• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.860-865
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• 2006

The traditional Korean Ondol System that is a radiant floor heating system was made as warm floor and cool indoor temperature. Nowaday, Ondol is developed as the hydronic floor heating system. But unbalance of floor temperature and indoor temperature is occurred bocause strengthen thermal insulation and airtightness in building changes thermal performance. To solve these problems, we examine actual indoor environment of heating system methods in existing apartments and present the new method of floor heating system. The existing heating system made definite indoor temperatures but floor temperatures that is $22^{\circ}C-26^{\circ}C$ was maintained. To solve these problems, we adopted the differential heating system which made warm area and cool area. A differential heating system was made different pitches of heating pipe in single zone and ratio of warm area to cool area is 1 to 2. As a result of experiments, warm area temperature is $40.7^{\circ}C$, cool area temperature is $36.1^{\circ}C$. A difference of temperature between both area is 4K. A distribution of indoor vertical temperature is similar to both warm area and cool area.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.2_2
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• pp.271-278
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• 2022

The solar energy has been widely used to reduce the fossil fuel and prevent the environmental pollution. The renewable energy including solar heat tends to spread due to carbon neutrality for main country of the world. Targets of solar collector are usually acquisitions of hot water or hot air. Especially, air-heating collector using solar heat is known as the technology for obtaining hot air. This study aims to investigate of characteristics of thermal flow when the hot air by air-heating collector using solar heat flows inside of indoor space. The thermal flow of heating indoor space was simulated using ANSYS-CFX program and thus the behaviors of hot air in indoor space were evaluated with standard k-𝜀 turbulence model. As the results, as the inlet velocity was increased, the behaviors of hot air became simple, and temperature range of 25~75℃ had almost no effect on behavior of flow. As the inlet temperature was increased, the temperature curve of indoor space from bottom to top was changed from linear to quadratic. Furthermore, it was confirmed that inlet velocity as well as inlet temperature also should be considered to heat indoor space equally by air-heating collector using solar heat.

• The Korean Journal of Community Living Science
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• v.26 no.1
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• pp.115-126
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• 2015

The study investigates the clothes-wearing behaviors of female college students based on differences in indoor heating systems and cold sensitivity. The respondents included a total of 281 female college students living in South Korea and China. Data were analyzed through an ANOVA and, a paired t-test based on SPSS 21.0. Korean students were less dependent on winter clothing than Chinese students for the whole body parts except for the trunk. Korean students were more likely to feel coldness more but wore less clothing. Korean students' clothes-wearing behaviors with respect to coldness depended on the indoor heating system. Korean students tended to buy warmer clothing, although they preferred not to wear undergarments and tended to wear and to wear less winter clothing. Chinese students showed more active clothes-wearing behaviors to keep their feet warm. Finally, groups divided by indoor heating systems and cold sensitivity showed different clothes-wearing behaviors in comparison to those groups based only on indoor heating systems. Even in similar weather conditions, clothes-wearing behaviors for cold adaptation depended on the indoor heating systems and cold sensitivity. The results suggest that this perspective should be taken into consideration when evaluating clothes-wearing behaviors of certain groups or individuals.

• KIEAE Journal
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• v.16 no.2
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• pp.5-10
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• 2016

Purpose: Recently, many public office buildings which were built by curtain wall increased rapidly, but the results of the investigation of the government, these buildings have been found that the heating and cooling thermal load is high, and showed low energy efficiency. Method: To evaluate the effects by applying outdoor louver and indoor blind, which can control solar radiation in order to reduce the heating and cooling load of public office building which was built by glass curtain wall. The heating and cooling load was calculated via Energyplus, building and outdoor louver, indoor blind were modeled by Google sketchup connected to Energyplus. Result: The results of this study were as follows; the case of applying various outdoor louver, the heating and cooling load all decreased as compared to the case without applying outdoor louver, the case of applying indoor blind, the heating and cooling load decreased as compared to the case without applying indoor blind, but indoor blind showed low energy performance comparing outdoor louver.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.9
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• pp.4197-4203
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• 2013

