillary tube radiant floor heating system maintains set temperature more stable than a PB pipe radiant floor heating system due to its lower supply temperature of hot water. In terms of energy consumption, the capillary tube radiant floor heating system is more efficient than the PB pipe radiant floor heating system.

• Korean Journal of Adult Nursing
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• v.20 no.1
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• pp.135-148
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• 2008

Purpose: This study compared the effects of forced air warming and radiant heating on body temperature and shivering of patients with postoperative hypothermia. Methods: The quasi-experimental study was conducted with two experimental groups who had surgery under general anesthesia; 20 patients of group 1 experimented with the Bair Hugger as a forced air warming and 20 patients of group 2 experimented with the Radiant heater. The study was performed from July 3 to August 31, 2006 in a recovery room of an university hospital in a city. The effects of the experiment were measured by postoperative body temperature and chilling score at arrival and after every 10 minutes. The data were analyzed by t-test or ${\chi}^2$-test, repeated measures ANCOVA using SPSS/WIN 12.0. Results: The mean body temperature showed differences between the Bair Hugger group and Radiant Heater group at 40 minutes(F=-2.579, p=.034), 50minutes(F=-2.752, p=.027), and 60 minutes(F=-2.470, p=.047) after arrival to the recovery room. So, hypothesis 1 was partially accepted. The mean score of shivering showed differences between the Bair Hugger group and the Radiant Heater group, but it had no significant meaning. Hypothesis 2 was not accepted. Conclusion: We need more study to explore the effects and side effects of heating modalities to select a more effective heat treatment. The efficiency of heat modalities with regards to cost benefit, time consumption, and patients' discomfort such as burns should be considered.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.12
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• pp.1140-1148
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• 2004

Recently the Predicted Mean Vote (PMV) has been used as an important index to evaluate the degree of the indoor thermal comfort in modern residential buildings. It is known that the PMV is mainly affected by four major factors, which are the air temperature, the air velocity, the humidity and the mean radiant temperature (MRT). Through the numerical calculation of the temperature and the modeling of the mean radiant temperature considering the solar radiation, we proposed the new modeling strategies of the mean radiant temperature and investigated the PMV index and evaluated the MRT. Also, we compared the numerical results with the experimental values. As the results, we found out that the MRT is affected by the wall temperature and the solar radiation. We also knew that the new modeling strategies of the mean radiant temperature is a more correct way of PMV calculation. Especially, the new modeling is necessary for the spaces like an atrium and large rooms with windows mainly influenced by solar radiation.