• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 춘계학술발표대회 논문집
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• pp.109-114
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• 2009

The dominant heating system used in Korean residential apartment buildings is a hydronic radiant floor heating system, known as the Ondol system. The most common control strategy applied to this traditional hydronic radiant system is a simple on-off control that intermittently supplies "hot water of a fixed temperature" at a "constant flow rate" to each room. However, the current problems with the aforementioned control are as follows: (1) since the simple on-off control is usually based on a one point measured temperature (a signal from a thermostat installed in a living room) in each dwelling unit, heating energy use for unoccupied rooms as well as a difference in temperatures between spaces (master bedroom, living room, bedroom1, bedroom2) can occur occasionally. (2) the most widely used residential water splitter has static valves, and is thus not able to change the flow rate to each room depending on the space heating load. In other words, the ratio of flow rates to rooms is fixed after construction, resulting in over- or under-heating and an improper use of energy. The aim of this paper is therefore to investigate the differences in the system's performance between control strategies in terms of the flow rate control and sensor location. It is shown that energy savings of control strategies are strongly influenced by occupant schedule.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2000년도 춘계학술강연 및 발표대회 강연 및 발표논문 초록집
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• pp.18-19
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• 2000

• 한국재료학회:학술대회논문집
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• 한국재료학회 1999년도 춘계학술발표강연 및 눈문개요집
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• pp.79-79
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• 1999

• 설비공학논문집
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• 제16권5호
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• pp.421-429
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• 2004

In Korea, the radiant heating system has been widely used as a residential heating method, which has been modernized to use hot water running into the tubes embedded in the floor structure. According to the recent improvement of living standard of residential buildings, the requirement of the thermal comfort and energy saving in heating system has been raised. Until now, the radiant floor heating system has been controlled by room thermostat installed in the living room, but for better thermal comfort, an individual room control method is adopted as an alternative. Therefore, it is necessary to evaluate the control performance between the current control method and the individual room control method. In this study, the control performance between the two systems is evaluated through the field experiment. And the control performances of room air temperature and energy performances are analyzed through the simulation using TRNSYS. Firstly, the simulations are performed in the various outdoor conditions and the flow rates and the simulation results are analyzed for the control performances. Also, to evaluate the energy performance, the simulations are performed under the operating conditions in which the set-point of the room air temperature is fixed or changed according to the schedule of occupancy, and the simulation results are analyzed between the two methods.

• 한국세라믹학회지
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• 제16권3호
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• pp.135-141
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• 1979

This study seeks to find optimum conditions for the heating schedule of the Diopside-Devitrite system, to find the amounts and the kinds of nucleus which effect the crystal growth and forming nucleus. Generally, crystallization in the glass depends on the number of nucleus growing in the internal system and the rate of crystal growth. In order to obtain homogeneous polystalline phae, Diopside as MgO source and $ZrO_2$.$P_2O_5$, $TiO_2$, NaF, $CaF_2$ as nucleating agents were added to the $Na_2O$.CaO.$6SiO_2$ glass. The results obtained were Summarized as follows. 1) Optimum Batch Composition of base glass is 76.82 wt.% $SiO_2$, 5.84 wt.% CaO, 4.54 wt.% MgO and 9.80 wt.% $Na_2O$. 2) Best heating schedule.140$0^{\circ}C$(Melting)coolinglongrightarrow95$0^{\circ}C$reheatinglongrightarrow$1100^{\circ}C$coolinglongrightarrowRoom Temp. 3) The optimum amounts of $ZrO_2$.$P_2O_5$, $TiO_2$ and $CaF_2$ are 3wt.% and that of NaF is 4 wt.% as a nucleating agents.

• 한국분말재료학회지
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• 제17권1호
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• pp.29-35
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• 2010

We produced cylindrical porous TiNi bodies by Self-propagating High-temperature Synthesis (SHS) process, varying the heating schedule prior to ignition of a loose preform compact made from (Ti+Ni) powder mixture. To investigate the effect of the heating schedule on the behaviour of combustion wave propagation and the structure of porous TiNi shape-memory alloy (SMA) body, change of temperature in the compact during SHS process was measured as a function of time and used for determining combustion temperature and combustion wave velocity. Microstructure of produced porous TiNi SMA body was observed and the results were discussed with the combustion characteristics. From the results it was concluded that the final average pore size could be controlled either by the combustion wave velocity or by the average temperature of the preform compact prior to ignition.

