• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.403-407
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• 2005

Objective of the research is to demonstrate solar thermal space and ground heating system which is integrated to a greenhouse culture facility for reducing heating cost, increasing the value of product by environment control, and developing advanced culture technology by deploying solar thermal system. Field test for the demonstration was carried out in horticulture complex in Jeju Island. Medium scale solar hot water system was installed in a ground heating culture facility. Reliability and economic aspect of the system which was operated complementary with thermal storage and solar hot water generation were analyzed by investigating collector efficiency, operation performance, and control features. Short term day test on element performance and Long term test of the whole system were carried out. Optimum operating condition and its characteristics were closely investigated by changing the control condition based on the temperature difference which is the most important operating parameter. For establishing more reliable and optimal design data regarding system scale and operation condition, continuous operation and monitoring on the system need to be further carried out. However, it is expected that, in high-insolation areas where large-scale ground storage is adaptable, solar system demonstrated in the research could be economically competitive and promisingly disseminate over various application areas.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.1911-1913
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• 1998

This paper has described about a SEPP Inverter for induction heating load. It is analyzed theoretically about the Inverter operation for induction heating. According to the parameters of induction heating load, it is proposed a method of circuit analysis and operation characteristics of the Inverter. In addition, the soft switching technology known as ZVS(Zero Voltage Switching) is used to reduce turn on and off loss at switching. The Proposed inverter shows it can be practically used as power source system for high frequency induction heating appliancs.

• Solar Energy
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• v.18 no.4
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• pp.95-100
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• 1998

Indoor environment of the classrooms in most school buildings have not been maintained comfortably during the heating and cooling seasons due to the insufficient installation of the heating and cooling systems and their operation in our country. This study aimed to suggest the guideline for installing the appropriate heating systems to make a better environment of the classrooms in the elementary school buildings. Field survey and the computer simulation of the model school were carried out, and the cost of the both installation and operation were compared with different heating systems.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.27 no.1
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• pp.31-38
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• 2015

Geothermal heat pump (GHP) systems have become an efficient alternative to conventional cooling and heating methods due to their higher energy using efficiency. These systems use the ground as a heat source in heating mode operation and a heat sink in cooling mode operation. The aim of this study is to evaluate the heating performance of the GHP system for a residential building ($420m^2$) in Ulaanbaatar, Mongolia. In order to demonstrate the feasibility of a sustainable performance of this system, we installed the water-to-water geothermal heat pump with ten vertical ground heat exchangers and measured operation parameters from October 19, 2013 to March 26, 2014. The results showed that the entering source temperature of brine from the ground heat exchangers was in a range of the design target temperature of $-10^{\circ}C$ for heating. For total values of the representative results, the ground heat exchangers extracted heat of 53.51 MWh from the ground. In addition, the GHP system supplied heat of 83.55 MWh to the building and consumed power of 30.27 MWh. Consequently, the average heating seasonal performance factor ($SPF_h$) of the overall system was evaluated to be 2.76 during the measurement period of the heating season.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.2545-2552
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• 2014

This study is aiming to suggest the effective thermal management system design technologies for the high voltage and capacity battery system of the electricity driven vehicles and introduce the theoretical designing methods. In order to investigate the effective operation of the battery system for the electricity driven vehicles, the heat generation model for Li-ion battery system using the chemical reaction while charging and discharging was suggested and the thermal loads of the heat sources (air or liquid) for cooling and heating were calculated using energy balance. Especially, the design methods for the cooling and heating of the battery system for maintaining the optimum operation temperature were investigated under heating, cooling and generated heat (during charging and discharging) conditions. The battery thermal management system for the effective battery operation of the electricity driven vehicles was suggested reasonably depending on the variation of the season and operation conditions. In addition, at the same conditions under summer season, the cooling method using the liquid and active cooling technique showed a relatively high capacity, while cooling method using the passive cooling technique showed a relatively low capacity.

• Journal of the Korean housing association
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• v.2 no.2
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• pp.35-40
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• 1991

In this study, the operation(heating) period of heat source(boiler) machineries in apartment building for periodic heat load analysis has been established by investigating their heat source machineries actural operation period, energy consumption, the capacity of heat source machineries, and their building element. Thus, the purpose of this paper is at bring up the various pre-estimate expression for energy conservatiove, efficient operation and amount of water supplied.

• Journal of environmental and Sanitary engineering
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• v.17 no.2
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• pp.18-25
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• 2002

The comparison of the air quality with the evaluation of the environmental assessment before and after operations of the heat source and of the flue-gas desulfurization facilities were studied. First of all, several sites were selected for the representative sample points, and then they were examined air quality of the surroundings. The results were that TSP(total suspended particulate) analysis after an operation of the heat source facility was $74~81{\mu}g/m^3$, PM-10 was $31~94{\mu}g/m^3$, and $SO_2$concentration was 0.002~0.009ppm, respectively. As the result of examination to the concentrations of diffused pollutants, there was no relations between TSP concentration of sample points and the effect of air quality according to the heating source. When we compared the neighbored area of the heating source with the other area, the concentration of air pollutants after an operation of the facility of the heating source was similar to the heating source, the neighbored area, and the other area. So we concluded that there was no the effect of the air pollution by producted pollutants from the heating source.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.7
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• pp.551-556
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• 2003

The present study concerns an experiment on the heating characteristics of a system air-conditioner (A/C) using PWM method or inverter method at low temperature con-ditions. The compressors used are digital scroll type and BLDC inverter type. Under the low outside temperature condition, -5$^{\circ}C$, -1$0^{\circ}C$, -15$^{\circ}C$, heating capacities and COPs are mea-sured by the psychometric calorimeter using air enthalpy method. Also, outlet air temperatures at heating operation mode are measured at -5$^{\circ}C$, -1$0^{\circ}C$ and -15$^{\circ}C$. Experimental results show that COPs of the system A/C using a PWM method are more effective than those of the inverter method at heating operation mode. Although the heater is on, COPs of PWM method are similar to those of BLDC inverter method. Moreover, the heating capacities of PWM method at -5$^{\circ}C$, -1$0^{\circ}C$ and -15$^{\circ}C$ are larger about 10~20% and outlet air tempe-rature at -15$^{\circ}C$ is larger about 10%, compared to the inverter method.

• 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.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.12
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• pp.979-986
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• 2003

The performance characteristics of heating and cooling operation for a heat pump system using seawater heat source and exhaust energy are presented. The heat pump system is made of a waste heat recovery system and a vapor compression refrigeration system. The working fluid is R-22. The heat pump system COPs are measured during heating and cooling operation modes, and the resultant COPs were 9.7 and 7.9, respectively, which are three times higher than those of the heat pump itself. Therefore, the performance of the heat pump system using exhaust energy is excellent compared to that of a general heat pump. The experimental data can be effectively used for the design of the high efficient heat pump using a seawater heat source.