• Journal of the Korean housing association
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• v.20 no.6
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• pp.39-46
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• 2009

It has been a serious problem to consume the energy of apartment while increasing to use of heating & cooling System because of residence environmental upgrades. Great attention has been shown to the problem of the rental apartment, so there are few reports of energy consumption about the rental apartment in korea. To solve the lack of housing, our country has supplied an enormous volume of apartments, and these days it occupies 75% of our buildings. As apartments occupy most of our housings, the rate of energy usage from them are also high. On this, setting apartment energy reduction as a target, by researching the actual conditions of energy consumption and drawing a basis data, we can apply this as a way of saving energy, rationalization of the scale of energy supply facilities and a standard when planning facilities. To grasp the present condition of energy usage of the urban rental apartment, this research analysed the use of electricity, gas and water monthly and annually of a rental apartment that is located in Daegu. The results showed that in 2003 the electricity usage was 1,198MWh but 1,315MWh in 2007, which means 9% of electricity usage increases every year. The average of water usage was $85,072\;m^2$ per year and typical energy consumption unit was $604.2\;MJ/m^2$ on $74.4\;m^2$ of area and $448.8\;MJ/m^2$ on $105.8\;M^2$. By showing the usage of energy and water of the urban rental apartment, understanding the tendency and preparing an typical energy consumption unit standard through this research, apartments should use energy more efficiently.

• Korean Journal of Construction Engineering and Management
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• v.18 no.1
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• pp.27-36
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• 2017

Ministry of Land, Infrastructure and Transport established Heating and cooling energy conservation plan of apartment for 2017, reducing 90% compared to energy consumption of 1990. Also, at 2015 United Nations Climate Change Conference, the Ministry announced to reduce 37% of estimated $CO^2$ emission(850 million ton) at 2030. To satisfy this, it is urgent to reduce $CO^2$ emission due to the building, which takes majority amount of total $CO^2$ emission, and public interest for the commissioning of intensified building performance is uprising. However, the building commissioning at construction is not enacted, and not activated due to the lackness of promotion and will of general contractor. Furthermore, commissioning is not mandatory for obtaining G-SEED certification. Therefore, this paper describes effectiveness of commissioning with comparison of commissioning evaluation criteria of G-SEED with LEED and BREEAM, to propose making commissioning as mandatory process and drive changes in perception among stakeholders for activation of domestic building commissioning.

• Journal of the East Asian Society of Dietary Life
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• v.26 no.6
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• pp.517-530
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• 2016

This research was conducted on Seoul region elementary, middle, and high school nutritionists to analyze execution conditions of HACCP control standards, focusing on PHF and CCP 3~CCP 7, in order to determine more efficient methods for school meals' sanitation system settlement. All surveys were distributed and collected via email. A total of 305 survey papers were collected, and 300 school results were analyzed. The following percentage of nutritionists perceived the following foods as potentially hazardous foods(PHF): raw or cooked animal foods (94.7%), blossomed seed products (93.7%), packed pickled radish (36.7%), unopened mayonnaise (30.2%), and unopened snails & corn cans 54.8%. Exactly 51.2% of nutritionists believed that foods were properly supplied via CCP 3's food quality standard. Exactly 33.9% of nutritionists answered that they had never corrected the digital thermometer since there were no issues with the CCP 4's digital thermometer correction frequency level. As for CCP 5's chroline disinfection of green vegetables, 57.1% of nutritionists answered that vegetables were slightly softened while 36.2% said there were no changes at all. According to the nutritionists, the most difficult execution level of CCP levels (excluding CCP 3, CCP 4) was CCP 7 (37.1%), CCP 6 (16.4%), and CCP 2 (16.4%). For the above results, proper training/education must be enforced so that nutritionists can have a clear notion of the PHF. A solution must be developed enhancing the execution of CCP 4's digital thermometer correction frequency level. For CP 5's chroline disinfection of green vegetables, food characteristics must be considered to suggest an appropriate number and method of cleansing. Furthermore, cooking employees are needed that properly use and manage cooling & heating equipments to maintain heated foods above $57^{\circ}C$ under the CCP 7 standard.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.6
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• pp.183-190
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• 2004

This paper proposes a methodology to solve problems upon the circuit design applied to inductor load by applying a circuit to improve power factor with is partial switching PFC module to the power supply system for cooling/heating inverter air conditioner and by designing an input power section in compliance with IEC555-2 on the basis of better input power factor and minimized harmonic components of current. On the other hand, this paper suggested how to control the increase of output voltage along with tぉw current waves and partial switching PFC circuit as well, which can provide the output as twice as input voltage This study applied a method to control the compressors of air conditioner by means of increased the voltage applicable to compressor motor by lowering switching number conclusively, it could solve questions about efficiency, economics, electronic noise and so forth. and so that the reasonable voltage for running moor could be set up along with lower power consumption of air conditioner than estimated It was demonstrated that total sum of energy efficiency to operate system was increased to the extent of valid level. And all this merits and appropriateness was proved by computer simulation and experience.