In order to investigate the heating performance of multi-heat pump applying an inverter compressor, the experiment on heat pump with 3 indoor units was performed under the heating standard and heating low-temperature conditions. The performance data of heat pump with 3 indoor units were measured by the multi-psychrometric calorimeter. The operation characteristics and the behavior of the refrigerant cycle of the heat pump with 3 indoor units were understood from the heating capacity, heating COP, and P-h diagram by indoor-unit combination. The present experimental results show that the operating load and performance of the multi-heat pump depends on the indoor-unit combination. The heating capacity and heating COP of the low temperature condition were smaller than those of the standard one. Also the refrigerant cycles on indoor-unit combination were analyzed by using P-h diagram.

• Journal of the Korean Solar Energy Society
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• v.25 no.4
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• pp.125-131
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• 2005

This study identified satisfaction with gas heating and indoor thermal environment, targeting houses using gases for heating. 1) Thermal environment is relatively satisfactory except that indoor humidity is low. 2) A question that indoor temperature has to be decreased for saving energy was given and about two thirds of the respondents answered that temperature has to be lowered. When they were asked how to save energy 57% answered that they put on more clothes and 27% answered that they lower indoor temperature If consistent promotion on energy saving is implementer it's believed that energy can be effectively saved. 3) People wear simple clothes when they stay indoor because they think it is comfortable. However, for energy saving. they gave to wear warm clothes though they stay indoor.

• Journal of the Korean housing association
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• v.18 no.4
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• pp.1-7
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• 2007

The principle of Korean Traditional Housing was to be harmonized with the nature with shapes according to regional climate and materials easily available from the region. These environmentally friendly characteristics protected indoor environment from climate changes. The characteristics of Korean traditional housing to control indoor environment would be very useful for contemporary housing in that current issues, improving housing amenity and wellbeing, had basic goals same with what Korean Traditional Housing had. Though it could be found characteristics of indoor thermal environment heated by Ondol Heating System, analyses of evaluation made by occupants of the rooms were insufficient because most of the studies had been focused on the measurement of indoor thermal factors. Thus, with an evaluation of occupants for the indoor thermal comfort and an estimation of discomfort derived from the result of vertical temperature distribution, it was studied whether the agreeable indoor range of rooms, of which was Jeonju Hanok Living Experience Center, heated by Ondol Heating System corresponded to the agreeable indoor range presented in references.

• 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.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.2
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• pp.69-74
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• 2016

Most hot water heating valves for apartments are constant-flow types, which limit the flow rate through an individual household for even distribution of heating water to other households. The constant-flow type is implemented by an on-off control. As a result, heating water is supplied intermittently and hence, indoor air temperature also fluctuates. Returning water temperature is also high, which reduces energy efficiency. To implement continuous feedback control, the indoor temperature dynamics was simulated to fit a measured temperature history by a state-of-the-art physical model. From the model, it was found that the most important disturbance is outdoor temperature and its effect on indoor temperature lasts about an hour. To cope with the slow response and the significant disturbance, a prediction control with proportional feedback is proposed. The control was found to be successful in implementing continuous heating water flow and improved indoor temperature control.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.5
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• pp.314-320
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• 2008

The cooling load in winter is significant in buildings and hotels because of the usage of office equipments and the improved wall insulation. Hence, a multi~heat pump is required to cover heating and cooling simultaneously for each indoor unit. In this study, the operating characteristics and performance of a simultaneous heating and cooling heat pump in the cooling-main operating mode were investigated experimentally. The system adopted a variable speed compressor using R410A with four indoor units and one outdoor unit. In the cooling-main mode, the heating capacity decreased due to reduction of flow rate to the indoor unit under heating mode operation. The EEV opening was adjusted to increase flow rate to the indoor unit under heating mode operation. The total capacity and COP in the cooling-main mode increased by 20.5% and 29.2%, respectively, compared with those in the cooling-only mode.