• 한국태양에너지학회 논문집
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• 제32권5호
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• pp.11-17
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• 2012

In this study, a simulation program was developed with heat transfer model in the thermal storage tank for a solar collector and burner combined heating and hot water supply system. Analysis was conducted with variation of operating condition and schedule to analyze performance of a hot water supply and panel heating system with a solar collector and burner combined thermal storage tank. The simulation program is divided two sections. One part is calculation of temperature variation of water which flows through the panel in the floor for heating of the residential house during 24 hours, and the other part is heat transfer calculation for the reaction time to get desired water temperature in the thermal storage tank. As results, light oil consumption and system performance during operation period were analyzed with variation of climate condition and with or without solar collector. Most of the case, oil could be saved about from 24 to 41% with installing the solar collector. The performance of the system is more dependent on radiation time of the solar collector rather than the intensity of the solar radiation which was adopted for the climate analysis.

• KIEAE Journal
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• 제13권4호
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• pp.69-74
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• 2013

It is difficult to apply a design standard uniformly to university buildings because various education courses are conducted. However, a design guideline for saving energy is necessary in order to prepare for low-energy days. A library in any university is one of the buildings that a lot of people use and most of the energy is spent. Therefore, the investigation on the energy savings of library facilities is very important and urgent. This study finally presents the design guideline of those facilities for low-energy. In this paper, the trend of space layout, utilization schedule and performance of materials are investigated, and the impact on energy savings and effective energy saving strategies are analyzed and illustrated by energy simulation. As a result of energy analysis from the case of 'H' university, it is confirmed that the utilization schedule effects mostly to energy consumption and the layout and orientation of the rooms in the library are the major parameters. Among the investigated saving strategies, green roofs are found as the most effective part for heating energy savings, and outdoor air cooling is known as the most effective method for cooling energy savings.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2009년도 추계학술대회 논문집
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• pp.279-283
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• 2009

Distributed generation(DG) of combined cooling, heat. and power(CCHP)has been gaining momentum in recent year as efficient, secure alternative for meeting increasing energy demands. This paper presents the energy performance of microturbine CCHP system equipped with an absorption chiller by modelling it in hospital building. The orders of study were as following. 1)The list and schedule of energy consumption equipment in hospital were examined such as heating and cooling machine, light etc. 2) Annual report of energy usage and monitoring data were examined as heating, cooling, DHW, lighting, etc. 3) The weather data in 2007 was used for simulation and was arranged by meteorological office data in Daejeon. 4) Reference simulation model was built by comparison of real energy consumption and simulation result by TRNSYS and ESP-r. The energy consumption pattern of building were analyzed by simulation model and energy reduction rate were calculated over the cogeneration. As a result of this study, power generation efficiency of turbine was about 30% after installing micro gas turbine and lighting energy as well as total electricity consumption can be reduced by 40%. If electricity energy and waste heat in turbine are used, 56% of heating energy and 67% of cooling energy can be reduced respectively, and total system efficiency can be increased up to 70%.

• 설비공학논문집
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• 제22권6호
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• pp.392-397
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• 2010

Energy loss from windows accounts for large scores of heating and cooling loads also in energy saving apartments that is reduced over 30% of total energy consumption. Movable reflective insulations, insulation shutters, blinds, insulated shades are used to reduce energy loads from windows. In this study, energy saving performance of insulated shades was simulated by control methods. According to installation of insulated shades, heating loads were decreased about 10.5~11.3%, and cooling loads are decreased about 29.1~38.3% on an energy saving apartment. The heating peak load was reduced about 9.5% by insulated shades and the cooling peak load was reduced about 25.7~31.5%. In the case of insulated shades with automatic control system, simple time schedule control system would be more efficient than outdoor detection control system that should use several sensors.