• Applied Chemistry for Engineering
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• v.19 no.3
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• pp.338-344
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• 2008

The improvement of energy conservation is mandatory to decrease consumption of fossil fuels and to minimize negative impacts on the environment which originates from large cooling and heating demand. The absorption heat pump technology has a large potential for energy-saving in this respect. Absorption heat pump is a means to upgrade waste heat without the addition of extra thermal energy. The higher performance of absorber is of great importance for absorption heat pump cycle. In this study, in order to improve the performance of absorber, the absorber of tangential feed of a liquid phase with spiral tube has been investigated using methanol-glycerine as a working fluid. The spiral tube and tangential feeding generate the turbulence into the liquid flow while increasing the mass and heat transfer coefficients. The simultaneous heat and mass transfer were found to take place in a liquid turbulent film in the absorber with the spiral tube during the process of gas absorption. By calculating mass and heat transfer coefficients by measurement of the concentration and the temperature of each position in the absorber, the entrance was found to be more effective in enhancing mass and heat transfer.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.6
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• pp.232-241
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• 2016

Installing a ventilator for an apartment house composed of over 100 dwelling units was mandated in 2006 to improve indoor air quality. In the case of mechanical ventilators, the air change rate is kept stable, however 68% of dwellers do not operate their ventilator because of an increased electrical bill and noise. In the case of natural ventilators, the former problems are settled, but there are concerns about cold draught and an increase of heating/cooling cost. Authors are developing a heat recovery type natural ventilator which is a natural ventilator equipped with total heat recovery element, and it is expected that those problems of mechanical ventilator and natural ventilator are resolved by this. The combined type diffuser of this study is an under developed fit to the heat recovery type natural ventilator above. There are no standards to evaluate the performance for this type of diffuser. Due to this issue this study investigated the performance of the ventilation and maintained a thermal environment for the combined type diffuser by comparing it with existing diffusers. The results revealed that the performances of the combined type of diffusers showed different features from the existing ones, and was estimated to be high enough in the performances above.

• The Journal of the Korea institute of electronic communication sciences
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• v.18 no.1
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• pp.205-212
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• 2023

In the modern society, the extreme weather caused by climate change has brought about exceptional damage in succession over the world due to the use of fossil fuels, and infectious diseases such as COVID-19 worsen the quality of human life. It is urgently necessary to reduce green-house gas and use new renewable energy. The global environmental pollution should be decreased by reducing the use of fossil fuels and using new renewable energy. This paper suggests a system which can function for the environment of four seasons, safety and communication, through the photovoltaic power-based intelligent CCTV, internet and WiFi, and cooling and heating systems, and can optimally manage power, through the real-time monitoring of the production and the consumption of the photovoltaic power. It suggests a hybrid generation system supporting diesel generation without discontinuation in the case of emergency such as system power outage caused by cold waves, typhoons and natural disasters in which the photovoltaic power generating system cannot be used.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.19 no.1
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• pp.1-13
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• 2023

Many government in the world have conducted building energy performance certification program to reduce building energy consumption. In this study, a reference building and its HVAC system was modeled, and the energy load and consumption were estimated by the ECO2 program. The software is a simple building energy simulation program based on monthly calculated method. The building energy efficiency rating the the reference building was 1+ under baseline condition. The simulation results showed that the insulation performance slightly affected building energy load and consumption, but light density had a significant effect on them. The application of geothermal heat pumps gave improvement of building energy efficiency rating but it could not make it possible to get zero energy building(ZEB) certification. The ZEB 5 certification could be achieved by using photovoltaics, however getting better grade was difficult. The simulation results showed that the ZEB 4 certification, one grade higher than ZEB 5, could be attained by using more than one renewable energy source such as geothermal and solar energy in this study.

• Journal of the Korean Geotechnical Society
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• v.26 no.2
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• pp.33-43
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• 2010

Geothermal energy is gaining wide attention as a highly efficient renewable energy and being increasingly used for heating/cooling systems of buildings. The standing column well (SCW) is especially efficient, cost-effective, and suitable for Korean geological and hydrological conditions. However, a numerical model that simulates the SCW has not yet been developed and applied in Korea. This paper describes the development of the SCW numerical model using a finite-volume analysis program. The model, through hydro-thermal coupled analyses, simulates heat transfer through advection, convection, and conduction. The accuracy of the model was verified through comparisons with field data measured at SCWs in the U.S. and Korea. Comparisons indicated that the SCW numerical model can closely predict the performance of a SCW. The numerical model was used to perform a comprehensive parametric study in the companion paper.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.5 no.4
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• pp.257-264
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• 1993

This is the second report of a three part study on the absorption and heat transfer characteristics of absorber, the correlation of refrigerating capacity and heating capacity. The 2nd report deals with the heat transfer characteristics of a vertical falling film type absorber of inner copper tube. The solute is LiBr-Water solution(60wt%) and the solvent is water vapor. The film Reynoles numbers are varied in the range of 35~130. The states of LiBr solution at the top of absorber are supercooled liquid and superheated liquid. The results are summarized as follows ; Heat transfer results reveal that for the absorption of falling film, the state of LiBr solution appears to be influential in determining the heat transfer. Thus, for the state of supercooled liquid, heat transfer coefficient decreases with increasing the film Reynolds number, but in the condition of superheated liquid, it increases conversely. The mass transfer coefficients that were presented in the 1st.report and heat transfer coefficients of this paper are presented as the dimensionless correlation. The optimum water flowrate which brings about maximum value of heat flux in the film exists, and that increases with increasing the cooling water temperature.